Long-term variation of satellite-based PM2.5 and influence factors over East China.

With the explosive economic development of China over the past few decades, air pollution has attracted increasing global concern. Using satellite-based PM2.5 data from 2000 to 2015, we found that the available emissions of atmospheric compositions show similar yearly variation trends to PM2.5, even if the synchronization is not met for each composition, implying that the intensity of anthropogenic emissions dominates the temporal variation of PM2.5 in East China. Empirical orthogonal function analysis demonstrates that the dominant variability in the seasonal PM2.5 is closely associated with climate circulation transformation, incarnated as the specific climate index such as the Asia Polar Vortex intensity in spring, the Northern Hemisphere Subtropical High Ridge Position for the leading mode and the Kuroshio Current SST for the second mode in summer, the Asia Polar Vortex Area for the leading mode and the Pacific Polar Vortex Intensity for the second mode in autumn, the NINO A SSTA for the leading mode and the Pacific Decadal Oscillation for the second mode in winter. Therefore, apart from anthropogenic emissions effects, our results also provide robust evidence that over the past 16 years the climate factor has played a significant role in modulating PM2.5 in eastern China.