[Regionalization and Analysis of PM_2.5 and O₃ Synergetic Prevention and Control Areas Based on Remote Sensing Data]

Site-based air pollution monitoring data cannot support the regionalization of air pollution prevention and control areas. Faced with this problem, this study proposed a method of regionalizing synergetic prevention and control areas based on multi-source remote sensing data and GIS spatial statistical analysis methods and carried out quantitative analyses of PM_2.5 and O₃ air pollution in China from 2015 to 2020. The results showed that there was an obvious decrease in PM_2.5 concentrations, and O₃concentrations remained stable; PM_2.5 pollution mostly occurred in autumn and winter, and O₃ pollution occurred in spring and summer. A significant spatial inconsistency was shown between the change rate of PM_2.5 and O₃ concentrations, in which the proportions of PM_2.5 decreasing and O₃ increasing, PM_2.5 and O₃ both decreasing, PM_2.5 and O₃ both increasing, and PM_2.5 increasing and O₃ decreasing accounted for 38.34%, 35.12%, 15.24%, and 10.89%, respectively. The results also showed that the boundary of PM_2.5 and O₃ synergetic prevention and control areas was dynamic during 2015 and 2020, showing a trend of expanding from 2015 to 2018 and then becoming smaller after 2019. Generally, the scope of PM_2.5 and O₃ synergetic prevention and control areas was concentrated in "2+26" cities, Fenwei plain, north of the Yangtze River Delta, and Shandong. In contrast, the regional scopes of "PM_2.5 first" and "O₃ first" were relatively stable. Areas of "PM_2.5 first" were mainly carried out in Liaoning-Jilin, Hubei-Hunan-Jiangxi, Chengdu-Chongqing, and Taklimakan-Hexi Corridor, whereas "O₃ first" areas were mainly in specific regions of the Pearl River Delta, Yangtze River Delta, and surrounding areas of Bohai Bay. Remote sensing-based PM_2.5 and O₃ mapping has the advantages of full-coverage and fine spatial simulation, which can support the regionalization of synergetic prevention and control areas and implementation of policies.