Investigation of Spatiotemporal Variation and Drivers of Aerosol Optical Depth in China from 2010 to 2020

Abstract

China has experienced rapid economic growth and serious control of aerosol emissions in the past decade. Thus, the spatiotemporal variations and driving factors of aerosol optical depth (AOD) are urgently needed to evaluate the effectiveness of aerosol control activities. The innovation of this study is a detailed spatial and temporal analysis of aerosol pollution in eight major regions of China from 2010 to 2020 using the MERRA-2 AOD reanalysis product and the driving mechanism based on the Granger causality test, sensitivity, and contribution analysis. The results show that the spatial distribution of AOD varied across the areas. Divided by the Hu Line, the AOD values of the Eastern areas were significantly higher than those of the Western areas. The temporal trend in the last eleven years was dominated by a continuous decline and moderate fluctuations at both annual and seasonal scales. The relationship between socioeconomic factors and AOD drivers was more significant in economically developed regions, suggesting that China pays more attention to haze control while developing its economy. The driving relationship between AOD and temperature was weak, while wind speed and relative humidity were more influential. For vegetation factors, Granger effects were mainly observed in the Northeast, Beijing-Tianjin-Hebei, Guangdong, Central China, and Southwest regions. In the Guangdong and Southwest regions, vegetation and economic factors were the more influential drivers. This study provides a scientific basis for the detection of aerosol changes, driving mechanisms and pollution management in China.