Trends in atmospheric particles and their light extinction performance between 1980 and 2015 in Beijing, China.

This study explored the interdecadal variations and their horizontal and vertical light extinction performances of atmospheric particulate matter with aerodynamic diameters ≤2.5 μm (PM2.5 ), particulate matter with aerodynamic diameters ≤ 10 μm (PM10 ), and total suspended particulates (TSPs) in Beijing from 1980 to 2015, using data available from historical publications. Prominent declines of PM2.5 , PM10 , and TSPs were detected with long-term linear trends of -6.7, -4.3, and -1.9 μg m-3  yr-1 , respectively. Generally, on the annual scale during the studied period, it was found that PM2.5 displayed negative correlation (R2  = 0.38, p < 0.01) with visibility and positive correlation (R2  = 0.41, p < 0.01) with aerosol optical depth (AOD). Comparably, PM10 exhibited robust negative correlation (R2  = 0.61, p < 0.01) with visibility and positive correlation (R2  = 0.82, p < 0.01) with AOD. The complicated interdecadal variations and light extinction performances of PM2.5 were found, suggesting the changes on particle composition and vertical distribution of PM2.5 in the atmosphere.