Investigation of PM2.5 pollution during COVID-19 pandemic in Guangzhou, China

Luyao Wen, Chun Yang, Xiaoliang Liao, Yanhao Zhang, Xuyang Chai, Wenjun Gao, Shulin Guo, Yinglei Bi, Suk Ying Tsang, Zhi Feng Chen, Zenghua Qi*, Zongwei Cai*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

27 Citations (Scopus)

Abstract

The COVID-19 pandemic has raised awareness about various environmental issues, including PM2.5 pollution. Here, PM2.5 pollution during the COVID-19 lockdown was traced and analyzed to clarify the sources and factors influencing PM2.5 in Guangzhou, with an emphasis on heavy pollution. The lockdown led to large reductions in industrial and traffic emissions, which significantly reduced PM2.5 concentrations in Guangzhou. Interestingly, the trend of PM2.5 concentrations was not consistent with traffic and industrial emissions, as minimum concentrations were observed in the fourth period (3/01-3/31, 22.45 μg/m3) of the lockdown. However, the concentrations of other gaseous pollutants, e.g., SO2, NO2 and CO, were correlated with industrial and traffic emissions, and the lowest values were noticed in the second period (1/24-2/03) of the lockdown. Meteorological correlation analysis revealed that the decreased PM2.5 concentrations during COVID-19 can be mainly attributed to decreased industrial and traffic emissions rather than meteorological conditions. When meteorological factors were included in the PM2.5 composition and backward trajectory analyses, we found that long-distance transportation and secondary pollution offset the reduction of primary emissions in the second and third stages of the pandemic. Notably, industrial PM2.5 emissions from western, southern and southeastern Guangzhou play an important role in the formation of heavy pollution events. Our results not only verify the importance of controlling traffic and industrial emissions, but also provide targets for further improvements in PM2.5 pollution.

Original languageEnglish
Pages (from-to)443-452
Number of pages10
JournalJournal of Environmental Sciences (China)
Volume115
Early online date15 Jul 2021
DOIs
Publication statusPublished - May 2022

Scopus Subject Areas

  • Environmental Engineering
  • Environmental Chemistry
  • Environmental Science(all)

User-Defined Keywords

  • COVID-19 pandemic
  • Meteorological analysis
  • PM2.5 composition
  • PM2.5 pollution
  • Source appointment

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