Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science &Technology, Nanjing, 210044, China.
Suzhou Environmental Monitoring Center, Suzhou, 215000, China.
Environ Pollut. 2021 Feb 15;271:116298. doi: 10.1016/j.envpol.2020.116298. Epub 2020 Dec 21.
To control the spread of the 2019 novel coronavirus (COVID-19), China imposed rigorous restrictions, which resulted in great reductions in pollutant emissions. This study examines the characteristics of air pollutants, including PM (particles with aerodynamic diameters < 2.5 μm), gas pollutants, water-soluble ions (WSIs), black carbon (BC) and elements, as well as the source apportionment of PM in Suzhou before, during and after the Chinese New Year (CNY) holiday of 2020 (when China was under an unprecedented state of lockdown to restrict the COVID-19 outbreak). Compared to those before CNY, PM, BC, SNA (sulfate, nitrate and ammonium), other ions, elements, and NO and CO mass concentrations decreased by 9.9%-64.0% during CNY. The lockdown policy had strong (weak) effects on the diurnal variations in aerosol chemical compositions (gas pollutants). Compared to those before CNY, source concentrations and contributions of vehicle exhaust during CNY decreased by 72.9% and 21.7%, respectively. In contrast, increased contributions from coal combustion and industry were observed during CNY, which were recorded to be 2.9 and 1.7 times higher than those before CNY, respectively. This study highlights that the lockdown policy that was imposed in Suzhou during CNY not only reduced the mass concentrations of air pollutants but also modified their diurnal variations and the source contributions of PM, which revealed the complex responses of PM sources to the rare, low emissions of anthropogenic pollutants that occurred during the COVID-19 lockdown.
为了控制 2019 年新型冠状病毒（COVID-19）的传播，中国实施了严格的限制措施，导致污染物排放量大幅减少。本研究考察了空气污染物的特征，包括 PM（空气动力学直径<2.5μm 的颗粒）、气体污染物、水溶性离子（WSIs）、黑碳（BC）和元素，以及 2020 年中国新年（CNY）期间苏州 PM 的源分配（当中国处于前所未有的封锁状态以限制 COVID-19 爆发时）。与 CNY 之前相比，PM、BC、SNA（硫酸盐、硝酸盐和铵盐）、其他离子、元素以及 NO 和 CO 质量浓度在 CNY 期间下降了 9.9%-64.0%。封锁政策对气溶胶化学成分（气体污染物）的日变化有很强（弱）的影响。与 CNY 之前相比，CNY 期间汽车尾气的源浓度和贡献分别下降了 72.9%和 21.7%。相比之下，在 CNY 期间观察到煤炭燃烧和工业的贡献增加，分别比 CNY 之前高 2.9 倍和 1.7 倍。本研究强调，苏州在 CNY 期间实施的封锁政策不仅降低了空气污染物的质量浓度，而且改变了它们的日变化和 PM 的源贡献，这揭示了 PM 源对 COVID-19 封锁期间人为污染物罕见的低排放的复杂响应。
