Jia Haohao, Huo Juntao, Fu Qingyan, Duan Yusen, Lin Yanfen, Jin Xiaodan, Hu Xue, Cheng Jinping
School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
Shanghai Environmental Monitor Center, Shanghai, 200235, China.
Environ Pollut. 2020 Dec;267:115612. doi: 10.1016/j.envpol.2020.115612. Epub 2020 Sep 9.
To investigate chemical characteristics, abatement mechanisms and regional transport of atmospheric pollutants during the COVID-19 outbreak control period in the Yangtze River Delta (YRD) region, China, the measurements of air pollutants including fine particulate matter (PM) and volatile organic compounds (VOCs) on non-control period (NCP, 24 December 2019-23 January 2020) and control period (CP, 24 January-23 February 2020) were analyzed at the urban Pudong Supersite (PD) and the regional Dianshan Lake Supersite (DSL). Due to the stricter outbreak control, the levels of PM and VOCs, and the occurrence frequencies of haze-fog episodes decreased substantially from NCP to CP, with average reduction rates of 31.6%, 38.9% and 35.1% at PD, and 34.5%, 50.7% and 37.9% at DSL, respectively. The major source for PM was secondary sulfate & nitrate in both periods, and the emission control of primary sources such as coal burning and vehicle exhaust decreased the levels of precursors gas sulfur dioxide and nitrogen oxide, which highly contributed to the abatement of PM from NCP to CP. The higher levels of ozone at both PD and DSL on CP might be due to the weak nitrogen monoxide titration, low relative humidity and high visibility compared with NCP. Vehicle exhaust and fugitive emission from petrochemical industry were the major contributors of ambient VOCs and their decreasing activities mainly accounted for VOCs abatement. Moreover, the high frequency of haze-fog events was closely impacted by medium-scale regional transport within Anhui and Jiangsu provinces. Therefore, the decreasing regional transported air pollutants coincided with the emission control of local sources to cause the abatement of haze-fog events in YRD region on CP. This study could improve the understanding of the change of atmospheric pollutants during the outbreak control period, and provide scientific base for haze-fog pollution control in YRD region, China.
为研究中国长江三角洲（YRD）地区在新冠疫情防控期间大气污染物的化学特征、减排机制和区域传输情况，对城市浦东新区超级站点（PD）和区域淀山湖超级站点（DSL）在非管控期（NCP，2019年12月24日至2020年1月23日）和管控期（CP，2020年1月24日至2月23日）的空气污染物进行了测量分析，这些污染物包括细颗粒物（PM）和挥发性有机化合物（VOCs）。由于疫情防控措施更加严格，从NCP到CP，PM和VOCs的浓度以及雾霾天气的发生频率大幅下降，PD站点的平均下降率分别为31.6%、38.9%和35.1%，DSL站点分别为34.5%、50.7%和37.9%。两个时期PM的主要来源均为二次硫酸盐和硝酸盐，燃煤和汽车尾气等一次源的排放控制降低了前体气体二氧化硫和氮氧化物的浓度，这对从NCP到CP期间PM的减排起到了很大作用。与NCP相比，CP期间PD和DSL站点的臭氧浓度较高，可能是由于一氧化氮滴定作用较弱、相对湿度较低和能见度较高。汽车尾气和石化行业的无组织排放是环境VOCs的主要贡献源，其排放活动的减少主要导致了VOCs的减排。此外，雾霾事件的高频率发生受到安徽省和江苏省内中尺度区域传输的密切影响。因此，区域传输空气污染物的减少与本地源的排放控制相吻合，导致了CP期间YRD地区雾霾事件的减少。本研究有助于增进对疫情防控期间大气污染物变化的理解，并为中国YRD地区的雾霾污染控制提供科学依据。
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