Joint International Research Laboratory of Atmospheric and Earth System Sciences, School of Atmospheric Sciences, Nanjing University, Nanjing 210023, China.
Institute of Tropical and Marine Meteorology/Guangdong Provincial Key Laboratory of Regional Numerical Weather Prediction, China Meteorological Administration, Guangzhou 510640, China.
Environ Sci Technol. 2021 May 4;55(9):5721-5730. doi: 10.1021/acs.est.0c08383. Epub 2021 Apr 2.
Despite the large reduction in anthropogenic activities due to the outbreak of COVID-19, air quality in China has witnessed little improvement and featured great regional disparities. Here, by combining observational data and simulations, this work aims to understand the diverse air quality response in two city clusters, Yangtze River Delta region (YRD) and Pearl River Delta region (PRD), China. Though there was a noticeable drop in primary pollutants in both the regions, differently, the maximum daily 8 h average ozone (O) soared by 20.6-76.8% in YRD but decreased by 15.5-28.1% in PRD. In YRD, nitrogen oxide (NOx) reductions enhanced O accumulation and hence increased secondary aerosol formation. Such an increment in secondary organic and inorganic aerosols under stationary weather reached up to 36.4 and 10.2%, respectively, which was further intensified by regional transport. PRD was quite the opposite. The emission reductions benefited PRD air quality, while regional transport corresponded to an increase of 17.3 and 9.3% in secondary organic and inorganic aerosols, respectively. Apart from meteorology, the discrepancy in O-VOCs-NOx relationships determined the different O responses, indicating that future emission control shall be regionally specific, instead of one-size-fits-all cut. Overall, the importance of regionally coordinated and balanced control strategy for multiple pollutants is highly emphasized.
尽管由于 COVID-19 的爆发，人为活动大幅减少，但中国的空气质量几乎没有改善，而且存在很大的地区差异。在这里，通过结合观测数据和模拟，这项工作旨在了解中国两个城市群（长江三角洲地区（YRD）和珠江三角洲地区（PRD））的不同空气质量响应。尽管两个地区的主要污染物都明显下降，但不同的是，最大日 8 小时平均臭氧（O）在 YRD 地区飙升了 20.6-76.8%，而在 PRD 地区则下降了 15.5-28.1%。在 YRD 地区，氮氧化物（NOx）的减少促进了 O 的积累，从而增加了二次气溶胶的形成。在静止天气下，二次有机和无机气溶胶的这种增加分别达到了 36.4%和 10.2%，而区域传输则进一步加剧了这种增加。PRD 则恰恰相反。减排措施使 PRD 的空气质量受益，而区域传输则导致二次有机和无机气溶胶分别增加了 17.3%和 9.3%。除了气象因素外，O-VOCs-NOx 关系的差异决定了 O 的不同响应，这表明未来的排放控制应具有区域性，而不是一刀切。总的来说，强调了区域协调和平衡控制策略对于多种污染物的重要性。
