Characteristics of air quality changes in Quanzhou during the COVID-19 epidemic

On January 8, 2020, there was an outbreak of coronavirus disease 19 (COVID-2019), and on January 24, 2020, Fujian Province issued the "Fujian Provincial Emergency Plan for Public Health Emergencies", which restricted crowd gathering activities such as markets, greatly reducing transportation and industry. The difference between air quality before and after the epidemic was studied, and the results show that the mass concentrations of SO2, NO2, CO, PM10, and PM2.5 in Quanzhou City in February 2020 all decreased in January, with decline rates of 5.8–8.8%, 34.7–46.7%, 14.9–25.1%, 9.4–15.9%, and 5.4– 14.3%; O3 did not show the same change pattern. NO2, CO, O3, PM10, and PM2.5 decreased compared with the same period in 2018 and 2019, of which SO2 and NO2 declined the most, and CO and O3 declined the least. The spatial distribution map of air quality in Quanzhou City in the first half of 2020 was obtained by the Arcgis anti-distance weighting method, and the results showed that the Qingyuanshan area had the best air quality in Quanzhou and was the least affected by the epidemic; the air quality in Tushan Street and Jintoupu changed the most, showing the most obvious impact of the epidemic. The changes in air quality in Quanzhou during the epidemic period show that traffic and industrial pollution sources were more likely to be affected by the epidemic, and the sources of domestic pollution were relatively stable.