Spatial disparities of ozone pollution in the Sichuan Basin spurred by extreme, hot weather

作者：Nan Wang, Yunsong Du, Dongyang Chen, Haiyan Meng, Xi Chen, Li Zhou, Guangming Shi, Yu Zhan, Miao Feng, Wei Li, Mulan Chen, Zhenliang Li, Fumo Yang · 发表于：Atmospheric chemistry and physics · 年份：2024 · DOI：10.5194/acp-24-3029-2024 · 被引用次数：41 · 研究领域：Atmospheric chemistry and aerosols、Atmospheric Ozone and Climate、Air Quality and Health Impacts

Abstract. Under the influence of climate change, the increasing occurrence of extreme weather events, such as heatwaves, has led to an enhanced frequency of ozone (O3) pollution issues. In August 2022, the Sichuan Basin (SCB), a typical large-scale geographical terrain located in southwestern China, experienced the most severe heatwave in the last 20 years. The heatwave led to substantial disparities in O3 levels across the region. Here, by integrating observations, machine learning, and numerical simulations, we aim to understand the diverse O3 formation mechanisms in two megacities, Chengdu (western location) and Chongqing (eastern location). Observational data showed that Chengdu experienced a consecutive 17 d period of O3 exceedance, in contrast to Chongqing, where O3 concentrations remained below the standard. Meteorological and precursor factors were assessed, highlighting high temperatures, intense solar radiation, and overnight accumulative pollutants as key contributors to O3 concentrations. The interplay of isoprene, temperature, and O3, alongside the observation-based box model and MEGAN simulations, underscored the significant role of intensified biogenic volatile organic compounds (BVOCs) in O3 formation. Interestingly, Chongqing exhibited nearly double the BVOC emissions of Chengdu, yet contributed less to O3 concentrations. This discrepancy was addressed through CMAQ-DDM (Decoupled Direct Method) simulations and satellite diagnosis by investigating the O3–NOx–V...