Spatiotemporal variations of PM2.5 concentrations in the Fen–Wei Plain of China between 2015 and 2020 based on MAIAC

This paper aims to study the spatiotemporal variations in PM2.5 concentrations between 2015 and 2020 in the Fen–Wei Plain. The AOD products of MCD19A2 based on MAIAC were utilized. Besides of AOD, some of its arithmetic values were also introduced to determine the best variable. AOD was determined as the variable for retrieval because of its highest correlation coefficient with PM2.5, reaching up to 0.526**. Several statistical models and SVR have been used and compared for establishing the best retrieval model. Results showed, the determination coefficient r2 of the cubic function was the best (r2 = 0.294**), and the correlation between the predicted and measured values was strong (k = 1.1478, r2 = 0.532**). Both monthly and annual variations of PM2.5 concentrations were researched, which indicated the changing trend was fluctuating. The mean value in 2015 was the largest, reaching up to 38.02 μg/m3, the smallest value of 28.28 μg/m3 appeared in 2019. It can be concluded the influencing mechanism of PM2.5 was complicated, as proven by correlation analysis and gray relational analysis. The influencing factors should be introduced as auxiliary data to promote the retrieval accuracy. With advancements in remote sensing technology, the monitoring efficiency can be effectively improved, which will greatly promote sustainable development.