Abstract
Responding to the 2020 COVID-19 outbreak, China imposed an unprecedented lockdown producing reductions in air pollutant emissions. However, the lockdown driven air pollution changes have not been fully quantified. We applied machine learning to quantify the effects of meteorology on surface air quality data in 31 major Chinese cities. The meteorologically normalized NO2, O3, and PM2.5 concentrations changed by −29.5%, +31.2%, and −7.0%, respectively, after the lockdown began. However, part of this effect was also associated with emission changes due to the Chinese Spring Festival, which led to ∼14.1% decrease in NO2, ∼6.6% increase in O3 and a mixed effect on PM2.5 in the studied cities that largely resulted from festival associated fireworks. After decoupling the weather and Spring Festival effects, changes in air quality attributable to the lockdown were much smaller: −15.4%, +24.6%, and −9.7% for NO2, O3, and PM2.5, respectively.
Original language | English |
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Article number | e2021GL093403 |
Number of pages | 12 |
Journal | Geophysical Research Letters |
Volume | 48 |
Issue number | 11 |
Early online date | 1 Jun 2021 |
DOIs | |
Publication status | Published - 16 Jun 2021 |
Bibliographical note
Funding Information:This work was funded by the Ministry of Science and Technology of the People's Republic of China (2016YFC0208505).
Publisher Copyright:
© 2021. The Authors.
Keywords
- air quality
- COVID-19
- machine learning
- meteorological normalization
- source
- spring festival
ASJC Scopus subject areas
- Geophysics
- General Earth and Planetary Sciences