Peroxy radical chemistry during ozone photochemical pollution season at a suburban site in the boundary of Jiangsu-Anhui-Shandong-Henan region, China

Nana Wei; Weixiong Zhao; Yichen Yao; Huarong Wang; Zheng Liu; Xuezhe Xu; Masudur Rahman; Cuihong Zhang; Christa Fittschen; Weijun Zhang

doi:10.1016/j.scitotenv.2023.166355

Peroxy radical chemistry during ozone photochemical pollution season at a suburban site in the boundary of Jiangsu-Anhui-Shandong-Henan region, China

Sci Total Environ. 2023 Dec 15:904:166355. doi: 10.1016/j.scitotenv.2023.166355. Epub 2023 Aug 16.

Authors

Nana Wei¹, Weixiong Zhao², Yichen Yao³, Huarong Wang³, Zheng Liu³, Xuezhe Xu¹, Masudur Rahman⁴, Cuihong Zhang⁵, Christa Fittschen⁶, Weijun Zhang⁷

Affiliations

¹ Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei 230031, Anhui, China.
² Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei 230031, Anhui, China. Electronic address: wxzhao@aiofm.ac.cn.
³ Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei 230031, Anhui, China; School of Environmental Science and Optoelectronics Technology, University of Science and Technology of China, Hefei 230026, China.
⁴ Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei 230031, Anhui, China; Department of Electrical and Electronic Engineering, Pabna University of Science and Technology, Pabna 6600, Bangladesh.
⁵ Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei 230031, Anhui, China; School of Environmental Science and Optoelectronics Technology, University of Science and Technology of China, Hefei 230026, China; Université Lille, CNRS, UMR 8522 - PC2A -Physicochimie des Processus de Combustion et de l'Atmosphère, F-59000 Lille, France.
⁶ Université Lille, CNRS, UMR 8522 - PC2A -Physicochimie des Processus de Combustion et de l'Atmosphère, F-59000 Lille, France.
⁷ Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei 230031, Anhui, China; School of Environmental Science and Optoelectronics Technology, University of Science and Technology of China, Hefei 230026, China. Electronic address: wjzhang@aiofm.ac.cn.

PMID: 37595920
DOI: 10.1016/j.scitotenv.2023.166355

Abstract

Ambient peroxy radical (RO₂^⁎ = HO₂ + RO₂) concentrations were measured at a suburban site in a major prefecture-level city (Huaibei) in the boundary of Jiangsu-Anhui-Shandong-Henan region, which is the connecting belt of air pollution in the Beijing-Tianjin-Hebei region and the Yangtze River Delta. Measurements were carried out during the period of September to October 2021 to elucidate the formation mechanism of O₃ pollution. The observed maximum concentration of peroxy radicals was 73.8 pptv. A zero-dimensional box model (Framework for 0-Dimensional Atmospheric Modeling, F0AM) based on Master Chemical Mechanism (MCM3.3.1) was used to predict radical concentrations for comparison with observations. The model reproduced the daily variation of peroxy radicals well, but discrepancies still appear in the morning hours. As in previous field campaigns, systematic discrepancies between modelled and measured RO₂^⁎ concentrations are observed in the morning for NO mixing ratios higher than 1 ppbv. Between 6:00 and 9:00 am, the model significantly underpredicts RO₂^⁎ by a mean factor of 7.2. This underprediction can be explained by a missing RO₂^⁎ source of 1.2 ppbv h^-1 which originated from the photochemical conversion of an alkene-like chemical species. From the model results it shows that the main sources of RO_x (= OH + HO₂ + RO₂) are the photolysis of oxygenated volatile organic compounds (OVOCs, 33 %), O₃ and HONO (25 %), and HCHO (24 %). And the major sinks of RO_x transitioned from a predominant reaction of radicals with NO_x in the morning to a predominant peroxy self- and cross-reaction in the late afternoon. The introduction of an alkene-like species increased RO₂ radical concentration and resulted in 14 % increase in net daily integrated ozone production, indicating the possible significance of the mechanism of alkene-like species oxidation to peroxy radicals. This study provides important information for subsequent ozone pollution control policies in Jiangsu-Anhui-Shandong-Henan region.

Keywords: Ozone production rate; Peroxy radical (RO(2)(⁎) = HO(2) + RO(2)); RO(x) budget.