Air pollutant spatiotemporal evolution characteristics and effects on human health in North China.

North China, the political, economic, and cultural center of China, has been greatly harmed by frequent air pollution incidents. Therefore, it is vital to study air pollution characteristics and clarify their impact on human health. In this study, we first analyzed the spatiotemporal variations of air pollutants (PM, PM, CO, SO, NO, and O) in North China from 2016 to 2019. Then, the air quality index (AQI), aggregate air quality index (AAQI), and health risk based air quality index (HAQI) were used to assess health risks. Based on these, the AirQ model was used to quantify health effects. The results showed that the major pollutant in the cities surrounding Beijing was PM, while PM dominated in distant cities. Annual concentrations decreased (except for O), which is related to governmental emission reduction policies. However, O concentrations increased owing to the complex precursor emissions. The AQI underestimated air pollution, while the AAQI and HAQI were accurate; the latter indicated that 55% of the study region population was exposed to polluted air. The AirQ model quantified the total mortality proportions attributable to PM, PM, SO, CO, NO, and O, which were 1.87%, 3.12%, 1.11%, 1.40%, 4.19%, and 2.52%, respectively. In high concentrations, PM and PM pose significant health risks. The health effects of SO, NO, CO, and O at lower concentrations were more obvious, indicating that the expected mortality rate due to low concentrations of some pollutants was much higher than that due to high concentrations of other pollutants.