Understanding Anthropogenic PM_2.5 Concentrations and Their Drivers in China during 1998-2016

Air pollution poses serious challenges for human health and wellbeing. It also affects atmospheric visibility and contributes to climate change. As social and economic processes have increased, anthropogenic PM2.5 pollution caused by intensive human activities has led to extremely severe air pollution. Spatiotemporal patterns and drivers of anthropogenic PM2.5 concentrations have received increasing attention from the scientific community. Nonetheless, spatiotemporal patterns and drivers of anthropogenic PM2.5 concentrations are still inadequately understood. Based on a time series of remotely sensed anthropogenic PM2.5 concentrations, this study analyzed the spatiotemporal patterns of this crucial pollutant in China from 1998 to 2016 using Sen's slope estimator and the Mann-Kendall trend model. This, in combination with grey correlation analysis (GCA), was used to reveal the socioeconomic factors influencing anthropogenic PM2.5 concentrations in eastern, central, and western China from 1998 to 2016. The results were as follows: (1) the average annual anthropogenic concentration of PM2.5 in China increased quickly and reached its peak value in 2007, then remained stable in the following years; (2) only 63.30 to 55.09% of the land area reached the threshold value of 15 mu g/m(3) from 1998 to 2016; (3) regarding the polarization phenomenon of anthropogenic PM2.5 concentrations existing in eastern and central China, the proportion of gradient 1 (<= 15 mu g/m(3)) gradually decreased and gradient 3 (>= 35 mu g/m(3)) gradually increased; and (4) the urbanization level (UR), population density (PD), and proportion of secondary industry to gross domestic product (SI) were the dominant socioeconomic factors affecting the formation of anthropogenic PM2.5 concentrations in eastern, central, and western China, independently. The improvements in energy consumption per gross domestic product (EI) have a greater potential for mitigating anthropogenic PM2.5 emissions in central and western China. These findings allow an interpretation of the spatial distribution of anthropogenic PM2.5 concentrations and the mechanisms influencing anthropogenic PM2.5 concentrations, which can help the Chinese government develop effective abatement strategies.