Long-term variation of O3 in the Yangtze River Delta and its influencing factors from a regional perspective

IF 6 2区工程技术 Q1 ENVIRONMENTAL SCIENCES

Urban Climate Pub Date : 2025-03-01 DOI:10.1016/j.uclim.2025.102353

Qiuyue Bao , Weili Lin , Junli Jin , Xiaobin Xu , Gang Zhao , Xiaoyi Zhang , Qianli Ma

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引用次数: 0

Abstract

To tackle regional O₃ pollution, understanding long-term trends and drivers of background O₃ is crucial. This comprehensive study analyzed O₃ data from the Lin'an regional atmospheric background station (LAN) in the Yangtze River Delta (YRD), utilizing the Ensemble Empirical Mode Decomposition (EEMD) method to discern trends and the Random Forest (RF) model to evaluate anthropogenic and meteorological impacts, while also employing the satellite-based HCHO/NO₂ column ratio (FNR) as a proxy to assess O₃ production sensitivity. EEMD effectively filtered out high-frequency signals, revealing a significant decreasing trend of −0.7 ppb/decade (p < 0.001) in O₃ mixing ratios from 2005 to 2022. In contrast, direct analysis of the raw O₃ data showed an insignificant increase of 0.4 ± 0.9 ppb/decade (p = 0.67), highlighting the importance of data preprocessing methods in assessing long-term trends. Meteorological normalization using the RF model, anthropogenic emissions drove a slight O₃ rise (1.7 ppb/decade), partly offset by meteorology. Using the FNR, a noticeable shift in O₃ photochemical production sensitivity from VOCs-limited to transitional regime was observed since 2014, potentially attributed to decreased NO_x emissions. Effective regional O₃ pollution mitigation in the YRD demands a comprehensive strategy, focusing on concurrent reductions in NO_x and VOCs emissions, with emphasis on efficient VOCs control measures.

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来源期刊

Urban Climate Social Sciences-Urban Studies

CiteScore

9.70

自引率

9.40%

发文量

286

期刊介绍： Urban Climate serves the scientific and decision making communities with the publication of research on theory, science and applications relevant to understanding urban climatic conditions and change in relation to their geography and to demographic, socioeconomic, institutional, technological and environmental dynamics and global change. Targeted towards both disciplinary and interdisciplinary audiences, this journal publishes original research papers, comprehensive review articles, book reviews, and short communications on topics including, but not limited to, the following: Urban meteorology and climate[...] Urban environmental pollution[...] Adaptation to global change[...] Urban economic and social issues[...] Research Approaches[...]