Since the 1970s, China has continuously improved air pollution treatment and emission standards, but polluted weather still occurs frequently in some areas, especially haze weather. At present, most of the research on haze weather focuses on particulate matter, while ignoring the mechanism of aerosol-radiation-surface ozone interaction under haze weather. Therefore, this paper analyses the relationship between aerosol-radiation-surface ozone with the help of the (SBDART) model for the Guangdong-Hong Kong-Macao Greater Bay Area (GBA), using 2013-2021 as the time line. The results show similar trends in total column ozone and tropospheric ozone, and separate trends in surface ozone. Total column ozone and tropospheric ozone concentrations are at high values in spring and summer and low values in fall and winter; surface ozone is higher in summer and fall and lower in winter and spring. In contrast, Absorbing aerosol index (AAI) had high values in both spring and winter, and low values in summer and autumn. AAI, PM10 and Black carbon (BC) showed negative relations with ozone overall, but AAI and tropospheric ozone reached high values simultaneously in spring, indicating a rapid increase of pollutants caused by meteorological factors and human activities. Ozone concentration decreases from high values when precipitable water increases significantly. The analysis of potential sources of AAI indicated that local sources centered in Guangzhou were the primary source of AAI in the urban agglomeration of GBA, while other potential sources include biomass sources in the south and ozone sources in the northeast. The photolysis rate of fine-grained urban/industrial aerosols did not decrease significantly, leading to an increase in surface ozone concentration. Therefore, low aerosol radiative forcing (ARF) may increase surface ozone concentrations in the fine-particle aerosol mode.

Air pollutants can be transported to the pristine regions such as the Tibetan Plateau, by monsoon and stratospheric intrusion. The Tibetan Plateau region has limited local anthropogenic emissions, while this region is influenced strongly by transport of heavy emissions mainly from South Asia. We conducted a comprehensive study on various air pollutants (PM2.5, total gaseous mercury, and surface ozone) at Nam Co Station in the inland Tibetan Plateau. Monthly mean PM2.5 concentration at Nam Co peaked in April before monsoon season, and decreased during the whole monsoon season (June-September). Monthly mean total gaseous mercury concentrations at Nam Co peaked in July and were in high levels during monsoon season. The Indian summer monsoon acted as a facilitator for transporting gaseous pollutants (total gaseous mercury) but a suppressor for particulate pollutants (PM2.5) during the monsoon season. Different from both PM2.5 and total gaseous mercury variabilities, surface ozone concentrations at Nam Co are primarily attributed to stratospheric intrusion of ozone and peaked in May. The effects of the Indian summer monsoon and stratospheric intrusion on air pollutants in the inland Tibetan Plateau are complex and require further studies. (C) 2021 China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V.