Abstract:
Surface ozone pollution has become one of the most prominent environmental problems in China, especially in the topographically isolated basin areas. However, the spatial and temporal evolution, regional transport processes and driving factors of O
3 in the basin topographic region have not been systematically studied and confirmed. In this study, the Sichuan basin was chosen as a typical case site, and real-time ozone monitoring data derived from long time scale monitoring stations were selected for analysis. The integrated trajectory, geographically and temporally weighted regression model were used to explore the spatiotemporal variation characteristics, transport paths, potential source areas and distribution characteristics of driving factors of ozone. The results showed that the annual average O
3 concentration in Sichuan Basin from 2015 to 2021 was 143±7 µg/m
3, and the average O
3 concentration in summer was higher than that in other seasons. The O
3 pollution in May should be paid more attention, and there was an significant diurnal difference in O
3 concentration. In addition, O
3 concentration varied significantly between day and night. In terms of spatial pattern, the O
3 concentration in the Sichuan Basin was generally high in the west and low in the east, and the core pollution area was located in the Chengdu plain. From 2015 to 2021, 74.24% of O
3 in Chengdu was supplied by short-range transmission, while the average contribution rate of long-distance transmission was 25.76%. The potential source area of O
3 pollution in Chengdu moved from west to east, and the potential source area gradually gathered around the basin. The driving factor analysis showed that air temperature (0.747) and sunshine duration (0.289) were the dominant meteorological driving factors for O
3 in the Sichuan Basin. Population density(0.412) and per capita GDP (0.369) were the main socio-economic factors leading to the increase of O
3 concentration. The findings of this study attempted to provide theoretical support for regional joint prevention and control of O
3 pollution in the basin topography area.