Diverse response of surface ozone to COVID-19 lockdown in China

Yiming Liu, Tao Wang, Trissevgeni Stavrakou, Nellie Elguindi, Thierno Doumbia, Claire Granier, Idir Bouarar, Benjamin Gaubert, Guy P. Brasseur

Research output: Journal article publicationJournal articleAcademic researchpeer-review

41 Citations (Scopus)


Ozone (O3) is a key oxidant and pollutant in the lower atmosphere. Significant increases in surface O3 have been reported in many cities during the COVID-19 lockdown. Here we conduct comprehensive observation and modeling analyses of surface O3 across China for periods before and during the lockdown. We find that daytime O3 decreased in the subtropical south, in contrast to increases in most other regions. Meteorological changes and emission reductions both contributed to the O3 changes, with a larger impact from the former especially in central China. The plunge in nitrogen oxide (NOx) emission contributed to O3 increases in populated regions, whereas the reduction in volatile organic compounds (VOC) contributed to O3 decreases across the country. Due to a decreasing level of NOx saturation from north to south, the emission reduction in NOx (46%) and VOC (32%) contributed to net O3 increases in north China; the opposite effects of NOx decrease (49%) and VOC decrease (24%) balanced out in central China, whereas the comparable decreases (45–55%) in these two precursors contributed to net O3 declines in south China. Our study highlights the complex dependence of O3 on its precursors and the importance of meteorology in the short-term O3 variability.

Original languageEnglish
Article number147739
JournalScience of the Total Environment
Publication statusPublished - 1 Oct 2021


  • COVID-19
  • Emission reduction
  • Meteorological condition
  • Surface ozone

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution


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