Published Papers - SHIMADA Kojiro

Size-segregated sulfate on top of Mt. Fuji transported from Sakurajima volcano eruption

Kojiro Shimada, Kei Suzuki, Shungo Kato, Shuuichi Itahashi, Shiro Hatakeyama

■■■     2024.05

Type of publication: Research paper (other science council materials etc.)

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Size-segregated aerosol samples were collected on Mt. Fuji with a cascade impactor during daytime and nighttime. We analyzed for their ionic and element compositions. Samples were collected from 29 July to 2 August (first period) and from 19 to 21 August 2013 (second period). Based on combined chemical components and CMAQ, in the first period, the air masses had been transported from East Asia. In the second period, the Sakurajima volcano eruption had been transported. NH4+, SO42–and elements were the major ions in 2.5 < Dp ≤ 10 during the second period. The slope of a linear regression of non-sea-salt (nss)-SO42– versus NH4+ was nearly unity, particularly during the first period. However, nss-SO42– in coarse aerosol was shifted in great excess in the second period. We have observed a rare phenomenon in which sulfate shifts to 2.5 < Dp ≤ 10. Although the formation process of (NH4)2SO4 in coarse particle is hypothesized two mechanisms, we hypothesize the third mechanism in this study. Currently, radiative forcing is being discussed for the detection of volcanic aerosols using satellites with particle sizes of 1.2 µm. If this can be clarified, it will improve the reproducibility of sulfate radiative forcing.

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Possibility of condensation of nitric acid for cloud condensation nucleus in the summer at Mt. Fuji

Kojiro Shimada, Yoshun Geka, Shungo Kato, Chak K. Chan, Yong Pyo Kim, Chang-Feng Ou-Yang, Neng-Huei Lina, Shiro Hatakeyama

Atmospheric Pollution Research     2023.09 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Possibility of condensation of nitric acid for cloud condensation nucleus in the summer at Mt. Fuji

Kojiro Shimada, Yoshun Geka, Shungo Kato, Chak K. Chan, Yong Pyo Kim, Chang-Feng Ou-Yang, Neng-Huei Lina, Shiro Hatakeyama

■■■     2023.09 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Evaluation of oxidative ability after photoirradiation using urban aerosols

Yurie Gotoh, Kojiro Shimada, Shuhei Murakami, Takumi Yamawaki, Ayaka Mitsukawa, Hiroshi Okochi

    2023.07 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Evaluation of oxidative ability after photoirradiation using urban aerosols

Yurie Gotoh, Kojiro Shimada, Shuhei Murakami, Takumi Yamawaki, Ayaka Mitsukawa, Hiroshi Okochi

    2023.07 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

Offline analysis of the chemical composition and hygroscopicity of sub-micrometer aerosol at an Asian outflow receptor site and comparison with online measurements

Yange Deng;Hiroaki Fujinari;Hikari Yai;Kojiro Shimada;Yuzo Miyazaki;Eri Tachibana;Dhananjay Deshmukh;Kimitaka Kawamura;Tomoki Nakayama;Shiori Tatsuta;Mingfu Cai;Hanbing Xu;Fei Li;Haobo Tan;Sho Ohata;Yutaka Kondo;Akinori Takami;Shiro Hatakeyama;Michihiro Mochida

Atmospheric Chemistry and Physics     2022.05 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Offline analysis of the chemical composition and hygroscopicity of sub-micrometer aerosol at an Asian outflow receptor site and comparison with online measurements

Yange Deng, Hiroaki Fujinari, Hikari Yai, Kojiro Shimada, Yuzo Miyazaki, Eri Tachibana, Dhananjay Deshmukh, Kimitaka Kawamura, Tomoki Nakayama, Shiori Tatsuta, Mingfu Cai, Hanbing Xu, Fei Li, Haobo Tan, Sho Ohata, Yutaka Kondo, Akinori Takami, Shiro Hatakeyama, Michihiro Mochida

Atmospheric Chemistry and Physics ( Copernicus GmbH )  22 ( 8 ) 5515 - 5533   2022.05 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Abstract. Filter-based offline analysis of atmospheric aerosol hygroscopicity coupled to composition analysis provides information complementary to that obtained from online analysis. However, its application itself and comparison to online analysis have remained limited to date. In this study, daily submicrometer aerosol particles (PM0.95, 50 % cutoff diameter: 0.95 μm) were collected onto quartz fiber filters in Okinawa Island, a receptor of East Asian outflow, in the autumn of 2015. The chemical composition of water-soluble matter (WSM) in PM0.95 and PM0.95 itself, and their respective hygroscopicities were characterized through the offline use of an aerosol mass spectrometer and a hygroscopicity tandem differential mobility analyzer. Thereafter, results were compared with those obtained from online analyses. Sulfate dominated the WSM mass (60 %), followed by water-soluble organic matter (WSOM, 20 %) and ammonium (13 %). WSOM accounted for most (93 %) of the mass of extracted organic matter (EOM) and the atomic O to C ratios (O : C) of WSOM and EOM were high (mean ± standard deviation were, respectively, 0.84 ± 0.08 and 0.79 ± 0.08), both of which indicate highly aged characteristics of the observed aerosol. The hygroscopic growth curves showed clear hysteresis for most samples. At 85 % RH, the calculated hygroscopicity parameter κ of the WSM (κWSM), WSOM, EOM, and PM0.95 (κPM0.95) were, respectively, 0.50 ± 0.03, 0.22 ± 0.12, 0.20 ± 0.11, and 0.47 ± 0.03. An analysis using the thermodynamic E-AIM model shows, on average, that inorganic salts and WSOM respectively contributed 88 % and 12 % of the κWSM (or κPM0.95). High similarities were found between offline and online analysis for chemical compositions that are related to particle hygroscopicity (the mass fractions and O : C of organics, and the degree of neutralization), and also for aerosol hygroscopicity. As possible factors governing the variation of κWSM, the influences of WSOM abundance and the neutralization of inorganic salts were assessed. At high RH (70–90 %), the hygroscopicity of WSM and PM0.95 was affected considerably by the presence of organic components; at low RH (20–50 %), the degree of neutralization could be important. This study not only characterized aerosol hygroscopicity at the receptor site of East Asian outflow, but also shows that the offline hygroscopicity analysis is an appropriate method, at least for aerosols of the studied type. The results encourage further applications to other environments and to more in-depth hygroscopicity analysis, in particular for organic fractions.

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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 ( Springer Nature )  12 ( 4249 ) 1 - 9   2022.03 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Effects of changes in polycyclic aromatic hydrocarbons (PAHs) emissions and degradation on their concentrations in Tokyo from 2007 and 2016.

Shimada K, Nohchi M, Maeshima K, Uchino T, Kobayashi Y, Ono K, Ogata H, Katsumi N, Inazu K, Okochi H

Scientific reports ( Springer Science and Business Media LLC )  12 ( 1 ) 4249   2022.03 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Abstract The 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.

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Disentangling the contribution of the transboundary out-flow from the Asian continent to Tokyo, Japan

Kojiro Shimada, Manatsu Mizukoshi, Chak K.Chan, Yong PyoKim, Neng-Huei Lin, Kazuhide Matsuda, Syuichi Itahashi, Yoshihiro Nakashima, ShungoKato, ShiroHatakeyama

Environmental Pollution ( Elsevier )  281 ( 1 )   2021.10 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Disentangling the contribution of the transboundary out-flow from the Asian continent to Tokyo, Japan.

Shimada K, Mizukoshi M, Chan CK, Kim YP, Lin NH, Matsuda K, Itahashi S, Nakashima Y, Kato S, Hatakeyama S

Environmental pollution (Barking, Essex : 1987) ( Elsevier )  286 ( 1 ) 117280   2021.10 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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We assessed the contribution of transboundary air pollutants (TAPs) transported from China to Tokyo using the Pb(0.5<Dp < 1)/Cu(2.5<Dp < 10) index. We conducted intensive observations over four seasons during 2014–2015 and analyzed ionic components and thirteen elements in size-segregated aerosols collected at the top of a 30-m-high tower in a hilly forested area of the Field Museum Tamakyuryo (FM Tama), in a western suburb of Tokyo. In order to evaluate if the Pb(0.5<Dp < 1)/Cu(2.5<Dp < 10) ratio can be applied in Tokyo as the megacity, the annual average concentration of Pb at Cape Hedo, Kumamoto city, on the west side of Japan, was higher than that of Pb at Tokyo, on the east side; this result indicates that TAPs affect western Japan more than eastern Japan. We inferred the main source of Cu to be braking abrasion from cars at local scale on the basis of its enrichment factor and size distribution. From the Pb(0.5<Dp < 1)/Cu(2.5<Dp < 10) ratio and sulfate concentration, we inferred that the highest contribution of TAPs to the total mass concentration in Tokyo occurred in spring, when TAPs accounted for 55%, 72%, and 53% of the total mass concentration in the 0.1 < Dp < 0.5, 0.5 < Dp < 1, and 1 < Dp < 2.5 fractions, respectively. These results can contribute to assessment of TAPs in Tokyo.

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Long-term Measurements of Carbonaceous Aerosol at Cape Hedo, Okinawa, Japan: Effects of Changes in Emissions in East Asia

Shimada Kojiro, Takami Akinori, Ishida Takatsugu, Taniguchi Yuta, Hasegawa Shuichi, Chan Chak K., Kim Yong Pyo, Lin Neng-Hue, Hatakeyama Shiro

AEROSOL AND AIR QUALITY RESEARCH   21 ( 9 )   2021.09 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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東アジアの越境大気汚染問題:国際共同観測ネットワークによる東アジアの 越境大気汚染の解明

Kojiro Shimada

Chemistry & chemical industry   74 ( 3 ) 212 - 213   2021.03 [ Peer Review Accepted ]

Type of publication: Research paper (bulletin of university, research institution)

Degradation of PAHs during long range transport based on simultaneous measurements at Tuoji Island, China, and at Fukue Island and Cape Hedo, Japan.

Shimada K, Nohchi M, Yang X, Sugiyama T, Miura K, Takami A, Sato K, Chen X, Kato S, Kajii Y, Meng F, Hatakeyama S

Environmental pollution (Barking, Essex : 1987)   260   113906   2020.05 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Estimation of background PM2.5 concentrations for an air-polluted environment

Wang, S. H., Hung, R. Y., Lin, N. H., Gómez-Losada, Á., Pires, J. C. M., Shimada, K., Hatakeyama, S., & Takami, A.

Atmospheric Research ( Elsevier )  231   2020 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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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 ( Japan Society for Atmospheric Environment )  55 ( 5 ) 191 - 203   2020 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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<p>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, <i>n</i>=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, <i>o</i>-xylene, and limonen in the cloud water were several times higher than their Henry'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.</p>

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Estimation of background PM2.5 concentrations for an air-polluted environment

Wang, S. H, Hung, R. Y, Lin, N. H, Gómez-Losada, Á, Pires, J. C. M, Shimada, K, Hatakeyama, S, Takami, A

Atmospheric Research ( Elsevier )  231   104636 - 104636   2020 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Seasonal and annual changes in PAH concentrations in a remote site in the Pacific Ocean.

Miura K, Shimada K, Sugiyama T, Sato K, Takami A, Chan CK, Kim IS, Kim YP, Lin NH, Hatakeyama S

Scientific reports   9 ( 1 ) 12591   2019.08 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Seasonal and annual changes in PAH concentrations in a remote site in the Pacific Ocean

Miura, K; Shimada, K; Sugiyama, T; Sato, K; Takami, A; Chan, CK; Kim, IS; Kim, YP; Lin, NH; Hatakeyama, S

SCIENTIFIC REPORTS ( Scientific Reports )  9 ( 1 ) 12591   2019.08 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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Sources of high sulfate aerosol concentration observed at cape hedo in spring 2012

Itahashi S.

Aerosol and Air Quality Research ( Aerosol and Air Quality Research )  19 ( 3 ) 587 - 600   2019.03 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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