Faculty Profiles - OSADA, Kazuo

Papers - OSADA, Kazuo

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Vehicular exhaust contributions to high NH3 and PM2.5 concentrations during winter in Tokyo, Japan Reviewed International journal

Osada Kazuo, Saito Shinji, Tsurumaru Hiroshi, Hoshi Junya

ATMOSPHERIC ENVIRONMENT Vol. 206 page： 218-224 2019.6

Decreasing trend of elemental carbon concentration with changes in major sources at Mega city Nagoya, Central Japan Reviewed International journal

M. Yamagami, F. Ikemori, H. Nakashima, K. Hisatsune, K. Osada

Atmospheric Environment Vol. 199 page： 155-163 2019.2

Behavior of total peroxy and total organic nitrate concentrations at Suzu on the Noto Peninsula, Japan: Long-range transport and local photochemical production Reviewed

Sadanaga, Y., A. Ishiyama, R. Takaji, A. Matsuki, S. Kato, K. Sato, K. Osada, H. Bandow

Atmospheric Environment Vol. 196 page： 20-26 2019.1

Sources of Optical Black Carbon in Nagoya Bay Area: Analysis Under Sea Breeze Condition Reviewed

Osada Kazuo, Yamagami Makiko, Hisatsune Kunihiro, Ikemori Fumikazu, Chatani Satoru

Journal of Japan Society for Atmospheric Environment / Taiki Kankyo Gakkaishi Vol. 54 ( 2 ) page： 55-61 2019

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

The hourly optical black carbon (OBC) concentrations in PM2.5 were measured in the south (NCIES) and north (Konan) of Nagoya City in Aichi Prefecture, Japan. In the summer, the OBC concentrations were high in the daytime under the sea breeze conditions in NCIES but no strong diurnal variation for the OBC was observed in Konan. The V and Ni in the PM2.5 also showed high concentrations in the daytime in the NCIES. The source analysis of elemental carbon in the PM2.5 in NCIES using a chemical transport model (CMAQ) showed dominant contributions from automobile exhausts in the morning and from ship exhausts during the daytime. The simulated daytime OBC concentrations in NCIES were higher than those at Konan, which properly fit the observed data at the sites. According to the results of tracer elements and the model simulation, the high OBC concentration observed in the daytime in the NCIES was caused by contribution from heavy oil combustion around the bay area under the sea breeze conditions.

DOI： 10.11298/taiki.54.55

光散乱式粒子計数器を用いたPM2.5吸湿特性の連続計測―2016年12月の高濃度事例を交えて― Reviewed

岩本洋子, 関根広貴, 齊藤伸治, 三浦和彦, 西川雅高, 永野勝裕, 長田和雄

エアロゾル研究 Vol. 33 ( 4 ) page： 238-248 2018.12

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

In order to deduce water content of PM2.5 in quasi-real-time, an observation system for hygroscopic characteristics of fine particles by using an optical particle counter (OPC) was developed. Measurements of volume concentrations (V0.3-2.0) from 0.3 to 2.0 μm in diameter to approximate PM2.5 in both dried and ambient (without dried) conditions were conducted at inland and coastal sites located in the south part of Kanto plain, Japan from December 2016. The relationship between relative humidity and hygroscopic change of V0.3-2.0 was analyzed by using hygroscopicity parameters (κv). The mean values of κv were 0.37 and 0.58 at the inland and coastal site, respectively. The mean κv was larger than the value calculated from chemical compositions of PM2.5 based on the simple mixing rule at the coastal site. This result suggests that mixing states and organic species also have important role to determine the hygroscopic behaviors of PM2.5. Since our system is easy to handle without frequent maintenance, it is suitable for simultaneous observation at multiple points for long term. These data will help to obtain representative hygroscopicity parameters of PM2.5 at various regions and seasons.

DOI： 10.11203/jar.33.238

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Important contributions of sea-salt aerosols to atmospheric bromine cycle in the Antarctic coasts Reviewed International coauthorship International journal

Hara Keiichiro, Osada Kazuo, Yabuki Masanori, Takashima Hisahiro, Theys Nicolas, Yamanouchi Takashi

SCIENTIFIC REPORTS Vol. 8 ( 1 ) 2018.9

名古屋港で観測された夏季海陸風のホドグラフの鉛直分布 Reviewed

永尾一平，菊本雄紀，河合　慶，長田和雄，柴田　隆，甲斐憲次

天気 Vol. 65 ( 8 ) page： 503－520 2018.8

Morphological features and mixing states of soot-containing particles in the marine boundary layer over the Indian and Southern oceans Reviewed

Ueda Sayako, Osada Kazuo, Hara Keiichiro, Yabuki Masanori, Hashihama Fuminori, Kanda Jota

ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. 18 ( 13 ) page： 9207-9224 2018.7

Sudden increase in atmospheric NH3 concentration after drying using a hydrometeor Reviewed

Osada Kazuo, Yamagami Makiko, Ikemori Fumikazu, Hisatsune Kunihiro, Nakashima Hironori, Miwa Atsushi, Yabutani Syouki

Journal of Japan Society for Atmospheric Environment / Taiki Kankyo Gakkaishi Vol. 53 ( 4 ) page： 130-135 2018.7

Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal)

A sudden increase up to 16 ppbv of the hourly NH3 concentration was observed after drying rain and dew on 11th December 2015. Factors related to the sudden NH3 increase were investigated by using meteorological data and the chemical constituents of the rainwater. For the chemical composition of the rainwater on December 11, the pH was about 5.6 with high sea salt and Ca2+concentrations, allowing the volatilization of NH4+ in the rainwater after drying. Another important factor was considered to be the dew formation under the high NH3 concentration. Combined with these factors, the NH3 concentration in the atmosphere sharply increased with the decreasing humidity after drying hydrometeor.

DOI： 10.11298/taiki.53.130

Retrieval of Aerosol Components Using Multi-Wavelength Mie-Raman Lidar and Comparison with Ground Aerosol Sampling Reviewed

Hara Yukari, Nishizawa Tomoaki, Sugimoto Nobuo, Osada Kazuo, Yumimoto Keiya, Uno Itsushi, Kudo Rei, Ishimoto Hiroshi

REMOTE SENSING Vol. 10 ( 6 ) 2018.6

Seasonal Variations of Gaseous and Size-Segregated Particulate NHx and Inorganic Nitrate at Chikushi Campus, Kyusyu University Reviewed

OSADA Kazuo, KAMIGUCHI Yusuke, KUWAHARA Shohei, PAN Xiaole, HARA Yukari, UNO Itsushi, YAMAMOTO Shigekazu

Earozoru Kenkyu Vol. 33 ( 1 ) page： 31-39 2018.3

Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal)

Gaseous compounds (NH3 and HNO3) and size-segregated aerosol particles (NH4+ and NO3-) were measured at Chikushi Campus, Kyusyu University from July 31, 2014 to October 19, 2015. NH3 and fine NH4+ concentrations were semi-continuously (34 min interval) measured by using a micro flow analytical system. HNO3 and size-segregated aerosol particles were collected for 1 to 3 days intervals by using an annular denuder with a multiple filter set (Nuclepore, PTFE, and Nylon). Intensive sampling (ca. 8 hours interval) was conducted twice from September 24 to October 9, 2014 and from January 7 to 17, 2015. NH3 and HNO3 concentrations were high in warm season, whereas NH4+ and NO3- concentrations in fine particles were high in cold season. NH3 concentrations were low after rain in the ensuing days and were higher after days without rain. HNO3 concentration during fall experiment was periodically high in daytime under sunny and sea breeze wind conditions, suggesting contribution of local NO2 oxidation to high HNO3 during daytime. Seasonal variations of gas-particle phase relationships of NH3 and HNO3 were discussed in terms of temperature dependence of NH4NO3 equilibrium. Concentration products between NH3 and HNO3 were mostly below equilibrium of NH4NO3 estimated from air temperature during sample collection, suggesting that formation of NH4NO3 was limited during late winter to early spring.

DOI： 10.11203/jar.33.31

Modeling the Long-Range Transport of Particulate Matters for January in East Asia using NAQPMS and CMAQ

Wang Zhe, Itahashi Syuichi, Uno Itsushi, Pan Xiaole, Osada Kazuo, Yamamoto Shigekazu, Nishizawa Tomoaki, Tamura Kei, Wang Zifa

AEROSOL AND AIR QUALITY RESEARCH Vol. 17 ( 12 ) page： 3065-3078 2017.12

Importance of Long-Range Nitrate Transport Based on Long-Term Observation and Modeling of Dust and Pollutants over East Asia Reviewed International coauthorship

Uno Itsushi, Osada Kazuo, Yumimoto Keiya, Wang Zhe, Itahashi Syuichi, Pan Xiaole, Hara Yukari, Yamamoto Shigekazu, Nishizawa Tomoaki

AEROSOL AND AIR QUALITY RESEARCH Vol. 17 ( 12 ) page： 3052-3064 2017.12

Observations of Aerosols and Trace Gases around the Chikushi Campus of Kyushu University

Wang Zhe, Uno Itsushi, Osada Kazuo, Pan Xiaole, Yamamoto Shigekazu, Kanaya Yugo

Vol. 153 page： 113 - 129 2017.9

Language：English Publishing type：Research paper (scientific journal) Publisher：Research Institute for Applied Mechanics, Kyushu University

To better understand seasonal variations in the components of PM_〈2.5〉 and related trace gases, and the impacts of long-range transport from the Asian continent to Japan, we analyzed long-term, simultaneous observations of fineand coarse-mode nitrate, related aerosol components (SO_4^〈2-〉, NH_4^+, BC, OC), and trace gases (CO, NH_3, HNO_3) around the Chikushi Campus of Kyushu University, Fukuoka (33.52°N, 130.47°E), from August 2014 to October 2015. Daily and monthly mean aerosol concentrations were analyzed to assess the main seasonal variation in pollution. We found that fine aerosols (fSO_4^〈2-〉, fNO_3^-, and fNH_4^+) explained most of the seasonal change in PM_〈2.5〉. Polarization optical particle counter measurements were useful for detecting the onset of dust transport from the Asian continent, and we observed high concentrations of coarse-mode NO_3^- (cNO_3^-) during dust period, which indicated the formation of dust nitrate during transport. We also analyzed diurnal variation in the basic aerosol components for different seasons, weekday/weekend effects (for CO, BC, and NH3), and sensitivity on days with and without precipitation (for CO, BC, NH_3, PM_〈2.5〉, and PMc). Observational data for HNO_3, fNO_3^-, and cNO_3^- demonstrated that cNO_3^- accounted for the largest proportion of total nitrate (defined as the sum of fNO_3^-, cNO_3^-, and HNO_3), constituting 40–55% of the total nitrate during the winter, whereas HNO_3 gas constituted approximately 40% of the total nitrate in summer and fNO_3^- peaked during the winter.

DOI： 10.15017/1924421

CiNii Research

Analysis of the Seasonal Variation in Atmospheric NH_3 over East Asia International coauthorship

Wang Zhe, Uno Itsushi, Osada Kazuo, Itahashi Syuichi, Yumimoto Keiya, Yamamoto Shigekazu

Vol. 153 page： 130 - 141 2017.9

Language：English Publishing type：Research paper (scientific journal) Publisher：Research Institute for Applied Mechanics, Kyushu University

Atmospheric ammonia (NH_3) plays an important role in the formation and understanding of secondary inorganic aerosols, but has not been examined using chemical transport models (CTMs) and atmospheric levels have not been compared with satellite observations. Here, we analyzed the seasonal variation in atmospheric NH_3 using long-term hourly NH_3/NH_4^+ measurements made at the Chikushi Campus of Kyushu University in Fukuoka, nationwide filter pack (FP) network observations over Japan, GEOS-Chem CTM results, and Infrared Atmospheric Sounding Interferometer (IASI) satellite retrievals over East Asia. We found that the IASI NH_3 retrieval over central and north China had a strong correlation with the CTM results (R = 0.74). There was a similar correlation over south China, but the IASI NH_3 retrieval was only 48% of the CTM value. CTM results over Japan reproduced the major seasonal variations compared with surface observations, but IASI observations over Japan were below or near the detection limit and it was difficult to obtain a reasonable correlation with measurements.

DOI： 10.15017/1924422

CiNii Research

PM2.5高濃度イベント時のエアロゾル粒子中有機トレーサー成分 β線自動測定機のテープろ紙を用いた高時間分解能解析 Reviewed

池盛文数, 山神真紀子, 久恒邦裕, 長田和雄

大気環境学会誌 Vol. 52 ( 4 ) page： 118 - 128 2017.7

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：(公社)大気環境学会

2015年12月9、10日に名古屋で観測されたPM2.5質量濃度の日内変動が大きい高濃度イベントに対して、PM2.5自動測定機のテープろ紙を用いて3時間ごとに15種類の有機トレーサー成分の測定を行った。植物燃焼とプラスティック燃焼による一次粒子の有機トレーサー成分(レボグルコサンなど)は、PM2.5質量濃度と同じく9日夜間および10日深夜に濃度が上昇した。一方、二次的に生成した有機トレーサー成分(リンゴ酸など)の多くは、一次粒子の有機トレーサーとは異なり、12月10日のピークは見られるものの、9日夜間には明確な濃度ピークが見られなかった。また、PM2.5質量濃度に対する各有機トレーサーの含有率は、一次粒子の有機トレーサー成分の多くがPM2.5質量濃度と類似の時間変化を示した。このため、一次粒子濃度の増加が観測期間のPM2.5高濃度化に寄与したと考えられる。これに対して、二次性成由来の有機トレーサー成分は、12月9日夜間にはその前後の期間に対し含有率が減少する傾向にあり、10日深夜は、他の期間よりコハク酸と3-ヒドロキシグルタル酸のみ含有率が高い傾向にあった。このように、PM2.5の高濃度化現象に対する有機物質の寄与は、一次粒子と二次粒子とで大きく異なっていた。高時間分解能での有機トレーサー成分の解析は、時間変動の大きい高濃度事例の要因を解析するために有用である。(著者抄録)

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Nitrate transboundary heavy pollution over East Asia in winter Reviewed International journal

Itahashi Syuichi, Uno Itsushi, Osada Kazuo, Kamiguchi Yusuke, Yamamoto Shigekazu, Tamura Kei, Wang Zhe, Kurosaki Yasunori, Kanaya Yugo

ATMOSPHERIC CHEMISTRY AND PHYSICS Vol. 17 ( 6 ) page： 3823-3843 2017.3

立山における粗大粒子体積濃度から見た黄砂飛来頻度の季節変化 Reviewed

長田和雄, 清水厚, 飯田肇, 木戸瑞佳

エアロゾル研究 Vol. 32 page： 44-51 2017.3

Trans-boundary transport of PM2.5 to the western Japan and Japan Sea side regions based on the Source-Receptor Analysis

Kuwahara Shohei, Uno Itsushi, Wang Zhe, Itahashi Syuichi, Yumimoto Keiya, Osada Kazuo, Yamamoto Shigekazu

Vol. 152 page： 1 - 11 2017.3

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Research Institute for Applied Mechanics, Kyushu University

Long-term synergetic fine and coarse mode aerosol observations were analyzed at 1-h intervals at the Chikushi-campus of Kyushu University, Fukuoka, Japan, from December 2013 to March 2015. The GEOS-Chem chemical transport model, including dust and sea-salt acid uptake processes, was used for detailed analysis of observation data. Long-range anthropogenic aerosol trans-boundary transport events were observed during our analysis period, and the numerical model generally captured the observed time variation of PM_〈2.5〉 aerosols. In order to have a better understanding of trans-boundary PM_〈2.5〉 contribution, the model domain was divided into 15 major source regions, and emission intensity sensitivity analysis was conducted to show the detailed source-receptor relationship. We found the Japanese domestic contribution to annual averaged PM_〈2.5〉 concentration at Fukuoka was 20 %, and another 80% were coming from outside Japan (19.6 % and 16.3% were coming from central north China region and Korea, respectively). From late fall to early spring when the PM_〈2.5〉 concentration became higher, the trans-boundary fraction reached up to 90%, and this fraction was higher when the daily PM_〈2.5〉 concentration exceeded the environmental standards of 35μm/m^3.

DOI： 10.15017/1917875

CiNii Research

Optical properties of mixed aerosol layers over Japan derived with multi-wavelength Mie-Raman lidar system

Hara Yukari, Nishizawa Tomoaki, Sugimoto Nobuo, Matsui Ichiro, Pan Xiaole, Kobayashi Hiroshi, Osada Kazuo, Uno Itsushi

JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER Vol. 188 page： 20-27 2017.2

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Papers - OSADA, Kazuo