1. Peculiar COVID-19 effects in the Greater Tokyo Area revealed by spatiotemporal variabilities of tropospheric gases and light-absorbing aerosols.
- Author
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Damiani, Alessandro, Irie, Hitoshi, Belikov, Dmitry, Kaizuka, Shuei, Hoque, Hossain Mohammed Syedul, and Cordero, Raul R.
- Abstract
This study investigated the spatiotemporal variabilities in nitrogen dioxide (NO
2 ), formaldehyde (HCHO), ozone (O3 ), and light-absorbing aerosols within the Greater Tokyo Area, Japan, the most populous metropolitan area in the world. The analysis was based on total column, partial column, and in situ observations retrieved from multiple platforms and additional information obtained from reanalysis and box model simulations. This study mainly covers the 2013--2020 period, focusing on 2020, when air quality was influenced by the coronavirus disease 2019 (COVID-19) pandemic. In 2020 overall, NO2 concentrations were reduced by about 10% annually, with reductions exceeding 40% in some areas during the pandemic state of emergency. Light-absorbing aerosol levels were also reduced for most of 2020, while smaller fluctuations in HCHO and O3 were observed. Moreover, the degree of weekly cycling of NO2 , HCHO, and light-absorbing aerosol levels was significantly enhanced in urban areas during 2020. The latter changes were unprecedented in recent years and potentially related to coincident reduced mobility in Japan, which, in contrast to other countries, was anomalously low on weekends in 2020. This finding suggests that, despite the lack of strict legal restrictions in Japan, widespread adherence to recommendations designed to limit the spread of the pandemic caused modification of common habits, resulting in unique air quality changes. [ABSTRACT FROM AUTHOR]- Published
- 2022
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