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

資料種別:
論文(リポジトリ)
責任表示:
Shimada, Kojiro ; Nohchi, Masayuki ; Maeshima, Koji ; Uchino, Tomonori ; Kobayashi, Yusuke ; Ogata, Hiroko ; Katsumi, Naoya ; Inazu, Koji ; Okochi, Hiroshi
言語:
英語
出版情報:
© The Author(s) 2022, 2022-03-11
著者名:
Shimada, Kojiro
Nohchi, Masayuki
Maeshima, Koji
Uchino, Tomonori
Kobayashi, Yusuke
Ogata, Hiroko
Katsumi, Naoya
Inazu, Koji
Okochi, Hiroshi
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掲載情報:
scientific reports
通号:
4249
開始ページ:
1
終了ページ:
9
バージョン:
VoR
概要:
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. 続きを見る
URL:
http://hdl.handle.net/20.500.12000/0002020135
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