Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Rm 510, Engineering Facility Building No.3, Guangzhou 510006, China.
State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong, China.
J Environ Sci (China). 2022 May;115:443-452. doi: 10.1016/j.jes.2021.07.009. Epub 2021 Jul 15.
The COVID-19 pandemic has raised awareness about various environmental issues, including PM pollution. Here, PM pollution during the COVID-19 lockdown was traced and analyzed to clarify the sources and factors influencing PM in Guangzhou, with an emphasis on heavy pollution. The lockdown led to large reductions in industrial and traffic emissions, which significantly reduced PM concentrations in Guangzhou. Interestingly, the trend of PM 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/m) of the lockdown. However, the concentrations of other gaseous pollutants, e.g., SO, NO 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 PM 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 PM 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 PM 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 PM pollution.
新冠疫情提高了人们对各种环境问题的认识，包括 PM 污染。本研究追踪和分析了新冠疫情封锁期间的 PM 污染，以阐明广州 PM 的来源和影响因素，重点关注重度污染。封锁导致工业和交通排放大量减少，显著降低了广州的 PM 浓度。有趣的是，PM 浓度的趋势与交通和工业排放不一致，封锁的第四阶段（3/01-3/31，22.45μg/m）观察到的浓度最低。然而，其他气态污染物（如 SO、NO 和 CO）的浓度与工业和交通排放相关，封锁的第二阶段（1/24-2/03）浓度最低。气象相关分析表明，新冠疫情期间 PM 浓度降低主要归因于工业和交通排放减少，而非气象条件。当将气象因素纳入 PM 成分和后向轨迹分析时，我们发现远距离运输和二次污染抵消了疫情第二和第三阶段的一次排放减少。值得注意的是，广州西部、南部和东南部的工业 PM 排放对重度污染事件的形成起着重要作用。本研究结果不仅验证了控制交通和工业排放的重要性，还为进一步改善 PM 污染提供了目标。
