TY - JOUR
T1 - The impact of air pollutants on rainwater chemistry during “urban-induced heavy rainfall” in downtown Tokyo, Japan
AU - Uchiyama, Ryunosuke
AU - Okochi, Hiroshi
AU - Katsumi, Naoya
AU - Ogata, Hiroko
N1 - Funding Information:
The meteorological data with a 10 min interval (temperature, relative humidity, air pressure, wind direction, and wind speed) and that with a 60 min interval (global solar radiation amount) are available at the JMA website: http:// www.data.jma.go.jp/obd/stats/etrn/ index.php. Air pollutants concentration data sets with a 60 min interval are available upon request from the Shinjuku City Office: http://www.city. shinjuku.lg.jp/seikatsu/file10_05_00002. html. The rainfall amount data with 10 min interval obtained from Shinjuku, Toshima, Chuo, Nakano, and Shibuyabashi observatories are avail able upon request from the Bureau of Construction, Tokyo Metropolitan Government: http://www.kensetsu. metro.tokyo.jp/. The rainwater chemical components data used in this study are available in Table S3. This research was partly supported by the Nippon Life Insurance Foundation.
Publisher Copyright:
© 2017. American Geophysical Union. All Rights Reserved.
PY - 2017
Y1 - 2017
N2 - 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.
AB - 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.
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U2 - 10.1002/2017JD026803
DO - 10.1002/2017JD026803
M3 - Article
AN - SCOPUS:85018899534
SN - 0148-0227
VL - 122
SP - 6502
EP - 6519
JO - Journal of Geophysical Research
JF - Journal of Geophysical Research
IS - 12
ER -