Spatio-temporal Distribution of Ozone Pollution and Population Exposure Level Assessment in the Sichuan Basin, 2015-2022

In recent years, the severe surface ozone (O₃) pollution has become one of the key environmental risks affecting public health. To study the spatial and temporal distribution of O₃ pollution and its quantitative impact on population exposure in the Sichuan Basin (SCB), the air quality data from national-controlled environmental monitoring stations from 2015 to 2022, the Tracking Air Pollution (TAP) dataset of atmospheric composition in China, and the population density information were used, and the statistical analysis and a population-weighted O₃ exposure model were employed. The findings are as follows: (1) The TAP dataset demonstrates high reliability, with strong correlation to observational data. (2) O₃ concentrations exhibited a fluctuating upward trend, increasing by 11.73% in the SCB from 2015 to 2022. The high-value centers of ozone concentration were mainly in the central urban areas of Chengdu and Chongqing, and gradually spreading to form a spatial pattern of regional ozone pollution. (3) The population-weighted average O₃ concentration in each city was higher than the regional average, indicating a significant potential health risk associated to O₃. From 2015 to 2022, the proportion of the population in the SCB exposed to medium-to-high O₃ concentration reached a peak of 63.67% and showed an upward trend; the annual growth rate for the population exposed to high O₃ concentration was the highest at 12.45%, suggesting that the impact of O₃ pollution on the population is gradually shifting toward higher concentration ranges. The research findings provide a scientific basis for implementing health risk-based ozone pollution management in the SCB.