Effects of COVID-19 Control Measures on the Concentration and Composition of PM2.5-Bound Polycyclic Aromatic Hydrocarbons in Shanghai

In order to explore the effects of COVID-19 control measures on concentration and composition PM2.5-bound polycyclic aromatic hydrocarbons (PAHs), better understand sources PAHs, PM2.5, samples were collected at two sites in urban suburban areas Shanghai before lockdown, during after lockdown 2020, same periods 2019. The mass concentrations 21 individual PAHs determined via GC-MS analysis. While significantly reduced absolute they had no significant effect their relative abundances, indicating that traffic emission may not originally be major source Shanghai. differences three different lockdown-related caused by gas-particle distribution semi-volatile PAHs. similarity functional brings more uncertainties identification PAH using diagnostic ratios. During period, toxic equivalent was estimated decrease about 1/4, which still exhibits substantial carcinogenic risk upon exposure inhalation.