Ozone Formation in a Representative Urban Environment: Model Discrepancies and Critical Roles of Oxygenated Volatile Organic Compounds
Xiangpeng Huang, Wei Zheng, Yanchen Li, Changping Li, Yue’e Li, Ning Zhang, Chao‐Yang Pan, Yali Lei, Haiwei Li, Y. Zhang, Yiming Qin, Yi Zheng, Tzung‐May Fu, Xin Yang, Xinlei Ge, Hongliang Zhang, Jianhuai Ye
Abstract
Ozone (O 3 ) significantly impacts air quality. Despite reductions in PM 2.5 since the 2013 Clean Air Act, the level of the O 3 concentration has continued to rise in China, underscoring the need for targeted pollution control measures. This study examined the seasonal and spatial variations of pollutants and meteorological variables in a major industrial city in Eastern China. Three widely used approaches, including the ozone formation potential (OFP) calculation, an observation-based model (OBM), and a random forest algorithm, were employed to investigate O 3 formation in urban environments. Results show that oxygenated volatile organic compounds were the most significant contributors to summer urban O 3, whereas their impact was significantly reduced during the winter. Each O 3 formation evaluation model provided unique insights, with OFP offering rapid estimates, the OBM revealing detailed chemistry, and random forest capturing nonlinear interactions. However, the study also identified limitations in these models. OFP failed to account for seasonal variations in the level of O 3 formation, and the random forest model struggled to distinguish causal relationships from correlations. These findings highlight the need for caution when relying on a single model and underscore the importance of integrating multiple methods to gain an accurate understanding of urban O 3 formation dynamics, which is crucial to developing effective control strategies.