Chen Gaojie, Shi Qiao, Xu Lingling, Yu Shaocai, Lin Ziyi, Ji Xiaoting, Fan Xiaolong, Hong Youwei, Li Mengren, Zhang Fuwang, Chen Jinfang, Chen Jinsheng
Fujian Key Laboratory of Atmospheric Ozone Pollution Prevention, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Education, Research Center for Air Pollution and Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China.
Sci Total Environ. 2023 Nov 25;901:166318. doi: 10.1016/j.scitotenv.2023.166318. Epub 2023 Aug 14.
The concentrations of ground-level ozone (O) in China have undergone a rapid increase in recent years, resulting in adverse impacts on the air quality and climate change. However, limited research has been conducted on the coastal urban agglomerations with increasingly serious O pollution. Therefore, in order to better understand in situ photochemistry, comprehensive field observations of O and its precursors, coupled with the model simulation, were conducted in autumn of 2019 at six sites in an urban agglomeration along the coastline of southeastern China. Results indicated that O pollution in the southern part of the urban agglomeration was more severe than that in the northern part, due to higher levels of O precursors and stronger atmospheric oxidation capacity (AOC) in the southern regions. Oxygenated volatile organic compounds (OVOCs), NO, and CO dominated the total OH reactivity, and the site-average daytime Ox (O + NO) increments correlated well (R = 0.94) with the total OH reactivity of CO and VOCs at these sites except for Quanzhou, where industrial emissions (35.1 %) and solvent usages (33.7 %) dominated the VOC sources. However, vehicle exhausts (31.1 %) were the most predominant contributors to the VOC sources at other sites. The results of model simulations showed that net O formation rates were larger at the southern sites. Furthermore, O production was mainly controlled by VOCs at most sites, but co-limited by VOCs and NOx at Quanzhou. The most significant VOC groups contributing to O formation were aromatics and alkenes, with m/p-xylene, toluene, propene, and ethene being the main contributors at these sites. This study offers a more comprehensive understanding of the characteristics and formation of photochemical pollutions on the scale of the urban areas, indicating the critical need to reduce VOC emissions as a means of mitigating their photochemical effects.
近年来，中国地面臭氧（O）浓度迅速上升，对空气质量和气候变化产生了不利影响。然而，对于臭氧污染日益严重的沿海城市群，相关研究较少。因此，为了更好地了解原位光化学过程，于2019年秋季在中国东南沿海一个城市群的六个站点进行了臭氧及其前体物的综合实地观测，并结合模型模拟。结果表明，该城市群南部的臭氧污染比北部更严重，这是由于南部地区臭氧前体物水平较高且大气氧化能力（AOC）更强。含氧挥发性有机化合物（OVOCs）、NO和CO主导了总OH反应活性，除泉州外，这些站点的日间平均Ox（O + NO）增量与CO和VOCs的总OH反应活性具有良好的相关性（R = 0.94），在泉州，工业排放（35.1%）和溶剂使用（33.7%）是VOCs的主要来源。然而，在其他站点，汽车尾气（31.1%）是VOCs的最主要来源。模型模拟结果表明，南部站点的净臭氧生成率更高。此外，在大多数站点，臭氧生成主要受VOCs控制，但在泉州则受VOCs和NOx共同限制。对臭氧形成贡献最大的VOCs类别是芳烃和烯烃，间/对二甲苯、甲苯、丙烯和乙烯是这些站点的主要贡献者。本研究为城市尺度上光化学污染的特征和形成提供了更全面的理解，表明迫切需要减少VOCs排放以减轻其光化学影响。
