Abstract:centration 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 andXuzhou from January 1 to February 29, 2020. The results showed that after the prevention and controlof 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 inVOCs were aromatic hydrocarbons in Nanjing and Nantong, and olefins in Xuzhou. The contributionrates of TVOCs to ozone formation potential (OFP) in the three cities decreased by 44%, 44% and COVID-19VOCs54%, respectively. The contribution rate of aromatic hydrocarbons decreased the most. The positive ma⁃trix factorization source analysis results showed that the prevention and control measures of COVID-19had the most significant impact on the petrochemical and industrial solvent sources in Nanjing and Nan⁃tong. and had a great impact on chemical sources, motor vehicle emission sources and combustionsources in Xuzhou. In order to effectively reduce the VOCs concentration and the O3generation , it wassuggested to limit the VOCs emission from petrochemical and industrial solvent sources in Nanjing andNantong. For Xuzhou, it was more effective to control VOCs emission from petrochemical and motor ve⁃hicle sources. Close-