Guangdong-Hong Kong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Institute for Environmental and Climate Research, Jinan University, Guangzhou 510632, PR China.
School of Atmospheric Sciences, Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-sen University, Guangzhou 510275, China.
Sci Total Environ. 2022 Mar 20;813:151883. doi: 10.1016/j.scitotenv.2021.151883. Epub 2021 Nov 23.
Given the leveling off of fine particulate matter (PM), ground-level ozone (O) pollution has become one of the most significant atmospheric pollution issues in the Pearl River Delta (PRD) region in China, especially in the manufacturing city of Dongguan, which faces more severe O pollution. The development of strategies to control O precursor emissions, including volatile organic compounds (VOCs) and nitrogen oxide (NO), depends to a large extent on the source region of the O pollution. In this study, by combining the Weather Research and Forecasting model coupled with chemistry (WRF-Chem), the Empirical Kinetic Modeling Approach (EKMA), and the Flexible Particle model (FLEXPART), more effective strategies of controlling O precursor emissions were identified under two typical types of O pollution episodes: local formation (LF)-dominant (8-12 September 2019) and regional transport (RT)-dominant (23-27 October 2017) episodes, distinguished by the WRF-FLEXPART model. During the LF-dominant episode, the EKMA revealed that the O formation in Dongguan was in a transitional regime, and the abatement of solvent use-VOCs emissions in the key area of Dongguan was more effective in reducing O levels, with an emission reduction benefit 1.7 times that of total VOCs emission sources throughout Dongguan. With respect to the RT-dominant episode, the reduction in VOCs emissions in the local region did not effectively curb O pollution, although the photochemical regime of the O formation in Dongguan was VOCs-limited. A 50% reduction in NO emissions in the upwind regions (parts of Guangzhou and Huizhou) effectively decreased the O concentration in Dongguan by 17%. The results of this study emphasize the importance of the source region of O pollution in the implementation of effective O control strategies and provide valuable insights for region-specific precursor emission policy formulation, not only in Dongguan, but also in other regions facing severe O pollution.
鉴于细颗粒物（PM）的水平稳定，地面臭氧（O）污染已成为中国珠江三角洲（PRD）地区最重要的大气污染问题之一，尤其是在制造业城市东莞，其面临着更为严重的 O 污染问题。控制 O 前体污染物排放的策略的制定在很大程度上取决于 O 污染的源区。本研究通过结合天气研究和预测模型与化学模型（WRF-Chem）、经验动力学建模方法（EKMA）和灵活粒子模型（FLEXPART），在两种典型的 O 污染事件下，即本地形成（LF）占主导地位（2019 年 8 月 12 日）和区域传输（RT）占主导地位（2017 年 10 月 23 日至 27 日）事件下，确定了更有效的 O 前体污染物排放控制策略。在 LF 占主导的事件中，WRF-FLEXPART 模型表明，东莞的 O 形成处于过渡区，在东莞关键区域减少溶剂使用 VOC 排放对降低 O 水平更为有效，其减排效益是整个东莞 VOC 排放源的 1.7 倍。对于 RT 占主导的事件，尽管东莞的 O 形成光化学机制是 VOC 限制的，但减少本地区域的 VOC 排放并不能有效遏制 O 污染。在上风向地区（广州和惠州的部分地区）减少 50%的 NO 排放可使东莞的 O 浓度有效降低 17%。本研究结果强调了 O 污染源区在实施有效的 O 控制策略中的重要性，为特定区域前体排放政策的制定提供了有价值的见解，不仅对东莞，而且对其他面临严重 O 污染的地区都具有重要意义。
