Spatio-temporal variation of O3 concentration and exposure risk assessment in key regions of China, 2015-2021

In recent years, the increasing Ozone (O3) concentration has become a significant concern for human life and health. In this study, O3 concentration data at 10 km resolution and population density data at 1 km resolution for China were utilized. Methods such as the Global Moran's I index, Getis-Ord Gi* index, and population exposure risk index, to analyze the spatial-temporal variation, meteorological influences, aggregation characteristics, exposure risk levels and health impact of O3 in China and six key regions from 2015 to 2021. The results revealed an increasing trend with a bimodal fluctuation pattern, peak in May and August. Only Pearl River Delta (PRD) showed the highest in autumn, five other key regions were highest O3 concentration in the summer. And the spatial autocorrelation in China is obvious among regions. Among the five meteorological factors, temperature and sunshine duration predominantly influenced O3 concentration in China. Relative humidity was the main factor affecting O3 concentration in Beijing-Tianjin-Hebei (BTH), Yangtze River Delta (YRD) and Sichuan Basin (SCB), while precipitation had the greatest impact on FenWei Plain (FWP) and Hexi Corridor (HXC) and exhibited a positive correlation. Wind speed in PRD showed a strong negative correlation with O3 concentration. The Ri exhibited significant differences between the eastern and western sides of the Hu Huanyong line, demonstrating a distribution pattern of "high in the east and low in the west". Through this research, we aim to provide valuable insights for public health policies and the prevention and control of regional air pollution.