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早稲田大学研究者データベース Waseda University Researchers Database Details of a Researcher Home 日本語 English 早稲田大学研究者データベース Waseda University Researchers Database Menu Japanese Page Back to Waseda Univ. Waseda University Researchers Database Personnel Information ▼ ◆ Profile Information ◆ Research Experience ◆ Education Background ◆ Committee Memberships ◆ Professional Memberships ◆ Research Areas ◆ Research Interests ◆ Awards Research Activity ▼ ◆ Papers ◆ Books and Other Publications ◆ Presentations ◆ Research Projects ◆ Misc Education Activity ▼ ◆ Syllabus Contribution to Society ▼ ◆ Sub-affiliation ◆ Research Institute ◆ Internal Special Research Projects × Updated on 2024/05/16 　Personnel Information ◆ Profile Information ◆ Research Experience ◆ Education Background ◆ Committee Memberships ◆ Professional Memberships ◆ Research Areas ◆ Research Interests ◆ Awards 　Research Activity ◆ Papers ◆ Books and Other Publications ◆ Presentations ◆ Research Projects ◆ Misc 　Education Activity ◆ Syllabus 　Contribution to Society ◆ Sub-affiliation ◆ Research Institute ◆ Internal Special Research Projects Updated on 2024/05/16   OKOCHI, Hiroshi   Scopus Paper Info   Paper Count: 100  Citation Count: 1483  h-index: 22 Click to view the Scopus page. The data was downloaded from Scopus API in May 15, 2024, via http://api.elsevier.com and http://www.scopus.com . Google Scholar Information (Citations per year) Google Scholar Information (Citations per year)   Citation Count: 2094 h-index: 26 i10-index: 52 Click to view the Google Scholar page. Scopus Information News & Topics 2024.04.02 Innovators: Research Recap 2024, Waseda University Affiliation Faculty of Science and Engineering, School of Creative Science and Engineering Job title Professor Degree 博士（工学） ( 東京大学 ) Mail Address Homepage URL http://www.okochi.env.waseda.ac.jp/index.html Profile 早稲田大学理工学部環境資源工学科•大気水圏環境化学研究室です．ガイア(生きている地球)の健康管理を目標に，水・物質循環の視点から環境化学研究を展開しています．フィールドは，富士山，丹沢，生田，福島，カンボジアです．『空気・水・森林の化学情報を解読し，人と自然の共生を探る』がモットーです．アース・ドクター（地球医）の育成を目指しています． Research Experience Research Experience 2008.04 - 　 ・2008年4月 早稲田大学理工学術院 創造理工学部教授(現在に至る) 2007.04 - 　 ・2007年4月 早稲田大学理工学術院 創造理工学部准教授 2006.04 - 　 ・2006年4月 早稲田大学理工学術院 理工学部助教授 2005.04 - 　 ・2005年4月 首都大学東京 都市環境学部准教授 2003.04 - 　 ・2003年4月 東京都立科学技術大学工学部助教授 2000.09 - 　 Peter Brimblecombe教授グループ博士研究員(2000年9月まで) 1999.09 - 　 ・1999年9月 英国イースト・アングリア大学環境科学部 1997.02 - 　 ・1997年2月 論文博士(工学)の学位授与（東京大学，指導教授：定方正毅教授） 1991.04 - 　 ・1991年4月 神奈川大学工学部助手（応用化学科 井川研究室） 　 　 　 Professor, School of Science and Engineering, Waseda University 　 　 　 Associate Professor, School of Science and Engineering, Waseda University 　 　 　 Associate Professor, Faculty of Urban Environmental Sciences, Tokyo Metropolitan University 　 　 　 Visiting Fellow, School of Environmental Sciences, University of East Anglia (UK) 　 　 　 Research Associate, Faculty of Engineering, Kanagawa University ▼display all Education Background Education Background 　 - 1993 Tokyo Institute of Technology   Interdisciplinary Science and Engineering   　 - 1993 Tokyo Institute of Technology   Graduate School, Division of Integrated Science and Engineering   　 - 1991 Waseda University   School of Science and Engineering   　 - 1991 Waseda University   Faculty of Science and Engineering   Committee Memberships Committee Memberships 2020.09 - Now 大気環境学会  常任理事 2020.07 - Now NPO法人富士山測候所を活用する会  副理事長 2015.04 - Now 日本環境化学会  理事 2014.04 - Now 日本化学会  環境教育小委員会・委員 2013.04 - Now 日本女子大学  客員研究員 2011.04 - Now 東京理科大学  客員教授 2011.04 - Now 埼玉県環境科学国際センター  客員研究員 2014.09 - 2015.07 大気環境学会  編集委員会・副編集委員長 2012.09 - 2014.07 大気環境学会  編集委員会・編集委員長 2010.04 - 2014.03 日本化学会  環境・安全推進委員会環境教育小委員会 小委員長 2008.09 - 2012.07 大気環境学会  編集委員会・副編集委員長 2007.04 - 2009.03 日本分析化学会  編集委員 2003.09 - 2008.07 大気環境学会  編集委員 ▼display all Professional Memberships Professional Memberships 　 　 　 環境放射能除染学会 　 　 　 日本水環境学会 　 　 　 日本分析化学会 　 　 　 日本化学会 　 　 　 大気環境学会 Research Areas Research Areas Chemical substance influence on environment / Radiation influence / Environmental policy and social systems / Environmental impact assessment / Environmental dynamic analysis Research Interests Research Interests Airborne microplastics Transboundary Air Pollution Air-Forest Interaction Cloud water chemistry 環境分析 水圏化学 大気化学 降水化学 Environmental Analysis Aquatic Chemistry Precipitation Chemistry Atmospheric Chemistry ▼display all Awards Awards 大気環境学会学術賞（齋藤潔賞） 2018.09   大気環境学会   Winner： 大河内 博 環境化学学術賞 2017.06   日本環境化学会   Winner： 大河内 博   Papers Papers Preliminary insight into the relationship between bioaerosols and urban environment obtained from the COVID-19 self-quarantine period in the Tokyo metropolitan area Kotaro Murata, Hiroshi Okochi, Masashi Kamogawa Environmental Research Communications   5 ( 12 ) 121001 - 121001  2023.12 　View Summary Abstract Anthropogenic activities and meteorological conditions influence the composition of urban bioaerosols. The COVID-19 epidemic drastically reduced anthropogenic activities in the metropolitan areas of Japan in 2020. This study examined inter-day fluctuations in airborne bacterial and fungal compositions in Tokyo, Japan, between April and June 2020, under exceptionally unusual conditions where the movement of people and economic activity had been greatly reduced. The result showed, as expected, that local meteorological factors, especially wind and precipitation, substantially impacted emissions and changes in bacterial and fungal aerosols. However, we found that variations in the composition of urban bioaerosols could potentially be affected by anthropogenic influences, such as the concentrations of nitrogen oxides, ozone, and particulate matter, and human density. Although such factors are not as influential as wind and precipitation, it was shown for the first time that drastic changes in human activities within an area can affect the dynamics of bioaerosols. This could be a finding that should be considered for public health issues related to air quality in changing urban areas such as fast-growing cities. DOI Scopus Current Status and Issues of Plastic Air Pollution Okochi Hiroshi, Tani Yuto, Onozuka Yosuke, Wang Yize, Hayami Hiroshi, Takeuchi Masaki, Sorimachi Atsuyuki, Fujii Yusuke, Takenaka Norimichi, Miyazaki Akane, Sunaga Natsu, Hayama Shin-ichi, Tokunaga Yurika, Yamaguchi Takashi, Katsumi Naoya, Matsuki Atsushi, Ikemori Fumikazu, Kajino Mizuo, Adachi Kouji, Ishihara Yasuhiro, Iwamoto Yoko, Niida Yasuhiro Earozoru Kenkyu   38 ( 3 ) 145 - 159  2023.09 DOI Scopus Airborne hydrophilic microplastics in cloud water at high altitudes and their role in cloud formation Yize Wang, Hiroshi Okochi, Yuto Tani, Hiroshi Hayami, Yukiya Minami, Naoya Katsumi, Masaki Takeuchi, Atsuyuki Sorimachi, Yusuke Fujii, Mizuo Kajino, Kouji Adachi, Yasuhiro Ishihara, Yoko Iwamoto, Yasuhiro Niida Environmental Chemistry Letters   21 ( 6 ) 3055 - 3062  2023.08 　View Summary AbstractMicroplastic pollution is occurring in most ecosystem, yet their presence in high altitude clouds and their influence on cloud formation and climate change are poorly known. Here we analyzed microplastics in cloud water sampled at the summits of Japan mountains at 1300–3776 m altitude by attenuated total reflection imaging and micro-Fourier transform infrared spectroscopy. We observed nine microplastics including polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polyamide 6, polycarbonate, ethylene–propylene copolymer or polyethylene–polypropylene alloy, polyurethane, and epoxy resin. Microplastic were fragmented, with mean concentrations ranging from 6.7 to 13.9 pieces per liter, and with Feret diameters ranging from 7.1 to 94.6 μm. Microplastics bearing hydrophilic groups such as carbonyl and/or hydroxyl groups were abundant, suggesting that they might have acted as condensation nuclei of cloud ice and water. Overall, our finding suggest that high-altitude microplastics cloud influence cloud formation and, in turn, might modify the climate. DOI Scopus 19 Citation (Scopus) Long term trends of dry and wet deposition of air pollutants at declining forest site of Mt. Oyama in Japan during 1994–2019 Yize Wang, Hiroshi Okochi, Manabu Igawa Water, Air, and Soil Pollution   234 ( 4 )  2023.04 　View Summary Forest decline, which occurs in mountainous regions in many countries, may result from the effects of acid fog, ozone, or deposition of other pollutants. We observed wet deposition of air pollutants at different altitudes on Mt. Oyama, situated southwest of Tokyo, for 1994 until 2019. During this period, the domestic atmospheric environment was improved in Japan. The average concentration of air pollutants around all the sampling sites on Mt. Oyama decreased by 63.01%, 32.08%, 8.80%, and 39.73% for NH3, HCl, HNO3, and SO2, respectively. The volume weighted mean (VWM) pH values showed an increasing trend for bulk deposition (+0.70% y-1), fog water (+2.58% y-1), and throughfall (+2.60% y-1). Stemflow also increased (cedar, +1.17% y-1; fir, +0.82% y-1), although it included organic acids dissolved from the stem and it primarily had a low VWM pH value. The overall pH value of the fog water increased at the site, although acidic fog was still observed. Comparing fog water between winter and summer, a significant increase in pH occurred in summer, whereas no change occurred in winter. In summer, the sources of pollutants at Mt. Oyama are mainly from mainland Japan, and the frequency of low-pH acidic fog decreased annually. In winter, Mt. Oyama was affected by transboundary pollution, and acid fog occasionally occurred. Improvements in the domestic atmospheric environment and control of transboundary pollution will provide better conditions for mountain ecology that are free from acidic pollutants. DOI Scopus 2 Citation (Scopus) Current Status and Issues of Plastic Air Pollution Hiroshi Okochi, Yuto Tani, Yosuke Onozuka, Yize Wang, Hiroshi Hayami, Masaki Takeuchi, Atsuyuki Sorimachi, Yusuke Fujii, Norimichi Takenaka, Akane Miyazaki, Natsu Sunaga, Shin Ichi Hayama, Yurika Tokunaga, Takashi Yamaguchi, Naoya Katsumi, Atsushi Matsuki, Fumikazu Ikemori, Mizuo Kajino, Kouji Adachi, Yasuhiro Ishihara, Yoko Iwamoto, Yasuhiro Niida Earozoru Kenkyu   38 ( 3 ) 145 - 159  2023 DOI Scopus Effects of changes in polycyclic aromatic hydrocarbons (PAHs) emissions and degradation on their concentrations in Tokyo from 2007 and 2016 Kojiro Shimada, Masayuki Nohchi, Koji Maeshima, Tomonori Uchino, Yusuke Kobayashi, Kazuki Ono, Hiroko Ogata, Naoya Katsumi, Koji Inazu, Hiroshi Okochi Scientific Reports   12 ( 1 )  2022.12  [Refereed] Authorship：Corresponding author 　View Summary AbstractThe concentrations of polycyclic aromatic hydrocarbons (PAHs) in aerosol were measured in Shinjuku, which is central Tokyo, Japan, for 10 years from 2007 to 2016. The effects of changes in emission sources and their degradation by reaction with ozone were assessed in this study. There was no significant increasing or decreasing trend of the PAH concentrations during 10 years (P > 0.05). The average selected seven the PAH concentrations (0.88 ng m−3) during 10 years was lower than those in New York and Paris. However, the trend of ozone concentrations is increasing in central Tokyo. This inconsistency raises a question. Did the fact that the ozone concentration was higher than the PAH concentrations promote PAH degradation? To apportion the PAH sources, we used PAH concentration profiles and positive matrix factorization analysis. The contribution of vehicle emissions to the PAHs ranged from 40 to 80%. Ozone concentrations increased by 3.70%/year during 10 years. The theoretical degradation rates of PAHs by ozone, which were calculated using a pseudo-first-order rate equation, suggested that the lifetimes of benzo[a]pyrene (BaP) decreased by 1 min from 2007 to 2016. We investigated the aging of BaP using the profile of the isomer ratios. We found that the aging of BaP at the urban and roadside sites were nearly identical indicating aging regardless of the season. Although the decomposition of BaP is promoted by the photochemical oxidation reaction, this result suggests that a certain threshold value exists as the degree of the decomposition. This degradation of PAH can improve chemical loss processes in air quality model. DOI Scopus 7 Citation (Scopus) Addition of polyvinyl pyrrolidone during density separation with sodium iodide solution improves recovery rate of small microplastics (20–150 μm) from soils and sediments Naoya Katsumi, Seiya Nagao, Hiroshi Okochi Chemosphere   307   135730 - 135730  2022.11  [Refereed] DOI Scopus 13 Citation (Scopus) Growth of New Particles into Cloud Condensation Nuclei at the Summit of Mt. Fuji during Summer Shun KIMURA, Hiroki IGARASHI, Kazuhiko MIURA, Tatsuhiro MORI, Yoko IWAMOTO, Shungo KATO, Hiroshi OKOCHI, Ryuichi WADA Earozoru Kenkyu   37 ( 3 ) 202 - 211  2022.09  [Refereed] DOI Scopus Annual Trend of Aerosol Number Concentration at the Summit of Mt. Fuji During Summer of 2006-2019 五十嵐博己, 森樹大, 森樹大, 三浦和彦, 三浦和彦, 岩本洋子, 大河内博, 和田龍一, 加藤俊吾 エアロゾル研究   37 ( 1 ) 36 - 44  2022.03  [Refereed] DOI J-GLOBAL Scopus 3 Citation (Scopus) Exploration of New Sources of Aerosol and Volatile Organic Compound in Urban Area 島田幸治郎, 島田幸治郎, 後藤友里絵, Hai Guo, 茶谷聡, 大河内博 エアロゾル研究   37 ( 1 ) 28 - 34  2022.03  [Refereed]  [Invited] DOI J-GLOBAL Scopus On-line analysis of free-tropospheric water-soluble acidic gases and particulate anions on the summit of Mt. Fuji, Japan Masaki Takeuchi, Naoya Tomiyasu, Makoto Namikawa, Hideji Tanaka, Kei Toda, Naoya Katsumi, Hiroshi Okochi Atmospheric Environment   273   118977 - 118977  2022.03  [Refereed] DOI Scopus 3 Citation (Scopus) Biogenic Diamines and Their Amide Derivatives Are Present in the Forest Atmosphere and May Play a Role in Particle Formation Kentaro Saeki, Kazuya Ikari, Hiroyuki Yokoi, Shin-Ichi Ohira, Hiroshi Okochi, Kei Toda ACS Earth and Space Chemistry   6 ( 2 ) 421 - 430  2022.02  [Refereed] DOI Scopus 5 Citation (Scopus) Research Trends and Challenges of Airborne Microplastics 大河内博, 吉田昇永, Zhao Heli, 藤川真智子, 谷悠人, 勝見尚也, 宮崎あかね, 高田秀重, 板谷庸平, 緒方裕子, 新居田恭弘, 梅澤直樹, 小林華栄, 浦山憲雄 大気環境学会誌(Web)   57 ( 3 )  2022 J-GLOBAL Online Collector for Water-Soluble Atmospheric Particulate Matter Compatible with a Parallel Plate Wet Denuder Maeda Kaho, Tanaka Haruka, Wada Riona, Okochi Hiroshi, Toda Kei, Tanaka Hideji, Takeuchi Masaki Earozoru Kenkyu   36 ( 4 ) 273 - 278  2021.12  [Refereed] 　View Summary A particle collector that allows high time resolution monitoring of particulate matter was fabricated and coupled with an ion chromatograph for online analysis of particulate ions in the atmosphere. The system was applied to the atmospheric observation for over a month in Tokushima, Japan. The average particulate anion concentrations were 6.42 nmol m−3 for Cl−, 18.8 nmol m−3 for NO3−, and 22.1 nmol m−3 for SO42−. The atmospheric particle collection efficiency was more than 98.4%, and the continuous observations were successfully achieved without problems. DOI CiNii Scopus The input–output balance of microplastics derived from coated fertilizer in paddy fields and the timing of their discharge during the irrigation season Naoya Katsumi, Takasei Kusube, Seiya Nagao, Hiroshi Okochi Chemosphere   279   130574 - 130574  2021.09  [Refereed] DOI Scopus 25 Citation (Scopus) Characteristics of Fog and Fog Collection with Passive Collector at Mt. Oyama in Japan Yize Wang, Hiroshi Okochi, Manabu Igawa Water, Air, and Soil Pollution   232 ( 7 )  2021.07 　View Summary Fog is formed frequently in mountain areas and is apt to cause forest decline, because fog has highly concentrated air pollutants and is readily acidified. The elucidation of the fog characteristics in the areas has been limited because successive observation is difficult in mountains. We have observed wet depositions and meteorological conditions at Mt. Oyama, located about 56 km west–southwest of Tokyo. The mountain meteorology was observed with various devices and the fog frequencies dependent on the altitude were roughly estimated from the meteorology of the base of the mountain. The precipitation amount of the throughfall at the mountain is much larger than that of rainfall, and the large deposition on the canopy is caused by not only fog but also drizzle. Fog and drizzle sample was collected by string-type passive fog collector, PFC, and the meteorological data relating to the collecting rate of PFC sample were observed. PFC samples were affected by rainwater under windy condition and the contribution of the rain to the PFC sample volume was evaluated to be about 30% in average. The sampling rate of PFC was related to the precipitation intensity of throughfall, and it became possible to estimate the air pollutants deposition on the canopy via wet deposition by the analysis of the samples of PFC as well as rain. The fog and drizzle may cause several times larger deposition of air pollutants on the canopies than the deposition via rain at high mountain forest. DOI Scopus 7 Citation (Scopus) Accumulation of microcapsules derived from coated fertilizer in paddy fields Naoya Katsumi, Takasei Kusube, Seiya Nagao, Hiroshi Okochi Chemosphere   267   129185 - 129185  2021.03 DOI Scopus 91 Citation (Scopus) Online Analysis of Water-soluble Acidic Gases and Anions in Particles at the Southeastern Foot of Mt. Fuji Masaki Takeuchi, Makoto Namikawa, Kazumasa Okamoto, Tatsuya Oda, Haruka Tanaka, Hiroshi Okochi, Kei Toda, Kazuhiko Miura, Hideji Tanaka BUNSEKI KAGAKU   70 ( 1 ) 65 - 69  2021 　View Summary During the summer of 2018, we monitored the concentrations of water-soluble acid gases and particulate anions at the southeastern foot (1284 m a.s.l.) of Mt. Fuji, Japan, using gas/particleion chromatographs. All samples analyzed contained quantifiable levels of anions. The average concentrations of acid gas and particulate anion concentrations were, respectively, 1.10 +/- 0.37 nmol m(-3) for HCl, 3.49 +/- 1.72 nmol m(-3) for HONO, 1.23 +/- 0.59 nmol m(-3) for HNO3, 0.33 +/- 0.20 nmol m(-3) for SO2, 3.61 +/- 3.69 nmol m(-3) for Cl-, 0.65 +/- 0.22 nmol m(-3 )for NO2-, 4.29 +/- 2.98 nmol m(-3) for NO3- and 4.47 +/- 3.57 nmol m(-3) for SO42-. We found that the concentration of soluble acidic gases increased during the daytime, while no characteristic diurnal patterns were observed in the particulate anions. 富士山南東麓における水溶性酸性ガス及び粒子状物質に含まれる陰イオンのオンライン観測 竹内 政樹, 並川 誠, 岡本 和将, 小田 達也, 田中 遥, 大河内 博, 戸田 敬, 三浦 和彦, 田中 秀治 分析化学    2020.11  [Refereed] The role of coated fertilizer used in paddy fields as a source of microplastics in the marine environment. Naoya Katsumi, Takasei Kusube, Seiya Nagao, Hiroshi Okochi Marine pollution bulletin   161 ( Pt B ) 111727 - 111727  2020.10  [Refereed]  [International journal] 　View Summary Fixed-point and multi-point field survey was conducted to determine the actual contamination of the Japanese coast by microcapsules derived from coated fertilizers. The results indicated that the amount of microcapsules increased during the irrigation season (9423-74,869 pieces/m2) and decreased in the non-irrigation season (77-1471 pieces/m2). Microcapsules accounted for 90% of all microplastics sampled during the irrigation season. The lack of correlation between the area of agricultural land in the watershed and the microcapsule density on the coast suggested that the density of microcapsules on the coast was not only dependent on the total load to the ocean, but also on topographic and meteorological conditions. More than 90% of the microcapsules collected from the shoreline were made of polyethylene. Scanning electron microscopic observation of the surface of the microcapsules revealed that portions of the microcapsules were removed as secondary microplastics in the process of migration to the ocean. DOI PubMed Scopus 34 Citation (Scopus) Precision spectroscopy of cesium-137 from the ground to 150 m above in Fukushima Takuya Kurihara, Kazuhisa Tanada, Jun Kataoka, Hiroki Hosokoshi, Saku Mochizuki, Leo Tagawa, Hiroshi Okochi, Yurie Gotoh NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   978   164414  2020.10  [Refereed] 　View Summary After the Fukushima nuclear disaster in 2011, large amounts of radioisotopes (mainly Cs-137 and Cs-134) were released into the environment. Various monitoring activities have revealed radiation on the ground both in local and wide areas; however, aerial dose variation in the vertical direction is poorly known. This paper presents the results of airborne gamma-ray spectroscopy of a contamination field in Namie, Fukushima, as measured from 0 m to 150 m above the ground by drone. We found that the gamma-ray dose rate measured at 100 m height is about seven times higher than that expected based on ground measurements, which is caused by two factors: (1) the integrated dose includes contamination of upward scattered 662-keV gamma rays and (2) radiation from Cs-137 is vertically collimated because Cs-137 is buried in the soil. We also propose a novel method to obtain the distribution of radioactive substances in the soil only through aerial mapping. DOI Scopus 2 Citation (Scopus) Controlling Factors of Volatile Organic Compounds in Cloud Water at the Summit of Mt. Fuji in the Free Troposphere during the Summer Yamawaki Takumi, Miura Kazuhiko, Toda Kei, Wada Ryuichi, Takeuchi Masaki, Kobayashi Hiroshi, Dokiya Yukiko, Hatakeyama Shiro, Okochi Hiroshi, Yamamoto Shuji, Yamanokoshi Eri, Shimada Kojiro, Ogata Hiroko, Katsumi Naoya, Minami Yukiya, Kato Shungo Journal of Japan Society for Atmospheric Environment / Taiki Kankyo Gakkaishi   55 ( 5 ) 191 - 203  2020.07  [Refereed] Authorship：Corresponding author 　View Summary

At the summit of Mt. Fuji in July and August from 2012 to 2018, 27 kinds of anthropogenic volatile organic compounds (AVOCs) and 6 types of biogenic volatile organic compounds (BVOCs) in the air and in cloud water were determined. AVOCs occupied about 90% of the VOCs in the cloud water (volume-weighted mean VOCs concentration: 2.07 nM, n=159) and the main component was toluene, reflecting its high concentration in the ambient air. The concentration of the AVOCs in the cloud water was high when the airmass was transported from the southern continent and was about 1.5 times higher than that when it came from the ocean. The concentration of toluene in the cloud water decreased exponentially with the increase in the total ion concentration. The concentrations of some VOCs such as chloroform, o-xylene, and limonen in the cloud water were several times higher than their Henry&＃39;s law predicted values. Among the chlorinated hydrocarbons, highly hydrophobic chloroform was more concentrated than dichloromethane in the cloud water. Atmospheric surfactants such as HULIS (Humic-like Substances) could affect the enrichment of the VOCs in the cloud water even in the free troposphere.

DOI CiNii The role of humic-like substances as atmospheric surfactants in the formation of summer-heavy rainfall in downtown Tokyo Toshiki Sugo, Hiroshi Okochi, Ryunosuke Uchiyama, Eri Yamanokoshi, Hiroko Ogata, Naoya Katsumi, Takanori Nakano City and Environment Interactions   3   100022  2020.03  [Refereed] Authorship：Corresponding author Impact assessment of air pollutants on the formation of summer urban heavy rainfall: Utilization of newly-developed sequential heavy rain collection system and geographic information system Toshiki Sugo, Hironobu Saito, Hiroshi Okochi, Ryunosuke Uchiyama, Takanori Nakano, Hitoshi Kamogawa, Toyoaki Arai Japan Society for Atmospheric Envrionment    2020.03  [Refereed] Authorship：Corresponding author Investigation of the Formation Mechanism of Urban-induced Heavy Rainfall Using Chemical and Stable Isotope Analysis Ryunosuke Uchiyama, Hiroshi Okochi, Takanori Nakano, Hiroko Ogata, Naoya Katsumi, Chiho Kaneko, Junichi Kamiya, Daisuke Asai BUNSEKI KAGAKU   69 ( 1-2 ) 45 - 68  2020.01  [Refereed] 　View Summary In order to clarify the impact of air pollution on the formation of sudden and locally distributed heavy rain in urban areas (hereafter UHR = urban-induced heavy rain), we analyzed inorganic ions concentration, dissolved and suspended fraction of trace metals, and stable isotope ratio of water (delta D and delta O-18) in rainwater samples collected from 2008 to 2016 in Tokyo. Acidic substance-derived components (H+, NH4+, NO3-, nss-SO42-) have high concentrations in UHR, and acidic deposition increased locally along with rainfall amount near urban centers when UHR occurs. In addition, UHR has stable isotopes of hydrogen and oxygen smaller than normal rainfall, indicating that the influence of marine-derived water vapor was small. The concentration of air pollutants before the UHR was high, and secondary reaction rapidly progressed just before the UHR. Based on these results, we proposed the following UHR formation mechanism: (1) Air pollutants accumulate from the surrounding area into the area with the low atmospheric pressure due to the development of upflow by urban warming. (2) Due to oxidants formed by photochemical reactions, sulfate and nitrate that are produced secondarily from SO2 and NOx become cloud condensation tuberculosis (CCN). (3) These CCNs generate many small cloud particles using water vapor evaporated from the urban area. (4) When the updraft is further developed, moist sea breezes containing sea salt particles, which are giant cloud condensations, flow in to form large cloud particles, which rapidly grow into raindrops due to collection with small water droplets. Study on the Formation Mechanism of Urban-induced Heavy Rainfall using the Combination of Chemical and Stable Isotope Analysis Ryunosuke Uchiyama, Hiroshi Okochi, Takanori Nakano, Hiroko Ogata, Naoya Katsumi, Chiho Kaneko, Junichi Kamiya, Daisuke Asai   68 ( 11 )  2019.11  [Refereed] Authorship：Corresponding author 福島県内の里山地域における大気中Cs濃度の変遷 五十嵐 康人, 北 和之, 木名瀬 健, 林 奈穂, 南 光太郎, 木村 茉央, 反町 篤行, 大河内 博, 後藤 友里絵, 石塚 正秀, 牧 輝弥, 保坂 健太郎, 羽田野 祐子 大気環境学会年会講演要旨集   60回   1E1610 - 4  2019.09 Ground-based observation of lightning-induced nitrogen oxides at a mountaintop in free troposphere Ryuichi Wada, Y. Sadanaga, S. Kato, N. Katsumi, H. Okochi, Y. Iwamoto, K. Miura, H. Kobayashi, M. Kamogawa, J. Matsumoto, S. Yonemura, Y. Matsumi, M. Kajino, S. Hatakeyama JOURNAL OF ATMOSPHERIC CHEMISTRY   76 ( 2 ) 133 - 150  2019.06  [Refereed] 　View Summary Lightning is an important source of nitrogen oxides (LNOx). The actual global production of LNOx is still largely uncertain. One of the reasons for this uncertainty is the limited available observation data. We measured the concentrations of total reactive nitrogen (NOy), nitric oxide (NO) and nitrogen dioxides (NO2) and then obtained NOx oxidation products (NOz: NOz=NOy - NOx) at a station at the top of Mount Fuji (3776ma.s.l.) during the summer of 2017. Increases in NOy and NO2 were observed on 22 August 2017. These peaks were unaccompanied by increases in CO, which suggested that the observed air mass did not contain emissions from combustion. The backward trajectories of the above air mass indicated that it moved across areas where lightning occurred. The NOy concentration was also calculated by using a chemical transport model, which did not take NOx produced by lightning into account. Therefore, the NOy concentration due to lightning can be inferred by subtracting the calculated NOy from the observed NOy concentrations. The concentration of NOy at 13:00 on 22 August 2017 originating from lightning was estimated to be 1.11 +/- 0.02 ppbv, which comprised 97 +/- 2% of the total NOy concentration. The fractions of NO2 and NOz in the total NOy were 0.54 +/- 0.01 and 0.46 +/- 0.03, respectively. The NO concentration was below the detection limit. We firstly observed increase of concentrations of NOy originating from lightning by ground-based observation and demonstrated the quantitative estimates of LNOx using model-based calculation. DOI Scopus 7 Citation (Scopus) Characteristics of trace metal concentration and stable isotopic composition of hydrogen and oxygen in "urban-induced heavy rainfall" in downtown Tokyo, Japan; The implication of mineral/dust particles on the formation of summer heavy rainfall Ryunosuke Uchiyama, Hiroshi Okochi, Hiroko Ogata, Naoya Katsumi, Takanori Nakano ATMOSPHERIC RESEARCH   217   73 - 80  2019.03  [Refereed] 　View Summary To investigate the impact of mineral/road dust particles on the formation of sudden and locally distributed heavy rain in urban areas (hereafter, urban-induced heavy rain: UHR), we analyzed the trace metal elements and the stable isotope composition of hydrogen and oxygen in rainwater. Rainwater samples, which were collected in Shinjuku (Japan) from April 2014 to December 2015, were analyzed for 12 trace metal elements (Al, V, Cr, Mn, Fe, Ni, Cu, Zn, Cd, Pb, Se, and As) in three fractions: coarse suspended particles (> 1.2 mu m, CSP), acid-insoluble fine suspended particles (0.45-1.2 mu m), and a dissolved/acid-soluble fine suspended fraction. Concentrations and wet deposition fluxes of trace metal elements in CSP were markedly higher in UHR than other types of rainfall, i.e., normal rain, typhoon heavy rain, and frontal heavy rain. There were strong positive correlations between 3180 and the total concentration of trace metal elements in UHR (r = 0.902) and specifically for Fe, Mn, Al, V, and Pb in CSP (r = 0.919, 0.883, 0.823, 0.843, and 0.820, respectively). These findings indicate that mineral/road dust particles were removed by in-cloud scavenging process under the meteorological conditions causing UHR. There is one possibility that they could play important roles as giant cloud condensation nuclei and/or effective ice nuclei for the formation of UHR. DOI Scopus 18 Citation (Scopus) Fungal spore involvement in the resuspension of radiocaesium in summer. Yasuhito Igarashi, Kazuyuki Kita, Teruya Maki, Takeshi Kinase, Naho Hayashi, Kentaro Hosaka, Kouji Adachi, Mizuo Kajino, Masahide Ishizuka, Tsuyoshi Thomas Sekiyama, Yuji Zaizen, Chisato Takenaka, Kazuhiko Ninomiya, Hiroshi Okochi, Atsuyuki Sorimachi Scientific reports   9 ( 1 ) 1954 - 1954  2019.02  [Refereed]  [International journal] 　View Summary We observed the atmospheric resuspension of radiocaesium, derived from the Fukushima Dai-ichi Nuclear Power Plant accident, at Namie, a heavily contaminated area of Fukushima, since 2012. During the survey periods from 2012 to 2015, the activity concentrations of radiocaesium in air ranged from approximately 10-5 to 10-2 Bq per m3 and were higher in the warm season than in the cold season. Electron microscopy showed that the particles collected on filters in summer were predominantly of biological origin (bioaerosols), with which the observed radiocaesium activity concentration varied. We conducted an additional aerosol analysis based on fluorescent optical microscopic observation and high-throughput DNA sequencing technique to identify bioaerosols at Namie in 2015 summer. The concentrations of bioaerosols fluctuated the order of 106 particles per m3, and the phyla Basidiomycota and Ascomycota (true Fungi) accounted for approximately two-thirds of the bioaerosols. Moreover, the fungal spore concentration in air was positively correlated with the radiocaesium concentration at Namie in summer 2016. The bioaerosol emissions from Japanese mixed forests in the temperate zone predominately included fungal cells, which are known to accumulate radiocaesium, and should be considered an important scientific issue that must be addressed. DOI PubMed Scopus 30 Citation (Scopus) Ultracompact Compton camera for innovative gamma-ray imaging J. Kataoka, A. Kishimoto, T. Taya, S. Mochizuki, L. Tagawa, A. Koide, K. Sueoka, H. Morita, T. Maruhashi, K. Fujieda, T. Kurihara, M. Arimoto, H. Okochi, N. Katsumi, S. Kinno, K. Matsunaga, H. Ikeda, E. Shimosegawa, J. Hatazawa, S. Ohsuka, T. Toshito, M. Kimura, Y. Nagao, M. Yamaguchi, K. Kurita, N. Kawachi Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment   912   1 - 5  2018.12  [Refereed] 　View Summary © 2017 Elsevier B.V. A multipixel photon counter (MPPC) features excellent photon-counting capability as a radiation detector. In particular, a two-plane Compton camera consisting of Ce:GAGG scintillators coupled with MPPC arrays has significant application potential owing to its compact size and low weight. For example, the camera can be easily mounted on a commercial drone to identify radiation hot spots from the sky. In Fukushima, we demonstrated that a 137Cs distribution within a 100 m diameter can be mapped correctly within a couple of tens of minutes. The advanced use of the Compton camera is also anticipated in the field of proton therapy. We evaluated an image of 511 keV annihilation gamma-rays emitted from a PMMA phantom irradiated by 200 MeV protons to mimic an in-beam monitor for proton therapy. Finally, we developed an ultracompact Compton camera (weight = 580 g), for 3-D multicolor molecular imaging. In order to demonstrate the performance capabilities of the device, 131I (365 keV), 85SrCl2 (514 keV), and 65ZnCl2 (1116 keV) were injected into a living mouse and the data were taken from 12 angles with a total acquisition time of 2 h. We confirmed that all tracers had accumulated on the target organs of the thyroid, bone, and liver, and that the obtained 3-D image was quantitatively correct with an accuracy of ±20%. DOI Scopus 14 Citation (Scopus) The seasonal variations of atmospheric 134,137Cs activity and possible host particles for their resuspension in the contaminated areas of Tsushima and Yamakiya, Fukushima, Japan Takeshi Kinase, Kazuyuki Kita, Yasuhito Igarashi, Kouji Adachi, Kazuhiko Ninomiya, Atsushi Shinohara, Hiroshi Okochi, Hiroko Ogata, Masahide Ishizuka, Sakae Toyoda, Keita Yamada, Naohiro Yoshida, Yuji Zaizen, Masao Mikami, Hiroyuki Demizu, Yuichi Onda Progress in Earth and Planetary Science   5 ( 1 )  2018.12  [Refereed] 　View Summary © 2018, The Author(s). A large quantity of radionuclides was released by the Fukushima Daiichi Nuclear Power Plant accident in March 2011, and those deposited on ground and vegetation could return to the atmosphere through resuspension processes. Although the resuspension has been proposed to occur with wind blow, biomass burning, ecosystem activities, etc., the dominant process in contaminated areas of Fukushima is not fully understood. We have examined the resuspension process of radiocesium (134,137Cs) based on long-term measurements of the atmospheric concentration of radiocesium activity (the radiocesium concentration) at four sites in the contaminated areas of Fukushima as well as the aerosol characteristic observations by scanning electron microscopy (SEM) and the measurement of the biomass burning tracer, levoglucosan. The radiocesium concentrations at all sites showed a similar seasonal variation: low from winter to early spring and high from late spring to early autumn. In late spring, they showed positive peaks that coincided with the wind speed peaks. However, in summer and autumn, they were correlated positively with atmospheric temperature but negatively with wind speed. These results differed from previous studies based on data at urban sites. The difference of radiocesium concentrations at two sites, which are located within a 1 km range but have different degrees of surface contamination, was large from winter to late spring and small in summer and autumn, indicating that resuspension occurs locally and/or that atmospheric radiocesium was not well mixed in winter/spring, and it was opposite in summer/autumn. These results suggest that the resuspension processes and the host particles of the radiocesium resuspension changed seasonally. The SEM analyses showed that the dominant coarse particles in summer and autumn were organic ones, such as pollen, spores, and microorganisms. Biological activities in forest ecosystems can contribute considerably to the radiocesium resuspension in these seasons. During winter and spring, soil, mineral, and vegetation debris were predominant coarse particles in the atmosphere, and the radiocesium resuspension in these seasons can be attributed to the wind blow of these particles. Any proofs that biomass burning had a significant impact on atmospheric radiocesium were not found in the present study. [Figure not available: see fulltext.]. DOI Scopus 28 Citation (Scopus) Humic-like substances global levels and extraction methods in aerosols. Naoya Katsumi, Shuhei Miyake, Hiroshi Okochi, Yukiya Minami, Hiroshi Kobayashi, Shungo Kato, Ryuichi Wada, Masaki Takeuchi, Kei Toda, Kazuhiko Miura Environmental Chemistry Letters     1 - 7  2018.10  [Refereed] Diurnal Variations in Partitioning of Atmospheric Glyoxal and Methylglyoxal between Gas and Particles at the Ground Level and in the Free Troposphere Kasumi Mitsuishi, Masakazu Iwasaki, Masaki Takeuchi, Hiroshi Okochi, Shungo Kato, Shin-Ichi Ohira, Kei Toda ACS EARTH AND SPACE CHEMISTRY   2 ( 9 ) 915 - 924  2018.09  [Refereed] 　View Summary This work presents diurnal variations of gas and particle-phase dicarbonyls (glyoxal (Gly) and methylglyoxal (Mgly)) in the atmosphere, which are important compounds that contribute to the formation and growth of atmospheric particulate matter. To obtain variations in partitioning, continuous collection of gaseous dicarbonyls was performed using a parallel plate wet denuder, and at the same time, the dicarbonyls in particle were collected using a spray-type particle collector downstream. Hourly samples were analyzed by high performance liquid chromatography-electrospray ionization-tandem mass spectrometry. This method is advantageous to monitor the gaseous and particulate carbonyls separately without loss during sampling. Sampling was performed in summer and winter in a midsize city (Kumamoto, Japan). The concentrations of the dicarbonyls increased in the summer daytime, which suggests that they are mostly formed by secondary production in the local atmosphere. The dicarbonyls and formaldehyde (HCHO) were found in both gas and particle phases, and partitioning to the particle phase was highest for Gly, followed by Mgly and HCHO. It was observed that the compounds moved to the particle phase in the midnight and early morning hours according to the growth of hygroscopic aerosols in summer. The particle/gas ratio also increased in the presence of high PM2.5, which is transported from the Chinese Continent in winter. The dicarbonyls were also observed on Mt. Fuji (3776 m) in the free troposphere. From back trajectory data and information on volatile organic compounds, they were most likely produced from relatively long-lifetime organic compounds from the Chinese Continent and biogenic volatile organic compounds emitted in the Japan Alps mountain range. Higher particle/gas ratios at the Mt. Fuji station indicate that low temperatures and high humidity precede the partition. The estimated effective Henry&＃39;s law constants for the dicarbonyls, 108 order in mol/kgH(2)O/atm for summer data, were much higher than those for ideal liquid/vapor equilibrium but close to reported results obtained by chamber experiments. In the proposed method, oligomers in particle were also counted as the compounds. The dicarbonyl compounds existed up to submolar levels in real atmospheric aerosols, which suggests they undergo further reactions in the particle phase. DOI Scopus 27 Citation (Scopus) Contributing factor of PM2.5 pollution in Kanto area in summer 2015 evaluated by simultaneous observation of PM2.5 at the top of Mt. Fuji and Kazo, Saitama 米持真一, 大河内博, 廣川諒祐, 小西智也, LEE Ki‐Ho, KIM Yung‐Joo, LU Senlin 大気環境学会誌   53 ( 4 ) 144‐152  2018.07  [Refereed] J-GLOBAL Development of an Analytical Method for the Detection of NOz and Its Application to the Atmospheric Analysis at a Mountain Site Ryuichi Wada, Yasuhiro Sadanaga, Shungo Kato, Naoya Katsumi, Hiroshi Okochi, Yoko Iwamoto, Kazuhiko Miura, Hiroshi Kobayashi, Masashi Kamogawa, Jun Matsumoto, Seiichiro Yonemura, Yutaka Matsumi, Mizuo Kajino, Shiro Hatakeyama BUNSEKI KAGAKU   67 ( 6 ) 333 - 340  2018.06  [Refereed] 　View Summary Analytical methods for the detection of NOz have been developed by using a laser-induced fluorescence spectroscopy (LIF) technique and a chemiluminescence (CL) method. NOz (= NOy - NOx) represents NOx oxidation products. The NO2 concentrations are measured by LIF, which has a high sensitivity and no chemical interferences when a conversion technique to NO is applied by such as a CL method. The NO and NOy concentrations are measured by an improved CL method. The NOz concentrations are obtained by subtracting the concentrations of NO and NO2 from NOy. The NOz concentrations in the atmosphere were measured at the top of Mt. Fuji in August, 2017. The average concentration of NOz was 0.28 +/- 0.26 ppb. A back-trajectory analysis suggested that the air mass from the Asian continent showed a high concentration of NOz, and the air mass from the Pacific Ocean showed a low concentration of NOz. The concentrations of NOz and O-3 showed a correlation, and ozone production efficiencies (OPE) were obtained from correlation plots. The obtained OPEs at a mountain site showed that the air mass from the Asian continent was 3 to 10 and from the Pacific Ocean was 18. An analytical method of NOz in the atmosphere at a mountain site was established. DOI Scopus 3 Citation (Scopus) Chemical Structural Features of Humic-like Substances (HULIS) in Urban Atmospheric Aerosols Collected from Central Tokyo with Special Reference to Nuclear Magnetic Resonance Spectra Katsumi Naoya, Miyake Shuhei, Okochi Hiroshi ASIAN JOURNAL OF ATMOSPHERIC ENVIRONMENT   12 ( 2 ) 153 - 164  2018.06  [Refereed] DOI Scopus 5 Citation (Scopus) The impacts of "urban-induced heavy rains" on the distribution of deposition fluxes of inorganic acidic substances in the Tokyo metropolitan area in summer Ryunosuke Uchiyama, Hiroshi Okochi, Junichi Kamiya, Daisuke Asai, Chiho Kaneko, Hiroko Ogata, Naoya Katsumi ATMOSPHERIC RESEARCH   200   109 - 116  2018.02  [Refereed] 　View Summary We analyzed the trends in rainfall amounts and the number of heavy rain events with hourly rainfall amounts over 30 mm at the inland section of the 23-ward Tokyo metropolitan area (nine wards and ten sites) in the warm season (July to September) from 1978 to 2008. Heavy rain events in the Nerima Ward occurred nine times during decade I (1978-1987; 0.90 times/yr), 13 times during decade II (1988-1997; 1.3 times/yr), and 23 times during decade III (1998-2008; 2.1 times/yr). The annual average number of heavy rain events was 1.43 times/yr in Nerima from 1978 to 2008, while it was 0.98 times/yr on average at nine locations excluding Nerima. The frequency of extremely strong heavy rain events with hourly rainfall amounts greater than 50 mm during decade III was the highest in Nerima (six times) among ten sites. These data suggest that the frequency of heavy rain events has increased at Nerima during the past 30 years. Bulk precipitation data were collected biweekly by filtration-type collectors at 14 sites around Nerima from 2008 to 2010 to determine the impacts of urban-induced heavy rains (hereafter UHR), defined as a heavy rain event other than typhoons and frontal heavy rains, on the distribution of deposition fluxes of inorganic acidic substances. The NO3- and nss-SO42- concentrations in bulk precipitation were higher during the periods including UHR than those not including UHR. The deposition fluxes of NO3- and SO42- showed clear differences at the center of UHR (NO3-: 231 mu eq/m(2)/d, SO42-: 234 mu eq/m(2)/d) and its surrounding area (NO3-: 76.4 mu eq/m(2)/d, SO42 -: 86.1 mu eq/m(2)/d). Our results suggest that large amounts of inorganic acidic substances are deposited locally by UHR in urban areas in summer. DOI Scopus 8 Citation (Scopus) NOx酸化物質(NOz)計測手法の開発と山岳地域における実大気への応用 和田龍一, 定永靖宗, 加藤俊吾, 勝見尚也, 大河内博, 岩本洋子, 三浦和彦, 小林拓, 鴨川仁, 松本淳, 米村正一郎, 松見豊, 梶野瑞王, 畠山史郎 分析化学   67   333 - 340  2018  [Refereed] H and O isotopic differences in typhon and urban-induced heavy rain in Tokyo Ryunosuke Uchiyama, Hiroshi Okochi, Hiroko Ogata, Naoya Katsumi, Daisuke Asai, Takanori Nakano ENVIRONMENTAL CHEMISTRY LETTERS   15 ( 4 ) 739 - 745  2017.12  [Refereed] 　View Summary Stable isotope ratios of hydrogen and oxygen of water are useful tracers of the hydrological cycle. For example, isotopes monitor the evapotranspiration in vegetated areas, local snow ice processes and stream water flow processes. delta O-18 and delta D in rainwater reflect the processes of evaporation, condensation and precipitation. Heavy rains thus modify the stable isotope ratio of ground water, stream water and transpiration water vapor. However, the controlling factors of delta O-18 and delta D are not clear. Here we analyzed the inorganic ion concentration and stable isotope ratio in 38 normal rainwater and 15 heavy rainwater samples were collected in Shinjuku, Tokyo, Japan, during four years from October 2012 to December 2015. Results show a decrease in delta O-18 and delta D values with the total rainfall amount, thus highlighting the amount effect. delta O-18 and delta D volume-weighted mean values in typhoon heavy rain were higher than the values estimated from amount effect, whereas delta O-18 and delta D volume-weighted mean values in urban-induced heavy rain were lower. Typhoon heavy rain has high Na+ ratio and stable isotope ratios, while urban-induced heavy rain has low Na+ ratio and stable isotope ratio. DOI Scopus 9 Citation (Scopus) First demonstration of aerial gamma-ray imaging using drone for prompt radiation survey in Fukushima S. Mochizuki, J. Kataoka, L. Tagawa, Y. Iwamoto, H. Okochi, N. Katsumi, S. Kinno, M. Arimoto, T. Maruhashi, K. Fujieda, T. Kurihara, S. Ohsuka JOURNAL OF INSTRUMENTATION   12  2017.11  [Refereed] 　View Summary Considerable amounts of radioactive substances (mainly Cs-137 and Cs-134) were released into the environment after the Japanese nuclear disaster in 2011. Some restrictions on residence areas were lifted in April 2017, owing to the successive and effective decontamination operations. However, the distribution of radioactive substances in vast areas of mountain, forest and satoyama close to the city is still unknown; thus, decontamination operations in such areas are being hampered. In this paper, we report on the first aerial gamma-ray imaging of a schoolyard in Fukushima using a drone that carries a high sensitivity Compton camera. We showthat the distribution of Cs-137 in regions with a diameter of several tens to a hundred meters can be imaged with a typical resolution of 2-5 m within a 10-20 min flights duration. The aerial gamma-ray images taken 10 m and 20 m above the ground are qualitatively consistent with a dose map reconstructed from the ground-based measurements using a survey meter. Although further quantification is needed for the distance and air-absorption corrections to derive in situ dose map, such an aerial drone system can reduce measurement time by a factor of ten and is suitable for place where ground-based measurement are difficult. DOI Scopus 36 Citation (Scopus) Geochemical and stable isotope characteristics of urban heavy rain in the downtown of Tokyo, Japan Ryunosuke Uchiyama, Hiroshi Okochi, Hiroko Ogata, Naoya Katsumi, Daisuke Asai, Takanori Nakano ATMOSPHERIC RESEARCH   194   109 - 118  2017.09  [Refereed] 　View Summary In order to make clear the impact of air pollution on the formation of sudden and locally-distributed heavy rain in urban area (hereafter Urban Heavy Rain: UHR), we analyzed inorganic ion concentration and stable isotope ratio of water (delta D and delta O-18) in rainwater. Rainwater samples were collected in Shinjuku, which is a representative downtown of Tokyo, Japan, during four years from October 2012 to December 2015. The concentration and wet deposition fluxes of acidic components (H+, NH4+, NO3-, and nss-SO42-) in UHR were especially higher than those in other types of rain events, i.e. normal rain, typhoon heavy rain, and frontal heavy rain. UHR had distinctly lower stable isotope ratios than those in other urban rains with same rainfall amount and summer precipitation systems. There was a high negative correlation between delta O-18 and the distances from the sampling point to the formation area of UHR within 10 km, while there were high positive correlations between delta O-18 and the concentration of acidic components in UHR. These findings indicate that UHR could effectively scavenge acidic substances within cloud and suggest the use of stable isotope ratios as tracers of an urban heavy rain&＃39;s water and in-cloud scavenging process. DOI Scopus 13 Citation (Scopus) High Time-Resolution Monitoring of Free-Tropospheric Sulfur Dioxide and Nitric Acid at the Summit of Mt. Fuji, Japan Masaki Takeuchi, Yuki Miyazaki, Hideji Tanaka, Takaharu Isobe, Hiroshi Okochi, Hiroko Ogata WATER AIR AND SOIL POLLUTION   228 ( 9 )  2017.09  [Refereed] 　View Summary This is the first paper that describes the atmospheric sulfur dioxide (SO2) and nitric acid (HNO3) monitored with a good time-resolution at the summit (3776 m a. s. l.), which is located in the free troposphere, and southeastern foot (1284 m a.s.l.) of Mt. Fuji. Japan. During the summer of 2012, two analytical systems consisting mainly of a parallel-plate wet denuder and ion chromatograph operated simultaneously at both the sampling sites. All the samples collected at both the sampling sites contained detectable levels of sulfate from gas-phase SO2 while the nitrate from gas-phase HNO3 was detectable in 97.8% of air samples at the southeastern foot and 88.4% at the summit. The average concentrations of SO2 and HNO3 were, respectively, 0.061 +/- 0.071 and 0.031 +/- 0.020 ppbv at the summit (n = 672), and 0.347 +/- 0.425 and 0.146 +/- 0.070 ppbv at the southeastern foot (n = 1344) of Mt. Fuji. Both the acidic gases at the southeastern foot and the HNO3 at the summit showed a diurnal pattern with daytime maxima and nighttime minima. Meanwhile, the SO2 at the summit did not show a distinct shift, which indicates the SO2 concentrations at the summit would be principally controlled by the advection of air parcel in the free troposphere. DOI Scopus 5 Citation (Scopus) The impact of air pollutants on rainwater chemistry during "urban-induced heavy rainfall" in downtown Tokyo, Japan Ryunosuke Uchiyama, Hiroshi Okochi, Naoya Katsumi, Hiroko Ogata JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES   122 ( 12 ) 6502 - 6519  2017.06  [Refereed] 　View Summary In order to clarify the impact of air pollution on the formation of sudden and locally distributed heavy rain in urban areas (hereafter UHR = urban-induced heavy rain), we analyzed inorganic ions in rainwater samples collected on an event basis over 5 years from October 2012 to December 2016 in Shinjuku, Tokyo. Hourly rainfall amounts and wet deposition fluxes of acidic components (the sum of H+, NH4+, NO3-, and nonsea-salt SO42-) in UHR were 13.1 and 17.8 times larger than those in normal rainfall, respectively, indicating that large amount of air pollutants were scavenged and deposited by UHR with large amounts of rainfall. The level of air pollutants, such as NO2, SO2, and potential ozone, in the ambient air increased just before the formation of UHR and decreased sharply at the end of the UHR event. These results indicate that NO2, which was formed secondarily by oxidants, was further oxidized by HO radicals and formed HNO3 just before the formation of UHR, which was subsequently scavenged by UHR. DOI Scopus 25 Citation (Scopus) 福島県の里山に大気沈着した放射性Csの長期変動 金野俊太郎, 大河内博, 勝見尚也, 緒方裕子, 片岡淳, 岸本彩, 岩本康弘, 反町篤行, 床次眞司 分析化学会誌   66 ( 3 ) 17  2017.03  [Refereed] Long-term Variations in the Distribution of Radioactive Cs in Plant, Soil, Stream Bottom Sand in a Small Forest in Fukushima Prefecture Shuntaro Kinno, Hiroshi Okochi, Naoya Katsumi, Hiroko Ogata, Jun Kataoka, Aya Kishimoto, Yasuhiro Iwamoto, Atsuyuki Sorimachi, Shinji Tokonami BUNSEKI KAGAKU   66 ( 3 ) 163 - 174  2017.03  [Refereed] 　View Summary Radio-Cs concentrations in fresh leaves/needles, litter, surface soil, and stream sand were continuously investigated in a deciduous broadleaf forest and cedar forest in Namie-town, Fukushima prefecture from June 2012 to June 2016, except for snow-cover periods. The result of a car-borne survey from Fukushima city to Minamitsushima showed that the air dose rate declined faster than the physical attenuation due to decontamination, outside of forests. Radio-Cs concentrations (Cs-137 + Cs-134) in litter and surface soil in broadleaf forest were constant at 52.0, 102 kBq kg-dry(-1), respectively from 2014. In a cedar forest, however, the radio-Cs concentrations in fresh needles and litter declined from 2012 to 2015, probably because of washing and leaching by throughfall, and radio-Cs was accumulated in surface soil. In broadleaf forest, the buffer depth of radio-Cs in soil (1.26 cm) which indicates the extent of infiltration into deeper layers was greater than in the cedar forest (1.14 cm) in April 2013. However, the buffer depth in the cedar forest overtook that in the broadleaf forest in December, 2015 (1.5 cm in broadleaf forest and 2.6 cm in cedar forest). The radio-Cs values in the stream bottom sand were concentrated in smaller sand (over 2 mm, 3.04; 0.21-2.0 mm, 10.2; under 0.21 mm, 54.5 kBq kg-dry(-1) in downstream near the broadleaf forest and over 2.0 mm, 2.67, 0.21-2.0 mm, 7.95; under 0.21 mm, 41.3 kBq kg-dry(-1) in the upstream area near the cedar forest). It is concerned that a part of them causes the outflow of radio-Cs as suspended sand. The relative radio-Cs concentration ratio between smaller bottom sand and surface soil, which indicates the outflow of radio-Cs from forest via stream declined (2013: 0.54, 2016: 0.29 in downstream and 2013: 1.4, 2016: 0.31 in the upstream region). However, we found that floating male flowers of cedar containing high radio-Cs (23.8 kBq kg-dry(-1)) could be another transport media in the spring. DOI Scopus 2 Citation (Scopus) The impact of air pollutants on rainwater chemistry during “urban-induced heavy rainfall” in downtown Tokyo, Japan Ryunosuke Uchiyama, Hiroshi Okochi, Naoya Katsumi, Hiroko Ogata Journal of Geophysical Research   122 ( 12 ) 6502 - 6519  2017  [Refereed] 　View Summary In order to clarify the impact of air pollution on the formation of sudden and locally distributed heavy rain in urban areas (hereafter UHR = urban-induced heavy rain), we analyzed inorganic ions in rainwater samples collected on an event basis over 5 years from October 2012 to December 2016 in Shinjuku, Tokyo. Hourly rainfall amounts and wet deposition fluxes of acidic components (the sum of H+, NH4 +, NO3, and nonsea-salt SO4 2-) in UHR were 13.1 and 17.8 times larger than those in normal rainfall, respectively, indicating that large amount of air pollutants were scavenged and deposited by UHR with large amounts of rainfall. The level of air pollutants, such as NO2, SO2, and potential ozone, in the ambient air increased just before the formation of UHR and decreased sharply at the end of the UHR event. These results indicate that NO2, which was formed secondarily by oxidants, was further oxidized by HO radicals and formed HNO3 just before the formation of UHR, which was subsequently scavenged by UHR. DOI Scopus 25 Citation (Scopus) Long-term variations in the distribution of radioactive Cs in plant, soil, stream bottom sand in a small forest in Fukushima prefecture Shuntaro Kinno, Hiroshi Okochi, Naoya Katsumi, Hiroko Ogata, Jun Kataoka, Aya Kishimoto, Yasuhiro Iwamoto, Atsuyuki Sorimachi, Shinji Tokonami Bunseki Kagaku   66 ( 3 ) 163 - 174  2017  [Refereed] 　View Summary Radio-Cs concentrations in fresh leaves/needles, litter, surface soil, and stream sand were continuously investigated in a deciduous broadleaf forest and cedar forest in Namie-town, Fukushima prefecture from June 2012 to June 2016, except for snow-cover periods. The result of a car-borne survey from Fukushima city to Minamitsushima showed that the air dose rate declined faster than the physical attenuation due to decontamination, outside of forests. Radio-Cs concentrations (137Cs +134Cs) in litter and surface soil in broadleaf forest were constant at 52.0, 102 kBq kg-dry–1, respectively from 2014. In a cedar forest, however, the radio-Cs concentrations in fresh needles and litter declined from 2012 to 2015, probably because of washing and leaching by throughfall, and radio-Cs was accumulated in surface soil. In broadleaf forest, the buffer depth of radio-Cs in soil (1.26 cm) which indicates the extent of infiltration into deeper layers was greater than in the cedar forest (1.14 cm) in April 2013. However, the buffer depth in the cedar forest overtook that in the broadleaf forest in December, 2015 (1.5 cm in broadleaf forest and 2.6 cm in cedar forest). The radio-Cs values in the stream bottom sand were concentrated in smaller sand (over 2 mm, 3.04 0.21-2.0 mm, 10.2 under 0.21 mm, 54.5 kBq kg-dry–1 in downstream near the broadleaf forest and over 2.0 mm, 2.67, 0.21-2.0 mm, 7.95 under 0.21 mm, 41.3 kBq kg-dry–1 in the upstream area near the cedar forest). It is concerned that a part of them causes the outflow of radio-Cs as suspended sand. The relative radio-Cs concentration ratio between smaller bottom sand and surface soil, which indicates the outflow of radio-Cs from forest via stream declined (2013: 0.54, 2016: 0.29 in downstream and 2013: 1.4, 2016: 0.31 in the upstream region). However, we found that floating male flowers of cedar containing high radio-Cs (23.8 kBq kg-dry–1) could be another transport media in the spring. DOI Scopus 2 Citation (Scopus) Atmospheric CO, O-3, and SO2 Measurements at the Summit of Mt. Fuji during the Summer of 2013 Shungo Kato, Yasuhiro Shiobara, Katsumi Uchiyama, Kazuhiko Miura, Hiroshi Okochi, Hiroshi Kobayashi, Shiro Hatakeyama AEROSOL AND AIR QUALITY RESEARCH   16 ( 10 ) 2368 - 2377  2016.10  [Refereed] 　View Summary Atmospheric trace gases CO, O-3, and SO2 were observed at the summit of Mt. Fuji (3776 ma.s.l.) during the summer of 2013. Considerable variations were observed in the concentrations of CO and O-3; however, they were correlated in most cases. Trends analyzed through backward trajectory calculations showed lower concentrations of CO and O-3 transported from the Pacific Ocean and South East Asia directions, while higher concentrations were detected from the direction of the Asian continent. High O-3 and low CO concentrations were observed during some periods; in these air masses, water content of the air was low indicating that the air originated from high altitudes and was influenced by the stratosphere. Gaseous SO2 was mostly lower than the detection limit of the instrument used for measurement (0.06 ppbv), but on August 20-21, high SO2 spikes of about 5 ppbv were observed. Backward and forward trajectory calculations confirmed that volcanic smoke from the Sakurajima volcano was transported to the summit of Mt. Fuji. DOI Scopus 27 Citation (Scopus) Novel methods for estimating 3D distributions of radioactive isotopes in materials Y. Iwamoto, J. Kataoka, A. Kishimoto, T. Nishiyama, T. Taya, H. Okochi, H. Ogata, S. Yamamoto NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   831   295 - 300  2016.09  [Refereed] 　View Summary In recent years, various gamma-ray visualization techniques, or gamma cameras, have been proposed. These techniques are extremely effective for identifying "hot spots" or regions where radioactive isotopes are accumulated. Examples of such would be nuclear-disaster-affected areas such as Fukushima or the vicinity of nuclear reactors. However, the images acquired with a gamma camera do not include distance information between radioactive isotopes and the camera, and hence are "degenerated" in the direction of the isotopes. Moreover, depth information in the images is lost when the isotopes are embedded in materials, such as water, sand, and concrete. Here, we propose two methods of obtaining depth information of radioactive isotopes embedded in materials by comparing (1) their spectra and (2) images of incident gamma rays scattered by the materials and direct gamma rays. In the first method, the spectra of radioactive isotopes and the ratios of scattered to direct gamma rays are obtained. We verify experimentally that the ratio increases with increasing depth, as predicted by simulations. Although the method using energy spectra has been studied for a long time, an advantage of our method is the use of low-energy (50-150 keV) photons as scattered gamma rays. In the second method, the spatial extent of images obtained for direct and scattered gamma rays is compared. By performing detailed Monte Carlo simulations using Geant4, we verify that the spatial extent of the position where gamma rays are scattered increases with increasing depth. To demonstrate this, we are developing various gamma cameras to compare low-energy (scattered) gamma -ray images with fully photo -absorbed gamma -ray images. We also demonstrate that the 3D reconstruction of isotopes/hotspots is possible with our proposed methods. These methods have potential applications in the medical fields, and in severe environments such as the nuclear-disaster-affected areas in Fukushima. (C) 2016 Elsevier B.V. All rights reserved. DOI Scopus 10 Citation (Scopus) Characterization of Elements and Sources of PM2.5 in Large Cities in China and the National Capital Region of Japan Focused on Rare Earth Elements (REEs) Yonemochi Shinichi, Liu Pinwei, Lu Senlin, Wenchao Zhang, Oishi Saki, Yanagimoto Yusuke, Nagoya Toshio, Okochi Hiroshi, Umezawa Natsumi, Oh Kokyo Journal of Japan Society for Atmospheric Environment / Taiki Kankyo Gakkaishi   51 ( 1 ) 33 - 43  2016  [Refereed] 　View Summary Rare earth elements (REEs) are essential and widely used in of high-technology industries all over the world. However, almost of them produced in the world are mined in China. The concentrations of the REEs (La-Lu) in the PM2.5 are rarely reported in China and Japan. We conducted simultaneous observations of PM2.5 at Beijing, Shanghai, Shinjuku and Kazo in August 2013, and evaluated all the data including those published in Beijing in January 2013. As the results, when compared with metalic elements between Beijing and Shanghai, the relative concentrations of the elements originatting from shipping, oil combustion and the steel industry were dominant in Shanghai. Those of coal combustion were dominant in Beijing. The enrichment factor of the REEs in PM2.5 at Beijing calculated based on the REEs in PM10 at Bayan obo, the largest mine in China, showed that neodymium (Nd) and dysprosium (Dy) were significantly higher than the others. Those of erbium (Er) and ytterbium (Yb) were also high. The combination of enriched REEs in the PM2.5 provides information about the products and industries of high-technology. DOI CiNii 揮発性有機化合物の雲内および雲底下洗浄機構と露水への乾性沈着(2) Rossini Giacomo, 山本 修司, 大河内 博, 緒方 裕子, 名古屋 俊士, 皆巳 幸也, 小林 拓, 加藤 俊吾, 三浦 和彦, 松尾 亜弓 大気環境学会年会講演要旨集   56回   270 - 270  2015.09  [Refereed] Recent progress of MPPC-based scintillation detectors in high precision X-ray and gamma-ray imaging J. Kataoka, A. Kishimoto, T. Fujita, T. Nishiyama, Y. Kurei, T. Tsujikawa, T. Oshima, T. Taya, Y. Iwamoto, H. Ogata, H. Okochi, S. Ohsuka, H. Ikeda, S. Yamamoto NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT   784   248 - 254  2015.06  [Refereed] 　View Summary The multi-pixel photon counter (MPPC) is a promising light sensor for various applications, not only in physics experiments but also in nuclear medicine, industry, and even high-energy astrophysics. In this paper, we present the current status and most recent progress of the MPPC-based scintillation detectors, such as (1) a high-precision X-ray and gamma-ray spectral image sensor, (2) next-generation PET detectors with MRI, TOF, and DOI measurement capabilities, and (3) a compact gamma camera for environmental radiation surveys. We first present a new method of fabricating a Ce:GAGG scintillator plate (1 or 2 mm thick) with ultra-fine resolution (0.2 mm/pixel), cut using a dicing saw to create 50 mu m wide micro-grooves. When the plate is optically coupled with a large-area MPPC array, excellent spatial resolution of 0.48 mm (FWHM) and energy resolution of 14% (FWHM) are obtained for 122 keV gamma rays. Hence, the detector can act as a convenient "multi-color" imaging device that can potentially be used for future SPECT and photon-counting CT. We then show a prototype system for a high-resolution MPPC-based PET scanner that can realize similar or equal to 1 mm (FWHM) spatial resolution, even under a strong magnetic field of 4.7 T. We develop a front-end ASIC intended for future TOF-PET scanner with a 16-channel readout that achieves a coincidence time resolution of 489 ps (FWHM). A novel design for a module with DOI-measurement capability for gamma rays is also presented by measuring the pulse height ratio of double-sided MPPCs coupled at both ends of scintillation crystal block. Finally, we present the concept of a two-plane Compton camera consisting of Ce:GAGG scintillator arrays coupled with thin MPPC arrays. As a result of the thin and compact features of the MPPC device, the camera not only achieves a small size (14 x 14 x 15 cm(3)) and light weight (1.9 kg) but also excellent sensitivity, compared to the conventional PMT-based pinhole camera used in Fukushima. Finally, we briefly describe a new product recently developed in conjunction with Hamamatsu Photonics K.K. that offers improved sensitivity and angular resolution of Delta theta similar to 8 degrees (FWHM) at 662 key, by incorporating DOI-segmented scintillator arrays. (C) 2014 Elsevier B.V. All rights reserved. DOI Scopus 51 Citation (Scopus) Diurnal variation of atmospheric electric field at the summit of Mount Fuji, Japan, distinctly different from the Carnegie curve in the summertime Masashi Kamogawa, Yuko Suzuki, Rikuma Sakai, Hironobu Fujiwara, Tatsuo Torii, Yoshihiro Kakinami, Yasuyuki Watanabe, Ryoe Sato, Satoshi Hashimoto, Hiroshi Okochi, Kazuhiko Miura, Hiroshi Yasuda, Yoshiaki Orihara, Tomoyuki Suzuki GEOPHYSICAL RESEARCH LETTERS   42 ( 8 ) 3019 - 3023  2015.04  [Refereed] 　View Summary In fair weather, a clear diurnal variation of atmospheric electric field (AEF), which is distinctly different from the global diurnal variation, i.e., Carnegie curve, was observed during the summer time (July and August) of the year 2010 and 2011 at the summit of Mount Fuji, Japan (3776m in altitude). The variation of the AEF at the summit showed a local time dependent feature, which means that the AEF increased at sunrise and decreased at sunset. This local diurnal variation is known as a mountain variation. The intensity of AEF in the daytime reached 1.5-3 times larger than that in the nighttime. From the multipoint observations of cloud images and AEF, the mountain variation was found to be attributable to the AEF generated by the positively charged top of a horizontally extensive sea of clouds below the summit. Since the sea of clouds grows with the temperature rise, the AEF variation follows local time. DOI Scopus 7 Citation (Scopus) 富士山体を利用した夏季自由対流圏におけるガス状水銀の観測：2014年夏季集中観測結果 小川智司, 大河内博, 緒方裕子, 梅沢夏実, 三浦和彦, 加藤俊吾 大気環境学会誌   50 ( 2 ) 100 - 106  2015.03  [Refereed] Performance and field tests of a handheld Compton camera using 3-D position-sensitive scintillators coupled to multi-pixel photon counter arrays A. Kishimoto, J. Kataoka, T. Nishiyama, T. Fujita, K. Takeuchi, H. Okochi, H. Ogata, H. Kuroshima, S. Ohsuka, S. Nakamura, M. Hirayanagi, S. Adachi, T. Uchiyama, H. Suzuki JOURNAL OF INSTRUMENTATION   9  2014.11  [Refereed] 　View Summary After the nuclear disaster in Fukushima, radiation decontamination has become particularly urgent. To help identify radiation hotspots and ensure effective decontamination operation, we have developed a novel Compton camera based on Ce-doped Gd3Al2Ga3O12 scintillators and multi-pixel photon counter (MPPC) arrays. Even though its sensitivity is several times better than that of other cameras being tested in Fukushima, we introduce a depth-of-interaction (DOI) method to further improve the angular resolution. For gamma rays, the DOI information, in addition to 2-D position, is obtained by measuring the pulse-height ratio of the MPPC arrays coupled to ends of the scintillator. We present the detailed performance and results of various field tests conducted in Fukushima with the prototype 2-D and DOI Compton cameras. Moreover, we demonstrate stereo measurement of gamma rays that enables measurement of not only direction but also approximate distance to radioactive hotspots. DOI Scopus 48 Citation (Scopus) 揮発性有機化合物の動態解析と降水洗浄機構(2) 山本 修司, 大河内 博, 緒方 裕子, 名古屋 俊士, 皆巳 幸也, 小林 拓, 加藤 俊吾, 三浦 和彦, 松尾 亜弓 大気環境学会年会講演要旨集   55回   525 - 525  2014.08  [Refereed] Individual aerosol particles in and below clouds along a Mt. Fuji slope: Modification of sea-salt-containing particles by in-cloud processing S. Ueda, Y. Hirose, K. Miura, H. Okochi ATMOSPHERIC RESEARCH   137   216 - 227  2014.02  [Refereed] 　View Summary Sizes and compositions of atmospheric aerosol particles can be altered by in-cloud processing by absorption/adsorption of gaseous and particulate materials and drying of aerosol particles that were formerly activated as cloud condensation nuclei. To elucidate differences of aerosol particles before and after in-cloud processing, aerosols were observed along a slope of Mt. Fuji, japan (3776 m a.s.l.) during the summer in 2011 and 2012 using a portable laser particle counter (LPC) and an aerosol sampler. Aerosol samples for analyses of elemental compositions were obtained using a cascade impactor at top-of-cloud, in-cloud, and below-cloud altitudes. To investigate composition changes via in-cloud processing, individual particles (0.5-2 mu m diameter) of samples from five cases (days) collected at different altitudes under similar backward air mass trajectory conditions were analyzed using a transmission electron microscope (TEM) equipped with an energy dispersive X-ray analyzer. For most cases (four cases), most particles at all altitudes mainly comprised sea salts: mainly Na with some S and/or CL Of those, in two cases, sea-salt-containing particles with Cl were found in below-cloud samples, although sea-salt-containing particles in top-of-cloud samples did not contain Cl. This result suggests that Cl in the sea salt was displaced by other cloud components. In the other two cases, sea-salt-containing particles on samples at all altitudes were without CL However, molar ratios of S to Na (S/Na) of the sea-salt-containing particles of top-of-cloud samples were higher than those of below-cloud samples, suggesting that sulfuric acid or sulfate was added to sea-salt-containing particles after complete displacement of Cl by absorption of SO2 or coagulation with sulfate. The additional volume of sulfuric acid in clouds for the two cases was estimated using the observed S/Na values of sea-salt-containing particles. The estimation revealed that size changes by in-cloud processing from below-cloud to top-of-cloud altitudes were less than 6% for sizes of 0.5-2 mu m diameter. The obtained results will be useful to evaluate the aging effect and transition of aerosol particles through in-cloud processing. (C) 2013 Elsevier B.V. All rights reserved. DOI Scopus 20 Citation (Scopus) Behavior of volatile organic compounds in the ambient air at the top and foot of Mt. Fuji during summer, 2012   49 ( 1 ) 34 - 42  2014  [Refereed] DOI CiNii 大河内博 越境大気汚染の実態, II. 越境大気汚染物質の計測と環境影響 ビルと環境     17 - 5  2014 Vertical distribution of atmospheric acidic substances and observation of the Forest Filter Effect in a suburban small forest in the Tokyo metropolitan area, Japan   49 ( 1 ) 26 - 32  2014  [Refereed] DOI CiNii Behavior and origin of water-soluble humic-like substances in particulate matter in central Tokyo   49 ( 1 ) 43 - 52  2014  [Refereed] DOI CiNii Distribution and behavior of the atmospherically deposited radioactive cesium in a small forest, Satoyama at Namie Town, Fukushima Prefecture Kuroshima Hiroto, Ogata Hiroko, Okochi Hiroshi, Tokonami Shinji, Sorimachi Atsuyuki, Hosoda Masahiro Journal of Japan Society of Air Pollution   49 ( 2 ) 93 - 100  2014  [Refereed] 　View Summary Fresh leaf/needle, litter, surface soil, and stream bottom sand were monthly collected from Japanese cedar and deciduous broadleaf forests in the so-called "Satoyama" of Namie town in Fukushima Prefecture for one year from June 2012 to July 2013. The concentration of radioactive cesium (134Cs and 137Cs) was measured by a commercially available NaI(Tl) scintillation detector. The order of the concentration of the radioactive cesium was litter>surface soil>fresh leaf/needle>bottom sand, indicating that radioactive cesium had accumulated in the litter. Snow covering in the winter and snow melt in the spring did not affect the concentration of radioactive cesium in the litter both in the Japanese cedar and deciduous broadleaf forests. There was a high positive correlation between the concentration of radioactive cesium in the bottom sand at the upstream and the following months concentration of radioactive cesium in bottom sand at the downstream, indicating that radioactive cesium was transported through the suspended sand at approximately 500 m per month in the studied small forest. DOI CiNii Development of Rapid Preparation Method for Simultaneous Analysis of Gas-Phase Polycyclic Aromatic Hydrocarbons and Oxygenated Polycyclic Aromatic Hydrocarbons Using Accelerated Solvent Extractor Yusuke Kobayashi, Hiroshi Okochi, Hiroko Ogata, Toshio Nagoya BUNSEKI KAGAKU   62 ( 10 ) 879 - 889  2013.10  [Refereed] 　View Summary We propose a rapid preparation method for the simultaneous analysis of gas-phase polycyclic aromatic hydrocarbons (PAHs) and oxygenated polycyclic aromatic hydrocarbons (OPAHs) by an accelerated solvent extractor (ASE) and solid-phase extraction (SPE). We used polyurethane foam (PUF) for collecting gas-phase PAHs and OPAHs. Recovery of selected PAHs and OPAHs from blank PUF ranged from 80 to 100 %, except for low molecular PAHs and OPAHs, such as acenaphthylene, acenaphthene, 1,4-naphthoquinone with a relative standard deviation (R.S.D.) of less than 5 %, while their recoveries from the collected PUF ranged from 80 to 120 %, except for benzanthrone with a R.S.D. from 10 % and 20 %. The proposed preparation method in combination with ASE and SPE could be useful for screening gas-phase PAHs and OPAHs, although there is a problem to some extent concerning the collection efficiencies of low molecular PAHs and OPAHs in the gas-phase. The application of the proposed method to samples collected at Shinjuku in June, 2012 revealed that the concentration of PAHs and OPAHs, mainly presented in the gas-phase, was significantly higher than that of PAHs and OPAHs, mainly presented in the particle phase. DOI Scopus 2 Citation (Scopus) Rapid Determination of Anionic Surfactants in Atmospheric Aerosol in an Urban Area Using an Improved Methylene Blue Method Minatsu Soda, Hiroshi Okochi, Hiroko Ogata, Hirokazu Okawa BUNSEKI KAGAKU   62 ( 7 ) 589 - 594  2013.07  [Refereed] 　View Summary The methylene blue method was troublesome and susceptible to operational error. In our improved method, we use only one vial (50 mL glass centrifuge tube) to determine the concentration of anionic surfactants as methylene blue active substances (MBAS). The combination of hand-shaking 20 times with shaking (1000 rpm) for 5 minutes by a shaker leads to a calibration curve (n = 4) with a high linearity (average r = 0.996) and a high sensitivity (average 1.07 mu M-1) within 0 - 0.12 mu M. In the optimum condition, the recovery of sodium dodecyl sulfate (SDS) was 94.7 +/- 3.3 % (n = 3) for a water extraction solution of blank quartz fiber filter, 92.3 +/- 1.5 % (n = 4) for that of atmospheric aerosol collected on a quartz fiber filter, and 90.8 +/- 3.5 % (n = 3) for the throughfall of Japanese ceder (Cyptomeria japonica), respectively. This improved method revealed that the concentration of anionic surfactants in atmospheric aerosol ranged from 44.9 to 163 pmol m(-3) (84.3 pmol m(-3) on average, n = 8) at Shinjuku, Tokyo in May, 2011. DOI Scopus 1 Citation (Scopus) Determination of polycyclic aromatic hydrocarbons in atmospheric water using stir bar sorptive extraction and HPLC with fluorescence detection Masatoshi Fujita, Hiroshi Okochi, Hiroko Ogata, Toshio Nagoya, Yukiya Minami Bunseki Kagaku   62 ( 12 ) 1111 - 1116  2013  [Refereed] 　View Summary Rapid and sample preparation using stir bar sorptive extraction (SBSE), followed by highperformance liquid chromatography with fluorescence detection to determine polycyclic aromatic hydrocarbons (PAHs) in atmospheric water was studied. Applying the SBSE method to authentic atmospheric water samples revealed that rainwater in Shinjuku contained a 226 pM concentration of total PAHs, which was 10-times as much as that at Mt. Fuji, especially in a higher concentration of soluble PAHs. There was no seasonal variation of the concentration and composition of PAHs in rainwater at Shinjuku. Comparing the concentration of PAHs in rain, cloud, and dew water collected at the foot of Mt. Fuji, 5- and 6-rings PAHs were enriched in cloud water. This result suggests that cloud droplets could condense PAHs, especially high molecular weight PAHs. © 2013 The Japan Society for Analytical Chemistry. DOI Scopus 1 Citation (Scopus) Development of rapid preparation method for simultaneous analysis of gas-phase polycyclic aromatic hydrocarbons and oxygenated polycyclic aromatic hydrocarbons using accelerated solvent extractor Yusuke Kobayashi, Hiroshi Okochi, Hiroko Ogata, Toshio Nagoya Bunseki Kagaku   62 ( 10 ) 879 - 889  2013  [Refereed] 　View Summary We propose a rapid preparation method for the simultaneous analysis of gas-phase polycyclic aromatic hydrocarbons (PAHs) and oxygenated polycyclic aromatic hydrocarbons (OPAHs) by an accelerated solvent extractor (ASE) and solid-phase extraction (SPE). We used polyurethane foam (PUF) for collecting gas-phase PAHs and OPAHs. Recovery of selected PAHs and OPAHs from blank PUF ranged from 80 to 100 %, except for low molecular PAHs and OPAHs, such as acenaphthylene, acenaphthene, 1,4-naphthoquinone with a relative standard deviation (R.S.D.) of less than 5 %, while their recoveries from the collected PUF ranged from 80 to 120 %, except for benzanthrone with a R.S.D. from 10 % and 20 %. The proposed preparation method in combination with ASE and SPE could be useful for screening gas-phase PAHs and OPAHs, although there is a problem to some extent concerning the collection efficiencies of low molecular PAHs and OPAHs in the gas-phase. The application of the proposed method to samples collected at Shinjuku in June, 2012 revealed that the concentration of PAHs and OPAHs, mainly presented in the gas-phase, was significantly higher than that of PAHs and OPAHs, mainly presented in the particle phase. © 2013 The Japan Society for Analytical Chemistry. DOI Scopus 2 Citation (Scopus) Rapid determination of anionic surfactants in atmospheric aerosol in an urban area using an improved methylene blue method Minatsu Soda, Hiroshi Okochi, Hiroko Ogata, Hirokazu Okawa Bunseki Kagaku   62 ( 7 ) 589 - 594  2013  [Refereed] 　View Summary The methylene blue method was troublesome and susceptible to operational error. In our improved method, we use only one vial (50 mL glass centrifuge tube) to determine the concentration of anionic surfactants as methylene blue active substances (MBAS). The combination of hand-shaking 20 times with shaking (1000 rpm) for 5 minutes by a shaker leads to a calibration curve (n = 4) with a high linearity (average r =0.996) and a high sensitivity (average 1.07 μM^-1) within 0 - 0.12 μM. In the optimum condition, the recovery of sodium dodecyl sulfate (SDS) was 94.7±3.3 % (n = 3) for a water extraction solution of blank quartz fiber filter, 92.3± 1.5 % (n = 4) for that of atmospheric aerosol collected on a quartz fiber filter, and 90.8± 3.5 % (n =3) for the throughfall of Japanese ceder (Cyptomeria japonica), respectively. This improved method revealed that the concentration of anionic surfactants in atmospheric aerosol ranged from 44.9 to 163 pmol m^-3 (84.3 pmol m^-3 on average, n =8) at Shinjuku, Tokyo in May, 2011. © 2013 The Japan Society for Analytical Chemistry. DOI Scopus 1 Citation (Scopus) Consideration on the concentration of volatile organic compounds in the ambient air and in atmospheric water based on the observation at Mt. Fuji KOBAYASHI Yusuke, OKOCHI Hiroshi, OGATA Hiroko, TAMECHIKA Kazuya, MINAMI Yukiya, NAGOYA Toshio Journal of Japan Society of Air Pollution   47 ( 1 ) 33 - 44  2012.01  [Refereed] 　View Summary Simultaneous sampling of 26 AVOCs (anthropogenic volatile organic compounds), namely seventeen chlorinated hydrocarbons (CHs), six monocyclic aromatic hydrocarbons (MAHs), three dicyclic aromatic hydrocarbons (DAHs), in the ambient air and atmospheric water was performed in an urban area (Shinjuku), mountainous area (at the southeastern foot of Mt. Fuji; 1284 m a.s.l.), and the free troposphere (at the top of Mt. Fuji; 3776 m a.s.l.) from 2007 to 2010. The atmospheric concentration of the AVOCs in 2010 was the highest at the top of Mt. Fuji (average in July: 11.6 ppbv, n=5) and then in Shinjuku (average in October, November, and December: 7.9 ppbv, n=52) and at the foot of Mt. Fuji (average in July: 6.8 ppbv, n=9). It was found that the concentrations of the MAHs at the top of Mt. Fuji were extremely high compared to those at Shinjuku and other high altitude sites, suggesting a highly suspicious contamination near the sampling site at the top of Mt. Fuji. The mean concentrations of the total AVOCs in the rainwater (15.8 nM, n=8) at the foot of Mt. Fuji and in cloud water (15.7 nM, n=19) at the top of Mt. Fuji were higher than those in the dew water (5.33 nM, n=15) and rainwater (3.36 nM, n=30) at Shinjuku. These results indicated that the enrichment of AVOCs in the atmospheric water was strongly influenced by factors other than the concentration of the AVOCs in the ambient air, temperature, and hydrophobicity of each AVOC. DOI CiNii Biogenic volatile organic compounds in a small forest near Greater Tokyo, Japan SUZUKI Keisuke, OKOCHI Hiroshi, OGATA Hiroko Journal of Japan Society of Air Pollution   47 ( 1 ) 51 - 57  2012.01  [Refereed] 　View Summary We have studied the biogenic volatile organic compounds (BVOCs, namely isoprene, α-pinene, β-pinene, δ-3-caren, and limonene) in the ambient air in a small forest (Tokyo Univ. of Agriculture and Technology Field Museum TAMA Hills, Hachioji City), which is located 33 km from Shinjuku. Simultaneous sampling of the BVOCs was performed at three points, namely, at the top of the canopy of Konara (14 m), under the canopy (1 m at the ground), and in the forest clearing (1 m at the ground) on 20-25 June, 2011. Isoprene showed a clear diurnal variation and was high in the daytime and low in the nighttime at the three points. The maximum concentration of isoprene was 11.1 ppbv at the top of the canopy. Monoterpenes such as α-pinene, β-pinene, and limonene did not show any diurnal variation and their concentrations were higher under the canopy and in the forest clearing than those at the top of the canopy. δ-3-Caren was below its detection limit at the three points. A correlation analysis showed that the sources of isoprene were different from those of the monoterpenes, and among the monoterpenes, the sources of the pinenes were different from the sources of limonene. A positively high correlation coefficient between the concentration of α-pinene and β-pinene showed that they were emitted from identical species. The concentration of the BVOCs in the ambient air at FM TAMA was about 10 times higher than at Shinjuku, indicating that Satoyama (the border zone or area between the mountain foothills and arable flat land) is the important source of the BVOCs. DOI CiNii Biogenic volatile organic compounds in a small forest near Greater Tokyo, Japan SUZUKI Keisuke, OKOCHI Hiroshi, OGATA Hiroko Journal of Japan Society of Air Pollution   47 ( 1 ) 51 - 57  2012.01  [Refereed] 　View Summary We have studied the biogenic volatile organic compounds (BVOCs, namely isoprene, α-pinene, β-pinene, δ-3-caren, and limonene) in the ambient air in a small forest (Tokyo Univ. of Agriculture and Technology Field Museum TAMA Hills, Hachioji City), which is located 33 km from Shinjuku. Simultaneous sampling of the BVOCs was performed at three points, namely, at the top of the canopy of Konara (14 m), under the canopy (1 m at the ground), and in the forest clearing (1 m at the ground) on 20-25 June, 2011. Isoprene showed a clear diurnal variation and was high in the daytime and low in the nighttime at the three points. The maximum concentration of isoprene was 11.1 ppbv at the top of the canopy. Monoterpenes such as α-pinene, β-pinene, and limonene did not show any diurnal variation and their concentrations were higher under the canopy and in the forest clearing than those at the top of the canopy. δ-3-Caren was below its detection limit at the three points. A correlation analysis showed that the sources of isoprene were different from those of the monoterpenes, and among the monoterpenes, the sources of the pinenes were different from the sources of limonene. A positively high correlation coefficient between the concentration of α-pinene and β-pinene showed that they were emitted from identical species. The concentration of the BVOCs in the ambient air at FM TAMA was about 10 times higher than at Shinjuku, indicating that Satoyama (the border zone or area between the mountain foothills and arable flat land) is the important source of the BVOCs. DOI CiNii Consideration on the concentration of volatile organic compounds in the ambient air and in atmospheric water based on the observation at Mt. Fuji KOBAYASHI Yusuke, OKOCHI Hiroshi, OGATA Hiroko, TAMECHIKA Kazuya, MINAMI Yukiya, NAGOYA Toshio Journal of Japan Society of Air Pollution   47 ( 1 ) 33 - 44  2012.01  [Refereed] 　View Summary Simultaneous sampling of 26 AVOCs (anthropogenic volatile organic compounds), namely seventeen chlorinated hydrocarbons (CHs), six monocyclic aromatic hydrocarbons (MAHs), three dicyclic aromatic hydrocarbons (DAHs), in the ambient air and atmospheric water was performed in an urban area (Shinjuku), mountainous area (at the southeastern foot of Mt. Fuji; 1284 m a.s.l.), and the free troposphere (at the top of Mt. Fuji; 3776 m a.s.l.) from 2007 to 2010. The atmospheric concentration of the AVOCs in 2010 was the highest at the top of Mt. Fuji (average in July: 11.6 ppbv, n=5) and then in Shinjuku (average in October, November, and December: 7.9 ppbv, n=52) and at the foot of Mt. Fuji (average in July: 6.8 ppbv, n=9). It was found that the concentrations of the MAHs at the top of Mt. Fuji were extremely high compared to those at Shinjuku and other high altitude sites, suggesting a highly suspicious contamination near the sampling site at the top of Mt. Fuji. The mean concentrations of the total AVOCs in the rainwater (15.8 nM, n=8) at the foot of Mt. Fuji and in cloud water (15.7 nM, n=19) at the top of Mt. Fuji were higher than those in the dew water (5.33 nM, n=15) and rainwater (3.36 nM, n=30) at Shinjuku. These results indicated that the enrichment of AVOCs in the atmospheric water was strongly influenced by factors other than the concentration of the AVOCs in the ambient air, temperature, and hydrophobicity of each AVOC. DOI CiNii Influence of secondary formation on atmospheric occurrences of oxygenated polycyclic aromatic hydrocarbons in airborne particles Yuki Kojima, Koji Inazu, Yoshiharu Hisamatsu, Hiroshi Okochi, Toshihide Baba, Toshio Nagoya ATMOSPHERIC ENVIRONMENT   44 ( 24 ) 2873 - 2880  2010.08  [Refereed] 　View Summary Temporal and spatial variations in concentrations of particle-associated polycyclic aromatic hydrocarbons (PAHs) and their nitrated and oxygenated derivatives (nitro-PAHs and oxy-PAHs) were investigated to assess the influence of secondary formation on atmospheric occurrences of oxy-PAHs associated with particulate matter in downtown Tokyo, Japan. The daily variation in concentration of 1,8-naphthalic anhydride (1,8-NA) in summer 2007 was similar to that for 2-nitrofluoranthene (2-NF), a representative secondary formed nitro-PAH, while the variation for benzanthrone (BA) was similar to PAHs. In addition, the concentrations of polycyclic aromatic compounds (PACs) associated with airborne particulate matter decreased in the order of PAHs > BA > 9-fluorenone (9-FO) or 9,10-anthraquinone (9,10-AQ)> 1,8-NA with an increase in distance from the roadside, whereas 2-NF was constant. These results suggest that a considerable fraction of some oxy-PAHs such as 1,8-NA associated with airborne particulate matter in downtown Tokyo originates from atmospheric secondary formation. (C) 2010 Elsevier Ltd. All rights reserved. DOI Scopus 69 Citation (Scopus) Development of Low Volume Air Sampling and Rapid Sample Preparation for the Determination of Atmospheric Gas-Phase Polycyclic Aromatic Hydrocarbons Using Styrene-Divinylbenzene Copolymer Resin Adsorbent Aya Kobayashi, Yuki Kojima, Hiroshi Okochi, Toshio Nagoya BUNSEKI KAGAKU   59 ( 8 ) 645 - 652  2010.08  [Refereed] 　View Summary A new sampling system of gas- and particle-phase polycyclic aromatic hydrocarbons (PAT-Is) in ambient air is proposed. The system is composed of a commercially available multi-nozzle cascade impact sampler for collecting particles less than 10 mu m and a newlydesigned glass cartridge (35 mm inner diameter) packed with 5.0 g of a styrene-divinylbenzene copolymer resin adsorbent (XAD-2) for collecting gas-phase PAHs at a flow rate of 20 L/min. A rapid sample preparation for the analysis of PAHs in XAD-2 resin by ultrasonic extraction was also studied. The recovery rates of selected PAHs, i.e. phenanthrene (PHEN), antrathene (ANT), fluorantene (FL), pyrene (PY), benzo[a]pyrene (BaP), benzo[k]fluoranthene (BkF), benzo[ghi]perylene (BghiP), and indeno[1,2,3-cd]pyrene (IP) after the pretreatment ranged from 80 to 100%. More than 95% of the PAHs were extracted from XAD-2 by ultrasonication twice for 20 min with dichloromethane. The newlydeveloped cartridge had more than 95% collection efficiencies of the gas-phase PAHs (PHEN, ANT, FL and PY) in both the summer and winter seasons. Storage at 30 C for 4 weeks did not have an adverse effect on the gas-phase PAHs collected with the cartridge. The application of the new sampling system to a field observation at a tower with a height of 12 m in a small forest at Field Museum Tama Hills revealed that the concentrations of the gas-phase PAT-Is at the lower level of the tower were lower than those at the upper level of the tower. However, there were no changes in the concentrations of the particle-phase PAHs between at the upper and lower levels. These results suggested that the forest filter effects for the gas-phase PAT-Is might be higher than those for the particle-phase PAHs. DOI Scopus 3 Citation (Scopus) Determination of Volatile Organic Compounds in Rainwater and Dew Water by Head Space Solid-Phase Microextraction and Gas Chromatography/Mass Spectrometry Emi Sato, Hiroshi Okochi, Manabu Igawa BUNSEKI KAGAKU   59 ( 7 ) 551 - 557  2010.07  [Refereed] 　View Summary The optimization of the analysis of volatile organic compounds in atmospheric water samples, such as rainwater and dew water by head space solid-phase microextraction and gas chromatography/mass spectrometry (HS SPME/GC/MS), was studied. The sensitivity of 23 VOCs, i.e. halogenated hydrocarbons and monocyclic aromatic hydrocarbons, was the highest after the extraction of VOCs in 16 mL of samples including 3.5 g of sodium chloride to SPME fiber (100 mu m PDMS) at 40 degrees C during 20 min of incubation. The repeatability of 1 ppb VOCs standard solution was below 10%, except for 1,2-dichloroethane (13%), and their detection limits ranged from 0.02 nM for dichloromethane to 0.30 nM for benzene. The recoveries of 22 VOCs, except for dichloromethane, ranged from 80 to 120% under the condition where 32 mu L of 0.5 ppm VOC standard solution and 5 ppm fluorobenzene as an internal standard was added to 16 mL of atmospheric water samples. The application of the HS SPME/GC/MS method to the determination of VOCs in rainwater and dew water, which was collected in the western part of Tokyo, Hino, revealed that 6 chlorinated hydrocarbons (CHs) and five monocyclic hydrocarbons (MAHs) were detected, and the concentrations of MAHs were higher than those of CHs. Toluene was the dominant VOCs both in rainwater and dew water in Hino, and the volume-weighted concentrations of toluene in rainwater and dew water were 3.31 nM (n = 39) and 5.21 nM (n = 38), respectively. The results of this study made clear that the observed concentrations of VOCs in rainwater and dew water were considerably higher than the estimated concentrations, which were based on Henry&＃39;s law equilibrium. DOI CiNii Scopus 4 Citation (Scopus) Long-Term Performance of a Solar-Powered Small Automatic Rainwater Collector and Its Application to Acid Deposition Monitoring in the Southeast Mountainside of Mt. Fuji Shohei Maruyama, Hiroshi Okochi, Naoki Takemura, Yukiya Minami BUNSEKI KAGAKU   59 ( 5 ) 357 - 362  2010.05  [Refereed] 　View Summary The performance of a solar-powered small automatic rainwater collector was investigated, which was developed with an emphasis on small-size, lightweight, and inexpensive for use in a wet deposition monitoring network in a mountainous area. It was studied at Tarobo, which is located at the southeast mountainside (1300 m a.s.l.) on Mt. Fuji, during four years from July 2005 to September 2009. The rainfall amounts estimated by the automatic rainwater collector corresponded to those observed by a rain gauge verified by Japan Meteorological Agency. A comparison of the rainwater chemistry by the automatic rainwater collector with that by a commercially available wet-only sampler indicates that the automatic rainwater collector is available for use in wet deposition monitoring in mountainous areas. The mean annual wet deposition fluxes of H(+), NH(4)(+), NO(3)(-), and SO(4)(2-) at Tarobo were 48.9, 35.0, 38.0 and 69.4 meq/m(2)/y during three years from 2006 to 2008, respectively, and were higher than those at remote sites in Japan, particularly NO(3)(-) deposition. The concentration of acidic substances at Tarobo was nearly equal to those at remote sites in Japan, so it is expected for Tarobo to be in use for a remote site of an acid-deposition monitoring network in Japan because of easy access to Tarobo. DOI CiNii Scopus 1 Citation (Scopus) Atmospheric deposition (3) Cloud water and fog deposition 大河内 博, 堅田 元喜 Journal of Japan Society for Atmospheric Environment   45 ( 1 ) A1 - A12  2010 DOI CiNii Development of low volume air sampling and rapid sample preparation for the determination of atmospheric gas-phase polycyclic aromatic hydrocarbons using styrene-divinylbenzene copolymer resin adsorbent Aya Kobayashi, Yuki Kojima, Hiroshi Okochi, Toshio Nagoya Bunseki Kagaku   59 ( 8 ) 645 - 652  2010  [Refereed] 　View Summary A new sampling system of gas- and particle-phase polycyclic aromatic hydrocarbons (PAHs) in ambient air is proposed. The system is composed of a commercially available multi-nozzle cascade impact sampler for collecting particles less than 10 μm and a newlydesigned glass cartridge (35 mm inner diameter) packed with 5.0 g of a styrene-divinylbenzene copolymer resin adsorbent (XAD-2) for collecting gas-phase PAHs at a flow rate of 20 L/min. A rapid sample preparation for the analysis of PAHs in XAD-2 resin by ultrasonic extraction was also studied. The recovery rates of selected PAHs, i.e. phenanthrene (PHEN), antrathene (ANT), fluorantene (FL), pyrene (PY), benzo[a]pyrene (BaP), benzo[k]fluoranthene (BkF), benzo[ghi]perylene (BghiP), and indeno[1,2,3-cd]pyrene (IP) after the pretreatment ranged from 80 to 100%. More than 95% of the PAHs were extracted from XAD-2 by ultrasonication twice for 20 min with dichloromethane. The newlydeveloped cartridge had more than 95% collection efficiencies of the gasphase PAHs (PHEN, ANT, FL and PY) in both the summer and winter seasons. Storage at -30°C for 4 weeks did not have an adverse effect on the gas-phase PAHs collected with the cartridge. The application of the new sampling system to a field observation at a tower with a height of 12 m in a small forest at Field Museum Tama Hills revealed that the concentrations of the gas-phase PAHs at the lower level of the tower were lower than those at the upper level of the tower. However, there were no changes in the concentrations of the particle-phase PAHs between at the upper and lower levels. These results suggested that the forest filter effects for the gas-phase PAHs might be higher than those for the particle-phase PAHs. © 2010 The Japan Society for Analytical Chemistry. DOI Scopus 3 Citation (Scopus) Changes in concentration levels of polycyclic aromatic compounds associated with airborne particulate matter in downtown tokyo after introducing government diesel vehicle controls Yuki Kojima, Koji Inazu, Yoshiharu Hisamatsu, Hiroshi Okochi, Toshihide Baba, Toshio Nagoya Asian Journal of Atmospheric Environment   4 ( 1 ) 1 - 8  2010  [Refereed] 　View Summary The effectiveness of the government regulation on tail-pipe emission for diesel vehicles issued in 2003 in Tokyo was evaluated in this study. Variations in annual average concentrations of polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs associated with airborne particulate matter were investigated in connection with the variation in airborne elemental carbon (EC) concentration in downtown Tokyo, Japan in 2006-2007 and in 1997-1998. The annual average concentrations of EC, seven different PAHs, and 1-nitropyrene were found to have decreased significantly from 1997-1998 to 2006-2007. The most prominent decrease in atmospheric concentration was observed for 1-nitropyrene, which is a representative nitro-PAH originating from diesel vehicles. This indicated that the government control has worked to considerably reduce both atmospheric mutagens and airborne particulate matter. In contrast, the concentrations of two nitro-PAHs, 2-nitrofluoranthene and 2-nitropyrene, remained the same. These nitro-PAHs are known to be formed by atmospheric nitration of their parent PAHs, and this result suggested factors other than the concentration of parent PAHs and NO2 affects the degree of atmospheric formation of nitro-PAHs. DOI Scopus 13 Citation (Scopus) Observation of forest filter effect on particle-bound polycyclic aromatic hydrocarbons using differences in ambient ground-level concentration between the outside and inside of a forest K. Maeshima, H. Okochi, K. Inazu, Y. Hisamatsu, H. Hara Journal of Japan Society for Atmospheric Environment   45 ( 1 ) 43 - 48  2010  [Refereed] DOI CiNii Canopy buffering capacity of Sugi and Konara and leaching process of inorganic nitrogen from the ecosystem in a small forest ecosystem in the Tokyo metropolitan area 関 圭祐, 大河内 博, 原 宏 Journal of Japan Society for Atmospheric Environment   45 ( 1 ) 32 - 42  2010  [Refereed] DOI CiNii COMPARISON OF PAHS, NITRO-PAHS AND OXY-PAHS ASSOCIATED WITH AIRBORNE PARTICULATE MATTER AT ROADSIDE AND URBAN BACKGROUND SITES IN DOWNTOWN TOKYO, JAPAN Yuki Kojima, Koji Inazu, Yoshiharu Hisamatsu, Hiroshi Okochi, Toshihide Baba, Toshio Nagoya POLYCYCLIC AROMATIC COMPOUNDS   30 ( 5 ) 321 - 333  2010  [Refereed] 　View Summary Atmospheric polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs and oxy-PAHs are emitted from primary sources. Some nitro-PAHs and oxy-PAHs can also arise from secondary formation in the atmosphere. To assess the relative importance of these sources, the polycyclic aromatic compound (PAC) concentrations were determined at a roadside (Roadside site) and on a rooftop (Urban Background site) in downtown Tokyo Japan. The concentrations of PAHs, 1-nitropyrene and oxy-PAHs at the Roadside site were higher than those at the Urban Background site, while 2-nitrofluoranthene levels were the same at both sites. However, the mean ratios of concentrations at the Urban Background site to the Roadside site were in the order 1,8-naphthalic anhydride9,10-anthraquinonePAHs or 1-nitropyrene or acenaphthenequinone or benzanthrone. This suggests that in addition to vehicle emissions, a considerable fraction of some of the oxy-PAHs studied originates from another source, which might be secondary formation by atmospheric PAH degradation, and this contribution varied among the oxy-PAHs. DOI Scopus 18 Citation (Scopus) Acid fog deposition on canopy and forest decline Igawa Manabu, Matsumoto Kiyoshi, Okochi Hiroshi Science reports of Research Institute for Engineering Kanagawa University.   ( 32 ) 67 - 76  2009.11 CiNii Observation of Atmospheric Chemistry and Effects of Acid Deposition on Forest Ecosystem in Mt. Oyama, Tanzawa Mountains IGAWA Manabu, OKOCHI Hiroshi Earozoru Kenkyu   24 ( 2 ) 97 - 104  2009 　View Summary On the mountain side of Mt. Oyama, fog is frequently formed and pH of fogwater is low due to nitric acid formed from NOx. Recently, the concentration of fog components has increased because of a decrease in liquid water content (LWC) , which may be caused by a decrease of SPM as the condensation nuclei. The concentration of fog components becomes high when LWC is low, and acid fog events with fog water pH lower than 3.5 occur for about 20 % of fog duration at the mountainside (680 m a.s.l.) every year. It has been observed that the throughfall amount increased with an increase in altitude, although the precipitation amount does not depend on the altitude. It is caused by the fog deposition, which may be dominated by the fog formation frequency and the deposition rate of fog droplets depending on the wind velocity. The deposition of air pollutants on the canopies is caused by many path ways, rain, fog, gas, and aerosol. Deposited hydrogen ion is exchanged with metal ions in the leaves, and the application of simulated acid fog to the seedlings of fir, cedar, and beech in an experimental chamber showed that the amount of base cations leaching from leaves increased with decreasing pH of the applied acid fog solutions. Fir and beech seedlings were severely damaged by the long term application of simulated acid fog. Acid depositions on the surface soil is large in Mt. Oyama, and the soil has been acidified for recent years. DOI CiNii Effect of atmospheric humic-like substances on the enhanced dissolution of volatile organic compounds into dew water H. Okochi, E. Sato, Y. Matsubayashi, M. Igawa ATMOSPHERIC RESEARCH   87 ( 3-4 ) 213 - 223  2008.03  [Refereed] 　View Summary Simultaneous sampling of chlorinated hydrocarbons (CHs) and monocyclic aromatic hydrocarbons (MAHs), potentially harmful to humans and/or responsible for the formation of ozone and secondary particles, in dew water and in the ambient air was carried out from August 2004 to July 2005 in Hino City, situated in the western part of Greater Tokyo, Japan. CHs were less contained in dew water than MAHs. Toluene (volume-weighted mean concentration, VWM: 4.77 nM) and m,p-Xylenes (VWM: 5.07 nM) except dichloromethane, which was abnormally high (VWM: 1.14 mu M), were abundant among eleven VOCs determined in dew water. Chloroform, carbon tetrachloride, 1,2-dichloroethane, and benzene were not detected in dew water during the study period. Dew water contained higher amounts of VOCs than would have been expected from the ambient gas-phase concentrations and the temperature-corrected Henry&＃39;s law constants. Following the determination method of humic substances in river water proposed by Hiraide et al. [Hiraide, M., Shima, T., Kawaguchi, H., 1994. Separation and determination of dissolved and particulate humic substances in river water. Mikrochim. Acta 113, 269-276], the VWM of soluble humic and fulvic acid fractions in dew water was found to be 1.00 mg/L and 0.87 mg/L (n = 20), respectively, while the VWM of particulate humic and fulvic acid fractions was found to be 0.61 mg/L and 0.42 mg/L (n=20), respectively. Surface tension decreased with an increase in dissolved fulvic acid fraction in dew water, indicating that humic-like substances with relatively lower molecular weight, which is soluble in acid solution, could be an effective surface-active species within dew water. The enrichment factors, which were defined as the ratio of the observed VOCs concentration to the estimated, were over 10(2) for MAHs except for benzene and increased as the increment of total humic-like substances (HULIS) concentration (the sum of humic and fulvic acid fractions in both dissolved and particulate form) normalized by total inorganic ion concentration in dew water. Our results indicate that total HULIS in dew water could enhance the dissolution of atmospheric VOCs into dew droplets. (c) 2007 Elsevier B.V. All rights reserved. DOI ATMOSPHERIC OCCURRENCE OF 2-NITROBENZANTHRONE ASSOCIATED WITH AIRBORNE PARTICLES IN CENTRAL TOKYO Koji Inazu, Vu Duc Nam, Takahiro Asato, Hiroshi Okochi, Yoshiharu Hisamatsu, Takaaki Kobayashi, Toshihide Baba POLYCYCLIC AROMATIC COMPOUNDS   28 ( 4-5 ) 562 - 577  2008  [Refereed] 　View Summary 2- and 3-Nitrobenzanthrones (NBAs) in airborne particles collected in central Tokyo on a seasonal basis from 1996 to 2001 are quantified and possible sources are investigated. The concentrations of 2- and 3-NBA are found to range from 49 to 831 fmol m-3and 0.5 to 3.5 fmol m-3, while the nitrated polycyclic hydrocarbons 1-nitropyrene and 2-nitrofluoranthene are found at concentrations of 100-492 fmol m-3 and 10-97 fmol m-3. Significant linear correlations are identified between 2-NBA and NO2, a photochemical product, suggesting that 2-NBA is formed by atmospheric reactions of benzanthrone initiated by hydroxyl or nitrate radicals in the presence of NO2. 2-NBA is not correlated with directly emitted compounds such as 1-nitropyrene. The concentration ratio of 2-NBA to 1-nitropyrene is 5 or greater in all samples. Nitrated polycyclic aromatic compounds formed by atmospheric reactions therefore appear to represent a substantial contribution to the mutagenicity of airborne particulate matter. DOI Scopus 5 Citation (Scopus) Development of Solar-Powered Rainwater Collector and Observation of Wet Deposition Fluxes on the Mountainside of Mt. Fuji(The First Papers of Prospective Analytical Chemists) FUNAKURA Takahiro, OKOCHI Hiroshi, NAGOYA Toshio, INAZU Koji, MINAMI Yukiya, IGARASHI Yasuhito BUNSEKI KAGAKU   56 ( 9 ) 805 - 811  2007.09  [Refereed] 　View Summary The wet deposition fluxes of acidic substances were observed on the mountainside (1300 m a.s.l.) of Mt. Fuji from July 2005 to November 2006 by a solar-powered automatic rainwater collector, which was developed with emphasis on its being small-size, lightweight, and inexpensive for use in wet deposition monitoring network in mountainous area. The collector is divided into two parts, namely rainwater collection and solar battery system. The former is composed of a capacitance-type rain sensor, an originally designed automatic switching cover, a polycarbonate filter holder (80 mm in diameter), which is equipped with a 47 mm diameter and 1.2 μm pore size membrane filter, a polyethylene bottle, and a polypropylene tube connecting the holder and the bottle. The latter is composed of a 20 watt solar panel, a solar charge controller, and a 12 V lead acid battery. A comparison of the deposition fluxes, estimated by the automatic rainwater collector with those by a filtering-type rainwater collector, indicated that they were free of the influence of dry deposition without a loss of rainfall in the automatic rainwater collector. Rainfall amounts estimated by the automatic rainwater collector corresponded to those observed by a commercially available rain gauge except for winter. Annual wet deposition fluxes of H+, NO3−, and SO42− in the mountainside on Mt. Fuji were 58.5, 40.4, and 78.8 meq/m2/y, respectively.
DOI CiNii Scopus 4 Citation (Scopus) Preliminary study on evaluation of effects of acid deposition on forested ecosystem in east Tanzawa mountains estimated from chemical characteristics of stream waters Taku Honda, Hiroshi Okochi, Koji Inadzu, Manabu Igawa BUNSEKI KAGAKU   56 ( 9 ) 791 - 798  2007.09  [Refereed] 　View Summary It has been reported that the nitrate concentration in stream water in the mountainside on Mt. Oyama (1252 m a.s.l), which is located at the western part of Kanagawa Prefecture, is higher than that in stream water in other regions, indicating that nitrogen saturation is occurring in the forested ecosystem. However, there has been no report on nitrogen saturation across the Tanzawa mountains, except Mt. Oyama. We investigated the current status of the stream water chemistry and the effect of acid deposition on the stream water chemistry across the East Tanzawa mountains. Thirty-eight samples were collected in nine mountain streams in this region. The mean pH and alkalinity in stream water in this region were 7.315 and 650 mu eq/L, respectively. There was no symptom of stream-water acidification by acid deposition in East Tanzawa, probably because of the high acid buffering capacity by the weathering of carbonate and silicate minerals. Nitrate concentrations in the stream water ranged from 27.6 to 87.8 peq/L and NH4+ was detected. High nitrate concentration in stream water suggests that nitrogen saturation is occurring in the forested ecosystem in East Tanzawa mountains. We divided our sampling sites into southeast (SE), southwest (SW), and north (N) regions by the ridge line of Mt. Tanzawa - Mt. Tonodake - Shindainichi - Mt. Sannoto - Mt. Takenodai - Mt. Oyama - Mt. Mitsumine. The stream water pH was lower and the concentrations of Na+ and NO3 were higher in south regions. There were high correlations between the concentrations of Na+ (r = - 0.854), Cl- (r = - 0.815) and NO3- (r = - 0.922) and the distance from the coast of Odawara City, Oisomachi, and Ninomiyamachi. In addition, a high correlation between the N03 and Cl concentrations (r = 0.741), which is an indicator of atmospheric deposition, in stream water was observed. Our preliminary investigation indicates that the runoff of nitrate, originated from atmospheric deposition, might occur in the forested ecosystem in the southern regions in East Tanzawa. DOI CiNii Scopus 1 Citation (Scopus) Development of solar-powered rainwater collector and observation of wet deposition fluxes on the mountainside of Mt. Fuji Takahiro Funakura, Hiroshi Okochi, Toshio Nagoya, Koji Inazu, Yukiya Minami, Yasuhito Igarashi BUNSEKI KAGAKU   56 ( 9 ) 805 - 811  2007.09  [Refereed] 　View Summary The wet deposition fluxes of acidic substances were observed on the mountainside (1300 m a.s.l.) of Mt. Fuji from July 2005 to November 2006 by a solar-powered automatic rainwater collector, which was developed with emphasis on its being small-size, lightweight, and inexpensive for use in wet deposition monitoring network in mountainous area. The collector is divided into two parts, namely rainwater collection and solar battery system. The former is composed of a capacitance-type rain sensor, an originally designed automatic switching cover, a polycarbonate filter holder (80 mm in diameter), which is equipped with a 47 mm diameter and 1.2 pm pore size membrane filter, a polyethylene bottle, and a polypropylene tube connecting the holder and the bottle. The latter is composed of a 20 watt solar panel, a solar charge controller, and a 12 V lead acid battery. A comparison of the deposition fluxes, estimated by the automatic rainwater collector with those by a filtering-type rainwater collector, indicated that they were free of the influence of dry deposition without a loss of rainfall in the automatic rainwater collector. Rainfall amounts estimated by the automatic rainwater collector corresponded to those observed by a commercially available rain gauge except for winter. Annual wet deposition fluxes of H+, NO3-, and SO42- in the mountainside on Mt. Fuji were 58.5, 40.4, and 78.8 meq/m(2)/y, respectively. DOI Scopus 4 Citation (Scopus) Erratum to "Adsorption of air pollutants on the grain surface of Japanese cedar pollen". [Atmospheric Environment 41 (2007) 253-260] (DOI:10.1016/j.atmosenv.2006.08.009) Yuji Okuyama, Kiyoshi Matsumoto, Hiroshi Okochi, Manabu Igawa Atmospheric Environment   41 ( 18 ) 3939 - 3940  2007.06  [Refereed] DOI Scopus 1 Citation (Scopus) Adsorption of air pollutants on the grain surface of Japanese cedar pollen (vol 41, pg 253, 2007) Yuji Okuyama, Kiyoshi Matsumoto, Hiroshi Okochi, Manabu Igawa ATMOSPHERIC ENVIRONMENT   41 ( 18 ) 3939 - 3940  2007.06  [Refereed] DOI Scopus 1 Citation (Scopus) Preliminary study on evaluation of effects of acid deposition on forested ecosystem in East Tanzawa Mountains estimated from chemical characteristics of stream waters Taku Honda, Hiroshi Okochi, Koji Inadzu, Manabu Igawa Bunseki Kagaku   56 ( 9 ) 791 - 798  2007  [Refereed] 　View Summary It has been reported that the nitrate concentration in stream water in the mountainside on Mt. Oyama (1252 m a.s.l), which is located at the western part of Kanagawa Prefecture, is higher than that in stream water in other regions, indicating that nitrogen saturation is occurring in the forested ecosystem. However, there has been no report on nitrogen saturation across the Tanzawa mountains, except Mt. Oyama. We investigated the current status of the stream water chemistry and the effect of acid deposition on the stream water chemistry across the East Tanzawa mountains. Thirty-eight samples were collected in nine mountain streams in this region. The mean pH and alkalinity in stream water in this region were 7.315 and 650 μeq/L, respectively. There was no symptom of stream-water acidification by acid deposition in East Tanzawa, probably because of the high acid buffering capacity by the weathering of carbonate and silicate minerals. Nitrate concentrations in the stream water ranged from 27.6 to 87.8 μeq/L and NH4+ was detected. High nitrate concentration in stream water suggests that nitrogen saturation is occurring in the forested ecosystem in East Tanzawa mountains. We divided our sampling sites into southeast (SE), southwest (SW), and north (N) regions by the ridge line of Mt. Tanzawa-Mt. Tonodake-Shindainichi-Mt. Sannoto-Mt. Takenodai-Mt. Oyama-Mt. Mitsumine. The stream water pH was lower and the concentrations of Na+ and NO3- were higher in south regions. There were high correlations between the concentrations of Na3+ (r = -0.854), Cl- (r = -0.815) and NO3- (r = -0.922) and the distance from the coast of Odawara City, Oisomachi, and Ninomiyamachi. In addition, a high correlation between the NO3- and Cl- concentrations (r = 0.741), which is an indicator of atmospheric deposition, in stream water was observed. Our preliminary investigation indicates that the runoff of nitrate, originated from atmospheric deposition, might occur in the forested ecosystem in the southern regions in East Tanzawa. © 2007 The Japan Society for Analytical Chemistry. DOI Scopus 1 Citation (Scopus) Adsorption of air pollutants on the grain surface of Japanese cedar pollen Yuji Okuyama, Kiyoshi Matsumoto, Hiroshi Okochi, Manabu Igawa ATMOSPHERIC ENVIRONMENT   41 ( 2 ) 253 - 260  2007.01  [Refereed] 　View Summary The contaminants adsorbed on the surface of pollen may affect the development of hay fever, because the patients of the fever are larger in areas with much air pollution than in nonpolluted areas and the fine particles and gases are susceptible to deposit on the nasal cavities and eyes by their transfer on the pollen. Since Japanese cedar pollinosis is the most common hay fever in Japan, we analyzed the air pollutants adsorbed on the surface of dispersed Japanese cedar pollen in the urban and mountainous districts. Fine anthropogenic particles were significantly adsorbed and many elements were concentrated on the surface of the pollen in the urban site of Yokohama, while they were not concentrated on the surface of the pollen collected at a mountainous site. The acid gases are also adsorbed and acidify the surface, and their amounts increase with their concentrations in the ambient air. The high adsorption of nitric acid on the pollen determined by an exposure experiment of nitric acid gas suggests that nitric acid is dissolved in the inner part of the pollen. The adsorption amounts of the gases on the pollen were especially greater than those on other natural particles, humic acid and yellow sand. (c) 2006 Elsevier Ltd. All rights reserved. DOI Scopus 50 Citation (Scopus) Scavenging effect of precipitation on volatile organic compounds in ambient atmosphere Emi Sato, Kiyoshi Matsumoto, Hiroshi Okochi, Manabu Igawa BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN   79 ( 8 ) 1231 - 1233  2006.08  [Refereed] 　View Summary Hydrophobic volatile organic compounds (VOCs) are usually found in rainwater with higher concentrations than the values determined from Henry&＃39;s law partitioning. Laboratory experiments demonstrated that dissolved organic compounds, such as humic acids, act as cosolvents to solubilize the VOCs. Wet removal by rainfall is a significant sink of trace VOCs. DOI Scopus 16 Citation (Scopus) Enhanced dissolution of volatile organic compounds into urban dew water collected in Yokohama, Japan H Okochi, M Kataniwa, D Sugimoto, M Igawa ATMOSPHERIC ENVIRONMENT   39 ( 33 ) 6027 - 6036  2005.10  [Refereed] 　View Summary Simultaneous sampling of six chlorinated hydrocarbons (CHs) and five monocyclic aromatic hydrocarbons (MAHs) in dew water and in the ambient air was performed from 1998 to 2000 in Yokohama, Japan. Dichloromethane (volume-weighted mean concentration (VWM): 2.43 nM) and trichloroethylene (VWM: 2.91 nM) were abundant among CHs in dew water, while toluene (VWM: 9.69 nM) and p-dichlorobenzene (VWM: 6.06 nM) were abundant among MAHs. The contribution of total measured volatile organic compounds (VOCs) concentration to dissolved organic carbon (DOC) concentration in dew water was only 0.02 wt% on average. The concentrations of VOCs except for dichloromethane and benzene in dew water were several hundred times higher than those in rainwater collected at the same site. In particular more hydrophobic VOCs with higher octanol-water partition coefficient K-OW tended to be concentrated in dew water, indicating that urban dew water has stronger hydrophobicity than rainwater. Dew water contained higher amounts of VOCs than would have been expected from the ambient gas-phase concentrations and Henry&＃39;s law constants. The enrichment factors, which were defined as the ratio of the observed concentration to the estimated, ranged from 6.98 (for dichloromethane) to 62.7 (for trichloroethylene) on average. Relatively high correlations (r > 0.55) between the enrichment factors of highly hydrophobic VOCs (K-ow> 10(3)) and the ratios of DOC to total inorganic ion concentration (TIC), which could be a potential surrogate of surface tension for urban dew water, indicated that the existence of any dissolved organic compounds, which could reduce the surface tension, in dew water also caused the enrichment of highly hydrophobic VOCs. (c) 200S Elsevier Ltd. All rights reserved. DOI Scopus 23 Citation (Scopus) An influence of PAHs, gaseous pollutants, and meteorological conditions on the mutagenic activity of soluble organic fraction of airborne particles collected in central Tokyo K. Inazu, T. Saito, V. D. Nam, H. Okochi, T. Kameda, T. Asato, Y. Hisamatsu, K. Aika, T. Baba Organohalogen Compounds   76   2668  2005  [Refereed] H. Okochi, M. Kataniwa, D. Sugimoto, M. Igawa Enhanced dissolution of volatile organic compounds into urban dew, water collected in, Yokohama, Japan Atmos. Environ   39   6027 - 6036  2005  [Refereed] 廃磁気テープを原料とした高機能活性炭の作製条件の検討 志摩 孝俊, 大河内 博, 野々村 誠 東京都立科学技術大学紀要   18   63 - 68  2004.11 CiNii Characteristics of water-soluble components of atmospheric aerosols in Yokohama and Mt. Oyama, Japan from 1990 to 2001 M Takeuchi, H Okochi, M Igawa ATMOSPHERIC ENVIRONMENT   38 ( 28 ) 4701 - 4708  2004.09  [Refereed] 　View Summary We continuously collected aerosol samples of PM7 from 1990 to 1997 and of PM10-2 and PM2 from 1998 to 2001 and measured their water-soluble components of pH, conductivity, major ions, dissolved organic carbon (DOC) and total mass (TM) in an urban site, Yokohama (35degrees28&＃39;N, 139degrees38&＃39;E) and the mountainside (680 m asl) of Mt. Oyama (35degrees28&＃39;N, 139degrees46&＃39;E, 1252 m asl), Japan, to contrast the aerosol composition between an urban site and a mountain site. In Yokohama, annual mean TM concentration decreased gradually for over 10 years with the decrease of NH4+, Mg2+, Cl-, and SO42- concentrations, and TM concentrations were the highest in winter and the lowest in summer. At Mt. Oyama, there was no significant change in the duration, and TM concentrations were the highest from late spring to early summer, although the seasonal variation was smaller. Equivalent concentration ratio of Cl- to Na+ at Mt. Oyama was lower than that in Yokohama, because Cl loss which occurred was larger for the aerosol collected at Mt. Oyama remote from the sea rather than Yokohama. The conversion ratio of sulfur to sulfate was calculated and the ratio was not affected strongly by the variation of O-x concentration at both sites and was high at Mt. Oyama in summer. NH4+, NO3-, SO42-, and DOC concentrations were higher under weak wind velocity than those under strong wind velocity regardless of the wind direction in both the sites. (C) 2004 Elsevier Ltd. All rights reserved. DOI Scopus 36 Citation (Scopus) The enhanced dissolution of some chlorinated hydrocarbons and monocyclic aromatic hydrocarbons in rainwater collected in Yokohama, Japan H Okochi, D Sugimoto, M Igawa ATMOSPHERIC ENVIRONMENT   38 ( 26 ) 4403 - 4414  2004.08  [Refereed] 　View Summary By simultaneous sequential sampling of gas and rainwater from 1999 to 2000 in the campus of Kanagawa University in Yokohama, Japan, we investigated the wet-scavenging process of volatile organic compounds, some chlorinated hydrocarbons (CHs) and monocyclic aromatic hydrocarbons (MAHs), via rain droplets. Their volume-weighted mean concentrations in 125 rainwater were 4.98 nM for dichloromethane, 3.71 nM for toluene, 2.00 nM for benzene, 0.93 nM for 1,2-dichloroethane, 0.62 nM for o-xylene, 0.57 nM for m,p-xylene, 0.51 nM for p-dichloro benzene, and 0.35 nM for trichloromethylene. Their rainwater concentrations did not depend on the rainfall intensity, and the temporal variation of their concentrations was similar to that of gas-phase concentrations. The dissolution of CHs and MAHs into rainwater, however, was larger than expected from their gas-phase concentrations at the ground and their temperature-corrected Henry&＃39;s law constants. A simple below-cloud scavenging model, which was developed by Levine and Schwartz (Atmos. Environ. 16 (1982) 1725) Could explain the independence of the rainfall intensity but not explain their enhanced dissolution in rainwater. The results of this study indicate the estimated concentrations, which were based on the Henry&＃39;s law equilibrium, considerably underestimate the wet-deposition fluxes of CHs and MAHs onto the ground. (C) 2004 Elsevier Ltd. All rights reserved. DOI Scopus 22 Citation (Scopus) Deposition of coarse soil particles and ambient gaseous components dominating dew water chemistry M Takeuchi, H Okochi, M Igawa JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES   108 ( D10 ) 4319 - 4323  2003.05  [Refereed] 　View Summary Dew water characteristics are not as acidic as those of rainwater and fog water, and they are abundant in weak acid components. The dew water components are dominated by the coarse-mode aerosol rather than the fine-mode aerosol, and calcium carbonate, the component of soil, is the important chemical species raising the pH of the dew water. Carbon dioxide is deposited as calcium carbonate into dew water and is the only major component released from dew water. The total concentration of carbon dioxide increased with an increase in the dew water pH, while the degassing rate increased with the decrease in dew water pH. In the low-pH region, the pepsilon values in dew water are lower than those in rainwater, and the dew water is in a reductive state. The concentration of the representative oxidant, hydrogen peroxide, was much lower in the dew water than in the rainwater in Yokohama (dew water, 0.4 muM; rainwater, 13.1 muM in 1998). The representative conjugate base ions of a weak acid, sulfite and hydrogen sulfite ions, are easily oxidized by hydrogen peroxide, and the lower concentration of hydrogen peroxide in dew water may cause the higher concentration of sulfite ion in dew water than in rainwater. The dew water pH is higher than the rainwater and fog water pH, and a weak acid is easily dissolved into the dew water. Therefore these weak acid ions are more abundant in dew water than in rainwater and fog water. DOI Transport characteristics of neutralization dialysis and desalination of tap water M Igawa, K Mikami, H Okochi BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN   76 ( 2 ) 437 - 441  2003.02  [Refereed] 　View Summary In neutralization dialysis, the salt solution is desalinated continuously. The cations in desalination compartment are exchanged with protons in the acid compartment across a cation-exchange membrane and the anions are exchanged with hydroxide ions in the base compartment across an anion-exchange membrane. A simple index (C/J), where C is the source phase concentration (mol cm(-3)) and J is the flux (mol cm(-2) min(-1)), was proposed for the estimation of the desalination properties in neutralization dialysis. The index was based on the concepts of the ion-exchange reaction rate at the membrane interface and was related to the permeation constant in the source-phase boundary layer at the membrane interface, P-a (cm min(-1)), as C/J = 1/(k(1).C-ex) + 1/P-a, where k(1) is the rate constant of ion-exchange reaction (mol(-1) cm(4) min(-1)) and C-ex is the ion exchange capacity of the membrane (mol cm(-3)). The desalination efficiency increased with the decrease of the desalination compartment thickness and the decrease of the linear velocity, which can be estimated well by using the index. Tap water was desalinated by neutralization dialysis and pure water was obtained at the outlet of the desalination cell. DOI Scopus 8 Citation (Scopus) Eco-friendly Lubricating Oil : Effects of Functional Groups in Methyl Oleate and Olive Oil on Lubrication MOCHIDA Yoshiyuki, KUDOU Kunio, OOKOUCHI Hiroshi, ARAI Gorou, NAKAMURA Shigeo J. Mass Spectrom. Soc. Jpn.   51 ( 1 ) 179 - 186  2003.02  [Refereed] 　View Summary The lubrication characteristics of the olive oils, which are used as biodegradable lubricants, on the steel ball were examined on the viewpoint of their growing area and quality of the olive oil. The discoloration of virgin olive oil and the friction face and/or the friction force of the steel ball were found to be dependent on their growing area as well as pure olive oil.<br>&nbsp;&nbsp;Property of the constituent metal constituents of steel ball on the air oxidation of methyl ester of oleic acid, which is major constituent fatty acid of olive oil and the lubrication characteristics of the resulting oxidation products, were investigated. The autoxidation of methyl oleate under the existence of each acetylacetonatos of Cr, Mn, Fe, Ni, Cu, and V was carried out by blowing dry air at 80&deg;C. All the metal salts except V facilitated the oxidation. The metals employed affect the yields and the types of the products, <i>i.e.,</i> hydroperoxide, hydroxide and epoxide whom the functional group exists for the center location of molecular chain.<br>&nbsp;&nbsp;Friction test for ball bearing was conducted by using each oxidation product and parent methyl oleate. The surface of the steel ball was the abrasive wear condition by hydroperoxide. The hydroxide gave excellent lubrication characteristics by hydroxy group adsorbed on the surface of steel ball. Epoxide increased the coefficient of friction. Methyl linoleate, having two double bonds, provided the flatted frictional surface at the ball bearing, but it is easy to be oxidized.<br>&nbsp;&nbsp;To sum up the major characteristics of the autoxidation products which affect friction surface of steel ball, the function groups of center position in molecular chain of methyl oleate are of most significance. It was found that double bond and hydroxyl function of &alpha;-position of double bond are effective under the boundary lubrication. DOI CiNii Acid fog removes calcium and boron from fir tree: One of the possible causes of forest decline Manabu Igawa, Kensuke Okumura, Hiroshi Okochi, Naoki Sakurai Journal of Forest Research   7 ( 4 ) 213 - 215  2002.11  [Refereed] 　View Summary We have observed acid fog in Mt. Oyama adjacent to the Kanto Plains in Japan, where acid fog under pH 3 has been frequently observed and natural fir forest (Abies firma) has been declining. We applied the simulated acid fog to the needles of fir twigs and the treatment removed calcium, boron, and cell-wall acidic sugars from the needles. We also observed high contents of calcium, boron, and acidic sugars in throughfall collected under the declining forest canopy. Ca++ and Mg++ ion leach via ion-exchange with major cations of fog-water and the amount of leached boron increased with the increase in the concentration of leached Ca++. The deficiency of calcium and boron by leaching could be one of the main causes of decline of the fir forest. DOI Scopus 11 Citation (Scopus) Selective transport of heavy metal ions across a cation-exchange membrane with a chelating agent in the receiving phase M Igawa, Y Narita, H Okochi BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN   75 ( 10 ) 2269 - 2273  2002.10  [Refereed] 　View Summary Heavy metal ions can be selectively transported under the concentration gradient across a cation-exchange membrane with a chelating agent in the receiving phase. The selectivity depends on the complex formation constants of the ions with the agent. Metal ions are adsorbed into a cation-exchange membrane via the ion-exchange reaction and diffuse across the membrane. The desorption process is facilitated by the complexation in the receiving phase, which causes a large transport rate across the membrane. A transport equation was established and the theoretical values estimated by the equation and the permeation characteristics values obtained experimentally agreed well with the measured ion flux. The selectivity of the metal ions in the mixed solution is increased in the adequate concentration of the chelating agent in the receiving phase, when the chelate formation reaction may occur competitively between the ions with the agent in the receiving phase. The metal ions in the complex solution can be stripped as free ions across a cation-exchange membrane via the ion-exchange reaction with protons under a concentration gradient of acid. DOI Scopus 2 Citation (Scopus) Size distribution of dew droplets and dew formation effect on deposition fluxes M Takeuchi, T Hasegawa, H Okochi, M Igawa BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN   75 ( 6 ) 1299 - 1300  2002.06  [Refereed] 　View Summary Dew droplets have a distribution of sizes up to 1.5 mm diameter. Large-sized droplets controlled the dewwater amount and the number of small-sized droplets decreased during the evaporation process. The wetting by dew formation enhances the dry deposition of air pollutants. DOI Scopus 5 Citation (Scopus) Controlling factors of weak acid and base concentrations in urban dewwater - Comparison of dew chemistry with rain and fog chemistry M Takeuchi, H Okochi, M Igawa BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN   75 ( 4 ) 757 - 764  2002.04  [Refereed] 　View Summary Dewwater was collected from January 1993 to December 2000 in Yokohama, Japan, and analyzed for weak acid anions with other major chemical components. The volume-weighted average and medium pH of the dewwater were 4.88 and 6.08, respectively, at our sampling site. Weak acids (carbonate, nitrite, sulfite, formate, and acetate ions) were the major species in the dewwater and were several times higher than those in the rain- and fogwater. The concentrations of these species and ammonium ion can be estimated by the resistance model. The estimated values of N(III) correlate relatively well with the measured values, which shows the origin of N(III) in dewwater is nitrous acid in the ambient air. On the other hand, ammonium ion in the dewwater originated from not only gaseous ammonia but also aerosol ammonium ions. Hydrogensulfite ions in the dewwater which originated from sulfur dioxide are an important species as the precursor of the sulfate and they were stabilized by forming hydroxyalkanesulfonate (HASA). Formic acid and acetic acid in the dewwater originated mainly from gas, while the oxalic acid is from aerosol. DOI Scopus 21 Citation (Scopus) Potential trace metal-organic complexation in the atmosphere. Hiroshi Okochi, Peter Brimblecombe TheScientificWorldJournal   2   767 - 86  2002.03  [Refereed]  [International journal] 　View Summary It is possible that metal-organic complexation enhances the uptake of gaseous organic compounds and the solubility of metals in aerosols and atmospheric water. We investigated potential atmospheric organic ligands and the enhanced uptake of hydroxy-, oxo-, and dicarboxylic acids as well as dicarbonyls into atmospheric aqueous aerosol. We examined complexation with transition metals (iron, manganese, nickel, copper, zinc) and lead on the basis of available references and our experimental data. Humic-like substances are most likely ligands in the atmosphere, although this is a poorly characterized material. A number of polycarboxylic acids and hydroxy forms (e.g., citric and tartronic acids) effectively complex metals such as copper in atmospheric aerosols. The simple equilibrium model calculations show that the effect of the complexation on the gas-aqueous phase partition of gaseous atmospheric ligands is quite small for the ligands with the high physical Henry&＃39;s law constants, e.g., dicarboxylic acids represented by oxalic acid, even if they have high affinity with metal ions. The lower Henry&＃39;s law constants of the alpha-dicarbonyls, such as glyoxal and methylglyoxal, mean that the complexation could lead to profound increases in their partition into the aqueous phase. Despite quantum mechanical arguments for copper-glyoxal complexes, experiments showed no evidence of complexation between either hydrated or unhydrated alpha-dicarbonyls and the cupric ion. By contrast the beta-dicarbonyl, malondialdehyde, has properties that would allow it to partition into atmospheric water via the complexation with metal ions under some conditions. DOI PubMed Scopus 60 Citation (Scopus) High frequency and large deposition of acid fog on high elevation forest. Manabu Igawa, Ko Matsumura, Hiroshi Okochi Environmental science & technology   36 ( 1 ) 1 - 6  2002.01  [Refereed]  [International journal] 　View Summary We have collected and analyzed fogwater on the mountainside of Mt. Oyama (1252 m) in the Tanzawa Mountains of Japan and observed the fog event frequency from the base of the mountain with a video camera. The fog event frequency increased with elevation and was observed to be present 46% of the year at the summit. The water deposition via throughfall increased with elevation because of the increase in fogwater interception and was about twice that via rain at the summit, where the air pollutant deposition via throughfall was several times that via rainwater. The dry deposition and the deposition via fogwater were dominant factors in the total ion deposition at high elevation sites. In a fog event, nitric acid, the major acid component on the mountain, is formed during the transport of the air mass from the base of the mountain along the mountainside, where gases including nitric acid deposit and are scavenged by fogwater. Therefore, high acidity caused by nitric acid and relatively low ion strength are observed in the fogwater at high elevation sites. DOI PubMed Scopus 48 Citation (Scopus) Severe leaching of calcium ions from fir needles caused by acid fog. Manabu Igawa, Toshiyuki Kase, Kosuke Satake, Hiroshi Okochi Environmental pollution (Barking, Essex : 1987)   119 ( 3 ) 375 - 82  2002  [Refereed]  [International journal] 　View Summary We have measured the components of the throughfall under fir trees (Abies firma) in the field around Mt. Oyama, where the forest appears to be declining, for the period 1994-1998. Exposure experiments of a simulated acid fog to fir twigs were performed under field conditions. There was a similarity between the acid response in the field and that in the laboratory. In both studies, the severe leaching of calcium ions from the needle surface was caused by exposure to acid fog. We also applied acid fog to fir seedlings over 1 year and observed a decrease in the growth of the seedlings due to this application in the dormant season. These results suggest that the severe leaching of calcium ions due to acid fog may cause the deficiency of calcium and be responsible for the decline of the fir trees. DOI PubMed Scopus 22 Citation (Scopus) Dominant factors of major and minor components and formation of hydroxyalkanesulfonate in urban dew-water M Takeuchi, H Okochi, M Igawa WATER AIR AND SOIL POLLUTION   130 ( 1-4 ) 613 - 618  2001.08  [Refereed] 　View Summary Dew-water was collected from January 1999 to February 2000 in Yokohama, Japan and analyzed for not only soluble major components but also insoluble or trace components. The pH of dew-water ranged from 5.36 to 6.71 and volume-weighted average pH was 5.81. In dew-water, Si, Al, Fe, Cl, and Na were abundant and they were confirmed to be transported from natural sources, sea and soil dust. The concentrations of Si, Al, Fe, and Ti contained in coarse mode aerosol were several times higher in dew-water than those in rain-water, while the concentrations of V and Pb contained in fine mode aerosol were about the same level to each other. Besides these elements derived from aerosol, the elements derived from gaseous species are also major components in dew-water. The high concentration of weak acid is one of the significant characteristics of dew-water. Bisulfite ion in dew-water is the important species as the precursor of the sulfate ion but it is stable by forming hydroxyalkanesulfonate (HASA). The HASA concentrations were evaluated by using concentrations of total S(IV) and aldehydes and hydroxymethanesulfonate (HMSA) was shown to be the dominant species in S(IV). Fog water chemistry at Mt. Oyama and its dominant factors M Igawa, K Matsumura, H Okochi WATER AIR AND SOIL POLLUTION   130 ( 1-4 ) 607 - 612  2001.08  [Refereed] 　View Summary We have observed acid fog in Mt. Oyama since 1988. Fog events occur frequently in Mt. Oyama; 47% of the time the mountain top is covered with fog. The pH of fog is lower than that of rain collected at the fog sampling station by about 1 unit and the lowest pH was 1.95. We have also collected gas and aerosol components at the station and observed fog events by a video camera from the mountain base, where there is an air pollution monitoring station. The air quality at the fog sampling station was affected by not only the air quality at the base but also the wind direction, valley or mountain wind. It is ascertained by using back trajectory analyses that polluted air masses are transported to the base from the Kanto plains or other big urban areas, Osaka and Nagoya. When the base is polluted, the relative humidity increases, and the valley wind blows, acid fog is formed at the mountainside. In the acid fog, nitrate ion is the most abundant anion. Nitrate ion concentration correlates well with hydrogen ion concentration. The annual mean total ion concentration has not changed much since 1988, but the concentration ratio of nitrate ion to sulfate ion has increased in recent years. The nitric acid gas concentration in the station is comparable to that in urban areas, while other gas concentrations are much lower. DOI Scopus 26 Citation (Scopus) Elevational patterns of acid deposition into a forest and nitrogen saturation on Mt. Oyama, Japan. H Okochi, M Igawa WATER AIR AND SOIL POLLUTION   130 ( 1-4 ) 1091 - 1096  2001.08  [Refereed] 　View Summary Virgin fir trees have been dying on Mt. Oyama, which is located in the southwestern part of Kanto Plain, although the frequency of death seems to be reducing recently. We report elevational patterns of acid depositions in precipitation and throughfall under fir and cedar canopies and nitrogen saturation in the forest ecosystem on Mt. Oyama. The deposition fluxes of major inorganic ions in precipitation were nearly constant regardless of elevation except for hydrogen and ammonium ions, whereas the deposition fluxes of all major inorganic ions in throughfall among cedar increased. The 5-year average of annual nitrate deposition in precipitation from 1994 to 1998 showed 19.3 - 23.5 kg ha(-1) yr(-1) (annual inorganic total N deposition: 9.6 - 10.7 kgN ha(-1) yr(-1)) at four sites ranging in elevation from 500 to 1252 m, whereas the deposition in both cedar and fir throughfall was over 6 times greater than that inn precipitation. The average soil surface nitrate concentration in 1998 was 140 mug g(-1) (the range: 21.1 - 429 mug g(-1), n=80) and the 7-year average of nitrate concentration in stream water from 1992 to 1998 was 4.81 mg L-1 (the range: 2.38 - 20.6 mg L-1, n=317). Our results indicate that nitrogen saturation is occurring in the forest ecosystem because of high N deposition, probably via acid fog, on Mt. Oyama. DOI Scopus 20 Citation (Scopus) Dominant factors of major and minor components and formation of hydroxyalkanesulfonate in urban dew-water M. Takeuchi, H. Okochi, M. Igawa Water, Air, and Soil Pollution   130 ( 1-4 ) 613 - 618  2001  [Refereed] 　View Summary Dew-water was collected from January 1999 to February 2000 in Yokohama, Japan and analyzed for not only soluble major components but also insoluble or trace components. The pH of dew-water ranged from 5.36 to 6.71 and volume-weighted average pH was 5.81. In dew-water, Si, Al, Fe, Cl, and Na were abundant and they were confirmed to be transported from natural sources, sea and soil dust. The concentrations of Si, Al, Fe, and Ti contained in coarse mode aerosol were several times higher in dew-water than those in rain-water, while the concentrations of V and Pb contained in fine mode aerosol were about the same level to each other. Besides these elements derived from aerosol, the elements derived from gaseous species are also major components in dew-water. The high concentration of weak acid is one of the significant characteristics of dew-water. Bisulfite ion in dew-water is the important species as the precursor of the sulfate ion but it is stable by forming hydroxyalkanesulfonate (HASA). The HASA concentrations were evaluated by using concentrations of total S(IV) and aldehydes and hydroxymethanesulfonate (HMSA) was shown to be the dominant species in S(IV). DOI Scopus 12 Citation (Scopus) A Study on Chemical Components and Acidification Mechanism of Dew-Water TAKEUCHI Masaki, OKOCHI Hiroshi, IGAWA Manabu Journal of Japan Society for Atmospheric Environment   35 ( 3 ) 158 - 169  2000.05  [Refereed] 　View Summary Dew-water was collected from 1995 to 1998 in Yokohama, Japan and analyzed for various chemical components. The frequency of dew events in 1998 was 22% and is the highest during the winter season. Precipitation resulting from dew was 7.7 mm/year and corresponded to about 0.4% of that from rain (rain precipitation, 1901 mm) in Yokohama. The pH of dew-water ranged from 3.04 to 7.82 and the volumeweighted average pH was 5.08. Dew-water chemistry was characterized by a relatively high ion concentration compared to rain- and fog-water. The dew-water composition was strongly affected by aerosol and gaseous components, and therefore varied depending on the location where dew-water was collected. The dry deposition velocities of dew-water were estimated from the concentrations of dew-water components, gas and aerosol concentrations, dewfall, and the period between dew collector set up and dew collection by regression analysis. Dew-water was acidified primarily by nitric acid gas absorbed in dew-water. The deposition velocities of nitric acid gas and nitrate ion in aerosol were calculated to be 1.28 cm s^<-1> and 0.11 cm s^<-1>, respectively, and estimated values from the atmospheric concentrations of gas and aerosol corresponded well with the measured values. The nitrate ion concentration in acidic dew-water differed slighty from the estimated value which may have been the result of dinitrogen pentaoxide gas absorption by the dew-water. DOI CiNii Deterioration of concrete structures by acid deposition - an assessment of the role of rainwater on deterioration by laboratory and field exposure experiments using mortar specimens H Okochi, H Kameda, S Hasegawa, N Saito, K Kubota, M Igawa ATMOSPHERIC ENVIRONMENT   34 ( 18 ) 2937 - 2945  2000  [Refereed] 　View Summary Deterioration of concrete structures caused by acid deposition was investigated by laboratory and field exposure of portland cement mortar specimens to acid deposition. Laboratory exposure experiment showed that the dissolved amount of calcium hydrates, which were the major components in mortar, increased with the increase in the acidity of simulated acid rain solution and the decrease in the flow rate. There was little difference in their amount among different temperature treatments after each exposure to the solution with the same acidity, namely left at room temperature, heated at 70 degrees C, and cooled at - 2 degrees C. The neutralization progressed more deeply under the heated and cooled condition and was accelerated by even acid rain with pH 4.7 during a long period (90 exposure cycles, which correspond to the rainfall amount of 15 years in Japan). A field exposure experiment for two years indicated that the carbonation of calcium hydrates and the formation of other corrosion products such as chloride, nitrate, and sulfate were limited to the surface of mortar specimens. The neutralization progressed more deeply in mortar specimens sheltered from rainwater than in those washed by rainwater. (C) 2000 Elsevier Science Ltd. All rights reserved. DOI Scopus 72 Citation (Scopus) Determination of Volatile Organic Compounds in Rainwater and the Dominant Factors of their Concentrations. IGAWA Manabu, NAKADA Norihide, OKOCHI Hiroshi Journal of Japan Society of Air Pollution   34 ( 3 ) 211 - 218  1999.05  [Refereed] 　View Summary Volatile organic compounds in rainwater and in the atmosphere were determined in Yokohama, Japan by purge and trap or adsorption column 'methods and GC/MS. The average concentrations of dichloromethane, toluene, chloroform, and 1,2-dichloromethane in rainwater were 9.8,2.4,2.1,and 1.5 nmol/L. The contribution of rainwater to VOCs pollution in surface water can be significant. The relative standard deviations of VOCs were very high (140-730%) in rainwater. In contrast with the ion concentration, the VOCs concentrations in rainwater were not dependent on the precipitation intensity and were not high at the beginning of the precipitation. The scavenging effect below cloud level was very small for VOCs. The concentrations of VOCs in rainwater were dependent on their concentrations in the atmosphere near the ground with some exceptions, such as benzene. DOI CiNii Pertraction of hydrophobic organic solutes with a hydrophobic membrane M Igawa, T Abe, H Okochi CHEMISTRY LETTERS   ( 7 ) 597 - 598  1998.07  [Refereed] 　View Summary Pertracion of hydrophobic organic solutes with a hydrophobic membrane is a continuous separation process, which can be used as a substitute of activated carbon. The permeability was affected by the hydrophobicity of the solute and the dissociation in the receiving phase. The pertraction of a hydrophobic solute against its concentration gradient is also possible under a concentration gradient of hydroxide ion. DOI Scopus 2 Citation (Scopus) Fogwater chemistry at a mountainside forest and the estimation of the air pollutant deposition via fog droplets dosed on the atmospheric quality at the mountain base M Igawa, Y Tsutsumi, T Mori, H Okochi ENVIRONMENTAL SCIENCE & TECHNOLOGY   32 ( 11 ) 1566 - 1572  1998.06  [Refereed] 　View Summary Fogwater chemistry has been observed at Mt. Oyama abutting on the Kanto Plain in Japan. Many air pollutants are deposited via fog droplets, and the nitrogen deposition rate via fogwater is at the same level as that via rainwater. The fogwater concentrations depend on the air pollutant concentrations, liquid water content, and the fog base altitude estimated from the meteorological data for the mountain base. The air pollution dominating the concentrations of fogwater components can be estimated from the sulfur dioxide concentration at the base of the mountain. The concentrations of fogwater components were dominated by the absorbing rates of air pollutants into the fog droplets and were not inversely proportional to the LWC. The concentration of fogwater can be estimated approximately from the SO2 concentration at the mountain base, the fog base altitude, and the LWC measured for the fogwater. DOI Scopus 85 Citation (Scopus) Effect of simulated acid fog on needles of fir seedlings M Igawa, H Kameda, F Maruyama, H Okochi, Otsuka, I ENVIRONMENTAL AND EXPERIMENTAL BOTANY   38 ( 2 ) 155 - 163  1997.11  [Refereed] 　View Summary Fir seedlings (Abies firma) were treated with simulated acid fog from September 1992 to April 1995. The simulated acid fog was at pH 3 and consisted of 1 mM nitric acid, 1 mM sodium chloride, and 1 mM ammonium sulfate. In 1993 spring, needles of the seedlings treated with the simulated acid fog became greener than those of the control, which were treated with pH 5 fog water of one hundredfold diluted solution of pH 3 fog water. However, from June 1993 in the acid-fog-treated seedlings, the needles shed, and the growth in height declined. Many buds with their bearing sprouts died in 1993, and few twig tips put forth new sprouts in the spring of 1994. Other symptoms also developed because of the treatment with the simulated acid fog: the water loss from the needles increased and the needles became susceptible to water stress, the weight per area of the needles decreased, and chlorophyll concentration increased. The results were observational in nature and the data were generated from plants exposed to the atmosphere in Yokohama so that there is a possibility of interaction with other pollutants. The long-term treatment with simulated acid fog at pH 3 induced a decline of fir seedling growth and general well-being, although the data warrant further study of the effects of chronic exposure of acid fog on plant growth. (C) 1997 Published by Elsevier Science B.V. DOI Scopus 23 Citation (Scopus) 降水の酸性化と酸性沈着物の森林生態系に及ぼす影響 大河内 博, 井川 学 神奈川大学工学研究所所報   ( 20 ) 47 - 68  1997.11 CiNii An Episode of pH1.95 Acid Fog Containing High Concentration of HCl in Mt. Oyama, Tanzawa Mountains. MORI Takashi, OKOCHI Hiroshi, IGAWA Manabu Journal of Japan Society of Air Pollution   32 ( 2 ) 157 - 161  1997.03  [Refereed] 　View Summary An extremely acidic fog of pH 1.95 was observed in Mt.Oyama, Tanzawa Mountains on April 25,1994. The major ions were H^+ and C1^-, and non-sea-salt chloride ion concentration of 12.8 mmol/1 was detected. The occurrence of acid fogs containing over 1 mmol/1 of non-sea-salt chloride ion was limited to the period between 15 : 00 and 19 : 00,and the concentration increased rapidly, then decreased again in a short time. The extremely acidic fog event may be caused by a local pollution of hydrogen chloride gas, which was discharged from an incinerator. The ion loading of hydrochloric acid in the extremely acidic fog corresponded to about 2 ppb of hydrogen chloride gas in atmosphere, which was often observed in an urban area in Japan. As a result, fog water pH will reach to an extremely low values again in future in a mountainous site close to an urban area. DOI CiNii Coupling of oscillation with transport mediated by polyoxyethylene p-nonylphenyl ether in liquid membrane system M Igawa, K Otani, S Horiguchi, H Okochi CHEMISTRY LETTERS   ( 9 ) 923 - 924  1997  [Refereed] 　View Summary Oscillation coupled with transport phenomena occurred in a liquid membrane system containing polyoxyethylene p-nonylphenyl ether under the concentration gradient of ethyl alcohol. The solutes of ethyl alcohol and some alkaline metal salts were transported without oscillation but their transport rates were enhanced by the periodical convection synchronous with the oscillation in this system. DOI Scopus 1 Citation (Scopus) Effect of acid deposition on urban dew chemistry in Yokohama, Japan H Okochi, T Kajimoto, Y Arai, M Igawa BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN   69 ( 11 ) 3355 - 3365  1996.11  [Refereed] 　View Summary Dews or frosts formed on artificial collectors were collected during the early morning in Yokohama in 1993 and 1994 and analyzed for weak acids as well as major inorganic ions. In 1993 (n = 21) the dew pH ranged from 3.23 to 7.12 and averaged 4.60; in 1994 (n = 56) it ranged from 4.11 to 7.74 and averaged 5.41. Based on the average, NH4+ and Ca2+ were major cations (423 and 178 mu equiv L(-1) for NH4+ and Ca2+ in 1993, respectively, and 454 and 274 mu equiv L(-1) in 1994, respectively) and SO42- was the dominant anion (344 mu equiv L(-1) in 1993 and 271 mu equiv L(-1) in 1994) in dew water. The dew chemistry was characterized by relatively high concentrations of weak acid anions, particularly hydrogensulfite ion (HSO3-). Dew water sometimes had very high acidity (the minimum pH was 3.23 during the period of this research), which might have been due to the aqueous oxidation of S(IV). From a resistance model calculation, the S(IV) concentration in dew water was suggested to be influenced by the dissolution of HCHO from the atmosphere and the subsequent formation of HMSA. DOI Scopus 45 Citation (Scopus) 酸性降下物の森林生態系への影響評価 新藤純子 環境科学会誌   9 ( 1 ) 101 - 108  1996.02 CiNii Enhanced dissolution of SO2 into dewwater by forming hydroxyalkanesulfonate Y Katagiri, N Sawaki, Y Arai, H Okochi, M Igawa CHEMISTRY LETTERS   ( 3 ) 197 - 198  1996  [Refereed] 　View Summary Hydroxymethanesulfonate ion (HMSA) is an important species in dewwater and the formation of HMSA enhances the dissolution of SO2. The HMSA stability constant calculated from the measured concentrations of free formaldehyde and S(IV) in dewwater agreed in the order with the reported value, which suggested the formation of HMSA and other S(IV) complexes. DOI Scopus 5 Citation (Scopus) Interaction between Acid Deposition and the Canopy of the Japanese Cedar and Fir in Mt. Oyama OKOCHI Hiroshi, HOSONO Tetsuya, MARUYAMA Fumitaka, IGAWA Manabu 環境科学会誌 = Environmental science   8 ( 3 ) 305 - 314  1995.08  [Refereed] DOI CiNii SEPARATION OF WEAK ACIDS AND BASES BY NEUTRALIZATION DIALYSIS H TANABE, H OKOCHI, M IGAWA INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH   34 ( 7 ) 2450 - 2454  1995.07  [Refereed] 　View Summary Neutralization dialysis is a deionization method based on a Donnan dialysis. Weak acids and bases, even urea and alcohols, were also removed by this method, and their transport rates increased with the decrease of their dissociation constants and with the increase of the concentrations of acid and base solutions in the neutralization system. Aqueous silica, which is a typical inorganic weak acid and abundant in surface water, was also effectively removed by this method. Therefore, tap water was effectively deionized to be pure water with a resistivity of 15 M Omega cm and a silica concentration ofless than 10 ppb as SiO2 and the neutralization dialysis was proven to be an effective deionization method. DOI Scopus 15 Citation (Scopus) Facilitated transport of carbohydrates via complexation with borate ion fixed on an anion-exchange membrane Manabu Igawa, Takehiko Sekimoto, Hiroshi Okochi Journal of Membrane Science   98 ( 1-2 ) 177 - 180  1995.01  [Refereed] 　View Summary The transport of sugar was facilitated via complexation with borate ion fixed on an anion-exchange membrane. The sugar was highly distributed on the membrane and was transported by the carrier-relay mechanism. The flux across the borate ion type membrane increased with increasing concentration but became constant at a lower flux than across a chloride ion type membrane. Sugars were selectively transported and the permeability of the sugar depends on its distribution in the membrane. © 1995. DOI Scopus 11 Citation (Scopus) 酸性降下物によるコンクリート構造物の劣化, 大河内 博 材料と環境   44   690 - 697  1995 DOI Scopus 5 Citation (Scopus) Deterioration of Concrete Structure by Acid Deposition Hiroshi Okochi Zairyo-to-Kankyo   44 ( 12 ) 690 - 697  1995 　View Summary Acid deposition causes the forest decline and the acidification of lakes and marshes. Furthermore, historic stone monuments, which were made of marble, limestone, and so on, have been reported to be deteriorated by acid deposition and concrete structures may be deteriorated as well. There are few studies on the effects of acid rain on mortar and concrete, though the effects of CO2 and SO2 have been studied. Deterioration of concrete structures by acid rain is guessed to proceed as follows. (1) Dissolution of aggregate, hydrated and unhydrated materials at the surface. (2) Conversion of CaCO3, which is formed by carbonation of hydrated materials, to water soluble salts. (3) Elution of the salts at the surface and development of stress by deposition of the salt beneath the surface. (4) Cracking by formation of corrosion materials such as ettringite, which occupy a large volume. (5) Cracking and spalling by the corrosion of reinforcing steel, which is lead to by neutralization and penetration of chloride and sulfate. At present, there is no obvious evidence showing that deterioration of well-constructed concrete structures is accelerated by acid rain, though the investigation is limited. © 1995, Japan Society of Corrosion Engineering. All rights reserved. DOI CiNii Scopus 5 Citation (Scopus) SELECTIVE ION-TRANSPORT ACROSS MONOMERIC OR REVERSED MICELLAR LIQUID MEMBRANE CONTAINING AN OPEN-CHAIN POLYETHER SURFACTANT M IGAWA, E KOBAYASHI, A ITAKURA, K KIKUCHI, H OKOCHI JOURNAL OF PHYSICAL CHEMISTRY   98 ( 47 ) 12447 - 12451  1994.11  [Refereed] 　View Summary The transport phenomena of salts across a liquid membrane containing a nonionic surfactant, polyoxyethylene p-nonylphenyl ether, as a carrier were investigated. The surfactant, complexing with metal cations selectively, functions as a monomeric carrier or a reversed micellar carrier of a self-assembly system depending on the concentrations of the carrier and the source phase salt. The fluxes of the hydrophobic salts were large in general, and potassium ion was selectively transported by the carrier containing 20 ethylene oxide units. The mole ratio of the salt to the carrier in the complex was 1 in the forms of both monomer and reversed micelle. The transport equation was derived from the complex formation, and its destruction rates and the diffusion resistance were found to be functions of the activities of the source phase salt and the carrier. The theoretical values agreed very well with the measured values. Both the reaction rate constant and the diffusion coefficient decreased significantly with the change of the carrier form from the monomer to the reversed micelle. Therefore, the increase of the flux with the increase of the concentrations of the source phase salt and the carrier was suppressed by the formation of the reversed micelle. DOI Scopus 11 Citation (Scopus) DETERMINATION OF FLUORIDE AND BROMIDE IONS IN FOGWATER BY ION CHROMATOGRAPHY H OKOCHI, T MORI, M IGAWA BUNSEKI KAGAKU   43 ( 11 ) 1005 - 1008  1994.11  [Refereed] 　View Summary Fluoride and bromide ions in fogwater were studied at an altitude of 700m on Mt. Oyama (1252 m a.s.l.). Concentration ranges of fluoride and bromide were 9.28 similar to 209 mu g 1(-1) and 0 similar to 120 mu g l(-1), respectively. Concentrations of both ions were higher than those estimated by the sea salt ratios, which shows that these ions originated not only from sea salt but also from other sources. The effects of volatilization of HBr from sea salt (Br loss) were also observed in the composition of some fogwater. A positive correlation coefficient (r=0.84) between NO3-/Na+ and Br-/Na+ indicates the influence of bromide exhausted from automobiles on fogwater. DOI CiNii Scopus ALDEHYDES IN ACID FOG AND THE DOMINANT FACTORS CONTROLLING THEIR CONCENTRATIONS Y KATAGIRI, S WATANABE, H OKOCHI, M IGAWA NIPPON KAGAKU KAISHI   1994 ( 11 ) 1007 - 1011  1994.11  [Refereed] 　View Summary Fogwater had been collected from 1992 to 1993 at the midslope of Mt. Oyama (a.s.l. 1252 m) at the southwest of the Kanto Plains. The concentrations of five species of aldehydes, formaldehyde, acetaldehyde, glyoxal, 2-oxopropanal, and hydroxyacetaldehyde, in fogwater were measured. The maximum value of the total concentration of these aldehydes was 187 mu M (April 1992). The maximum concentration of glyoxal, whose concentration was the highest among these aldehyde, was 97 mu M (June 1992). Much aldehydes were contained in highly polluted fogwater and the aldehyde concentrations in fogwater increased with the decrease of pH. When the lowest altitude of the upslope fog rose up to the sampling station, the total concentration of aldehydes increased. The fraction of aldehyde with a high Henry&＃39;s law constant increased with the elevation of the lowest altitude of fog. Aldehyde concentrations in fogwater are affected not only by liquid water content and air pollution but also by the lowest altitude of fog. DOI CiNii Scopus 4 Citation (Scopus) FOGWATER CHEMISTRY AT A MOUNTAINSIDE IN JAPAN T HOSONO, H OKOCHI, M IGAWA BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN   67 ( 2 ) 368 - 374  1994.02  [Refereed] 　View Summary Fogwater had been observed for 4.5 years from July 1988 to December 1992 at the midslope of Mt. Oyama at the southwest of the Kanto plains. Rainwater, aerosol, and gases had been also collected and analyzed at the fog sampling station to investigate the characteristics and acidification mechanism of fogwater. The pH of fogwater ranged from 2.61 to 7.00 and the fog with very low pH values and high ion and aldehyde concentrations were frequently observed in spring and summer. The fogwater at the site was acidified primarily by nitric acid gas absorbed in fogwater and the acid fraction of most of the fogwater ranged from 0.3 to 0.01. The acidity of fogwater is controlled by the amount of the acidic pollutants in the atmosphere, the concentrations of the neutralizing components for the acidic fogwater, primarily NH3 gas concentration, the liquid water content in air, and the distance between the sampling station and the lowest altitude of the fog in upslope fog. DOI FACILITATED TRANSPORT OF FORMALDEHYDE ACROSS HYDROGENSULFITE ION FORM ANION-EXCHANGE MEMBRANE M IGAWA, Y SURISAWA, H OKOCHI NIPPON KAGAKU KAISHI   1993 ( 11 ) 1295 - 1297  1993.11  [Refereed] 　View Summary Formaldehyde was transported efficiently across hydrogensulfite ion form anion-exchange membrane via the adduct formation reaction. The transport of formaldehyde was facilitated but onlywhen the concentration of formaldehyde in the source phase solution was low. The ion-exchange capacity of the membrane was saturated by formaldehyde distributed as its adduct in a low source phase concentration because the adduct formation constant was high. The transport of formaldehyde can be further facilitated and formaldehyde was transported against the concentration gradient with the counter-transport of hydrogensulfite ion when hydrogensulfite salt was added to the receiving phase. DOI CiNii Scopus FIA OF FOG-WATER AND RAINWATER ACIDITY H SUZAKI, H OKOCHI, M IGAWA BUNSEKI KAGAKU   42 ( 10 ) 631 - 636  1993.10  [Refereed] 　View Summary Both pH 4.8 and 8.3 acidities were determined by FIA. The carrier solution was a carbonate-free 1 X 10(-3) mol/l sodium hydroxide solution. For the pH 8.3 acidity measurement, the indicator was Bromothymol Blue; for pH 4.8, however, Bromophenol Blue was used. The half-width of the signal peak was used for the calibration. The values obtained by the FIA method agree with those obtained by the corresponding titration method, except for one case, in which the carrier sodium hydroxide concentration was much lower than those of the solutes in the sample solution. For all fog- and rain-water samples, both the pH 8.3 acidity obtained by FIA and the total acidity obtained by Gran&＃39;s plots in the titration method were much larger than the hydrogen-ion concentrations because of the presence not only of ammonium ions, but also organic acids. DOI CiNii Scopus 2 Citation (Scopus) SEPARATION OF WEAK ACIDS AND BASES BY NEUTRALIZATION DIALYSIS M IGAWA, H TANABE, T IDA, F YAMAMOTO, H OKOCHI CHEMISTRY LETTERS   ( 9 ) 1591 - 1594  1993.09  [Refereed] 　View Summary Neutralization dialysis is a very effective deionization method and the transport of weak acids and bases is also facilitated by the neutralization reaction in the system. The transport rates of weak acids and bases increased with the increase of their dissociation constants. DOI SIZE DISTRIBUTION EVALUATION OF METAL IN SURFACE-WATER BY FILTRATION METHOD M IGAWA, S OGAWA, H OKOCHI BUNSEKI KAGAKU   42 ( 5 ) 259 - 264  1993.05  [Refereed] 　View Summary In the surface water analysis, the existing forms of iron nd aluminium are apt to change during the preservation period and the filtration. The sample should be filtered within a day after the sampling and the sample volume should be small to avoid gel layer formation during filtration. Size distribution of metal in surface water was evaluated by filtration method. Sodium, potassium, calcium and magnesium are dissolved predominantly as free ions, whereas aluminium and iron are existing as particulate matters in surface water samples. DOI CiNii Scopus 酸性雨のpHと環境への影響を調べる 大河内 博, 井川 学 現代化学，7月号     53 - 57  1993 丹沢山塊大山の土壌の酸性度と化学組成 大河内 博, 長島律, 補伽栄一, 井川 学 環境科学会誌   6   29 - 34  1993  [Refereed] DOI 横浜市校外における降水中のF^-, Br^-イオンの挙動と起源の推定 大河内博 環境科学会誌   5   259 - 266  1992  [Refereed] DOI CiNii ▼display all Books and Other Publications Books and Other Publications 地球・環境・資源 : 地球と人類の共生をめざして 高木, 秀雄, 山崎, 淳司, 円城寺, 守, 小笠原, 義秀, 太田, 亨, 守屋, 和佳, 内田, 悦生, 大河内, 博, 香村, 一夫 共立出版  2019.03 ISBN: 9784320047341 越境大気汚染の物理と化学 藤田, 慎一, 三浦, 和彦, 大河内, 博, 速水, 洋, 松田, 和秀, 櫻井, 達也 成山堂書店  2014.04 ISBN: 9784425513611 東日本大震災と環境汚染 : アースドクターの診断 香村, 一夫, 名古屋, 俊士, 大河内, 博 早稲田大学出版部  2012.06 ISBN: 9784657123060 東日本大震災と環境 2012 地球・環境・資源 地球と人類の共生をめざして 共立出版  2008 化学物質等のリスクアセスメント・リスクマネジメントハンドブック（２巻） 日本作業環境測定協会  2007 続 身近な地球環境問題ー酸性雨を考えるー 東京化学同人  2002 楽しい化学の実験室II, コロナ社 日本化学会  1995 ▼display all Presentations Presentations 福島県浪江町の里山における大気エアロゾル中放射性セシウム濃度に及ぼす山林火災の影響 吉岡颯, 大河内博, CHO Gai, 勝見尚也, 二宮和彦, 北和之, 五十嵐康人 日本地球惑星科学連合大会予稿集(Web)  Presentation date： 2018 福島第一原子力発電所近隣における事故5年後の土壌中放射性物質の深度分布 二宮和彦, 北和之, 篠原厚, 河津賢澄, 箕輪はるか, 藤田将史, 大槻勤, 高宮幸一, 木野康志, 小荒井一真, 齊藤敬, 佐藤志彦, 末木啓介, 竹内幸生, 土井妙子, 千村和彦, 阿部善也, 稲井優希, 岩本康弘, 上杉正樹, 遠藤暁, 大河内博, 勝見尚也, 久保謙哉, 小池裕也, 末岡晃紀, 鈴木正敏, 鈴木健嗣, 高瀬つぎ子, 高橋賢臣, ZHANG Zijian, 中井泉, 長尾誠也, 森口祐一, 谷田貝亜紀代, 横山明彦, 吉田剛, 吉村崇, 渡邊明 日本地球惑星科学連合大会予稿集(Web)  Presentation date： 2018 福島高線量地区における夏季大気セシウム放射能濃度増加とバイオエアロゾル 北和之, 林奈穂, 南光太郎, 木村茉央, 五十嵐康人, 足立光司, 牧輝弥, 石塚正秀, 大河内博, 古川純, 二宮和彦, 篠原厚 日本地球惑星科学連合大会予稿集(Web)  Presentation date： 2018 首都圏近郊山間部森林域における渓流水の化学特性と大気沈着の影響評価(5) 大河内博, 真庭護, 西村寿々美, 中野孝教, 井川学 日本地球惑星科学連合大会予稿集(Web)  Presentation date： 2018 Wet denuder/particle collectorによる富士山頂における揮発性カルボニル化合物の分析 光石夏澄, 岩崎真和, 井上広太郎, 井本ゆりか, 平美咲, 大平慎一, 竹内政樹, 大河内博, 戸田敬 フローインジェクション分析講演会講演要旨集  Presentation date： 2017.11 首都圏における都市大気エアロゾル中多環芳香族炭化水素の動態と健康リスク評価(2) 能智雅之, 大河内博, 島田幸治郎 大気環境学会年会講演要旨集  Presentation date： 2017.08 富士山体を利用した大気境界層上層および自由対流圏における酸性ガスおよびエアロゾルの観測(3) 宮内洋輔, 大河内博, 島田幸治郎, 勝見尚也, 皆巳幸也, 小林拓, 三浦和彦, 加藤俊吾, 竹内政樹, 戸田敬, 米持真一 大気環境学会年会講演要旨集  Presentation date： 2017.08 富士山体を利用した大気境界層上層および自由対流圏におけるガス状水銀の観測 山地達也, 大河内博, 勝見尚也, 島田幸治郎, 小林拓, 皆巳幸也, 三浦和彦, 加藤俊吾, 米持真一, 梅沢夏実, 野尻喜好 大気環境学会年会講演要旨集  Presentation date： 2017.08 首都圏近郊山間部森林域における渓流水の化学特性と大気沈着の影響評価(3) 真庭護, 大河内博, 島田幸治郎, 中野孝教, 井川学 大気環境学会年会講演要旨集  Presentation date： 2017.08 富士山体を利用した大気境界層および自由対流圏の雲水化学特性の解明(3) 中村恵, 大河内博, 島田幸治郎, 勝見尚也, 皆巳幸也, 小林拓, 三浦和彦, 加藤俊吾, 和田龍一 大気環境学会年会講演要旨集  Presentation date： 2017.08 首都圏近郊山間部における渓流水を通じた微量金属元素の流出挙動と大気沈着の影響評価(3) 西村寿々美, 大河内博, 島田幸治郎, 中野孝教, 井川学 大気環境学会年会講演要旨集  Presentation date： 2017.08 森林除染に向けたドローン活用事例:里山における空間線量率の鉛直観測とドローン搭載ガンマ線カメラによる迅速調査への活用 大河内博, 片岡淳, 岸本彩, 岩本康弘, 金野俊太郎, 黒島碩人, 勝見尚也, 緒方裕子, 反町篤行, 床次眞司 大気環境学会年会講演要旨集  Presentation date： 2017.08 首都圏小規模森林における酸性物質と微量金属元素の森林フィルター効果(2) 永岡玲奈, 大河内博, 島田幸治郎, 宮崎あかね 大気環境学会年会講演要旨集  Presentation date： 2017.08 首都圏近郊丘陵地の森林表層土壌化学特性に及ぼす里山管理と大気汚染物質の影響評価 小松健善, 大河内博, 島田幸治郎, 勝見尚也, 宮崎あかね 大気環境学会年会講演要旨集  Presentation date： 2017.08 富士山頂観測から考察した2015年夏季の関東地方のPM2.5高濃度現象 米持 真一, 堀井 勇一, 小西 智也, 大河内 博, 加藤 俊吾 大気環境学会年会講演要旨集  Presentation date： 2017.08 3B1006 Atmospheric behavior of particle-associated PAHs on Mt.Fuji and its controlling factors(5 Substance-5 toxic chemical/2 Method-1 measurement/analysis,General Presentations) MAESHIMA Koji, OKOCHI Hiroshi, NAGOYA Toshio, INAZU Koji, HISAMATSU Yoshiharu, MINAMI Yukiya, IGARASHI Yasuhito 大気環境学会年会講演要旨集  Presentation date： 2008 P-89 Determination and characterization of atmospheric humic-like substances in the atmosphere (4)(Poster (Academic Promenade)) MATSUNOBU Akinori, OKOCHI Hiroshi, NAGOYA Toshio, MINAMI Yukiya, IGARASHI Yasuhito, INAZU Koji 大気環境学会年会講演要旨集  Presentation date： 2008 P-88 Behavior and precipitation scavenging of air toxics (6)(Poster (Academic Promenade)) MIYAKE Yuki, OKOCHI Hiroshi, TAMECHIKA Kazuya, MINAMI Yukiya, IGARASHI Yasuhito 大気環境学会年会講演要旨集  Presentation date： 2008 東京都郊外森林域における大気中PAH濃度に及ぼす森林樹冠の影響 第48回大気環境学会  Presentation date： 2007 大気中フミン様物質の定量と化学特性の解明 (3) 第48回大気環境学会  Presentation date： 2007 有害大気汚染物質の動態解析と降水洗浄機構(4) ～富士山における霧水中VOCの観測と促進吸収機構～ 第48回大気環境学会  Presentation date： 2007 “丹沢における渓流水の化学組成と窒素飽和現象（１ 日本化学会第87春季年会  Presentation date： 2007 富士山における霧水の化学組成と湿性沈着量（１） 日本化学会第87春季年会  Presentation date： 2007 Facilitated deposition of gas and aerosol by fog in Tanzawa mountains, Japan 4th International Conference on Fog and Fog Collection  Presentation date： 2007 Chemical composition of atmospheric water collected on Mt. Fuji during the summer observational campaign, 2006 4th International Conference on Fog and Fog Collection  Presentation date： 2007 Enhanced dissolution of volatile organic compounds and the possibility of the subsequent photolysis sensitized by atmospheric humic-like substances in dew water.2007年7月 (La Serena, Chili)． 4th International Conference on Fog and Fog Collection  Presentation date： 2007 雨・霧・露の環境化学 ～丹沢大山と横浜における観測を中心として～ 第47回大気環境学会  Presentation date： 2006 “有害大気汚染物質の動態解析と降水洗浄機構(4 第47回大気環境学会  Presentation date： 2006 東京都心部における大気浮遊粒子中のニトロベンヅアントロンの分析 第46回大気環境学会  Presentation date： 2005 山岳域大気汚染モニタリングシステムの開発と評価(1)?山岳域における酸性沈着モニタリングのための太陽電池駆動/小型自動雨水採取機の性能評価 第46回大気環境学会  Presentation date： 2005 大気中フミン様物質の定量と化学特性の解明 (1) 第46回大気環境学会  Presentation date： 2005 有害大気汚染物質の動態解析と降水洗浄機構(2) 第46回大気環境学会  Presentation date： 2005 有害大気汚染物質の動態解析と降水洗浄機構(1)?HS SPME-GCMSによる雨水および露水中VOCsの定量条件の検討 第46回大気環境学会  Presentation date： 2005 Evaluation of a newly-developed solar-powered automatic rainwater collector for use in acid deposition monitoring networks in mountainous area (1) Pacifichem2005  Presentation date： 2005 Behavior and precipitation scavenging of air toxics at a suburban site located in western part of Tokyo, Japan (3) Pacifichem2005  Presentation date： 2005 Determination and characterization of atmospheric humic-like substances at a suburban site located in western part of Tokyo, Japan Pacifichem2005  Presentation date： 2005 Change of surface soil and stream water chemistry on Mt. Oyama located near the metropolitan area in Japan.Deposition), 2005年6月 (Prague, Czech Republic). Acid Rain 2005  Presentation date： 2005 Indirect evidence of seeder-feeder precipitation scavenging of acidic substances via mist droplets in urban area. Acid Rain 2005  Presentation date： 2005 Acid depistion on forest in Tanzawa mountains, Japa Acid Rain 2005  Presentation date： 2005 丹沢大山における大気汚染物質の沈着挙動 第46回大気環境学会  Presentation date： 2004 酸性霧の化学組成と酸性化機構(20) 第46回大気環境学会  Presentation date： 2004 スギ花粉表面への大気汚染物質の吸着とその支配要因の検討 第46回大気環境学会  Presentation date： 2004 大気中におけるVOCsの成分分析とその濃度支配要因 第46回大気環境学会  Presentation date： 2004 ミスト粒子を介した大気汚染物質のSeeder-feeder降水洗浄過程 日本エアロゾル学会  Presentation date： 2004 Dominant factors of fog characteristics in Mt. Oyama 4th International Conference on Fog and Fog Collection  Presentation date： 2004 Enhanced dissolution of volatile organic compounds into urban dew water collected in Yokohama, Japan. 4th International Conference on Fog and Fog Collection  Presentation date： 2004 横浜と丹沢大山における大気汚染状況とその支配要因 第44回大気環境学会  Presentation date： 2003 大気および降水中アルデヒドの定量とその濃度支配要因 第44回大気環境学会  Presentation date： 2003 酸性霧の化学組成とその酸性化機構(19) 第44回大気環境学会  Presentation date： 2003 雨水の化学組成とその酸性化機構(15) 第44回大気環境学会  Presentation date： 2003 大気汚染物質の丹沢大山森林樹冠への沈着 第44回大気環境学会  Presentation date： 2003 大気中VOCsの雨水および露水への溶解機構 日本化学会第83回春季年会  Presentation date： 2003 大気エーロゾルおよび雨水中金属元素の状態分析とその濃度支配要因(2 日本化学会第83回春季年会  Presentation date： 2003 横浜と丹沢大山における大気汚染状況比較およびその濃度支配要因 日本化学会第83回春季年会  Presentation date： 2003 丹沢大山における酸性物質の沈着挙動と森林生態系に及ぼす影響 日本化学会第83回春季年会  Presentation date： 2003 リーゼガング環の生成による液滴中の硫酸イオンの分析 日本化学会第83回春季年会  Presentation date： 2003 “中和透析法による連続脱 日本化学会第83回春季年会  Presentation date： 2003 The dry deposition of atmospheric chlorinated and monocyclic aromatic hydrocarbons onto urban dew water ASAAQ  Presentation date： 2003 2D0930 Composition of Dewwater and Its Acidification Mechanism (12) Takeuchi M, Okochi H, Igawa M 大気環境学会年会講演要旨集  Presentation date： 2002 疎水性膜を用いた抽出透過法による有機物の分離 膜シンポジウム2002  Presentation date： 2002 をキャリヤーとして含むベンジルアルコール液膜系における振動現象と輸送減少 膜シンポジウム2002  Presentation date： 2002 花粉表面に吸着した大気汚染物質の分析 第43回大気環境学会  Presentation date： 2002 酸性沈着物のモミ針葉に及ぼす影響 第43回大気環境学会  Presentation date： 2002 露水の化学組成と酸性化機構（13） 第43回大気環境学会  Presentation date： 2002 降水中アルデヒドの定量とその濃度支配要因 第43回大気環境学会  Presentation date： 2002 エーロゾルとガス成分濃度およびそれらの相互変換の支配要因 第43回大気環境学会  Presentation date： 2002 露水の化学組成と酸性化機構（12） 第43回大気環境学会  Presentation date： 2002 酸性霧の化学組成とその酸性化機構(18) 第43回大気環境学会  Presentation date： 2002 雨水の化学組成とその酸性化機構(14) 第43回大気環境学会  Presentation date： 2002 イオン交換膜によるキレート生成重金属イオンの選択輸送 日本化学会第81春季年会  Presentation date： 2002 大気エーロゾルおよび雨水中金属元素の状態分析とその濃度支配要因 日本化学会第81春季年会  Presentation date： 2002 微量湿性沈着物の採取法の検討とそれらの濃度支配要因 日本化学会第81春季年会  Presentation date： 2002 酸性霧によるモミ葉内成分の溶脱とその影響 第42回大気環境学会年会  Presentation date： 2001 降水中アルデヒドの定量とその濃度支配要因 第42回大気環境学会年会  Presentation date： 2001 雨水の化学組成とその酸性化機構（13） 第42回大気環境学会年会  Presentation date： 2001 露水の化学組成と酸性化機構（11） 第42回大気環境学会年会  Presentation date： 2001 疎水性膜による有機物の抽出透過(4) 日本化学会第80秋季年会  Presentation date： 2001 中和透析法による連続脱塩 日本化学会第80秋季年会  Presentation date： 2001 酸性霧の化学組成とその酸性化機構(17) 日本化学会第80秋季年会  Presentation date： 2001 The possibility of the enhanced uptake of carboxylic acids and dicarbonyls into atmospheric water via the formation of metal-oragnic complexConference on Fog and Fog Collection，2001年7月 (St. John’s, Canada). 2nd International Conference on Fog and Fog Collection  Presentation date： 2001 Measurements of weak acid in dew-water and comparison with rain- and fog-waterCanada). 2nd International Conference on Fog and Fog Collection  Presentation date： 2001 Large deposition of acid fog rather than rain in high elevation forest 2nd International Conference on Fog and Fog Collection  Presentation date： 2001 2G1015 Acid deposition in Mt. Oyama and its hinder mountainous region Takahashi R, Hirayama H, Okochi H, Igawa M 大気環境学会年会講演要旨集  Presentation date： 2000 丹沢大山およびその後背地における酸性物質の沈着挙動 第41回大気環境学会  Presentation date： 2000 酸性霧の化学組成とその酸性化機構(16) 第41回大気環境学会  Presentation date： 2000 エ－ロゾルの全量分析とその濃度支配要因(2) 第41回大気環境学会  Presentation date： 2000 露水の化学組成とその酸性化機構(10) 第41回大気環境学会  Presentation date： 2000 Characteristics of atmospheric aerosol behaviors in urban and mountainous sites. Acid rain 2000  Presentation date： 2000 Fog-water chemistry in Mt. Oyama and its dominant factors Acid rain 2000  Presentation date： 2000 Elevational patterns of acid deposition into a forest and nitrogen saturation on Mt. Oyama, Japan Acid rain 2000  Presentation date： 2000 Dew-water chemistry and its dominant factors Acid rain 2000  Presentation date： 2000 酸性沈着物のモミ衰退に及ぼす影響 第40回大気環境学会  Presentation date： 1999 酸性霧の化学組成ととその濃度支配要因(15) 第40回大気環境学会  Presentation date： 1999 エーロゾルの全量分析とその濃度支配要因(1) 第40回大気環境学会  Presentation date： 1999 雨水の化学組成とその酸性化機構?溶存および非溶存成分濃度の支配要因 第40回大気環境学会  Presentation date： 1999 露水の化学組成とその酸性化機構(10) 第40回大気環境学会  Presentation date： 1999 疎水性膜による有機物の抽出透過(2) 日本化学会第76春季年会  Presentation date： 1999 ポリオキシエチレン型界面活性剤をキャリヤーとする液膜のイオン輸送特性 日本化学会第76春季年会  Presentation date： 1999 モザイク膜システムにおける電子輸送を伴う循環電流の支配要因 日本化学会第76春季年会  Presentation date： 1999 雨水の化学組成とその酸性化機構(10) 日本化学会第76春季年会  Presentation date： 1999 丹沢山塊大山土壌の酸性度と化学組成(2) 日本化学会第76春季年会  Presentation date： 1999 丹沢・大山における酸性ガスとアンモニアガスの濃度変動とその支配要因 日本化学会第76春季年会  Presentation date： 1999 丹沢大山の森林生態系内における酸性物質の挙動 日本化学会第76春季年会  Presentation date： 1999 雨水の化学組成とその酸性化機構(9) 日本化学会第76春季年会  Presentation date： 1999 モミの生育に及ぼす酸性霧の影響(2) 日本化学会第76春季年会  Presentation date： 1999 2A0915 Analysis of Rain Components and study of Acidification Mechanism (8) Kobayashi K, Okochi H, Igawa M 大気環境学会年会講演要旨集  Presentation date： 1998 酸性沈着物のモルタルへの影響(6) 環境科学会  Presentation date： 1998 雨水中の揮発性有機化合物とその支配要因(8) 環境科学会  Presentation date： 1998 酸性霧の化学組成とその酸性化機構(14) 環境科学会  Presentation date： 1998 酸性沈着物の森林樹冠に及ぼす影響 第39回大気環境学会  Presentation date： 1998 露水の化学組成とその酸性化機構(7) 第39回大気環境学会  Presentation date： 1998 雨水の化学組成とその酸性化機構(8) 第39回大気環境学会  Presentation date： 1998 Air Pollutants Deposition via Fog Droplets in the Forest of Tanaza Mountains, JapanCanada). First International Conference on Fog an Fog Collection  Presentation date： 1998 Effect of acid deposition on urban dew chemistry in Yokohama, Japan. First International Conference on Fog an Fog Collection  Presentation date： 1998 電位振動をともなうポリオキシエチレン液膜系の輸送特性 日本化学会第73秋季年会  Presentation date： 1997 疎水性膜の高い溶質分離機能とその応用 日本化学会第73秋季年会  Presentation date： 1997 降水中に含まれる揮発性有機化合物のGC／MSによる測定 日本化学会第73秋季年会  Presentation date： 1997 丹沢大山における金属元素の沈着挙動とその森林生態系に及ぼす影響（4） 第38回大気環境学会  Presentation date： 1997 丹沢大山における酸性物質の沈着挙動とその森林生態系に及ぼす影響 第38回大気環境学会  Presentation date： 1997 エ一ロゾル組成の変動とその支配要因（2） 第38回大気環境学会  Presentation date： 1997 大気中酸性ガスおよびアンモニアの定量とその濃度支配要因（3） 第38回大気環境学会  Presentation date： 1997 疎水性膜による有機物の抽出透過 日本膜学会第19年会  Presentation date： 1997 ポリオキシエチレン型界面活性剤被膜によるイオン輸送特性 日本膜学会第19年会  Presentation date： 1997 酸性霧の化学組成とその酸性化機構（12） 日本化学会第72春季年会  Presentation date： 1997 降水の化学組成とその酸性化機構（6） 日本化学会第72春季年会  Presentation date： 1997 丹沢大山におけるモミおよびスギ樹幹周辺の表層土壌の化学特性 日本化学会第72春季年会  Presentation date： 1997 エ一ロゾル組成の変動とその支配要因 日本化学会第72春季年会  Presentation date： 1997 雨，霧，露水中に含まれる有機物濃嚢度とその支配要因 大気環境学会第37回年会  Presentation date： 1996 モザイク膜システムにける電子輸送とイオン輸送の支配要因 第12回日本イオン交換研究会  Presentation date： 1996 中和透析法における脱塩 第12回日本イオン交換研究会  Presentation date： 1996 ホルモース反応の制御と反応生成物 日本化学会第71秋季年会  Presentation date： 1996 ポリオキシエチレン型界面活性剤液膜によるイオン輸送特性 日本化学会第71秋季年会  Presentation date： 1996 ポリオキシエチレン型界面活性剤液膜系における振動現象と輸送現象 日本化学会第71秋季年会  Presentation date： 1996 オリーブ油の潤滑特性 化学工学会第29回秋季大会  Presentation date： 1996 酸性降下物のモルタルへの影響（5） 環境科学会  Presentation date： 1996 丹沢大山における金属元素の沈着量とその沈着挙動（2） 環境科学会  Presentation date： 1996 丹沢大山における酸性降下物とその森林生態系に及ぼす影響 環境科学会  Presentation date： 1996 大気中酸性ガスおよぼアンモニアの定量とその濃度支配要因（2） 大気環境学会第37回年会  Presentation date： 1996 酸性降下物のモミ樹冠に及ぼす影響 大気環境学会第37回年会  Presentation date： 1996 降水の化学組成とその酸性化機構（5） 大気環境学会第37回年会  Presentation date： 1996 酸性霧の化学組成とその酸性化機構（第11報） 大気環境学会第37回年会  Presentation date： 1996 霧水の化学組成とその酸性化機構（4） 大気環境学会第37回年会  Presentation date： 1996 中和透析法による脱塩」，日本化学会第70春季年会，1996年3月（東京）. 日本化学会第70春季年会  Presentation date： 1996 モザイク膜システムにおけるイオン輸送と電子輸送のカップリング」，日本化学会第70春季年会，1996年3月（東京）. 日本化学会第70春季年会  Presentation date： 1996 丹沢大山における酸性降下物のスギ，モミ樹冠に及ぼす影響」，日本化学会第70春季年会, 1996年3月（東京）. 日本化学会第70春季年会  Presentation date： 1996 丹沢大山における金属元素の沈着量とその沈着挙動 日本化学会第70春季年会  Presentation date： 1996 Selective transport of an organic non‐electrolyte ICOM‐96  Presentation date： 1996 Coupling of electron with ion transport in mosaic membrane system ICOM‐96  Presentation date： 1996 液膜系における振動現象と輸送現象 膜シンポジウム  Presentation date： 1995 中和透析法による脱塩 膜シンポジウム  Presentation date： 1995 酸性霧のモミの成育に対する影響（2） 大気環境学会第36回年会  Presentation date： 1995 大気中酸性ガスおよぼアンモニアの定量とその濃度支配要因 大気環境学会第36回年会  Presentation date： 1995 酸性降下物のモルタルヘの影響（4） 大気環境学会第36回年会  Presentation date： 1995 雨，霧，露水中に含まれる有機物濃度とその支配要因 大気環境学会第36回年会  Presentation date： 1995 酸性霧の化学組成とその酸性化機構（第10報） 大気環境学会第36回年会  Presentation date： 1995 露水の化学組成とその酸性化機構（3） 大気環境学会第36回年会  Presentation date： 1995 丹沢大山における酸性降下物とその森林生態系への影響 環境科学会  Presentation date： 1995 降水の化学組成とその酸性化機構（4） 環境科学会  Presentation date： 1995 Selective ion transport with monomeric orreversed micellar liquid membrane containing an open‐chain polyether surfactant Pacifichem &＃39;95  Presentation date： 1995 Oscillations and transport mediated by polyoxyethylene surfactant Pacifichem &＃39;95  Presentation date： 1995 Acid deposition in forest ecosystems in Mt．Oyama in Southern Kanto district of Japan Pacifichem &＃39;95  Presentation date： 1995 Organic compounds in dew water and the dominant factors controlling their concentration Pacifichem &＃39;95  Presentation date： 1995 Dying young fir trees exposed to simulated acid fog Pacifichem &＃39;95  Presentation date： 1995 Analysis of acid fog and it&＃39;s acidification mechanism Pacifichem &＃39;95  Presentation date： 1995 丹沢大山における酸性降下物の化学組成と沈着量 環境科学会  Presentation date： 1994 酸性霧のモミの生育に対する影響 環境科学会  Presentation date： 1994 霧水における有機物濃度とその支配要因 環境科学会  Presentation date： 1994 逆ミセルおよび単分子キャリヤーとして機能するポリオキシエチレン型界面活性剤を含む被膜イオン 日本化学会第68秋季年会  Presentation date： 1994 ポリオキシエチレン型界面活性剤をキャリヤーとする液膜輪送に伴う振動現象 日本化学会第68秋季年会  Presentation date： 1994 中和透析法による脱塩 日本化学会第68秋季年会  Presentation date： 1994 中和透析法による弱酸と弱塩基の除去 日本化学会第68秋季年会  Presentation date： 1994 酸性降下物のモルタルへの影響（3） 日本化学会第68秋季年会  Presentation date： 1994 丹沢大山における酸性降下物の化学組成と降下分布 日本化学会第68秋季年会  Presentation date： 1994 霧水の化学組成と酸性化機構（2） 日本化学会第68秋季年会  Presentation date： 1994 酸性霧に含まれる有機物の組成とその支配要因 日本化学会第68秋季年会  Presentation date： 1994 酸性霧の化学組成とその酸性化機構（第9報） 日本化学会第68秋季年会  Presentation date： 1994 中和透析法による脱塩一イオン交換膜に弱酸，弱塩基の透過機構一 日本化学会第68春季年会  Presentation date： 1994 霧氷の化学組成とその酸性化機構 日本化学会第67春季年会  Presentation date： 1994 降水中有機物質の大気中における挙動 日本化学会第67春季年会  Presentation date： 1994 丹沢大山における酸性降下物とその森林への影響 日本化学会第67春季年会  Presentation date： 1994 酸性降下物のモルタルへの影響（2） 日本化学会第67春季年会  Presentation date： 1994 雨水および露水の化学組成とその酸性化機構 環境科学シンポジウム  Presentation date： 1993 丹沢大山における酸性物質と金属元素の降下量」 環境科学シンポジウム  Presentation date： 1993 膜システム内におけるホルモース反応の制御（l） 日本化学会第65春季年会  Presentation date： 1993 モザイク膜システムによる霧子輸送とイオンの輸送効率 日本化学会第65春季年会  Presentation date： 1993 酸性霧の化学組成とその酸性化機構（第8報） 日本化学会第69秋季年会  Presentation date： 1993 湿性降下物中の有機物の分析 日本化学会第68秋季年会  Presentation date： 1993 丹沢大山における酸性降下物の化学組成を降下量分布 日本化学会第67秋季年会  Presentation date： 1993 モザイク膜システムによる電子移動過程 日本化学会第67秋季年会  Presentation date： 1993 酸性降下物のモルタルへの影響 日本化学会第66秋季年会  Presentation date： 1993 丹沢大山におけるガスと工一ロゾルの化学組成 日本化学会第65春季年会  Presentation date： 1993 降水の化学組成と酸性化機構 日本化学会第65春季年会  Presentation date： 1993 Selective transport of an organic non‐electrolyte across anion‐exchange membrane The 1994 International Congress on Membranes and Membrane Process，  Presentation date： 1993 New separation methods of mosaic membrane systems The 1993 International Congress on Membranes and Membrane Process，  Presentation date： 1993 都市近郊山間部における酸性降下物」 環境科学シンポジウム  Presentation date： 1992 酸性霧の化学組成とその酸性化機構（第7報） 環境科学シンポジウム  Presentation date： 1992 疎水性腹のイオン選択透過性 日本化学会第64秋季年会  Presentation date： 1992 モザイク膜システムによる電子輸送とイオン輸送のカップリング 日本化学会第64秋季年会  Presentation date： 1992 丹沢山塊大山の土壌の酸性度と化学組成 日本化学会第64秋季年会  Presentation date： 1992 降水の化学組成と酸性化機構 日本化学会第64秋季年会  Presentation date： 1992 酸度の測定による雨水，親水の酸性度評価 日本化学会第64秋季年会  Presentation date： 1992 酸性霧の化学組成とその酸性化機構（第6報） 日本化学会第64秋季年会  Presentation date： 1992 中和透析法による脱塩 中和透析法による脱塩  Presentation date： 1991 陰イオン交換膜を用いるアルデヒドの輸送とその透過機構 日本分析化学会第62秋季年会  Presentation date： 1991 酸性降下物の植物に及ぼす影響 環境科学シンポジウム  Presentation date： 1991 酸性霧の化学粗成とその酸性化機構（第5報） 環境科学シンポジウム  Presentation date： 1991 酸性霧の化学組成とその酸性化機犠（第4報） 日本分析化学会第63秋季年会  Presentation date： 1991 フローインジェクション法による酸性降下物の酸度分析 日本分析化学会第62秋季年会  Presentation date： 1991 南関束地方における酸降下量の季節変化 環境科学シンポジウム  Presentation date： 1989 一回の降雨に含まれる化学成分の経時変化 環境科学シンポジウム  Presentation date： 1989 ▼display all Research Projects Research Projects Validation of air quality model to indicator ratios for ozone formation regimes Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Project Year : 2021.04 - 2024.03  Synergistic Environmental Effects of Heavy Summer Rainfall Formation and Air Pollution in Mountainous Areas Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Project Year : 2019.04 - 2022.03  Okochi Hiroshi 　View Summary The number of heavy rainfall events increased during the warm season in 70% of the rainfall observation sites above 400 m elevation nationwide, and the increase was significant in areas where heavy rainfall events were infrequent. The main causes of heavy rainfall around Mt. Fuji are frontal development and typhoons, and the increase in localized heavy rainfall is also a contributing factor. Air pollutants also contribute to the formation of localized heavy rainfall. Fog deposition is an important pathway for air pollutants in mountain forest ecosystems, and together with ozone.A network of fog deposition observation in mountainous areas in Japan was established, and a fog deposition map was created. The effect of transboundary air pollution on stream water was observed both in Tanzawa on the Pacific Ocean side and in Kajikawa on the Sea of Japan side. The pH of the stream water temporarily decreased and nitrate concentration increased during heavy rainfall. A new development of stone deterioration and multidiscipinaly research on conservation in Angkor monument group Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Project Year : 2017.04 - 2022.03  Aerosol Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Project Year : 2017.04 - 2020.03  Igarashi Yasuhito 　View Summary It is usual understanding that rainfall removes aerosols from the air. However, the question of whether rain plays a role in releasing aerosols to the air has been posed recently. In the present study, we found outbreak of radioCs-bearing aerosols in a contaminated Japanese forest due to rain. We carried out general radioactive aerosol observations in a typical mountainous village area within the exclusion zone in Fukushima. We also sampled according to the weather (rain or fine) inside a forest to better understand the process. Thus, we know that rain enhances/induces bursts of radioCs-bearing aerosols in forests. With further investigations, we confirmed that the fungal spore sources in the rainy weather seem to be different from those in the fine weather. Larger fungal particles (possibly conidia-ascospore) are emitted during rain than during fine weather, suggesting that the rain-splash mechanism for mold-like fungi could be the major mechanism. Development of an early detection system for volcanic gases released from Mt. Fuji Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Project Year : 2015.04 - 2018.03  Okochi Hiroshi, TODA Kei, TAKEUCHI Masaki 　View Summary Mt. Ontake and Mt. Kusatsu Shirane were suddenly erupted in recent years and many people were died. The objective of this research is to develope a continuous measurement observation telemeter system, which could detect trace amounts of volcanic gases such as hydrogen sulfide and sulfur dioxide at ppb level in preparation for the large eruption of Mt. Fuji. Volcanic gases were not detected at the top of Mt. Fuji during summer in 2017, but a trace amount of hydrogen sulfide was detected at Hoei&＃39;s crater during summer in 2016 and 2017. We built a volcanic gas early detection telemeter system at Tarobo (1300 m), which is located at the foot of Mt. Fuji on Gotemba trail. Hydrogen sulfide has not been detected from 2016. Sulfur dioxide was usually not detected, but peaks reaching several ppb were sometimes detected. At that time, it was thought that smoke from domestic volcanoes such as Mt. Ontake and Mt. Asama were transported to Mt. Fuji. Observation of transboundary acid pollutants at the summit of Mt. Fuji by parallel-plate wet denuder and mist-chamber based particle collector techniques Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Project Year : 2014.04 - 2017.03  TAKEUCHI Masaki, OKOCHI Hiroshi 　View Summary We have developed the analytical system for the monitoring of atmospheric water-soluble acidic gases and anions in particulate matter at the summit of Mt. Fuji. The system provides automatically one acidic gas and one particulate matter data in an hour. We applied the system to the continuous measurement of atmospheric HNO3, SO2, NO3-, and SO42- at the summit of Mt. Fuji, Japan. Backward trajectory analysis suggested that high concentration of SO42- emitted from the Asian Continent was transported to the sampling site. Understanding of the atmospheric deposition, diffusion processes and land atmospheric interaction of radioactive materials Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Project Year : 2012.06 - 2017.03  Igarashi Yasuhito, HIROTO KAWASHIMA, TANAKA YASUMICHI, SEKIYAMA TSUYOSHI, MAKI TAKASHI, YAMADA KEITA, ZAIZEN YUJI, ADACHI KOUJI, NAKAI IZUMI, YAMADA YUTAKA, UTANI KEISUKE, NISHIGUCHI KOHEI, ABE YOSHINARI, MIKAMI MASAO, HATANO YUKO, OGATA HIROKO, YOSHIKAWA CHISATO, AOYAMA TOMOO, TOYODA SAKAE, HATTORI SHOHEI, MURAKAMI SHIGEKI, KAJINO MIZUO, NIIMURA NOBUO, WATANABE AKIRA, OSADA NAOYUKI, YATAGAI AKIYO, MAKI TERUYA, SATOU YUKIHIKO 　View Summary Initial radioactive Cs release revealed for the first time that insoluble coarse spherical particles with a diameter of several μm existed in addition to the water-soluble submicron particles usually assumed.In typical Satoyama area, the Cs concentration derived from resuspension escalated in the summer and was low in the winter, unlike in urban areas. We discovered for the first time that Cs carrier in summer is mostly of biological.We developed a simplified scheme for resuspension of radioactive Cs, and we carried out flux quantification - budget calculation, including resuspension by biological particles from forest ecosystems using a regional aerosol transport model, and primary leakage continued from the accident site. As a result, similarly to other processes, it was found that resuspension contributes little to decrease and migration of Cs deposited on the earth&＃39;s surface. Clarification of chemical species of element in fine particulate matter using magnetic separation technic Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Project Year : 2012.04 - 2015.03  YONEMOCHI Shinichi, O Kokyo, UMEZAWA Natsumi, OKOCHI Hiroshi, NAGOYA Toshio, OGATA Hiroko 　View Summary (1)Magnetic separation technique with two-step, using neodymium magnets of 0.4T and 1.2T was developed in order to classify elements in fine particulate matter.(2)Simultanious sampling campaign in China and Japan was carried out in summer and winter in order to obtain PM2.5 and PM1 samples and characterize its chemical components in recent years.(3)Ratios of Magnetic fraction(MF) to total mass of samples at Beijing and Kazo were in the range of 0.01-0.02. EDX spectrum and individual particle analysis of MF showed oxides of Fe and Cu. The ratio of MF to total mass of fly ashes collected in China was more than 0.7. The ratio As/V, as an indicator of coal combustion increased when air mass came from China in summer. Characterization of submicron particles PM1 collected at large city and suburban, and its magnetic properties Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Project Year : 2009 - 2011  YONEMOCHI Shinichi, UMEZAWA Natsumi, O Kokyo, NAGOYA Toshio, OHKOCHI Hiroshi, NAKAMURA Kenji 　View Summary In order to investigate chemical components of PM1, airborne particles were collected by use of Andersen samplers at four sites : Shinjuku, Kazo, the top of Mt. Fuji and Shanghai. Water soluble inorganic ions and metal elements in PM1 samples were measured.New classification method of particulate matters based on the difference of magnetic properties was also developed. As a result of applying that for PM1 samples, we found that the ratios of magnetic fraction to total concentration of some elements were different between Kazo and Shanghai. Aerosol characterization by using Mt. Fuji as an observation tower Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Project Year : 2005 - 2007  YASUHITO Igarashi, KATAYAMA Yoko, KANEYASU Naoki, KOBAYASHI Hiroshi, OKOCHI Hiroshi, MIURA Kazuhiko 　View Summary East Asia is such a growing industrial region that many kinds of the aerosol and its precursor gas haying different composition are emitted. They display profound temporal and spatial variations due mainly to their relatively short residence time. For the better assessment of climatic impacts, etc., observations on aerosol characteristics (concentration, size distribution, composition, optical property and relations to cloud and fog processes, etc.) in the free troposphere are thus essential. Hence, research on aerosol and its precursor was carried out at Mt. Fuji, an isolated highest peak in Japan (3776m a.s.1.).Three intensified observation campaigns were carried out at the summit (3776m a.s.1.), 7.8 point (3400m a.s.1.) and Tarou-bou (1300m a.s.1.), etc. of the mountain during summers of 2005-2007. It was found that the aerosol and the precursor gas are ruled by local mountain and valley winds, being under a free tropospheric condition during night. The origin of the species found in the upper atmosphere seems different between night and day. Moreover, various continental pollutants could be observed even in summer if the frontal activity creates favorable conditions for the transport. The mountain and valley winds at Mt. Fuji were quantified for the first time by comparing the surface observations by simple equipments on the mountain body with those at the mountain foot and radiosounding. A scale of the developed mixed layer turned out to be, from vertical averaged profile of 0_3 and NO_x by passive samplers, about 2km during summer. Because of few pollution sources, foot of Mt. Fuji including Tarou-bou can serve reference concerning the air pollution of the city. Evaluation of ecosystem response against acid rain and the fog would be possible there. Although the observational data was generalized by a present atmospheric transport model, alternative regional transport model should be used, by which geography of Mt. Fuji is more properly expressed, in the future. Effect of atmospheric humic-like substances on the behavior of hazardous organic pollutants and heavy metals in the atmosphere Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Project Year : 2004 - 2006  OKOCHI Hiroshi, HARA Hiroshi 　View Summary Simultaneous sampling of chlorinated hydrocarbons(CHs) and monocyclic aromatic hydrocarbons(MAHs), which could be harmful to humans and/or responsible for the formation of ozone and secondary particles, in dew and rainwater and in the ambient air was performed from 2004 to 2006 in Hino City, which is located in western part of Tokyo, Japan. CHs were less contained in dew water than MAHs. Toluene(volume-weighted mean concentration, VWM : 4.77nM, sample number, n=49) and m, p-Xylene(VWM : 5.07nM, n=49) except dichloromethane, which was abnormally high(VWM : 1.14μM, n=49), were abundant among eleven VOCs determined in dew water. Chloroform, carbon tetrachloride, 1, 2-dichloroethane, and benzene were not detected in dew water during the study period. Dew and rainwater contained higher amounts of VOCs than would have been expected from the ambient gas-phase concentrations and the temperature-corrected Henry&＃39;s law constants. Following the determination method of humic substances in river water proposed by Hiraide, et. al.(1994), the VWM of soluble humic and fluvic acid fractions in dew water was found to be 1.00mg/L and 0.87mg/L(n=20), respectively, while the VWM of particulate humic and fluvic acid fractions was found to be 0.61mg/L and 0.42mg/L(n=20), respectively. Surface tension decreased with the increase of dissolved fulvic acid fraction in dew water, indicating that humic-like substances with relatively lower molecular weight, which is soluble in acid solution, could be effective surface-active species within dew water. The enrichment factors, which were defined as the ratio of the observed VOCs concentration to the estimated, were over 10^2 for MAHs except benzene and increased as the increment of total HULIS concentration(the sum of humic and fulvic acid fractions in both dissolved and particulate form) normalized by total inorganic ion concentration in dew water. Our results indicate that total HULIS, i.e. both humic and fulvic acid fractions present in both dissolved and particulate form, in dew water could enhance the dissolution of atmospheric VOCs into dew droplets. 有害有機汚染物質の大気微小液滴への促進吸収機構と増感光分解反応 日本学術振興会  科学研究費助成事業 Project Year : 2004 - 2005  大河内 博 　View Summary 首都大学東京(日野キャンパス)において,年間を通じて毎月1週間毎の降水,エアロゾル,大気中揮発性有機化合物(VOCs)の同時連続採取を行った.さらに,富士山山頂(3776m)と富士山中腹(太郎坊避難小屋,1300m)で2005年7月13日から17日まで,降水(雨,霧,露)とともに大気中VOCsの集中観測を行った.また,本年度は,昨年まで測定を行ってきた塩素化炭化水素(16種),単環芳香族炭化水素(7種)などのVOCsに加えて,多環芳香族炭化水素(PAHs)のうちで揮発性が高く,主にガス態として大気中に存在しているナフタレン類(3種)の二環芳香族炭化水素の観測も開始した.以下に,本年度得られた結果の概要を示す.1)大気微小液滴への微量有機汚染物質の濃縮機構大気中VOCsの観測とともに,雨水および露水中のVOCs濃度,フミン様物質(HULIS),溶存有機炭素(DOC),表面張力,主要無機イオンの測定を行い,大気微小水滴への大気中VOCsの濃縮機構を検討した.フミン様物質の定量には,河川水中フミン物質の定量法としてHiraide et al.(1994)によって開発された方法を改良して用いた.降水中HULIS濃度は雨水に比べて露水で約20倍濃縮されていた.降水中HULISは雨水,露水ともに春先に高濃度になることから,フミン様物質の起源として,花粉や黄砂などの春先特有の現象が関与している可能性があるが,カリウムイオンとの相関性から花粉など植物起源の可能性が高い.露水および雨水中VOCsは,大気中VOCs濃度とヘンリー則から推定される予測値に比べて数百倍以上濃縮されているが,このうち,トルエン,キシレンなどの単環芳香族炭化水素は単位総無機イオン濃度当たりのフミン様物質濃度が増加するにつれて濃縮されることが明らかになった.2)大気微小液滴内での微量有機汚染物質の増感光分解試薬から調整した模擬露水(VOCsのみの場合,VOCs+フミン酸(溶存態),VOCs+フミン酸(懸濁態))を晴天時に本学講義棟屋上に設置して実際の太陽光を照射することにより,VOCsのフミン様物質による増感光分解反応について検討した.ジクロロメタンを除く塩素化炭化水素,単環芳香族炭化水素はフミン物質の増感光分解効果はあまり明瞭ではなかったが,二環芳香族炭化水素であるナフタレン類ではフミン物質による増感光分解効果により水中で消失することが明らかになった.ジクロロメタンはフミン酸存在下での太陽光照射により生成がみられたが,ジクロロメタンが生成する原因は明らかにすることができなかった.今後,降水やエアロゾルから精製した大気中フミン様物質を用いて屋外実験と室内実験を行うことにより,有害有機大気汚染物質のフミン様物質による増感光分解反応について明らかにする必要がある. エアロゾルの降水による沈着の促進と山岳部と都市部における乾性沈着量の比較 日本学術振興会  科学研究費助成事業 Project Year : 2004 - 2005  井川 学, 松本 潔, 大河内 博 　View Summary 我々は丹沢大山において霧の研究を行なってきたが、その中で、大気から樹冠への沈着経路として霧は重要だが、同時にエアロゾルやガスとしての乾性沈着量も多いことが明らかになった。その原因として、丹沢大山では霧の発生頻度が高く(山頂では年間の46%)、樹冠が常に濡れていることが考えられる。我々は霧の研究に平行して露の研究を横浜で行なったが、露の発生により乾性沈着速度が大きく増大する。横浜では、露は年間の20%程度発生し、降雨期間も考えると物体表面の濡れている時間は都市部においても非常に長い。このように、霧、露、降雨などの湿性過程は、大気からのエアロゾルやその前駆ガスの沈着過程において重要である。本研究では、フィールド研究を横浜と大山において行ない、これら湿性過程が、山間部や都市部における大気からの化学成分の沈着特性にどのような影響を及ぼすのか検討してきた。この特定研究の期間の中で明らかになった研究成果は、まず山間部の大山については、次の通りである。(1)ふもとのSPMの経年的な減少のため、霧水量が減少し、霧水濃度が増大する傾向にある。(2)霧水組成の支配要因としては大気汚染、霧底高度、霧水量の他に、降雨、風がある。(3)降雨量は平野部より山間部が大きく、標高依存性は小さい。樹冠への霧水の沈着の標高依存性は大きく、これには霧発生頻度と風速が影響している。(4)大気汚染物質の樹冠への沈着は、霧(標高依存性大)、乾性沈着>>雨である。また、関東平野に面する樹冠で大きくなった。また、都市部の横浜については次の通りである。(1)二酸化硫黄と窒素酸化物濃度は経年的に減少しているが、オキシダントと硝酸ガスは減少傾向が見られない。(2)靄(もや)や露の発生頻度は高く、これらの影響により汚染物質の沈着速度は大きくなる。(3)VOCは雨やエーロゾル中に高く、これらの経路による沈着過程は重要である。 エアロゾルの降水による沈着の促進と山岳部と都市部における乾性沈着量の比較 日本学術振興会  科学研究費助成事業 Project Year : 2002 - 2003  井川 学, 大河内 博 　View Summary 都市近郊山間部の丹沢大山の大気中の主要な酸性ガス成分とそれに対応するエアロゾル中陰イオン成分濃度を大都市部の横浜と比較した。大山では酸性成分濃度が横浜に比していずれも低いが、大気中の中和成分濃度も低下するためガス状で存在する割合は横浜より高い。硝酸ガス濃度は横浜と同じレベルであるが、雄山の噴火以降、二酸化硫黄濃度が顕著に増加した。両地点とも硝酸ガスと塩化水素ガス濃度の増加傾向があり、今後も降水の酸性化が予想される。大山では霧の発生頻度は高く、山頂では年間の45%程度である。680m地点の霧について経年変化を見たところ、近年、霧水量の減少とこれに伴う霧水内成分濃度の増加が見られ、これは麓のエアロゾル濃度の減少のために霧が発生しにくくなっていることによる。一回の霧イベントにおける霧水内成分濃度の変化を見ると、麓の大気汚染の状況はほとんど変わっていない時も、採取地点の風速等の変化のため霧水量が変化すると、これにともなって霧水濃度も変化した。また、降雨強度が増大すると霧は消失した。大山で得られた林外雨とモミ林内雨および樹幹流を比較したところ、霧の寄与は680m地点では小さいために林内雨量は林外雨量より小さい。濃度は林外雨に比して林内雨の方が極めて高く、沈着量としても林内雨の方が大きい。乾性沈着、霧、林外雨の林内雨への寄与を検討したところ、ガス成分の乾性沈着の寄与が大きい。ただし、林内雨や樹幹流は葉からの溶脱成分を多く含んでいる。また降雨強度の影響を見たところ、降雨強度が0.2mm/時以下の時、蒸発のために林内雨降水量が極端に小さく、このようなときはガス成分の乾性沈着あるいは霧の影響を強く受けていた。降雨強度が高くなると、林雨濃度は林内外雨濃度に近づくが、濃度の開きはなおも大きかった。 露水の酸性化とその環境に及ぼす影響の評価 日本学術振興会  科学研究費助成事業 Project Year : 1997 - 1998  大河内 博 　View Summary 1. 露水の地域特性・・・露は1997〜1998年に横浜で151日発生した(615日間観測)。年間露水量は7.0mmであり、これは年間降雨量の約1/200であった。1998年8月下旬〜9月上旬に横浜と丹沢大山の中腹(標高700m)で露の連続観測を行ったが、台風通過の影響もあり、同時採取できたのは2日のみであった。大山の露水量は横浜の約1/10であったが、pHは両地点でほぼ等しかった。大山の露水組成は海塩の影響を強く受けており、亜硫酸、硫酸、硝酸、アンモニウムイオンの割合が低かった。これは大山と横浜の大気汚染度の違いを反映したものと考えられた。2. 露水の化学組成の支配要因・・・1998年には横浜で68試料の露水が採取されたが、平均pHは5.93、総イオン濃度は1.76meq/Lであった。アルデヒドではHCHO濃度が最も高く、CH_3CHO、CH_3COCHO、CH_2(OH)CHOが同程度含まれていた。露水中HCHOの約90%は、大気由来のS(IV)との反応により、ヒドロキシメタンスルホン酸(HMSA)として存在していることが分かった。しかし、HMSAはS(IV)の30%程度であり、残りのS(IV)は他のアルデヒドと付加物を形成しているか、あるいはHSO_33^-として存在しているものと考えられた。3. 露水酸性度の支配要因・・・過去4年分の露水pHと陰イオン組成との関係について検討したところ、PHの低下に伴ってNO_3^-の割合が増加していることが明らかになった。このことより、露水は主にHNO_3の吸収によって酸性化していることが示唆された。そこで、NHO_3の沈着抵抗モデルを用いて露水中NO_33^-濃度の支配要因について検討したが、HNO_3の露液滴への沈着だけでは露水中NO_33^-濃度を説明できないことが分かった。この原因としては、夜間大気中で生成されるN_2O_5の露液滴への溶解が考えられた。 露水の酸性化機構とその環境影響 日本学術振興会  科学研究費助成事業 Project Year : 1996 　 　  大河内 博 　View Summary 1.露水の生成量・発生頻度…1996年に67試料の露水が採取されたが、このうち14試料で生成・消滅速度の測定が可能であった。露水の生成速度は平均で17.2g/m^2/h(6.4〜23.3g/m^2/h)、消滅速度は平均で38.0g/m^2/h(10.5〜73.6g/m^2/h)であり、消滅速度は生成速度の2倍以上であった。露発生頻度の解明を試みたが、露は日の出後1〜2時間程度で消滅するために採取が困難であり、露水の生成量・発生頻度を解明するためには採取装置の自動化が不可欠であることが分かった。2.露水の化学組成…露水を採取後直ちに吸引ろ過した後に、pH、伝導度、主要無機イオンに加え、亜硫酸などの弱酸、無機炭素、有機炭素、アルデヒドの測定を行った。露水の平均pHは5.13(3.81〜7.82)、総イオン濃度は1.87meq/Lであった。露水pHは夏季に最も低いが(平均pH4.24)S(IV)濃度も最も低いことから、これはS(IV)の液相酸化が夏季に促進されたためと考えられた。P&T-ATD-GC/MS法により露水中のVOCを測定したところ、クロロホルム、ベンゼン、1,2-ジククロメタンが検出された(20μg/L以下)、露水は有機塩素化合物によっても汚染されていることが明らかとなった。3.露水酸性度の支配要因…露水中の各成分濃度は、大気中濃度(ガスとエ-ロゾル)、乾性降下速度、露水量に依存するが、さらに、Ca^<2+>など主にエ-ロゾル由来成分は露存在時間、NH_4^+など主にガス由来成分は採取器設置時間に依存することが明らかとなった。昨年度、露水はS(IV)の液相酸化によって進行することを明らかとしたが、S(IV)の液相酸化触媒であるFeとMnの測定を行ったところ、それぞれ平均濃度で43.4μM、10.7μM含まれていることが明らかとなった。 露水の化学組成とその酸性化機構 日本学術振興会  科学研究費助成事業 Project Year : 1995 　 　  大河内 博 　View Summary 1.露水の生成・消滅速度…台ばかり上に露水採取器(厚さ10cmの発泡スチロール板(90cm×90cm)上に厚さ0.1mmのテフロンシートを両面テープで張り付けて作製)を固定して当大学研究棟屋上に夜間設置し、その重量変化を翌朝まで1分毎にコンピューターに記録した。単位時間当たりの重量増加量および減少量を採取面積で割り、それぞれ露水の生成および消滅速度を求めた。1995年には計16回の測定を行ったが、露水生成速度の平均値は5.2g/m^2/h(2.1〜9.0g/m^2/h)、消滅速度の平均値は15g/m^2/h(6.4〜44g/m^2/h)であり、消滅速度は生成速度の約3倍大きいことが明らかとなった。2.露水の化学組成…露液滴はテフロンハケで掻き取ってテフロンビーカー内に回収した。この試料を孔径0.45μmのMFで吸引ろ過した後に、pH、伝導度、主要無機イオンに加え、亜硫酸、亜硝酸、ギ酸、酢酸、無機炭素、有機炭素および各アルデヒドの測定を行った。1995年の露水の平均はpHは5.09(3.50〜7.58)、総イオン濃度は0.275meq/Lであり、同時期に採取した雨水の平均pH(4.63)よりも高く、総イオン濃度は約6倍高かった。このうち、陽イオンではNH_4^+(全体の25%)、陰イオンではSO_4^<2->(全体の11%)の占める割合が高く、S(IV)を高濃度(全体の9%)に含んでいた。露水中にS(IV)が高濃度に含まれている原因として、S(IV)の一部がH_2O_2などの酸化剤による液相酸化をほとんど受けないヒドロキシメタンスルホン酸(HMSA)を形成しているためであることが明らかとなった(HMSAの平均濃度:65μM、濃度範囲:0.9〜580μM)。3.露水酸性度の支配要因…1995年には計3回の露水の経時採取を行った。いずれの場合も主要無機イオン濃度は露水の成長時には希釈効果により低下、消滅時には濃縮効果により増加するが、pHおよびS(IV)濃度の変化は必ずしも露水量の変化と対応していなかった。抵抗モデルにより、露水中のS(V)濃度は主に大気中のHCHO、SO_2濃度に支配されていることが分かった。また、このS(IV)の液相酸化はMnの触媒効果により進行することが示唆された。 酸性降下物によるモルタル・コンクリート建造物の劣化機構の解明 日本学術振興会  科学研究費助成事業 Project Year : 1994 　 　  大河内 博 　View Summary 1.疑似酸性雨曝露実験…実験はモルタル柱状試料(直径5cm×高さ10cm)にpH3、4.7の疑似酸性雨と純水を5mL/minで2時間曝露した後、pH3は放置および乾燥(70℃で4時間)という条件で、pH4.7と純水は放置条件のみで行った。pH3の疑似酸性雨のモルタル接触後の溶液pHは、ほぼ一年分の降水量に相当する曝露後5日目から3.2付近で一定となり、pH4.7と純水ではpH3と比べると溶液pHは高く、純水に比べてpH4.7の溶液の方がわずかに低いpH(約pH6.3)を示した。一方、モルタルからのCa積算溶出量はpH4.7と純水でほぼ同程度であるが、pH3の条件では圧倒的に多く、90日後にはpH4.7と純水に比べて5〜6倍となった。なお、この時のCaの溶出速度はpH3で3.32mg/day、pH4.7で0.632mg/dayであった。モルタルの中性化は酸性度が高い程進行するが、pH3の疑似酸性雨では放置条件(3.7mm)に比べて乾燥条件(5.5mm)では90日間で約1.5倍促進されることが明らかとなった。また、曝露液量が同じ場合には、降雨強度が小さいほどCa、Siの溶出量は増加するが、中性化はほとんど促進されなかった。2.疑似酸性雲(霧)曝露実験…平均液滴径10μm以上のpH3の酸性霧を曝露した後(一回に2L/hrで2時間)に放置および乾燥するという条件を1サイクルとして合計30回行ったところ、中性化深さはそれぞれ1.63mm、0.83mmであり、いづれもpH3の酸性雨を曝露した時(それぞれ1.33、0.67mm)に比べて中性化が促進されることが明らかとなった。3.大気曝露実験…モルタル試料を乾性降下物のみ、乾性と湿性降下物の両方の2条件で屋外に曝露した。1年後の中性化深さは乾性降下物と乾性+湿性降下物の曝露条件でそれぞれ2.6、1.1mmであり、乾性降下物のみの方が約2.5倍中性化が進行していることが分かった。また、曝露表面のNO_3^-、SO_4^<2->含有量も測定したところ乾性降下物のみの方が高く、大気中の酸性ガスと反応してCa(NO_3)_2、CaSO_4などの腐食物が生成している可能性が示唆された。 酸性降下物の成分分析と森林生態系への影響評価 日本学術振興会  科学研究費助成事業 Project Year : 1993 　 　  大河内 博 　View Summary 1.成分分析…ろ過式採取器で1週間毎に採取した降水の年平均pHは4.92であり、横浜の降水(pH4.75)に比べて若干高かった。自動採取装置で採取した霧水(277試料)のpH範囲は2.89-6.23(平均値4.06)で、酸性度の極めて高い霧水(pH3.5以下)ではNO_3^-の比率が高く霧水の酸性化には硝酸の寄与が大きかった。また、霧水中にはギ酸(最高値53.8muM)、酢酸(最高値22.8muM)、アルデヒド(グリオキサールが最大で42.8muM)が高濃度に含まれていることが分かった。露水の採取は、神奈川大学研究棟屋上で発砲スチロール板に貼り付けたテフロンシート(45cm×90cm、厚さ1mm)を夜間設置して行ったが、1993年(7、8月を除く)のpH範囲は3.23〜7.12(21試料)であった。露水ではS(IV)が高濃度であり、また、露水のNO_3^-/SO_4^<2->比は低い(平均値0.30)ので、露水の酸性化は主にSO_2の液相酸化によるものと推測された。2.酸性降下物の標高分布…大山の南・南東斜面に沿って標高400mから山頂(標高1252m)まで林外雨、林内雨(スギ、モミ)合わせてバルク採取器を42個設置し、1ヵ月後に回収した。すべての主要イオン降下量は標高とともに減少したが、H^+、NH_4^+、NO_3^-、SO_4^<2->降下量は他の成分に比べて減少率が小さいことが明らかとなった。また、スギ、モミ樹冠からのK^+、Ca^<2+>の溶脱量は同程度であり、モミ樹冠ではNH_4^+、NO_3^-の吸収があることが分かった。3.大山における物質収支…大山の南・南東斜面に沿って4月、7月、11月にそれぞれ約30試料土壌を採取した。土壌pHに季節変化はなかったが、水溶性成分のうちCa^<2+>、Mg^<2+>、NO_3^-の濃度増加が7月に大きいことが分かった。これは、大山の土壌カラムに0.02mM(NH_4)_2SO_4溶液を流して1〜4週間室温で放置後に、NO_3^-濃度の増加が見られたことから硝化によるものと考えられた。また、土壌カラムにpH3の酸溶液を流したところ、モミの立ち枯れが著しい標高900m〜1000mの土壌でA1の溶出が早いことから、この付近では土壌の酸緩衝能力が低いことが分かった。 生体膜機能に類似した新しい選択透過膜分離技術の開発 日本学術振興会  科学研究費助成事業 Project Year : 1993 　 　  井川 学, 大河内 博 　View Summary 本研究においては、生体膜に学んで新しい膜分離技術を実現するために、次の課題を行なった。1)有機非電解質の選択的な膜透過…有機非電解質は、これと特異的に反応する無機イオンを担持したイオン交換膜により、促進輸送される。そこで、糖はほう酸イオンと錯体を作ることからこれを利用し、陰イオン交換膜にほう酸イオンを担持させ、グルコースの透過実験を行なった。その結果、グルコースの促進輸送が確認され、流束はグルコース濃度に依存したが、濃度が高いときは膜内のほう酸イオンとの間の強い相互作用のために輸送速度に上限値が見られた。また、錯体の生成定数の高い糖は透過性が減少し、選択透過性が観測された。2)電子輸送膜システム…生体膜では一般的なイオン輸送と電子輸送のカップリングは、イオン交換膜と電子選択透過膜をシステム内に組み込む込むことにより、特殊なキャリヤーを用いることなく可能となる。この系において効率は最大でも30%程度であるが、反応を多段階にすることにより効率の向上が見らた。さらに、太陽光や高塩濃度海水エネルギーとして有効に利用された。3)疎水性膜による物質分離…有機非電解質を疎水性膜に高分配させて加圧下で透過濃縮させたり、無機イオンを選択的に透過させることができる。膜素材を変えてイオン選択透過性を測定すると、膜素材が疎水的になるほど選択性は高くなった。このイオン選択透過性は、加圧下においては親水性のイオンほど水流束とのカップリングのために透過性が高くなるが、圧力をかけず濃度匂配のみの移動のときはイオン選択透過性は逆転し、親水的なイオンほど透過しにくくなる。さらに、疎水性膜を活性炭と同様に用いることにより疎水性物質の連続的除去の可能性もあり、重金属についても疎水性のキレートとすることにより、加圧下で透過濃縮することができる。以上の手法についてその効率を高めるなら、新しい環境改善技術として有効であろう。 酸性霧の成分分析と酸性化機構の解明 日本学術振興会  科学研究費助成事業 Project Year : 1992 　 　  井川 学, 村野 健太郎, 大河内 博 　View Summary 霧は地表近くで発生するために大気汚染の影響が大きく、液滴の成長による希釈効果は小さいために、酸性度が高くなる。本研究においては、大山と赤城山における酸性霧の成分分析とその酸性化機構の解明を行った。1988年より行なっている丹沢・大山における酸性霧の観測の結果、霧水のpH範囲は2.61〜7.00、体積加重平均pHは3.95であった。霧水の組成には酸性ガスの影響が大きいのでガス濃度の測定を行なったところ、大山の硝酸ガスと塩化水素ガス濃度は横浜とあまり変わらないが、アンモニアガス濃度は横浜の1/2〜1/4であった。酸性ガス濃度がアンモニアガス濃度とほぼ一致している大山では、霧が発生するときに酸性化しやすい条件にあると言える。1992年6月19日に大山で発生した最低pH2.62の霧水の分析の結果、pHの低いときにNH^+_4の大気負荷量が長時間にわたって高いレベルを保ち続け、霧水量の変化によってpHが変動していることが明らかとなった。このこととこれまでの結果とをまとめると、霧水のpHは、(1)大気の汚染度、(2)霧底の位置、(3)大気中の霧水量、(4)酸中和成分濃度、特にNH_3濃度により支配されていると言える。首都圏で放出された大気汚染物質が変換を受けながら飛来して来る赤城山の南東斜面においても、酸性霧を含めた大気汚染物質の総合観測を行なった。観測の結果、霧は雨より10倍以上の酸性度を示すことがあり、霧の発生しない日でも、高濃度のオキシダントと硝酸ガスの移動が確認された。関東周辺の森林は、常時このような大気汚染物質の負荷というストレスがあることから、これらの森林は今後生存し得るのか危惧される。 - - ▼display all Misc Misc プラスチック大気汚染の現状と課題—Current Status and Issues of Plastic Air Pollution—特集 大気中マイクロプラスチック研究の現状と課題 大河内 博, 谷 悠人, 小野塚 洋介, 王 一澤, 速水 洋, 竹内 政樹, 反町 篤行, 藤井 佑介, 竹中 規訓, 宮崎 あかね, 須永 奈都, 羽山 伸一, 徳長 ゆり香, 山口 高志, 勝見 尚也, 松木 篤, 池盛 文数, 梶野 瑞王, 足立 光司, 石原 康宏, 岩本 洋子, 新居田 恭弘 エアロゾル研究 / 日本エアロゾル学会編集事務局 編   38 ( 3 ) 145 - 159  2023 富士山体を利用した自由対流圏および大気境界層における雲水化学観測(9) 押見基央, 大河内博, 王一澤, 速水洋, 勝見尚也, 皆巳幸也, 米持真一, 三浦和彦, 三浦和彦, 加藤俊吾, 和田龍一, 竹内政樹, 土器屋由紀子, 畠山史郎, 畠山史郎, 山田佳裕 大気環境学会年会講演要旨集   64th  2023 J-GLOBAL 首都圏近郊山間部における渓流水を通じた微量金属元素の流出挙動と大気沈着の影響評価(7) 阪口悠宇, 大河内博, 中野孝教, 佐瀬裕之, 諸橋将雪 大気環境学会年会講演要旨集   64th  2023 J-GLOBAL 富士山太郎坊における越境汚染の通年観測手法の開発 佐藤颯人, 和田龍一, 定永靖宗, 加藤俊吾, 大河内博, 三浦和彦, 三浦和彦, 小林拓, 皆巳幸也, 鴨川仁, 松見豊, 梶野瑞王, 松本淳, 米村正一郎, 速水洋, 畠山史郎, 畠山史郎 大気環境学会年会講演要旨集   64th  2023 J-GLOBAL 大気中マイクロプラスチックの起源・動態・健康影響(6):雲水中マイクロプラスチック 王一澤, 大河内博, 吉田昇永, 速水洋, 竹内政樹, 反町篤行, 藤井佑介, 竹中規訓, 山口高志, 勝見尚也, 松木篤, 梶野瑞王, 足立光司, 石原康宏, 岩本洋子, 新居田恭弘 大気環境学会年会講演要旨集   63rd  2022 J-GLOBAL 富士山麓におけるドローン採取による単一雲滴中の硫酸塩定量 神谷祐翔, 南齋勉, 山本祐志, 大河内博 大気環境学会年会講演要旨集   63rd  2022 J-GLOBAL 首都圏近郊山間部森林域における渓流水の化学特性と大気沈着の影響評価(7) 浅見匠洋, 大河内博, 速水洋, 井川学, 山田佳裕, 佐瀬裕之, 諸橋将雪, 中野孝教 大気環境学会年会講演要旨集   63rd  2022 J-GLOBAL 首都圏近郊山間部における渓流水を通じた微量金属元素の流出挙動と大気沈着の影響評価(6) 阪口悠宇, 大河内博, 中野孝教, 佐瀬裕之, 諸橋将雪 大気環境学会年会講演要旨集   63rd  2022 J-GLOBAL The Effect of Atmospheric deposition on Trace Metals in Stream Water in Mountains near the Tokyo Metropolitan Area (5) 阪口悠宇, 大河内博, 浅見匠洋, 森田雄介, 西村寿々美, 佐瀬裕之, 諸橋将雪 環境化学討論会要旨集(CD-ROM)   30th  2022 J-GLOBAL カンボジア・シェムリアップ-アンコール地域における大気汚染と熱帯性豪雨の化学組成に及ぼす影響(3) 石川翔, 大河内博, 梶川友貴, 島田幸治郎, 島田幸治郎, 長谷川朝香, 篠崎大樹, 篠原和将, 内田悦生, 中川武, 中野孝教, 松井敏也, 石塚充雅, 荒井豊明, 宇田川智, PHORSDA Phul, LAY Poty, HANG Peou 大気環境学会年会講演要旨集   63rd  2022 J-GLOBAL 富士山頂および富士山5合目太郎坊におけるNO,NO2,NOy濃度の同時計測 佐藤颯人, 和田龍一, 定永靖宗, 加藤俊吾, 大河内博, 森樹大, 三浦和彦, 三浦和彦, 小林拓, 鴨川仁, 皆巳幸也, 松見豊, 梶野瑞王, 松本淳, 米村正一郎, 速水洋, 畠山史郎, 畠山史郎 大気環境学会年会講演要旨集   63rd  2022 J-GLOBAL Airborne microplastics and health impact 大河内博, 吉田昇永, 藤川真智子, ZHAO Helli, 谷悠人, 速水洋, 竹内政樹, 反町篤行, 藤井佑介, 竹中規訓, 宮崎あかね, 梶野瑞王, 足立光司, 石原康宏, 岩本洋子 日本薬学会年会要旨集(Web)   142nd  2022 J-GLOBAL 都市型局地的豪雨の雷活動と水化学分析について 藤原博伸, 大河内博, 三原直之, 鴨川仁, 鈴木智幸, 鈴木智幸, 林修吾 大気電気学会誌(Web)   16 ( 1 )  2022 J-GLOBAL P2-1-7 被覆肥料に由来するマイクロカプセルの環境動態（2-1 土壌有機・無機成分の構造・機能・ダイナミクス 2021年度北海道大会） 川崎 美佐子, 勝見 尚也, 楠部 考誠, 長尾 誠也, 大河内 博 日本土壌肥料学会講演要旨集   67   23 - 23  2021.09 DOI CiNii 2 被覆肥料に由来するマイクロカプセルの環境動態（中部支部講演会 2020年度支部講演会） 勝見 尚也, 楠部 孝誠, 長尾 誠也, 大河内 博 日本土壌肥料学会講演要旨集   67   211 - 211  2021.09 DOI CiNii 大気沈着物中のイソプレン起源テトロール類の分析:BSOA主成分の解明 永冨加奈子, 榊原邦央, 大平慎一, 石川勇人, 大河内博, 戸田敬 日本分析化学会年会講演要旨集(Web)   70th  2021 J-GLOBAL Air pollution and its impact of tropical heavy rainwater chemistry in Siem Reap-Angkor region of Cambodia (2) 石川翔, 大河内博, 梶川友貴, 島田幸治郎, 島田幸治郎, 長谷川朝香, 中野孝教, 内田悦生, 中川武, 松井敏也, 石塚充雅, 荒井豊明, 宇田川智, PHUL Phorsda, POTY Lay, PEOU Hang 環境化学討論会要旨集(CD-ROM)   29th  2021 J-GLOBAL Stream Water Chemistry in Mountainous site near the Tokyo Metropolitan Area and the effect of Atmospheric Deposition (5) 浅見匠洋, 大河内博, 森田雄介, 真庭護, 西村寿々美, 中野孝教, 井川学, 佐瀬裕之, 諸橋将雪 環境化学討論会要旨集(CD-ROM)   29th  2021 J-GLOBAL 大気中マイクロプラスチックの実態解明と健康影響 大河内博 日本公衆衛生学会総会抄録集(CD-ROM)   80th  2021 J-GLOBAL 化学・安定同位体分析を用いた山間部豪雨の実態と生成機構の解明(2) 米戸鈴美香, 大河内博, 藤原博伸, 梶川友貴, 鴨川仁, 山田佳裕, 加藤俊吾, 三浦和彦, 三浦和彦, 中野孝教, 井川学, 岩崎貴也, 戸田敬, 高橋善幸, 清水英幸, 佐瀬裕之, 村田浩太郎, 藍川昌秀, 家合浩明, 栗林正俊 大気環境学会年会講演要旨集   62nd (CD-ROM)  2021 J-GLOBAL The behavior, origin, and environmental risk of humic-like substances in the atmosphere (3) 篠原和将, 大河内博, 光川彩夏, 速水洋, 勝見尚也, 松木篤 環境化学討論会要旨集(CD-ROM)   29th  2021 J-GLOBAL Primary and secondary organic aerosols in forest atmosphere and their impact on heavy rainfall formation (1) 篠崎大樹, 大河内博, WU Bendao, 長谷川朝香, 村上周平, 速水洋, 戸田敬, 宮崎あかね 環境化学討論会要旨集(CD-ROM)   29th  2021 J-GLOBAL 大気中マイクロプラスチックの分析法確立と動態解明(3):雲水および雨水を中心に 吉田昇永, 大河内博, 速水洋, 新居田恭弘, 小林華栄, 浦山憲雄, 緒方裕子, 勝見尚也, 皆巳幸也, 宮崎あかね, 竹内政樹, 戸田敬, 三浦和彦, 三浦和彦, 加藤俊吾, 小林拓, 和田龍一, 高田秀重 大気環境学会年会講演要旨集   62nd (CD-ROM)  2021 J-GLOBAL 富士山南東麓森林域におけるNOx酸化物質(NOz)の特徴の解明 和田龍一, 定永靖宗, 加藤俊吾, 大河内博, 森樹大, 三浦和彦, 三浦和彦, 小林拓, 鴨川仁, 皆巳幸也, 松見豊, 梶野瑞王, 松本淳, 米村正一郎, 速水洋, 土器屋由紀子, 畠山史郎, 畠山史郎 大気環境学会年会講演要旨集   62nd (CD-ROM)  2021 J-GLOBAL 光熱変換赤外分光法(O-PTIR)を用いた冬季富士山南東麓における大気中マイクロプラスチック観測の特徴 趙鶴立, 大河内博, 吉田昇永, 速水洋, 勝見尚也, 竹内政樹, 宮崎あかね, 緒方祐子, 板谷庸平, 小林華栄, 浦山憲雄, 新居田恭弘, 高田秀重 大気環境学会年会講演要旨集   62nd (CD-ROM)  2021 J-GLOBAL 富士山体を利用した大気境界層上層および自由対流圏における酸性ガスおよびエアロゾルの長期観測(4) 矢田崇将, 大河内博, 大力充雄, 速水洋, 勝見尚也, 皆巳幸也, 小林拓, 三浦和彦, 三浦和彦, 加藤俊吾, 和田龍一, 竹内政樹, 戸田敬, 米持真一, 荒井豊明, 福島颯太, 土器屋由紀子, 畠山史郎 大気環境学会年会講演要旨集   62nd (CD-ROM)  2021 J-GLOBAL 首都圏近郊山間部森林域における渓流水の化学特性と大気沈着の影響評価(6) 浅見匠洋, 大河内博, 速水洋, 井川学, 山田佳裕, 佐瀬裕之, 諸橋将雪, 中野孝教 大気環境学会年会講演要旨集   62nd (CD-ROM)  2021 J-GLOBAL 富士山南東麓における無人航空機を用いた揮発性有機化合物の鉛直観測(1) 石川翔, 大河内博, 速水洋, 勝見尚也, 皆巳幸也, 竹内政樹, 戸田敬, 加藤俊吾, 三浦和彦, 三浦和彦, 小林拓, 和田龍一, 南齋勉, 土器屋由紀子, 畠山史郎, 山本祐志, 三阪和弘 大気環境学会年会講演要旨集   62nd (CD-ROM)  2021 J-GLOBAL 富士山山頂の雲水からのイミダゾール類の検出:雲水にイミダゾールは存在するか?またその起源は? 永冨加奈子, 和泉椋, 大力充雄, 佐伯健太郎, 光石夏澄, 大平慎一, 大河内博, 戸田敬 日本分析化学会年会講演要旨集(Web)   69th  2020 J-GLOBAL 富士山頂における夏季の自由対流圏雲水化学に関する長期トレンド 大力充雄, 大河内博, 中村恵, 小川新, 田原大祐, 竹村尚樹, 緒方裕子, 勝見尚也, 皆巳幸也, 米持真一, 三浦和彦, 加藤俊吾, 小林拓, 和田龍一, 竹内政樹, 戸田敬, 鴨川仁, 土器屋由紀子, 畠山史郎 日本気象学会大会講演予稿集(CD-ROM)   ( 118 )  2020 J-GLOBAL 2-1-9 農地におけるマイクロプラスチックの実態把握と分析方法の検討（2-1 土壌有機・無機成分の構造・機能・ダイナミクス，2019年静岡大会） 勝見 尚也, 楠部 孝誠, 宮里 朗夫, 松木 篤, 長尾 誠也, 大河 内博, 岡崎 正規 日本土壌肥料学会講演要旨集   65   15 - 15  2019.09 DOI CiNii カンボジア・シェムリアップアンコール地域における大気汚染と熱帯性豪雨の化学組成に及ぼす影響 梶川友貴, 大河内博, 中野孝教, 島田幸治郎, 内田悦生, 中川武, 松井敏也, 石塚充雅, 荒井豊明, 宇田川智, PHORSDA Phul, LAY Poty, HANG Peou 大気環境学会年会講演要旨集   60th (CD-ROM)  2019 J-GLOBAL 揮発性有機化合物の大気圏動態と航空機及び船舶排ガスの影響評価(3) 山脇拓実, 大河内博, 島田幸治郎, 皆巳幸也, 三浦和彦, 小林拓, 戸田敬, 米持真一, 加藤俊吾, 土器屋由紀子 大気環境学会年会講演要旨集   60th (CD-ROM)  2019 J-GLOBAL 富士山頂における自由対流圏大気ナノ粒子中微量金属元素の観測 宇田颯馬, 大河内博, 島田幸治郎, 米持真一, 小林拓, 三浦和彦, 加藤俊吾, 和田龍一, 土器屋由紀子, 畠山史郎 大気環境学会年会講演要旨集   60th (CD-ROM)  2019 J-GLOBAL 農地におけるマイクロプラスチックの実態把握と分析方法の検討 勝見尚也, 楠部孝誠, 宮里朗夫, 松木篤, 長尾誠也, 大河内博, 岡崎正規, 岡崎正規 日本土壌肥料学会講演要旨集(Web)   65  2019 J-GLOBAL 福島県の里山に大気沈着した放射性セシウムの動態解明と環境調和型除染技術の開発(3) 大河内博, 後藤友里絵, 後藤健太郎, 金野俊太郎, 黒島碩人, 島田幸治郎, 反町篤行, 床次眞司 環境化学討論会要旨集(CD-ROM)   27th   ROMBUNNO.P‐168  2018.05 J-GLOBAL 大気中陰イオン界面活性物質の動態と起源推定(6) 村上周平, 大河内博, 廣川諒祐, 島田幸治郎, 勝見尚也, 皆巳幸也, 小林拓, 三浦和彦, 加藤俊吾, 竹内政樹, 戸田敬, 米持真一 大気環境学会年会講演要旨集   59th  2018 J-GLOBAL 化学・安定同位体分析を用いた都市型豪雨の実態と生成機構の解明(2) 須合俊貴, 大河内博, 内山竜之介, 島田幸次郎, 中野孝教, 藤原博信, 鴨川仁 大気環境学会年会講演要旨集   59th  2018 J-GLOBAL 揮発性有機化合物の大気圏動態と航空機および船舶排ガスの影響評価(2) 山脇拓実, 大河内博, 島田幸治郎, 三浦和彦, 加藤俊吾, 皆巳幸也, 勝見尚也, 小林拓, 戸田敬, 米持真一, 鴨川仁, 土器屋由紀子 大気環境学会年会講演要旨集   59th  2018 J-GLOBAL 首都圏小規模森林における酸性物質と微量重金属元素の森林フィルター効果(4) 大河内博, 斉藤啓介, 永岡玲奈, 島田幸治郎, 宮崎あかね 環境化学討論会要旨集(CD-ROM)   27th  2018 J-GLOBAL 化学・安定同位体分析を用いた都市型豪雨の実態と生成機構の解明(1) 須合俊貴, 大河内博, 内山竜之介, 島田幸治郎, 中野孝教, 藤原博伸, 鴨川仁 環境化学討論会要旨集(CD-ROM)   27th  2018 J-GLOBAL 大気中陰イオン界面活性物質の動態と起源推定(5) 村上周平, 大河内博, 廣川諒祐, 島田幸治郎, 勝見尚也, 皆巳幸也, 小林拓, 三浦和彦, 加藤俊吾, 竹内政樹, 戸田敬, 米持真一, 榎本孝紀 環境化学討論会要旨集(CD-ROM)   27th  2018 J-GLOBAL 揮発性有機化合物の大気圏動態と航空機および船舶排ガスの影響評価(1) 山脇拓実, 大河内博, 島田幸治郎, 三浦和彦, 加藤俊吾, 皆巳幸也, 勝見尚也, 小林拓, 戸田敬, 米持真一, 鴨川仁, 土器屋由紀子 環境化学討論会要旨集(CD-ROM)   27th  2018 J-GLOBAL 富士山体を利用した大気境界層および自由対流圏の雲水化学特性の解明(5) 大河内博, 大力充雄, 中村恵, 島田幸治郎, 勝見尚也, 皆巳幸也, 小林拓, 三浦和彦, 加藤俊吾, 和田龍一, 戸田敬 環境化学討論会要旨集(CD-ROM)   27th  2018 J-GLOBAL 富士山における火山ガスの調査と早期検知遠隔システムの開発 大河内博, 山地達也, 島田幸治郎, 岩崎真和, 光石夏澄, 戸田敬, 竹内政樹 環境化学討論会要旨集(CD-ROM)   27th  2018 J-GLOBAL 山間部豪雨の発生頻度と化学特性(2) 大河内博, 梶川友貴, 山地達也, 西村寿々美, 真庭護, 島田幸治郎, 中野孝教 環境化学討論会要旨集(CD-ROM)   27th  2018 J-GLOBAL 自由対流圏および都市上空大気中微小および超微小粒子に含まれる微量金属元素(1) 宇田颯馬, 大河内博, 島田幸治郎, 勝見尚也, 皆巳幸也, 小林拓, 三浦和彦, 加藤俊吾, 米持真一, 土器屋由紀子 環境化学討論会要旨集(CD-ROM)   27th  2018 J-GLOBAL 福島県浪江町の里山における大気エアロゾル中放射性セシウム濃度に及ぼす山林火災の影響 吉岡颯, 大河内博, CHO Gai, 勝見尚也, 二宮和彦, 北和之, 五十嵐康人 日本地球惑星科学連合大会予稿集(Web)   2018   ROMBUNNO.MAG33‐P08 (WEB ONLY)  2018 J-GLOBAL 福島高線量地区における夏季大気セシウム放射能濃度増加とバイオエアロゾル 北和之, 林奈穂, 南光太郎, 木村茉央, 五十嵐康人, 足立光司, 牧輝弥, 石塚正秀, 大河内博, 古川純, 二宮和彦, 篠原厚 日本地球惑星科学連合大会予稿集(Web)   2018   ROMBUNNO.MAG33‐15 (WEB ONLY)  2018 J-GLOBAL Bioaerosol Observation in Tsukuba Botanical Garden 五十嵐康人, 北和之, 牧輝弥, 保坂健太郎, 反町篤行, 羽田野祐子, 石塚正秀, 齊藤保典, 川端康弘, 大河内博, 白石浩一, 冨田孝幸, 足立光司, 財前祐二, 水谷耕平, 河村公隆 エアロゾル科学・技術研究討論会(CD-ROM)   35th   ROMBUNNO.P23  2018 J-GLOBAL 森林除染に向けたドローン活用事例:里山における空間線量率の鉛直観測とドローン搭載ガンマ線カメラによる迅速調査への活用 大河内博, 片岡淳, 岸本彩, 岩本康弘, 金野俊太郎, 黒島碩人, 勝見尚也, 緒方裕子, 反町篤行, 床次眞司 大気環境学会年会講演要旨集   58th   140‐142  2017.08 J-GLOBAL 首都圏における都市大気エアロゾル中多環芳香族炭化水素の動態と健康リスク評価(2) 能智雅之, 大河内博, 島田幸治郎 大気環境学会年会講演要旨集   58th  2017 J-GLOBAL 富士山体を利用した大気境界層および自由対流圏の雲水化学特性の解明(3) 中村恵, 大河内博, 島田幸治郎, 勝見尚也, 皆巳幸也, 小林拓, 三浦和彦, 加藤俊吾, 和田龍一 大気環境学会年会講演要旨集   58th  2017 J-GLOBAL 首都圏近郊山間部森林域における渓流水の化学特性と大気沈着の影響評価(3) 真庭護, 大河内博, 島田幸治郎, 中野孝教, 井川学 大気環境学会年会講演要旨集   58th  2017 J-GLOBAL 首都圏小規模森林における酸性物質と微量金属元素の森林フィルター効果(2) 永岡玲奈, 大河内博, 島田幸治郎, 宮崎あかね 大気環境学会年会講演要旨集   58th  2017 J-GLOBAL 富士山体を利用した大気境界層上層および自由対流圏におけるガス状水銀の観測 山地達也, 大河内博, 勝見尚也, 島田幸治郎, 小林拓, 皆巳幸也, 三浦和彦, 加藤俊吾, 米持真一, 梅沢夏実, 野尻喜好 大気環境学会年会講演要旨集   58th  2017 J-GLOBAL 富士山体を利用した大気境界層上層および自由対流圏における酸性ガスおよびエアロゾルの観測(3) 宮内洋輔, 大河内博, 島田幸治郎, 勝見尚也, 皆巳幸也, 小林拓, 三浦和彦, 加藤俊吾, 竹内政樹, 戸田敬, 米持真一 大気環境学会年会講演要旨集   58th  2017 J-GLOBAL 首都圏近郊山間部における渓流水を通じた微量金属元素の流出挙動と大気沈着の影響評価(3) 西村寿々美, 大河内博, 島田幸治郎, 中野孝教, 井川学 大気環境学会年会講演要旨集   58th  2017 J-GLOBAL 首都圏近郊丘陵地の森林表層土壌化学特性に及ぼす里山管理と大気汚染物質の影響評価 小松健善, 大河内博, 島田幸治郎, 勝見尚也, 宮崎あかね 大気環境学会年会講演要旨集   58th  2017 J-GLOBAL 自由対流圏大気エアロゾル中PFOS/PFOAの動態に関する予備検討:新規開発されたハイボリュームエアサンプラー用PM2.5サイクロンの富士山頂におけるフィールド観測への適用 大河内博, 村上周平, 廣川諒祐, 島田幸治郎, 勝見尚也, 皆巳幸也, 小林拓, 三浦和彦, 加藤俊吾, 竹内政樹, 戸田敬, 米持真一, 榎本孝紀 環境化学討論会要旨集(CD-ROM)   26th  2017 J-GLOBAL 首都圏近郊丘陵地の森林表層土壌化学特性に及ぼす里山管理と大気汚染物質の影響評価 小松健善, 大河内博, 島田幸治郎, 勝見尚也, 宮崎あかね 環境化学討論会要旨集(CD-ROM)   26th  2017 J-GLOBAL 首都圏における都市大気エアロゾル中多環芳香族炭化水素の動態と健康リスク評価(1) 能智雅之, 大河内博, 島田幸治郎, 勝見尚也 環境化学討論会要旨集(CD-ROM)   26th  2017 J-GLOBAL 富士山体を利用した大気境界層上層および自由対流圏における酸性ガスおよびエアロゾルの観測(1) 宮内洋輔, 大河内博, 島田幸治郎, 勝見尚也, 皆巳幸也, 小林拓, 三浦和彦, 加藤俊吾, 竹内政樹, 戸田敬, 米持真一 環境化学討論会要旨集(CD-ROM)   26th  2017 J-GLOBAL 富士山体を観測タワーとして活用した自由対流圏大気および雲水中揮発性有機化合物の観測(2) 大河内博, 山脇拓実, 麻生智香, 島田幸治郎, 勝見尚也, 皆巳幸也, 小林拓, 三浦和彦, 加藤俊吾, 竹内政樹, 戸田敬, 米持真一 環境化学討論会要旨集(CD-ROM)   26th  2017 J-GLOBAL 夏季‐秋季における放射性セシウム大気再飛散のメカニズム 西岡拓哉, 北和之, 林奈穂, 佐藤武尊, 五十嵐康人, 足立光司, 財前祐二, 豊田栄, 山田桂太, 吉田尚弘, 牧輝弥, 石塚正秀, 二宮和彦, 篠原厚, 大河内博, 阿部善也, 中井泉, 川島洋人, 古川純, 羽田野祐子, 恩田裕一 日本地球惑星科学連合大会予稿集(Web)   2017   ROMBUNNO.MAG34‐04 (WEB ONLY)  2017 J-GLOBAL 富士山頂におけるエアロゾルの新粒子生成,成長と雲生成に関する研究 三浦和彦, 片岡良太, 桃井裕広, 岩本洋子, 矢吹正教, 永野勝裕, 加藤俊吾, 小林拓, 速水洋, 大河内博, 植松光夫 エアロゾル科学・技術研究討論会(CD-ROM)   34th   ROMBUNNO.B02  2017 J-GLOBAL 降水によるエアロゾル発生現象?:大気‐森林相互作用の新展開をねらって 五十嵐康人, 北和之, 牧輝弥, 齊藤保典, 大河内博, 保坂健太郎, 白石浩一, 冨田孝幸, 足立光司, 財前祐二 エアロゾル科学・技術研究討論会(CD-ROM)   34th   ROMBUNNO.P19  2017 J-GLOBAL 福島県の里山に大気沈着した放射性セシウムの長期変動 金野俊太郎, 大河内博, 黒島碩人, 勝見尚也, 緒方裕子, 片岡淳, 岸本彩, 岩本康弘, 反町篤行, 床次眞司 日本地球惑星科学連合大会予稿集(Web)   2017   ROMBUNNO.MAG34‐P03 (WEB ONLY)  2017 J-GLOBAL 放射性セシウムの大気への再浮遊にバイオエアロゾルが果たす役割 五十嵐康人, 北和之, 牧輝弥, 竹中千里, 木名瀬健, 足立光司, 梶野瑞王, 関山剛, 財前祐二, 石塚正秀, 二宮和彦, 大河内博, 反町篤行 日本気象学会大会講演予稿集   ( 110 ) 485  2016.09 J-GLOBAL 福島第一原発事故由来放射性セシウムの再浮遊:バイオエアロゾルの役割? 五十嵐康人, 北和之, 牧輝弥, 竹中千里, 木名瀬健, 足立光司, 梶野瑞王, 関山剛, 財前祐二, 石塚正秀, 二宮和彦, 大河内博, 反町篤行 エアロゾル科学・技術研究討論会(CD-ROM)   33rd   ROMBUNNO.I01  2016.08 J-GLOBAL 里山に大気沈着した放射性Csの動態と環境調和型除染技術の開発(2) 金野俊太郎, 大河内博, 緒方裕子, 勝見尚也, 反町篤行, 床次眞司, 片岡淳, 岸本彩 大気環境学会年会講演要旨集   57th   250  2016.08 J-GLOBAL 2015年夏季に富士山頂および韓国済州島で採取したPM2.5の化学組成と起源 米持真一, 廣川諒祐, 大石沙紀, 大河内博, 加藤俊吾, 田中仁志, LEE Ki-Ho, KIM Young-Ju, HU Chul-Goo 大気環境学会年会講演要旨集   57th  2016 J-GLOBAL Current Status and Future Issues of Atmospheric Environmental Research on the Fukushima Dai-ichi Nuclear Power Plant Accident Tsuruta Haruo, Igarashi Yasuhito, Inoue Tomohiro, Okochi Hiroshi, Ohara Toshimasa, Kajino Mizuo, Kaneyasu Naoki, Kita Kazuyuki, Sorimachi Atsuyuki, Hiraki Takatoshi, Horie Yousuke, Moriguchi Yuichi, Morino Yu, Watanabe Akira Journal of Japan Society for Atmospheric Environment / Taiki Kankyo Gakkaishi   51 ( 2 ) A11 - A19  2016 DOI CiNii J-GLOBAL 福島第一原発事故由来放射性セシウムの再浮遊:胞子は重要な役割を果たすのか? 五十嵐康人, 北和之, 牧輝弥, 竹中千里, 木名瀬健, 足立光司, 梶野瑞王, 関山剛, 財前祐二, 石塚正秀, 二宮和彦, 大河内博, 反町篤行 日本地球惑星科学連合大会予稿集(Web)   2016   ROMBUNNO.MAG24‐P03 (WEB ONLY)  2016 J-GLOBAL 夏/秋季における大気中の放射性セシウムの再飛散過程~生物‐大気循環の可能性 北和之, 木名瀬健, 堀内貴明, 坂本宗一郎, 武井愛里, 出水宏幸, 五十嵐康人, 足立光司, 梶野瑞王, 山田桂太, 豊田栄, 吉田尚弘, 二宮和彦, 篠原厚, 大河内博, 緒方裕子, 石塚正秀, 牧輝弥, 阿部善也, 中井泉, 古川純, 恩田裕一 日本地球惑星科学連合大会予稿集(Web)   2016   ROMBUNNO.MAG24‐04 (WEB ONLY)  2016 J-GLOBAL 都市域,森林域,山岳域における微小および超微小粒子の観測(2) 松永昂樹, 大河内博, 緒方裕子, 名古屋俊士, 足立光司, 財前祐二, 五十嵐康人, 宮崎あかね 大気環境学会年会講演要旨集   56回   483 - 483  2015.09 J-GLOBAL 福島県の里山に大気沈着した放射性セシウムの動態解明と環境調和型除染技術の開発(1) 金野俊太郎, 大河内博, 黒島碩人, 緒方裕子, 反町篤行, 床次眞司, 細田正洋, 片岡淳, 岸本彩 環境化学討論会要旨集(CD-ROM)   24th   ROMBUNNO.P‐174  2015.06 J-GLOBAL 放射性セシウムの大気再飛散担体粒子の解明 北和之, 田村匠, 田中美佐子, 木野日美子, 木名瀬健, 出水宏幸, 足立光司, 財前祐二, 五十嵐康人, 豊田栄, 山田桂大, 吉田尚弘, 二宮和彦, 阿部善也, 中井泉, 大河内博, 石塚正秀, 恩田裕一 日本地球惑星科学連合大会予稿集(Web)   2015   ROMBUNNO.MAG38‐04 (WEB ONLY)  2015 J-GLOBAL 137Cs及び134Csの大気中放射能濃度と粒径分布の季節変動 木名瀬健, 北和之, 田中美佐子, 出水宏之, 五十嵐康人, 足立光司, 三上正男, 山田桂太, 豊田栄, 吉田尚弘, 篠原厚, 二宮和彦, 大河内博, 石塚正秀, 川島洋人, 中井泉, 阿部善也, 恩田裕一 日本地球惑星科学連合大会予稿集(Web)   2015   ROMBUNNO.MAG38‐03 (WEB ONLY)  2015 J-GLOBAL V 森林樹冠に微量金属元素の沈着挙動 宮崎 あかね, 大河内 博 日本女子大学総合研究所紀要   17   21 - 27  2014.11 CiNii 富士山頂における粒子の化学組成 大石沙紀, 米持真一, 村田克, 大河内博, 名古屋俊士 大気環境学会年会講演要旨集   55th   392  2014.08 J-GLOBAL 都市大気環境中におけるナノ粒子の動向 大石沙紀, 米持真一, 村田克, 大河内博, 名古屋俊士 大気環境学会年会講演要旨集   55th   391  2014.08 J-GLOBAL 福島県浪江町の里山における放射性セシウムの分布と動態(2) 黒島碩人, 緒方裕子, 大河内博, 床次眞司, 反町篤行, 細田正洋, 片岡淳 大気環境学会年会講演要旨集   55th   491  2014.08 J-GLOBAL 富士山頂で測定した雲凝結核特性と霧粒特性 渡辺彩水, 青柳聡太, 三浦和彦, 岩本洋子, 古谷浩志, 植松光夫, 大河内博 エアロゾル科学・技術研究討論会(CD-ROM)   31st   ROMBUNNO.G04  2014.07 J-GLOBAL 都市大気と山岳大気での雲凝結核特性 渡辺彩水, 三浦和彦, 青柳聡太, 古谷浩志, 植松光夫, 大河内博 日本気象学会大会講演予稿集   105 ( 105 ) 363 - 363  2014.04 CiNii J-GLOBAL 富士山頂で測定した雲粒濃度の変化の要因 青柳聡太, 渡辺彩水, 三浦和彦, 古谷浩志, 植松光夫, 大河内博 大気電気学会誌   8 ( 1 ) 120 - 121  2014.04 J-GLOBAL 放射性物質の森林動態と森林除染に関する基礎的検討(2) 黒島碩人, 大河内博, 緒方裕子, 床次眞司, 反町篤行, 細田正洋 大気環境学会年会講演要旨集   54th   335  2013.08 J-GLOBAL 西生田キャンパスの森の大気浄化能について (第16回総合研究所研究発表会) -- (西生田キャンパスの森の再生) 宮崎 あかね, 大河内 博 日本女子大学総合研究所ニュース   ( 24 ) 9 - 11  2013.03 CiNii 福島第一原子力発電所事故により放出された放射性セシウムの大気再飛散メカニズムと飛散係数推定 北和之, 田中美佐子, 佐藤かおり, 木名瀬健, 出水宏幸, 五十嵐康人, 三上正男, 吉田尚弘, 豊田栄, 山田桂大, 篠原厚, 川島洋人, 大河内博, 恩田裕一 日本気象学会大会講演予稿集   103 ( 103 ) 409 - 409  2013 CiNii J-GLOBAL 山岳で観測される地方時型晴天時大気電気変動の発生機構 阪井陸真, 鳥居建男, 保田浩志, 大河内博, 鴨川仁 大気電気学会誌   6 ( 1 ) 103 - 104  2012.03 CiNii J-GLOBAL P-62 A study on precipitation scavenging of polycyclic aromatic hydrocarbons in the atmosphere and estimation of their dry deposition fluxes on forest canopy (2)(Poster session) FUJITA Masatoshi, OKOCHI Hiroshi, OGATA Hiroko   ( 53 ) 292 - 292  2012 CiNii P-63 Forest Filter Effect for Acidic Substances and the amount of dry deposition of Small Forests in the Tokyo Metropolitan area(Poster session) TAKADA Ken, OKOCHI Hiroshi, OGATA Hiroko   ( 53 ) 293 - 293  2012 CiNii 1E1100 Biogenic volatile organic compounds in a small western forest in the Greater Tokyo, Japan (3)(5 Substance-1 gaseous matter,General Presentations) SUZUKI Keisuke, OKOCHI Hiroshi, OGATA Hiroko   ( 53 ) 216 - 216  2012 CiNii 1F1000 Observation of forest filter effect by vertical profile of aerosols in a small forest(5 Substance-2 particulate matter,General Presentations) OGATA Hiroko, OKOCHI Hiroshi, MIURA Kazuhiko   ( 53 ) 221 - 221  2012 CiNii P-52 Forest ecosystem service and Nitrogen Saturation (2)(Poster session) EGUCHI Hiroyuki, OKOCHI Hiroshi, OGATA Hiroko, MIYAZAKI Akane   ( 53 ) 282 - 282  2012 CiNii P-53 Observation of acidic gases and water-soluble aerosol in the free troposphere using Mt. Fuji (2)(Poster session) ISOBE Takaharu, OKOCHI Hiroshi, OGATA Hiroko, TAHARA Daisuke, MARUYAMA Syohei, MINAMI Yukiya   ( 53 ) 283 - 283  2012 CiNii 2G0930-3 Development of the methods for the evaluation of deposition amount and dynamics of aerosol in forest ecosystem(Effects of aerosol on plants,Special Meeting 2) HARA Hiroshi   ( 53 ) 82 - 85  2012 CiNii 3B1026 Behavior and precipitation scavenging of air toxics (10)(4 Process-4 deposition/5 dynamics,General Presentations) KOBAYASHI Yusuke, OKOCHI Hiroshi, OGATA Hiroko   ( 53 ) 449 - 449  2012 CiNii 1D1506 Effect of acid deposition on runoff of trace metals in stream water in eastern Tanzawa mountains (6)(5 Substance-3 acid rain,General Presentations) YONEYAMA Naoki, OKOCHI Hiroshi, ONISHI Toshirou, OGATA Hiroko, IGAWA Manabu   ( 53 ) 343 - 343  2012 CiNii P-80 Atmospheric behavior of surface-active substances and their effects on atmospheric environment (2)(Poster session) SODA Minatsu, OKOCHI Hiroshi, OGATA Hiroko   ( 53 ) 310 - 310  2012 CiNii 1D1453 Study on cloud water chemistry and its controlling factors using Mt. Fuji (4)(5 Substance-3 acid rain,General Presentations) TAHARA Daisuke, OKOCHI Hiroshi, OGATA Hiroko, MINAMI Yukiya   ( 53 ) 342 - 342  2012 CiNii 3F1339 Characterization of PM1 collected at Kanto, the top of Mt. Fuji and Shanghai, and application of magnetic separation to them(5 Substance-2 particulate matter,General Presentations) YONEMOCHI Shinichi, UMEZAWA Natsumi, OH Kokyo, OKOCHI Hiroshi, NAGOYA Toshio, OGATA Hiroko, HARADA Yuki, YANAGIMOTO Yusuke, Lu Senlin, Zhang Rui, Hu Xuefeng   ( 53 ) 521 - 521  2012 CiNii 学会報告 第51回大気環境学会年会に参加して 大河内 博 作業環境   32 ( 1 ) 59 - 62  2011.01 CiNii 「大気モデル」の連載にあたって 大河内 博, 大原 利眞 大気環境学会誌 = Journal of Japan Society for Atmospheric Environment   45 ( 5 ) A74  2010.08 CiNii 富士山山頂で捕集した個別エアロゾル粒子の性状 近藤 洋史, 錦織 由実, 三浦 和彦, 小林 拓, 大河内 博 大気電気学会誌 = / Society of Atmospheric Electricity of Japan   4 ( 1 ) 131 - 132  2010.04 CiNii 早稲田大学創造理工学部環境資源工学科(研究室紹介) 大河内 博 大気環境学会誌   44 ( 4 ) ii  2009.07 CiNii 第49回大気環境学会年会に参加して 大河内 博 作業環境   30 ( 1 ) 56 - 58  2009.01 CiNii 3E0942 Forest filter effect for polycyclic aromatic hydrocarbons and their dry deposition (1) : Determination of PAHs in precipitation and throughfall by stir bar sorptive extraction and high-performance liquid chromatography with a fluorescence detector(2 Method-3 field observation,General Presentations) SHIMADA Jumpei, OKOCHI Hiroshi, MAEJIMA Koji, HARA Hiroshi   ( 50 ) 503 - 503  2009 CiNii 2E1140 The effect of acid deposition on the small forest ecosystem in the Tokyo Metropolitan area and the acid buffering processes (2)(5 Substance-3 acid rain,General Presentations) SEKI Keisuke, OKOCHI Hiroshi, KURISHIMA Nozomu, HARA Hiroshi, MIYAZAKI Akane   ( 50 ) 447 - 447  2009 CiNii 2E1052 Study of fog water chemistry and wet deposition in Mt. Fuji (4)(5 Substance-3 acid rain,General Presentations) TAKEMURA Naoki, OKOCHI Hiroshi, MARUYAMA Syohei, Minami Yukiya   ( 50 ) 443 - 443  2009 CiNii 3H0900-1 Significance, science, and International Conference of Fog and Dew(Science of Fog and Its Environmental Effect-Toward 6th International Conference on Fog, Fog Collection and Dew 2013 in Yokohama-,Special Meeting 6) OKOCHI Hiroshi   ( 50 ) 104 - 104  2009 CiNii P-92 Forest Filter Effect for Polycyclic Aromatic Hydrocarbons and their Dry Deposition (2) : Development of sampling and rapid analytical technique of vapor- phase PAHs by low volume air sampler using XAD-2 resin adsorbent(Poster session) KOBAYASHI Aya, KOJIMA Yuki, OKOCHI Hiroshi, NAGOYA Toshio   ( 50 ) 384 - 384  2009 CiNii P-56 Forest Filter Effect for Acidic Substances and Cooling Effect of Small Forests in the Tokyo Metropolitan area (1)(Poster session) KURISHIMA Nozomu, OKOCHI Hiroshi, SEKI Keisuke, MIYAZAKI Akane, HARA Hiroshi   ( 50 ) 348 - 348  2009 CiNii P-76 Effect of heavy rainfall on acid deposition in the Tokyo Metropolitan area(Poster session) KANEKO Chiho, OKOCHI Hiroshi, MOCHIDA Yuichiro   ( 50 ) 368 - 368  2009 CiNii P-63 Determination and characterization of atmospheric humic-like substances (5)(Poster session) SAGA Shuntaro, OKOCHI Hiroshi, MATSUNOBU Akinori   ( 50 ) 355 - 355  2009 CiNii P-78 Study of fog water chemistry and wet deposition in Mt. Fuji (5) Long-term performance assessment of a newly-developed solar-powered automatic rainwater collection system in southeastern slope of Mt. Fuji(Poster session) MARUYAMA Shohei, OKOCHI Hiroshi, TAKEMURA Naoki, FUNAKURA Takahiro, MINAMI Yukiya   ( 50 ) 370 - 370  2009 CiNii 3A1544 Comparison of the concentration of particle-associated volatile organic compounds at a roadside and an urban background area(5 Substance-2 particulate matter,General Presentations) SAITO Junichi, TAMECHIKA Kazuya, KOJIMA Yuki, MATSUO Ayumi, OKOCHI Hiroshi, NAGOYA Toshio   ( 50 ) 535 - 535  2009 CiNii 3B1300 Behavior of organic compounds relevant to biomass fuels in the atmosphere and their atmospheric impacts (2)(5 Substance-1 gaseouos matter,General Presentations) OKADA Takuya, OKOCHI Hiroshi   ( 50 ) 537 - 537  2009 CiNii P-05 Occurrence and chemistry of hydrometeor in urban area(Poster session) MOCHIDA Yuichiro, OKOCHI Hiroshi   ( 50 ) 297 - 297  2009 CiNii 1F1116 Behavior and precipitation scavenging of air toxics (7)(5 Substances-5 toxic chemical/6 offensive odor,General Presentations) TAMECHIKA Kazuya, OKOCHI Hiroshi, MIYAKE Yuki, MATSUNOBU Akinori, NAGOYA Toshio   ( 50 ) 282 - 282  2009 CiNii 2E1128 Effect of acid deposition on trace metal concentrations in stream water in eastern Tanzawa mountains(5 Substance-3 acid rain,General Presentations) ARAI Saori, OKOCHI Hiroshi, ONISHI Toshirou, HONDA Taku, KODERA Koji, MIYAZAKI Akane, IGAWA Manabu   ( 50 ) 446 - 446  2009 CiNii バイオマス燃料関連物質の大気動態と大気環境に及ぼす影響評価(1) 岡田卓也, 大河内博, 中牟田圭, 皆巳幸也, 五十嵐康人 日本化学会講演予稿集   88th ( 1 ) 634  2008.03 J-GLOBAL 有害大気汚染物質の動態解析と降水洗浄機構(5) 為近和也, 三宅雄貴, 松延明典, 大河内博, 皆巳幸也, 五十嵐康人, 稲津晃司, 名古屋俊士 日本化学会講演予稿集   88th ( 1 ) 633  2008.03 J-GLOBAL 富士山における霧水の化学組成と湿性沈着量(2) 竹村尚樹, 船倉崇弘, 大河内博, 皆巳幸也, 五十嵐康人 日本化学会講演予稿集   88th ( 1 ) 632  2008.03 J-GLOBAL 第2回学生・若手研究者の論文特集によせて(あおぞら) 上野 広行, 大河内 博 大気環境学会誌   43 ( 1 ) i  2008.01 CiNii P-95 Atmospheric behavior of oxygenated polycyclic aromatic compounds associated with airborne particulate matter(Poster (Academic Promenade)) KOJIMA Yuki, INAZU Koji, OKOCHI Hiroshi, HISAMATSU Yoshiharu, BABA Toshihide, NAGOYA Toshio   ( 49 ) 483 - 483  2008 CiNii P-73 Study of stream water chemistry and nitrogen saturation in the Tanzawa mountains (3) : Effects of acid deposition on forested ecosystem in eastern Tanzawa mountains estimated from trace metal concentrations in stream water(Poster (Academic Promenade)) ARAI Saori, OKOCHI Hiroshi, MIZUNO Yuichi, HONDA Taku, MIYAZAKI Akane, IGAWA Manabu   ( 49 ) 461 - 461  2008 CiNii 1B1118 Study of stream water chemistry and nitrogen saturation in the Tanzawa mountains (2) : Effects of acid deposition on forested ecosystem in eastern Tanzawa mountains(5 Substance-3 Acid rain,General Presentations) HONDA Taku, OKOCHI Hiroshi, MIZUNO Yuichi, ARAI Saori, IGAWA Manabu   ( 49 ) 223 - 223  2008 CiNii P-74 Observation of the concentrations of gas and aerosol on Mt. Fuji and its controlling factors (1)(Poster (Academic Promenade)) FUNAKURA Takahiro, OKOCHI Hiroshi, TAKEMURA Naoki, MINAMI Yukiya, IGARASHI Yasuhito 大気環境学会年会講演要旨集   49th ( 49 ) 462 - 462  2008 CiNii J-GLOBAL P-89 Determination and characterization of atmospheric humic-like substances in the atmosphere (4)(Poster (Academic Promenade)) MATSUNOBU Akinori, OKOCHI Hiroshi, NAGOYA Toshio, MINAMI Yukiya, IGARASHI Yasuhito, INAZU Koji 大気環境学会年会講演要旨集   49th ( 49 ) 477 - 477  2008 CiNii J-GLOBAL 3B1006 Atmospheric behavior of particle-associated PAHs on Mt.Fuji and its controlling factors(5 Substance-5 toxic chemical/2 Method-1 measurement/analysis,General Presentations) MAESHIMA Koji, OKOCHI Hiroshi, NAGOYA Toshio, INAZU Koji, HISAMATSU Yoshiharu, MINAMI Yukiya, IGARASHI Yasuhito 大気環境学会年会講演要旨集   49th ( 49 ) 557 - 557  2008 CiNii J-GLOBAL P-88 Behavior and precipitation scavenging of air toxics (6)(Poster (Academic Promenade)) MIYAKE Yuki, OKOCHI Hiroshi, TAMECHIKA Kazuya, MINAMI Yukiya, IGARASHI Yasuhito 大気環境学会年会講演要旨集   49th ( 49 ) 476 - 476  2008 CiNii J-GLOBAL 1B1054 Study of fog water chemistry and wet deposition in Mt. Fuji (3)(5 Substance-3 Acid rain,General Presentations) TAKEMURA Naoki, OKOCHI Hiroshi, FUNAKURA Takahiro, MINAMI Yukiya, IGARASHI Yasuhito 大気環境学会年会講演要旨集   49th ( 49 ) 221 - 221  2008 CiNii J-GLOBAL 学会報告 第48回大気環境学会年会に参加して 大河内 博 作業環境   28 ( 6 ) 53 - 55  2007.11 CiNii 有害大気汚染物質の動態解析と降水洗浄機構(4)~富士山における霧水中VOCの観測と促進吸収機構~ 三宅雄貴, 大河内博, 皆巳幸也, 五十嵐康人, 稲津晃司, 名古屋俊士 大気環境学会年会講演要旨集   48   544 - 544  2007.08 CiNii J-GLOBAL 大気中フミン様物質の定量と化学特性の解明(3) 松延明典, 大河内博, 皆巳幸也, 五十嵐康人, 稲津晃司, 名古屋俊士 大気環境学会年会講演要旨集   48th   543  2007.08 J-GLOBAL 富士山の西側斜面における降水およびエアロゾルの化学組成 皆巳幸也, 大河内博, 船倉崇弘, 五十嵐康人 大気環境学会年会講演要旨集   48th   566  2007.08 J-GLOBAL 富士山を利用したエアロゾルの鉛直的観測研究2005‐2006―概要 五十嵐康人, 高橋宙, 篠田佳宏, 三浦和彦, 永野勝裕, 兼保直樹, 小林拓, 皆巳幸也, 大河内博, 片山葉子, 永淵修, 横田久里子, 速水洋, 藤田慎一, 加藤俊吾 エアロゾル科学・技術研究討論会   24th   207 - 208  2007.08 J-GLOBAL 富士山における霧水の化学組成と湿性沈着量(1) 船倉崇弘, 大河内博, 皆巳幸也, 五十嵐康人 日本化学会講演予稿集   87th ( 1 ) 115  2007.03 J-GLOBAL 学会報告 第47回大気環境学会年会に参加して 大河内 博 作業環境   27 ( 6 ) 40 - 42  2006.11 CiNii 東京都心部における大気浮遊粒子中のニトロベンヅアントロンの分析 稲津晃司, NAM Vu Duc, 大河内博, 亀田貴之, 安里隆寛, 久松由東, 馬場俊秀 大気環境学会年会講演要旨集   46th   297  2005.08 J-GLOBAL 096-2 Selective Transport of Heavy Metal Ions across a Cation-Exchange Membrane with a Chelating Agent in the Receiving Phase Igawa Manabu, Narita Yohei, Okochi Hiroshi     344 - 348  2003.03 CiNii 097-2 Transport Characteristics of Neutralization Dialysis and Desalination of Tap Water Igawa Manabu, Mikami Kentaro, Okochi Hiroshi     349 - 353  2003.03 CiNii Deposition of air pollutants on the forest canopies in Mt. Oyama Igawa Manabu, Nishino Shouichi, Okochi Hiroshi   ( 44 ) 618 - 618  2003 CiNii Analysis of aldehydes in ambient air and precipitation and the dominant factors of their concentrations Igawa Manabu, Kawai Syunji, Okochi Hiroshi   ( 44 ) 601 - 601  2003 CiNii Chemistry of rain water and its acidification mechanism (15) Tsutsumi Kumiko, Okochi Hiroshi, Igawa Manabu   ( 44 ) 396 - 396  2003 CiNii Composition of Acid Fog and It&＃39;s acidification Mechanism (19) Igawa Manabu, Takeda Tomoharu, Okochi Hiroshi   ( 44 ) 394 - 394  2003 CiNii Air pollution in Yokohama and Mt. Oyama and their dominant factors Igawa Manabu, Sato Yoshiaki, Okochi Hiroshi   ( 44 ) 580 - 580  2003 CiNii Report on the 2nd International Conference on Fog and Fog Collection at St.John&＃39;s,Canada ABE Koichi, OGAWA Nobuaki, OKOCHI Hiroshi, KAJIKAWA Masahiro, YAMAMOTO Akira 天気   49 ( 2 ) 151 - 159  2002.02 CiNii 3G1110 Analysis of air pollutants on the surface of pollen Igawa M., Okuyama Y., Horikawa T., Okochi H.   ( 43 ) 561 - 561  2002 CiNii P21 Analysis of aldehydes in precipitation and the dominant factors of concentrations Nagahama A., Namba T., Okochi H., Igawa M.   ( 43 ) 491 - 491  2002 CiNii P33 Effect of acid deposition on fir needles Igawa M., Yabuta M., Okochi H.   ( 43 ) 503 - 503  2002 CiNii P22 Composition of Dewwater and Its Acidification Mechanism(13) Takeuchi M., Maeda T., Okochi H., Igawa M.   ( 43 ) 492 - 492  2002 CiNii 2D0900 Chemistry of rain water and its acidification mechanism (14) Tsutrumi K., Okochi H., Igawa M.   ( 43 ) 393 - 393  2002 CiNii P06 Dominant factors of gaseous and particulate concentrations and their interconversion Igawa M., Ogura T., Aoki T., Okochi H.   ( 43 ) 476 - 476  2002 CiNii 2D0930 Composition of Dewwater and Its Acidification Mechanism (12) Takeuchi M., Okochi H., Igawa M.   ( 43 ) 395 - 395  2002 CiNii 国際交流研究 英国イースト・アングリア大学滞在記 大河内 博 神奈川大学工学研究所所報   ( 24 ) 132 - 139  2001.11 CiNii 1K1045 Leaching of components in fir needles caused by acid fog and its effect on the decline Igawa M., Kobayashi C., Okumura K., Yamashita A., Okochi H.   ( 42 ) 323 - 323  2001 CiNii 1G1145 Chemistry of rain water and its acidification mechanism (13) Okochi H., Tsutsumi K., Kurita K., Igawa M.   ( 42 ) 287 - 287  2001 CiNii 1G1130 Analysis of dew-water components and study of acidification mechanism (11) Takeuchi M., Hasegawa T., Okochi H., Igawa M.   ( 42 ) 286 - 286  2001 CiNii 1G1030 Determination of aldehydes in rain and fog water and the dominant factors of their concentrations Nagahama A., Okochi H., Igawa M.   ( 42 ) 282 - 282  2001 CiNii 丹沢・大山におけるオゾン，窒素酸化物および二酸化硫黄の測定 平川剛, 新垣雄光, 増田直樹, 三宅隆之, 智和正明, 佐久川弘, 吉田耕治, 石坂隆, 大河内博, 井川学 丹沢大山におけるモミ枯れと大気汚染に関する調査報告書     1 - 6  2000.04 2G0915 Analysis of dew-water components and study of acidification mechanism (10) Takeuchi M., Hasegawa T., Okochi H., Igawa M.   ( 41 ) 449 - 449  2000 CiNii 2G1100 Analysis of acid fog components and study of acidification mechanism (16) Matsumura K., Okochi H., Igawa M.   ( 41 ) 456 - 456  2000 CiNii 2G1015 Acid deposition in Mt. Oyama and its hinder mountainous region Takahashi R., Hirayama H., Okochi H., Igawa M.   ( 41 ) 453 - 453  2000 CiNii 1B1330 Analysis of elemental composition in aerosol and their controlling factors Yoshioka A., Okochi H., Igawa M.   ( 41 ) 289 - 289  2000 CiNii Report on the 1st International Conference on Fog and Fog Collection at Vancouver, Canada Yamamoto Akira, Okochi Hiroshi 天気   46 ( 6 ) 377 - 383  1999.06 CiNii 3C02 Analysis of Dew Components and Study of Acidification mechanism (8) Takeuchi M., Okochi H., Igawa M.   ( 40 ) 566 - 566  1999 CiNii 3C04 Analysis of Acid Fog Components and Study of Acidification Mechanism (15) Matsumura K., Okochi H., Igawa M.   ( 40 ) 568 - 568  1999 CiNii 3C01 Analysis of Rain Components and Study of Acidification Mechanism (11) : Factors Controlling Concentrations of Soluble nad Insoluble Components Kobayashi K., Okochi H., Igawa M.   ( 40 ) 565 - 565  1999 CiNii 1F03 Effect of acid deposition on the decline of fir trees Igawa M., Taniura Y., Kase T., Okochi H.   ( 40 ) 289 - 289  1999 CiNii 2E05 Analysis of Elemental Composition in Aerosol and Their Controlling Factors Yoshioka A., Amano K., Okochi H., Igawa M.   ( 40 ) 503 - 503  1999 CiNii 2D1030 Effect of acid deposition on forest canopy Kase T., Okochi H., Igawa M.   ( 39 ) 344 - 344  1998 CiNii 2A0930 Analysis of Dew Components and Study of Acidification Mechanism (7) Takeuchi M., Okochi H., Igawa M.   ( 39 ) 317 - 317  1998 CiNii 2A0915 Analysis of Rain Components and study of Acidification Mechanism (8) Kobayashi K., Okochi H., Igawa M.   ( 39 ) 316 - 316  1998 CiNii 共同研究b:環境に優しい潤滑油の開発 持田 由幸, 工藤 邦男, 大河内 博 神奈川大学工学研究所所報   ( 19 ) 142 - 147  1996.11 CiNii ▼display all   Syllabus Syllabus Resources and Environmental Engineering Laboratory A [S Grade] School of Creative Science and Engineering 2024   spring semester Applied Physical Chemistry and Exercise A School of Creative Science and Engineering 2024   spring semester Practice & International Cooperation in Environmental Study School of Creative Science and Engineering 2024   an intensive course(spring) Environmental Analytical Chemistry School of Creative Science and Engineering 2024   spring semester Environmental Geochemistry School of Creative Science and Engineering 2024   fall semester Graduation Thesis [S Grade] School of Creative Science and Engineering 2024   full year Graduation Thesis School of Creative Science and Engineering 2024   full year Resources and Environmental Engineering Laboratory B [S Grade] School of Creative Science and Engineering 2024   fall semester Resources and Environmental Engineering Laboratory A School of Creative Science and Engineering 2024   spring semester Resources and Environmental Engineering Laboratory B School of Creative Science and Engineering 2024   fall semester Applied Physical Chemistry and Exercise A [S Grade] School of Creative Science and Engineering 2024   spring semester Introduction to Environmental Studies [S Grade] School of Creative Science and Engineering 2024   spring semester Introduction to Environmental Studies School of Creative Science and Engineering 2024   spring semester Introduction to Environment and Safety Engineering [S Grade] School of Creative Science and Engineering 2024   spring semester Introduction to Environment and Safety Engineering School of Creative Science and Engineering 2024   spring semester Overview of Resources and Environmental Engineering [S Grade] School of Creative Science and Engineering 2024   spring semester Inorganic Chemical Analysis Laboratory [S Grade] School of Creative Science and Engineering 2024   full year Overview of Resources and Environmental Engineering School of Creative Science and Engineering 2024   spring semester Inorganic Chemical Analysis Laboratory School of Creative Science and Engineering 2024   full year Contributions of Resources and Environmental Engineering to Human Society [S Grade] School of Creative Science and Engineering 2024   fall semester Contributions of Resources and Environmental Engineering to Human Society School of Creative Science and Engineering 2024   fall semester Overview of Resources and Environmental Engineering [S Grade] School of Creative Science and Engineering 2024   spring semester Overview of Resources and Environmental Engineering School of Creative Science and Engineering 2024   spring semester Graduation Thesis or Project Spring [S Grade] School of Creative Science and Engineering 2024   spring semester Graduation Thesis or Project Spring School of Creative Science and Engineering 2024   spring semester Introduction to Earth and Environmental Engineering School of Creative Science and Engineering 2024   spring semester Graduation Thesis or Project Fall [S Grade] School of Creative Science and Engineering 2024   fall semester Graduation Thesis or Project Fall School of Creative Science and Engineering 2024   fall semester Master&＃39;s Thesis (Department of Earth Sciences,Resources and Environmental Engineering) Graduate School of Creative Science and Engineering 2024   full year Master&＃39;s Thesis (Department of Earth Sciences,Resources and Environmental Engineering) Graduate School of Creative Science and Engineering 2024   full year Advanced Topics in Aquatic Chemistry Graduate School of Creative Science and Engineering 2024   fall semester Research on Atmospheric and Aquatic Chemistry Graduate School of Creative Science and Engineering 2024   full year Research on Environmental and Occupational Hygiene Graduate School of Creative Science and Engineering 2024   full year Seminar on Atmospheric and Aquatic Chemistry C Graduate School of Creative Science and Engineering 2024   spring semester Seminar on Atmospheric and Aquatic Chemistry B Graduate School of Creative Science and Engineering 2024   fall semester Seminar on Atmospheric and Aquatic Chemistry A Graduate School of Creative Science and Engineering 2024   spring semester Seminar on Atmospheric and Aquatic Chemistry D Graduate School of Creative Science and Engineering 2024   fall semester Practice & International Cooperation in Environmental Study Graduate School of Creative Science and Engineering 2024   an intensive course(spring) Advanced Aquatic Chemistry Graduate School of Creative Science and Engineering 2024   fall semester Research on Atmospheric and Aquatic Chemistry Graduate School of Creative Science and Engineering 2024   full year Research on Environmental and Occupational Hygiene Graduate School of Creative Science and Engineering 2024   full year Research on Atmospheric and Aquatic Chemistry Graduate School of Creative Science and Engineering 2024   full year Research on Environmental and Occupational Hygiene Graduate School of Creative Science and Engineering 2024   full year Special seminar on Environmental Protection Graduate School of Creative Science and Engineering 2024   full year Seminar on Atmospheric and Aquatic Chemistry C Graduate School of Creative Science and Engineering 2024   spring semester Seminar on Atmospheric and Aquatic Chemistry B Graduate School of Creative Science and Engineering 2024   fall semester Seminar on Atmospheric and Aquatic Chemistry A Graduate School of Creative Science and Engineering 2024   spring semester Seminar on Atmospheric and Aquatic Chemistry D Graduate School of Creative Science and Engineering 2024   fall semester Athletic Club Second Year (KYUDO Club) Global Education Center 2024   full year Athletic Club First Year (KYUDO Club) Global Education Center 2024   full year ▼display all   Sub-affiliation Sub-affiliation Faculty of Science and Engineering   Graduate School of Creative Science and Engineering Affiliated organization   Global Education Center Research Institute Research Institute 2022 - 2024 Waseda Center for a Carbon Neutral Society   Concurrent Researcher 2022 - 2024 Waseda Research Institute for Science and Engineering   Concurrent Researcher Internal Special Research Projects Internal Special Research Projects カンボジア・シェムリアップにおける大気中マイクロプラスチックの実態解明 2020   　View Summary 　2020年は新型コロナウィルス感染拡大に伴う渡航制限のために，カンボジアに行くことができなかったが，2019年までに採取した大気試料の分析をすすめるとともに，解析をすすめた．　2019年４月に採取した大気中マイクロプラスチックのμFTIR分析で同定行ったところ，新宿とは異なり3 - 7 µmと1 µmの二山分布を示すが，熱帯性スコール豪雨後にも二山分布を示すことが明らかになった．空気動力学径1 µmは肺胞まで侵入する粒径であり，健康リスクが懸念される．なお，大気中個数濃度は豪雨後に1/5に減少したが，新宿における大気中個数濃度よりも高かった．　カンボジアでPM2.5濃度が高いのは，プラスチックごみの不適切管理とともに，高温高湿度と強い紫外線による気候の影響と考えられた．　東南アジアにおける大気中マイクロプラスチックの空気動力学径を解明したのは，本研究が世界で初めてである．研究成果は2021年の日本環境化学討論会で発表する． カンボジア・シェムリアップにおける大気汚染の実態解明 2019   　View Summary 近年，カンボジアでは観光客の急増に伴う自動車や二輪車による排気ガスがアンコール遺跡群に及ぼす影響が懸念されている．本研究では大気汚染の実態解明を目的としてアンコール遺跡群の玄関口であるカンボジア・シェムリアップで乾季（4月22日〜26日)と雨季（8月15日〜26日）にPM2.5（硫酸塩，硝酸塩），ガス（NO2，SO2，HNO3，HCl，NH3，O3，VOCs，GEM），雨水の採取を行った．乾季にはPM2.5が100 µg/m3を越えていたが，林野火災と野焼きが原因と考えられた．また，PM2.5が一時的に2000 µg/m3を越える事例が観測された．このときにはブラックカーボンも同時に増加した． 里山に沈着した放射性Csの再飛散機構の解明と環境調和型森林除染技術の開発 2018   　View Summary 　2011年3月に起こった東日本大震災に伴う福島第一原子力発電所の事故によって，大量の放射性核種が放出された．大量の放射性核種は大部分が森林に捕捉されているが，森林は未だに完全な除染は行われていない．汚染された森林は新たな放射性核種の排出源となりうる．実際に，福島県では春季や降雨時の大気中放射性セシウム濃度の上昇が報告されおり，その原因は未だ解明されていない．　本研究では，効率的で環境調和型の森林除染の方法を提案するため，森林内での放射性セシウムの動態解明，森林での原位置除染方法の開発，森林からの放射性セシウムの再飛散メカニズムの解明の3つを目的として検討を行った． 大気汚染が首都圏夏季豪雨の生成に及ぼす影響 2018   　View Summary 近年都市部で多発する都市型豪雨（通称ゲリラ豪雨）の発生に大気汚染物質が与える影響を解明するため，東京都内で雨水を採取し，主要無機イオン，微量金属元素および水の水素・酸素安定同位体比を分析した．その結果，都市型豪雨には酸性物質由来分 (H+,  NO3-, nss-SO42-,NH4+) が多く含まれており，都市型豪雨が発生した際にはその中心付近で降水量とともに，酸性物質沈着量も局地的に増加させることがわかった．また，都市型豪雨では道路堆積物が有効な氷晶核として作用している可能性がある．水の水素・酸素同位体比から，都市型豪雨の水蒸気は主に都市から蒸発していることが分かった． 福島県の里山に大気沈着した放射性Csの長期変動と環境調和型森林除染技術の開発 2017   　View Summary 2011年3月11日に起きた東日本大震災に伴う福島第一原子力発電所事故 (以下，福島原発事故) により放射性物質が大気中に放出され，陸域環境に沈着した．放射能汚染の影響は未だに続いている．福島県では森林が71 %を占め，農地は11 %，宅地と道路はそれぞれ4 %である．里地里山は都市周辺山地（12 %），中山間地（60 %），奥山周辺（19 %）に分布している．放射性物質による高汚染度地域は中山間地が多く，生活と密着していることから里山除染に対する地元の期待は強い．本研究では，里山に大気沈着した放射性セシウムの分布と動態を明らかにし，効率的な里山除染の方法と環境調和型除染技術を確立することを目的としている．2012年から2017年まで，福島駅から浪江町山林内部までの各観測地点における空間線量率の走行サーベイを行っている．どの地点も経年的に空間線量率は減少しているが，最も離れた福島市内でも空間線量率が高い地点が存在している．このような地点で山林であり，除染が未だに行われていないことを示している．浪江町南津島の小規模森林では，放射性セシウム濃度は内部のスギ/アカマツ混合林に比べて林縁部の広葉樹林で高濃度である．広葉樹林では生葉，落葉，表層土壌で減少傾向にあるが，2015年以降，生葉と表層土壌ではほぼ一定であり，放射性Cs濃度も両者でほぼ一致している．この地点では根が浅い広葉樹が生育しているため，表層土壌に蓄積した放射性Csを経根吸収し，内部循環していることを示している．森林内部のスギ/アカマツ混合林では，放射性セシウム濃度は2013年には落葉に蓄積していたが，落葉の分解とともに表層土壌に移行し，2016年には表層土壌に蓄積していた．この地域ではスギやアカマツによる経根吸収は起こっていない．里山除染と行うには樹種に応じた手法の開発が必要であり，磁性プルシアンブルーナノコンポジットを用いた放射性Csの環境調和型除染技術開発に継続して取り組んでいる． 国内山岳・離島大気環境モニタリングネットワークの戦略的構築 2014   緒方裕子 　View Summary 　東アジアにおける全球大気観測拠点として富士山を中心に据え，日本上空・離島の清浄大気の常時監視体制の確立を目的として行った．2014年は富士山における大気化学観測の充実に焦点を絞り，気相・固相・水相の大気汚染物質について総合大気化学観測を行った．大気中ガス状水銀（GEM），雲水中微量重金属の観測を初めて行い，富士山頂における日中GEM濃度は国内地上域よりも高いことを初めて明らかにした．これらの成果はInternationalConference on AsianEnvironmental Chemistry (ICAEC) 2014で優秀学生賞を獲得し，大気環境学会誌に掲載された． 大気中界面活性物質の起源・動態・界面活性能の解明 2013   　View Summary １．研究目的と概要　大気エアロゾルと大気水相(雨，雲/霧，露/霜，林内雨)中の界面活性物質濃度を明らかにし，その起源，大気圏動態，界面活性能の解明を目指して，大気中イオン界面活性物質濃度の簡易迅速定量を確立し，都市，郊外，山間部，自由対流圏における大気中陰イオン性界面活性物質濃度を明らかにすることを目的に行った．さらに，主要な界面活性物質と考えられるフミン様物質を定量し，季節変化，経時変化の解明を試みた．２．研究成果概要①メチレンブルー吸光光度法は操作が煩雑であり，誤差が生じやすいことから，メチレンブルー吸光光度法を大気試料に適用するため，再現性が高く，より高感度かつ迅速な陰イオン界面活性物質（MBAS）の定量法を検討した．その結果，50 mLガラス製遠沈管を1本用い，20回手で攪拌後に，振とう機（1000 rpm）で5分間振とうすることにより，0 - 0.12 µMの低濃度範囲で直線性が高く（r = 0.996），高感度（検量線の傾き：1.07 µM-1）の検量線が得られた．最適条件を用いたエアロゾル捕集用の石英繊維フィルター水抽出液（ブランク）からのドデシル硫酸ナトリウム（SDS）の添加回収率は94.7 ± 3.3 %（n = 3），エアロゾルを捕集した石英繊維フィルター水抽出液（実試料）からの添加回収率は92.3 ± 1.5 %（n = 4），降水試料からの添加回収率は90.8 ± 3.5 %（n = 3）であった．このことから，本法は陰イオン界面活性物質の抽出・分析方法として大気試料に適用可能であった．本法を，2011年5月に採取した都市大気エアロゾルに適用した結果，陰イオン界面活性物質濃度は44.9 - 163 pmol/m3（n = 8）の範囲であり，平均は84.3 pmol/m3 であることが分かった．②東京都新宿区に位置する早稲田大学西早稲田キャンパスで、大気エアロゾル中フミン様物質（HULIS）の定量を行った。試料採取はハイボリウムエアサンプラーにて昼夜12時間毎（6:00 – 18:00、18:00 – 6:00）に行い、 DEAE-UV法でHULISをフミン酸、フルボ酸分画に分けて分析した。その結果、HULIS中90 %をフルボ酸が占めていることが分かった。HULIS濃度は夏季に低く、秋・冬季に高いという季節変化を示すことが分かった。年間を通じて、HULIS濃度はNO2、CO濃度と相関が見られたことから、都市域におけるHULISは自動車などの移動排出源から主に生成されていることが示唆された。夏季にはOxと正の相関があり、一次生成以外に二次生成の可能性が考えられた． 雲過程を含む自由対流圏の総合化学観測：東アジア全球観測拠点としての富士山の活用 2013   緒方裕子 　View Summary １．はじめに　　全球大気観測拠点としての富士山の有効性を検証するため，自由対流圏高度に位置する富士山頂で以下の大気化学観測を行い，以下の3点を明らかにすることを目的とした。①日本上空自由対流圏における気相，固相（エアロゾル），水相（雲水）中化学種のバックグランド大気濃度を明らかにする．②日本上空自由対流圏における夏季バックグランド汚染機構を明らかにする．具体的には，越境汚染と日中の谷風による局地的・地域的汚染の影響評価を行う．③雲を介した化学的変質過程が自由対流圏大気質に及ぼす影響を解明する．　上記目的を達成するために、本年度はPILSを借用（東大海洋研から借用）してガス状・粒子状酸性物質の高時間分解能観測を行い，フィル-パック法およびウェットデニューダー法(徳島大)との比較を行った。また、ポータブルGCMS TRIDION-9（エス・ディ・ジャパンから借用）を借用して大気中VOCsの高時間分解能観測を行い，熱脱離法と比較について検討した。２．観測期間・観測地点・観測項目　自由対流圏高度に位置する富士山頂の旧富士山測候所は夏季しか利用できないため、2013年7月と8月に集中観測を行った。とくに、2013年7月18日から8月22日までは旧富士山測候所に泊まりこんで、エアロゾル(水溶性成分，多環芳香族炭化水素，フミン様物質，球状炭化粒子，黄砂)，ガス（酸性ガス、揮発性有機化合物），雲水，雨水の観測を行い，日本上空のバックグランド濃度の測定を行った．さらに，ウェットデニューダーを用いて富士山頂および富士山南東麓太郎坊における酸性ガス（塩化水素，亜硝酸，硝酸，二酸化硫黄）の連続観測を行うとともに，PILSを用いた粒子状物質の連続モニタリングを富士山頂で行った。３．観測結果　本研究により、以下のことが明らかになった。　①空気塊の流入経路と雲水内化学成分との関係を調べたところ，中国北部および南部からの空気塊のときにHg, Cd，Pb，As，SO42-が高濃度であった。②8月18日夕方に桜島最大規模の噴火があり，この空気塊が8月21日早朝に富士山頂に到達したが，このときにはHg，Pb，As，H+，SO42-が高濃度であった。大気中SO2濃度はフィルターパック法で計測したが，桜島噴煙到達時に高濃度であり、フィルターパック法で計測した塩化水素濃度も高いことから桜島噴火プリュームが富士山頂に渡到達していることを明らかにした。また，このときに発生した雲水は噴煙由来のH2SO4により酸性化していた。このように、桜島噴煙の影響により，雲水の酸性化が生じることを実証したのは本研究が初めてである。③フィルターパック法は6時間毎の採取であるため時間分解能が悪いものの，首都大学東京・加藤准教授による自動モニターの計測値，PILSを用いたSO2とSO42-の総和（PILS（SO2+SO42-））と同様な挙動を示し，濃度レベルも比較的一致することが分かった。④ポータブルGCMS TRIDION-9（エス・ディ・ジャパンから借用）を富士山で使用する前に予備観測を本学51号館屋上で行った結果から、富士山頂でVOCs観測を行うには感度が不足していることが分かった。そこで、富士山麓で大気中VOCsの高時間分解能観測を試みたが、ほとんどVOCsを検出することができなかった。 富士山を利用した越境汚染観測：高時間能型大気採取システムの開発 2012   竹内政樹 　View Summary 　本研究では，富士山を「越境大気汚染（国境を越えて運ばれてくる大気汚染）監視塔」とみたて、経済発展の著しいアジア大陸から上空（自由対流圏）を運ばれてくる酸性ガスや粒子状酸性物質の自動連続観測とともに、雲の採取・分析を早稲田大学と徳島大学との共同研究で行った．　自由対流圏とは、私達が普段生活している空気層（大気境界層）の上にある綺麗な空気層であり，およそ２ｋｍから１０ｋｍの範囲である．通常，地上から放出された大気汚染物質は大気境界層に留まっていて，なかなか上空の自由対流圏に運ばれないが，雲の発生を伴うような激しい上昇気流が起こると，大気汚染物質も上空の自由対流圏に運ばれる．日本列島が位置する北半球中緯度帯の自由対流圏では，偏西風と呼ばれる強い西風が常に吹いている．偏西風は冬季に強く，夏季に弱くなるが，大気汚染物質がいったん自由対流圏まで上昇すると，夏季であっても地上より速く運ばれるので，越境大気汚染をいち早く知ることができる．　本研究では，越境汚染物質として，特に酸性物質に着目した．酸性物質が地上に降り注ぐと，森林の立ち枯れを引き起こしたり，土壌を酸性化して有害な重金属が河川に流出し，河川や湖沼の水棲生物が住めなくなる．また，河川水や湖沼は私達の飲用水としても重要である．現在，日本国内の酸性物質排出量は減少しているが，国境を越えて酸性物質が運ばれてくれば，日本の自然環境を守ることはできない．そこで，上空のガス、粒子、雲の中の酸性物質を精密に分析して、大陸から酸性物質がどのような形態（ガス・粒子）でどれくらい運ばれてくるのか，それらが雲に取り込まれると雲水をどれくらい酸性化するのかを明らかにすることを本研究の目的とした．　上空の空気は綺麗なので，地上で使用されている採取装置では，長時間に渡って空気を吸引する必要がある．このため、これまでの観測では時々刻々と変化する空気中のガスや粒子を追跡することができなかった．そこで，本研究課題では，徳島大学の竹内政樹准教授が開発した酸性ガス・粒子の高時間分解能型自動分析装置（ウェットデニューダー＋イオンクロマトグラフ）を富士山頂と富士山麓に設置して観測を行った．これまでのフィルターパック法による観測では６時間を要したが，この装置では約１５分毎に連続観測を行うこと可能であった．　2011年には富士山麓で予備的な観測を行い，2012年には富士山頂と富士山麓で同時観測を行った．2012年7月14日から8月中旬までに膨大なデータ（3000以上）が得られたが，8月中旬以降には富士山頂，富士山山麓ともに流路内で目詰まりが起こった．データを取得できた7月中旬から8月中旬まで富士山頂で得られたデータについて，同時観測を行ったフィルターパック法によるSO2濃度，SO2計との比較を行った．フィルターパック法は時間分解能は悪いものの，市販のS02計と概ね同程度の値が得られたが，高時間分解能型自動分析装置では高めの値が得られた．現在，この原因について検討を行っているが，装置内のバックグランドの上昇の可能性が考えられた．絶対値についてはずれがあるものの，高時間分解能型自動分析装置とSo2計による変動は概ね一致していた．　高時間分解能型自動分析装置ではSO2以外にも，HNO3，HClの観測を行うことができたが，自由対流圏において酸性ガス濃度を１ヶ月以上に渡って自動連続観測した例は世界的にも例がなく，本課題の大きな成果と言える．今後は，酸性ガスに加えて水溶性エアロゾルとの同時観測を行う予定である． 界面活性物質の大気圏動態と雲形成過程に及ぼす影響評価 2010   　View Summary １．近年，界面活性物質が大気中に存在することが確認されている．界面活性物質は親水基と疎水基からなる有機化合物であり，溶媒の表面張力を低下させる性質を持つ．界面活性物質が雲粒に取り込まれると雲粒径を低下させ，雲の寿命を延ばすことから地球規模の水循環や気候に影響を及ぼす．また，雲粒への疎水性有害有機物の溶解度を増加させる．そこで，水中陰イオン界面活性物質の分析法として用いられているメチレンブルー吸光光度法を大気試料に適用するための最適条件を検討し，大気エアロゾル試料に適用した．また，陽イオン界面活性物質の定量法についても検討を行った．２．観測は早稲田大学西早稲田キャンパス(新宿)，富士山南東麓（御殿場口太郎坊，標高1284 m），富士山頂（3776 m）で行った．大気中エアロゾルはハイボリュームエアサンプラーを用いて捕集し，水抽出した後にメチレンブルー吸光光度法で定量した．富士山南東麓では雲水の採取も行った．３．Koga et al. (1999) は，分液ロートの代わりに遠沈管を用いる陰イオン界面活性物質の迅速分析法を報告しているが，2本の遠沈管を使用するため操作が煩雑であった．そこで，本法では，より簡便かつ迅速な分析法を確立するために遠沈管を1本とし，分析感度および再現性を向上させるために遠沈管の振とう条件を検討した．その結果，遠沈管を手で20回振とう後に1000 rpmで5分間振とうすることにより，水中濃度として0 – 0.8 µMの低濃度範囲で直線性が高い検量線が得られ，分析感度も向上した．最適条件を用いたエアロゾル捕集用の石英繊維フィルター水抽出液（ブランク）からの添加回収率は94.7±3.2 % (n=3)，エアロゾルを捕集した石英繊維フィルター水抽出液（実試料）からの添加回収率は92.3±1.4 %（n=4）であり，本法は界面活性物質の抽出・分析方法として大気エアロゾルに十分に適用可能であることが分かった．そこで，本法を実試料に適用でした．2011年5月17～20日の早稲田大学西早稲田キャンパス(新宿)における大気エアロゾル中陰イオン界面活性物質(MBAS)濃度を浮遊粒子状物質(SPM)濃度の動態を調べたところ，MBASは日中に高く，夜間に低い傾向があることが分かった．粒子状物質濃度（SPM）との相関は低いが(r=0.481)，SO2との相関は高かった(r=0.768)．したがって，大気中MBASはSO2と同排出源をもつか，同方向からの輸送されている可能性が示された．　大気中陰イオン界面活性物質が表面張力に及ぼす影響については引き続き検討を行っているところである． 富士山体を利用した自由対流圏高度におけるエアロゾル―雲―降水相互作用の観測 2010   　View Summary １．富士山は孤立峰で斜面が急峻であり，山頂は自由対流圏高度に位置することから，日本上空における大気中および雲水中の様々な大気汚染物質のバックグランド濃度，大陸からの長距離輸送によるバックグランド汚染，エアロゾルーガスー雲ー降水相互作用の観測を行うことができる．2010年に行った夏季集中観測で得られた結果を以下に述べる． ２．観測は富士山南東麓の太郎坊(1300 m)と富士山頂(3776m)で行った．富士山頂での雲水採取には細線式パッシブサンプラー(臼井工業, FWP-500)，南東麓での雲水採取には自動雲水採取機(北都電気，DFC-2200)を用いた．また，同時にフィルターパック法によりエアロゾル，酸性ガスおよびアンモニアを捕集した．試料は直ちに持ち帰り，分析を行った． ３．2010年夏季集中観測期間(7月13日～8月25日)における富士山頂の雲水pHは3.59～5.66 (平均4.95, n=40)，南東麓の雲水pHは3.23～5.53 (平均4.01, n=21)であった．山頂における観測期間中の平均雲水内総イオン濃度は113 µeq/L であり，南東麓の1/10程度であった．雲水のNO3-/nss SO42-比は山頂で0.30～1.80 (平均0.84)，南東麓で0.46～3.24 (平均2.63)であることから，富士山頂では南東麓に比べて大気中硝酸濃度が低いために雲水pHが高いと考えられる．　2010年8月中旬の山頂における雲水化学性状を示す．海洋性気塊が卓越していた8月9-12日には，雲水内総イオン濃度は20 µeq/L以下であり，pHは5.5付近を推移した．8月13日以降に大陸性気塊に変わると総イオン濃度は増加して1 meq/Lに達し，NO3-/nss SO42-比は0.30，pHは3.59まで低下した．この時にはCOとO3濃度も増加していることから，大陸からの汚染大気の輸送を示唆している． 富士山体を利用した自由対流圏高度におけるエアロゾルー雲ー降水相互作用の観測 2009   　View Summary 　雲はエアロゾルを凝結核として生成し，その成長過程で水溶性ガスを吸収する．雲粒径が臨界直径より小さければ，雲粒は消失して気相にエアロゾルを放出するが，この過程を通じてエアロゾル径を増加させるとともに，水溶性成分を増加させる．雲粒径が臨界直径より大きければ，雲粒はさらに液滴成長して併合衝突により雨滴となって地上に落下する．このエアロゾルー雲ー降水相互作用は，地球温暖化とその環境影響の将来予測の観点から注目されている．本研究では，自由対流圏高度に位置する富士山頂で雨水，霧水，水溶性ガス・エアロゾルの連続観測を行い，日本上空のバックグランド大気濃度の解明を行うとともに，エアロゾル-雲-降水相互作用について検討した．　観測期間は2008年7月19日～8月25日であり，7月23日～30日までは泊まり込んでの集中観測を行った．観測地点は，富士山頂（富士山測候所，3776 m）と富士山南東麓（太郎坊，1300 m）である．観測項目はエアロゾル水溶性主要無機成分，酸性ガス(二酸化硫黄，硝酸，塩化水素)およびアンモニア，雲水および雨水中主要無機成分である．エアロゾルおよびガス成分の捕集には４段フィルター法，富士山頂における雲水の採取には受動型霧水採取器，富士山南東麓における雲水の採取には強制通風型自動霧水採取機を用いた．富士山麓では通年観測も行った。　7月集中観測期間中の富士山頂における雲水pHは4.04 ～ 5.61（平均：4.71），同時期に南東麓で採取された雲水pHは3.85～ 5.85（平均：4.12）であり，富士山頂では雲水のpH範囲が狭く，南東麓の雲水に比べて酸性度が低かった．雲水の主要な酸性物質である硝酸イオン濃度と非海塩性硫酸イオン濃度の比（NO3-/nss SO42-比）は富士山頂で0.24 ～ 1.98（平均：0.66），南東麓で0.28 ～ 2.42（平均：1.51）であり，富士山頂では硝酸イオンの存在割合が小さかった．一方，７月集中観測期間中の山頂におけるHNO3濃度は0 ～ 0.09 ppbv（平均：0.02 ppbv），SO2濃度は0.06 ～ 0.33 ppbv（平均：0.19 ppbv）であり，南東麓におけるHNO3濃度は0 ～ 0.14 ppbv（平均：0.03 ppbv），SO2濃度は0 ～ 0.38 ppbv（平均：0.14 ppbv）であった．HNO3濃度は富士山頂と南東麓でほぼ同じか，富士山頂で低濃度の傾向にあるが，SO2濃度は富士山頂で高濃度となる傾向が見られた．SO2濃度の上昇時には，CO濃度（燃焼起源の指標）とラドン濃度（陸地起源）の上昇を伴い，このときにはアジア大陸方向から空気塊が輸送されていた．したがって，アジア大陸由来のSO2が偏西風によって日本上空に輸送され， その輸送過程における粒子化とともに，SO2が雲水に取り込まれることによって富士山頂の雲水では富士山麓に比べてNO3-/nss SO42-比が低下したものと考えられた．　 大気中フミン様物質の計測・動態・起源・大気環境影響評価に関する研究 2009   　View Summary 大気エアロゾルや雲・霧水中にフミン物質と類似した構造と特性を有する高分子有機物，すなわち，フミン様物質(HULIS)の存在が確認され，その起源と大気圏動態が注目されている．大気中フミン様物質は，エアロゾルの吸湿特性，界面活性特性，光学特性の変化を引き起こし，雲粒形成過程（雲粒の生成・蒸発速度，雲粒粒径分布）や疎水性有機化合物の大気水相への促進吸収などに関与することが指摘されている．しかし，エアロゾル粒子中フミン様物質の同定には至らず，その起源やエアロゾルの光学特性，吸湿特性に及ぼす影響については未解明のままであった．本研究では，以下の4点を目的に研究を行った．　１）大気中フミン様物質の計測手法の開発　２）大気中フミン様物質のキャラクタリゼーション　３）大気中フミン様物質の起源および動態解析　４）大気中フミン様物質の大気環境影響評価　2009年7月17日～8月25日まで夏季集中観測を行った．観測地点は，富士山頂（富士山測候所，3776 m），富士山南東麓（太郎坊，1300 m），早稲田大学西早稲田キャンパスである．観測項目は，エアロゾル化学特性（水溶性主要無機成分，水溶性有機物（WSOC），HULIS，PAHs），エアロゾル生物特性（細菌株の同定と細菌数，），ガス状物質（VOCs，酸性ガス，アンモニア），霧水・雨水・露水中化学成分（主要無機成分，溶存有機炭素（DOC），HULIS，VOCs）である．大気中フミン様物質の測定には，水圏フミン物質の分析手法であるHiraide et al. (1994)の方法を改良したDEAE-XAD-UV法を用いた．　2009年7月は梅雨明けが遅く，天候不順であったことから，富士山頂では観測期間中に54試料の雲水が得られた．雲水中フミン様物質(HULIS)濃度は日中に高く，夜間低いという明瞭な日変動を示した．富士山頂の雲水では，富士山南東麓で同時期に得られた霧水，雨水，大気エアロゾル中 HULISに比べて，フミン酸の割合が高い傾向にあるが，日中にはフルボ酸の割合が増加した．　HULISは界面活性能を有することが指摘されていることから，単位無機イオン濃度あたりのHULIS濃度，すなわち，HULIS濃度と主要無機イオン濃度(total ion concentration, TIC)との比(以下，HULIS/TIC比)が，大気中VOCsの雲水への促進吸収過程に及ぼす影響について検討した．その結果，雲水中のHULIS/TIC比が高いほど，雲水中VOCsの濃縮係数(定義：(降水中VOCsの実測値)/(降水中VOCsのヘンリー則からの予想値))が増加することが分かった．　本研究により，自由対流圏高度における雲水中HULISの濃度変動，フミン酸とフルボ酸の割合，さらに雲水中HULIS濃度が高いほど気相VOCsを効率的に取り込むことが明らかになった． 富士山を観測塔として利用した雲核および降水洗浄過程に関するフィールド研究―東アジアの高層大気化学観測拠点を目指して― 2008   　View Summary 　富士山を自然の観測タワーとみなせば，大気汚染物質の鉛直分布の解明に利用できる．また，霧水の化学組成を霧発生時から経時的に調べることにより，ガスおよびエアロゾルの雲内洗浄過程や霧水の酸性化機構の解明を行うことが期待できる．本研究では，富士山南東麓における霧水，ガスおよびエアロゾルの通年観測を行うとともに，夏季には富士山頂，富士山山麓における同時観測を行い，越境大気汚染物質の動態と雲(霧)による洗浄機構について検討を行った． 　霧水の採取は富士山南東麓の太郎坊(標高1300 m)で，本研究助成により新規開発した分割採取型自動霧水採取機DFC-2200(北都電機)を用いて行った．また，4段フィルター法により酸性ガス(SO2, HCl, HNO3, HNO2)およびアンモニア，大気エアロゾルを2週間毎に採取した．夏季集中観測時には，山頂と南東麓で揮発性有機化合物と多環芳香族炭化水素などの有害有機汚染物質の観測も行った．　富士山南東麓における霧水の最低pHは3.19であり，体積加重平均pHは3.86であることが分かった(n = 114)．霧水の主要陽イオンはNH4+で，主要陰イオンはNO3-であった．霧水酸性化の指標となるNO3-/nss SO42-比(当量比)は0.243～4.01(平均1.72)であり，富士山南東麓では霧水酸性度に及ぼす硝酸の寄与が大きいことが分かった．日本国内の他の山岳域(0.236 (立山)～2.81 (六甲山・夏季))で採取された霧水に比べても高い傾向にある．　夏季に富士山頂と南東麓で同時に観測を行ったところ，富士山頂の霧水ではNO3-に比してSO42-の割合が高いことが分かった．日本国内ではSO2濃度がきわめて低いことから，S042-濃度が高くなる要因としては越境汚染の可能性が考えられる．また，約4000m近い自由対流圏高度に位置する富士山頂においても，ベンゼン，トルエンなどの揮発性有機化合物の大気濃度は南東麓(1300m)と同程度のレベルにあることが分かった．さらに，富士山頂で採取された雲(霧)水中には，これらの揮発性有機化合物がヘンリー則からの予測値以上に雲(霧)水に取り込まれていることがはじめて明らかになった．本研究により，富士山を用いた大気化学観測の有用性が示された． 東アジア地域における対流圏大気化学観測タワーとして富士山を利用するための基礎研究 2006   　View Summary 富士山は孤立した高峰であり，4000m近い高さの観測用鉄塔に見なせる可能性に着目し，富士山山体を鉛直的に利用して大気化学観測を行った．今年度は，富士山山頂および山麓において夏期集中大気化学観測を行うとともに，富士山麓において雨水および霧水の通年観測を行った．その結果，以下のようなことが明らかになった．１） 本研究で新たに開発した“太陽電池駆動小型自動雨水採取装置”と従来から湿性沈着用の評価に使用されてきたろ過式採取器を用いて，富士山山麓における湿性沈着量の通年観測を行った．その結果，自動採取装置では降雨採取ロスがなく，乾性沈着の影響を防げることから，山岳域等の無電源地域における湿性沈着量を評価する上で有用な装置であることが明らかになった．２）山頂と山麓で雨水と霧水の同時採取を行った．その結果，山頂に比べて山麓で成分濃度は高く、pHは低いことが分かった．観測期間中の山頂における霧水の体積加重平均pHは4.49であり，山麓における霧水の体積加重平均pHは3.47であった．３）山頂，山麓ともに霧水pHの低下には，(硝酸イオン/硫酸イオン)比の増加を伴うことから，霧水pHの低下は大気中HNO3ガスの吸収によるものと推測された．４）山頂と山麓で，大気中および霧水中VOCs（塩素化炭化水素，単環芳香族炭化水素，二環芳香族炭化水素，カルボニル類）の同時観測を行った．大気および霧水ともにトルエンが主要なVOCsであることが分かった．カルボニル類ではアセトン濃度が高濃度であった．現時点では大気中VOCsの起源は特定できていないが，山頂のVOCs濃度は山麓や都心部と同程度に高いことが分かった．５）霧水中VOCsには大気中VOCsからヘンリー則によって予測される以上のVOCsが溶解しており，その濃縮率は山麓の方が高いことが分かった．特に，ナフタレン類の濃縮率が高く，霧水中に含まれる非溶存態のフミン様物質が関与している可能性が示唆された．６）都心域に比べて，富士山山麓ではエアロゾル中の多環芳香族炭化水素(PAHs)は低濃度であり，都心域の１／３以下であることが分かった．測定を行ったPAHsのなかでは，フルオランテンとピレンが主要であることが明らかになった． ▼display all   Copyright (C) 2020 WASEDA University, All Rights Reserved.