Photochemistry in the urban agglomeration along the coastline of southeastern China: Pollution mechanism and control implication

Gaojie Chen; Qiao Shi; Lingling Xu; Shaocai Yu; Ziyi Lin; Xiaoting Ji; Xiaolong Fan; Youwei Hong; Mengren Li; Fuwang Zhang; Jinfang Chen; Jinsheng Chen

doi:10.1016/j.scitotenv.2023.166318

Photochemistry in the urban agglomeration along the coastline of southeastern China: Pollution mechanism and control implication

Sci Total Environ. 2023 Nov 25:901:166318. doi: 10.1016/j.scitotenv.2023.166318. Epub 2023 Aug 14.

Authors

Gaojie Chen¹, Qiao Shi², Lingling Xu¹, Shaocai Yu³, Ziyi Lin¹, Xiaoting Ji¹, Xiaolong Fan¹, Youwei Hong¹, Mengren Li¹, Fuwang Zhang⁴, Jinfang Chen⁵, Jinsheng Chen⁶

Affiliations

¹ 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.
² 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.
³ 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. Electronic address: shaocaiyu@zju.edu.cn.
⁴ Environmental Monitoring Center of Fujian, Fuzhou 350003, China.
⁵ College of Harbour and Coastal Engineering, Jimei University, Xiamen 361021, China.
⁶ 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. Electronic address: jschen@iue.ac.cn.

PMID: 37586504
DOI: 10.1016/j.scitotenv.2023.166318

Abstract

The concentrations of ground-level ozone (O₃) 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 O₃ pollution. Therefore, in order to better understand in situ photochemistry, comprehensive field observations of O₃ 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 O₃ pollution in the southern part of the urban agglomeration was more severe than that in the northern part, due to higher levels of O₃ precursors and stronger atmospheric oxidation capacity (AOC) in the southern regions. Oxygenated volatile organic compounds (OVOCs), NO₂, and CO dominated the total OH reactivity, and the site-average daytime Ox (O₃ + NO₂) increments correlated well (R² = 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 O₃ formation rates were larger at the southern sites. Furthermore, O₃ 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 O₃ 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.

Keywords: Coastal urban agglomeration; Control implications; Ozone formation; Pollution mechanism; Volatile organic compounds.