Air pollutant concentration trends in China: correlations between solar radiation, PM2.5, and O3

In this study, we analyzed the spatial distribution and temporal variations of surface solar radiation and aerosol extinction to explain the recent increase in surface O3 concentration. Our results confirmed a marked PM2.5 concentration decrease between 2015 and 2019, especially in northern China, and a simultaneous O3 concentration increase. Surface solar radiation showed geographically consistent increases, likely caused by the decreasing PM2.5 concentrations and the resulting lower aerosol optical thickness. The surface solar radiation increasing enhanced photochemical O3 production. We also investigated cloud cover distribution and trends. It demonstrated that the surface solar radiation intensity increase in northern China was caused by decreasing aerosol concentrations, not by cloud cover differences. Moreover, most emission reduction policies focus on sulfur and nitrogen oxides, less on other important O3 precursors, such as the non-methane volatile organic compounds (NMVOCs). The emission of O3 precursors has not reached the level of suppressing O3 pollution. Stricter emission reduction policies are, therefore, required to mitigate O3 pollution.
Source: Air Quality, Atmosphere and Health - Category: Environmental Health Source Type: research