Chemistry of atmospheric fine particles during the COVID-19 pandemic in a megacity of eastern China
Research output: Contribution to journal › Letter › peer-review
Authors
Colleges, School and Institutes
External organisations
- School of Earth Sciences, Zhejiang University
- Hangzhou Meteorological Bureau
- Chinese Academy of Sciences
- Nanjing University
Abstract
Air pollution in megacities represents one of the greatest environmental challenges. Our observed results show that the dramatic NOx decrease (77%) led to significant O3 increases (a factor of 2) during the COVID-19 lockdown in megacity Hangzhou, China. Model simulations further demonstrate large increases of daytime OH and HO2 radicals and nighttime NO3 radical, which can promote the gas-phase reaction and nocturnal multiphase chemistry. Therefore, enhanced NO3− and SO42− formation was observed during the COVID-19 lockdown because of the enhanced oxidizing capacity. The PM2.5 decrease was only partially offset by enhanced aerosol formation with its reduction reaching 50%. In particular, NO3− decreased largely by 68%. PM2.5 chemical analysis reveals that vehicular emissions mainly contributed to PM2.5 under normal conditions in Hangzhou. Whereas, stationary sources dominated the residual PM2.5 during the COVID-19 lockdown. This study provides evidence that large reductions in vehicular emissions can effectively mitigate air pollution in megacities.
Bibliographic note
Details
Original language | English |
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Article number | 2020GL091611 |
Number of pages | 10 |
Journal | Geophysical Research Letters |
Volume | 48 |
Issue number | 2 |
Early online date | 17 Dec 2020 |
Publication status | Published - 28 Jan 2021 |
Keywords
- air pollution, chemical composition, COVID-19, fine particles, megacity