Summertime O₃ and related health risks in the north China plain: A modeling study using two anthropogenic emission inventories

Ground-level ozone (O-3), which is formed by photochemical reactions of nitrogen oxides (NOx) and volatile organic compounds (VOCs), exert adverse effects on human health. In China, the mechanism and influencing factors of high O-3 levels are not well understood in China despite the frequent occurrence of extreme episodes in recent years with decreasing concentrations of particulate matter. In this study, the O-3 concentrations in summer 2017 in the North China Plain (NCP) are simulated using the Community Multiscale Air Quality (CMAQ) model with anthropogenic emissions from the Multi-resolution Emission Inventory for China (MEIC) and improved Emission Database for Global Atmospheric Research (EDGAR+). Moreover, the performances of the model with the two emission inventories are validated and compared. The simulation using EDGAR+ is found to be highly accurate in predicting O-3 in the NCP, whereas that using MEIC has better performance in matching peak concentrations in extreme episodes. Weather conditions, such as high temperature, low relative humidity, and stable conditions, are associated with high O-3 concentrations in both inventories. Compared with MEIC, lower NOx emissions (by 200 tons/grid/month) from EDGAR+ induce higher O-3 concentrations when VOCs emissions are barely changed (by less than 5 tons/grid/month). In the EDGAR+ scenario, a total of 42,000 and 69,000 premature mortalities are estimated to be caused by O-3-related respiratory and cardiovascular diseases, respectively. These values are slightly lower than those in the MEIC scenario, i.e., 50,000 and 80,000, respectively. Megacities, such as Beijing and Tianjin, are classified as high-risk areas, with more than 15,000 mortalities.