COVID-19疫情期间江苏三市大气中VOCs浓度变化特征及来源分析

Variation characteristics and source analysis of atmospheric volatile organiccompounds in three cities of Jiangsu Province during COVID-19

为研究我国新冠疫情(COVID-19)期间防控措施对江苏省不同城市大气中挥发性有机物(Volatile organic compounds,VOCs)浓度和来源的影响,在2020年1月1日~2月29日在使用VOCs在线监测仪器对南京、南通以及徐州三市VOCs进行监测分析。结果表明:疫情防控开始后,南京、南通以及徐州三市总挥发性有机物(Total Volatile Organic Compounds,TVOCs)浓度分别下降35%、35%以及54%,南京市与南通市VOCs浓度受影响最为显著的物质均为芳香烃,徐州市烯烃降幅最大;三市TVOCs对臭氧生成潜势(Ozone Formation Potentials,OFP)的贡献分别下降了44%、44%和54%,芳香烃降幅最大;正矩阵因数分解源解析结果显示,疫情管控对南京与南通的石油化工源、工业溶剂源影响最为显著,对徐州化工源、机机动车排放源、燃烧源的影响较大。为了有效降低VOCs浓度并限制O_(3)生成,建议对南京、南通市的石油化工及工业溶剂源的排放进行限制。对徐州市,针对其石油化工及机动车源排放的控制则更为有效。

In order to study the effects of the prevention and control measures of COVID-19 on the concentration and source of volatile organic compounds(VOCs)in different cities of Jiangsu Province,VOCs online monitoring instruments were used to monitor and analyze VOCs in Nanjing,Nantong and Xuzhou from January 1 to February 29,2020.The results showed that after the prevention and control of COVID-19,the concentrations of total volatile organic compounds(TVOCs)in Nanjing,Nantong,and Xuzhou decreased by 35%,35%and 54%,respectively.The most significantly affected species in VOCs were aromatic hydrocarbons in Nanjing and Nantong,and olefins in Xuzhou.The contribution rates of TVOCs to ozone formation potential(OFP)in the three cities decreased by 44%,44%and 54%,respectively.The contribution rate of aromatic hydrocarbons decreased the most.The positive matrix factorization source analysis results showed that the prevention and control measures of COVID-19 had the most significant impact on the petrochemical and industrial solvent sources in Nanjing and Nantong.and had a great impact on chemical sources,motor vehicle emission sources and combustion sources in Xuzhou.In order to effectively reduce the VOCs concentration and the O_(3) generation,it was suggested to limit the VOCs emission from petrochemical and industrial solvent sources in Nanjing and Nantong.For Xuzhou,it was more effective to control VOCs emission from petrochemical and motor vehicle sources.