Roles of photochemical consumption of VOCs on regional background O3 concentration and atmospheric reactivity over the pearl river estuary, Southern China

Jiayin Sun; Xiaoyu Yu; Zhenhao Ling; Guizhen Fang; Lili Ming; Jun Zhao; Shichun Zou; Huatian Guan; Haichao Wang; Xuemei Wang; Zhe Wang; Yuan Gao; Yee Jun Tham; Hai Guo; Yanli Zhang

doi:10.1016/j.scitotenv.2024.172321

Roles of photochemical consumption of VOCs on regional background O₃ concentration and atmospheric reactivity over the pearl river estuary, Southern China

Sci Total Environ. 2024 Jun 10:928:172321. doi: 10.1016/j.scitotenv.2024.172321. Epub 2024 Apr 9.

Authors

Jiayin Sun¹, Xiaoyu Yu¹, Zhenhao Ling², Guizhen Fang³, Lili Ming⁴, Jun Zhao¹, Shichun Zou³, Huatian Guan¹, Haichao Wang¹, Xuemei Wang⁵, Zhe Wang⁶, Yuan Gao⁷, Yee Jun Tham⁸, Hai Guo⁹, Yanli Zhang¹⁰

Affiliations

¹ School of Atmospheric Sciences, Sun Yat-sen University, Key Laboratory of Tropical Atmosphere-Ocean System, Ministry of Education, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China.
² School of Atmospheric Sciences, Sun Yat-sen University, Key Laboratory of Tropical Atmosphere-Ocean System, Ministry of Education, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China. Electronic address: lingzhh3@mail.sysu.edu.cn.
³ School of Marine Sciences, Sun Yat-sen University, and Pearl River Estuary Marine Ecosystem Research Station, Ministry of Education, Zhuhai, China.
⁴ Technical Center of Gongbei Customs District of China, Zhuhai, China.
⁵ College of Environment and Climate, Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Jinan University, Guangzhou, China.
⁶ Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Hong Kong, China.
⁷ Instrumentation and Service Center for Science and Technology, Beijing Normal University, Zhuhai, China.
⁸ School of Marine Sciences, Sun Yat-sen University, and Pearl River Estuary Marine Ecosystem Research Station, Ministry of Education, Zhuhai, China. Electronic address: thamyj@mail.sysu.edu.cn.
⁹ Department of Civil and Environmental Engineering, Hong Kong Polytechnic University, Hong Kong, China.
¹⁰ Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China.

PMID: 38604373
DOI: 10.1016/j.scitotenv.2024.172321

Abstract

Understanding of the photochemical ozone (O₃) pollution over the Pearl River Estuary (PRE) of southern China remains limited. We performed an in-depth analysis of volatile organic compounds (VOCs) data collected on an island (i.e., the Da Wan Shan Island, DWS) located at the downwind of Pearl River Delta (PRD) from 26 November to 15 December 2021. Abundances of O₃ and its precursors were measured when the air masses originated from the inland PRD. We observed that the VOCs levels at the DWS site were lower, while the mixing ratio of O₃ was higher, compared to those reported at inland PRD, indicating the occurrence of photochemical consumption of VOCs during the air masses transport, which was further confirmed by the composition and diurnal variations of VOCs, as well as ratios of specific VOCs. The simulation results from a photochemical box model showed that the O₃ level in the outflow air masses of inland PRD (O_3(out-flow)) was the dominant factor leading to the intensification of O₃ pollution and the enhancement of atmospheric radical concentrations (ARC) over PRE, which was mainly contributed by the O₃ production via photochemical consumption of VOCs during air masses transport. Overall, our findings provided direct quantitative evidence for the roles of outflow O₃ and its precursors from inland PRD on O₃ abundance and ARC over the PRE area, highlighting that alleviation of O₃ pollution over PRE should focus on the impact of photochemical loss of VOCs in the outflow air masses from inland PRD.

Keywords: Atmospheric reactivity; Pearl River Estuary; Regional background O3 concentration; Volatile organic compounds.