Through GIS spatial analysis, this study firstly conducts spatial distribution of PM2.5 concentrations using PM2.5 data from 35 automatic air quality monitoring stations in Beijing during the period of 2014–2016. Then population spatial processing is carried out based on DMSP/OLS nighttime light data. On this basis, the authors assess the exposure risk to PM2.5 pollution in Beijing from four aspects: PM2.5 concentration, the characteristic of population exposure, the population exposure intensity, and the population weighted concentration. The results show that 1) high PM2.5 concentrations were mainly distributed in the south, while low concentrations were distributed in the north. There was a good spatial coincidence between the distribution of population exposure to PM2.5 and population distribution, i.e. the densely populated area had high risk of population exposure to PM2.5. 2) During 2014–2016, 100% of population exposed to high PM2.5 yearly mean concentrations (>35 μg/m3) which exceeded the secondary level of Ambient Air Quality Standards (GB 3095–2012), and the ratio of population exposed to 24 hourly mean concentrations (>75 μg/m3) declined over a 3-year period. The share of population exposure to exceeding standard PM2.5 concentration was much higher than those in global average level. 3) The population weighted PM2.5 yearly average concentrations and PM2.5 yearly average concentrations had difference, which is related with exposed population and the distribution of PM2.5 pollution. 4) The distributions of PM2.5 concentration and population are different, so the real impact level on health of human of PM2.5 pollution is different from PM2.5 concentration. Thus, taking the factor of population into account, the risk assessment of exposure to PM2.5 pollution is more accurate.
