Chemical reactivity of volatile organic compounds and their effects on ozone formation in a petrochemical industrial area of Lanzhou, Western China

Wenkai Guo; Yanping Yang; Qiang Chen; Yuhuan Zhu; Yaru Zhang; Yingnan Zhang; Yongle Liu; Guangyao Li; Wei Sun; Jing She

doi:10.1016/j.scitotenv.2022.155901

Chemical reactivity of volatile organic compounds and their effects on ozone formation in a petrochemical industrial area of Lanzhou, Western China

Sci Total Environ. 2022 Sep 15:839:155901. doi: 10.1016/j.scitotenv.2022.155901. Epub 2022 May 12.

Authors

Wenkai Guo¹, Yanping Yang², Qiang Chen³, Yuhuan Zhu¹, Yaru Zhang¹, Yingnan Zhang⁴, Yongle Liu¹, Guangyao Li¹, Wei Sun¹, Jing She¹

Affiliations

¹ Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China.
² Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China; Northwest Institute of Eco-environmental Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Gansu Environmental Monitoring Center, Lanzhou 730000, China.
³ Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China. Electronic address: chenqqh@lzu.edu.cn.
⁴ Environment Research Institute, Shandong University, Jinan 250000, China.

PMID: 35569665
DOI: 10.1016/j.scitotenv.2022.155901

Abstract

Measurements of ozone (O₃) and its precursors were performed in the summer of 2019 in Lanzhou, a petrochemical industrial city, to better understand the reactivity of volatile organic compounds (VOCs) and their effects on O₃ production. During the campaign, the daily maximum 8-hour average (MDA8) O₃, NO₂, and total VOC (TVOC) concentrations reached 72.2 ± 19.9 ppb, 24.9 ± 10.8 ppb, and 50.8 ± 46.1 ppb, respectively. Alkanes, alkenes, halocarbons, aromatics, and alkynes contributed 45.3%, 24.0%, 16.5%, 10.0%, and 4.2% to TVOCs, respectively. The OH reactivity and relative incremental reactivity (RIR) of VOCs at different times were calculated. The results indicated that alkenes played a predominant role, accounting for an average of 68.5% of the initial VOC reactivity. Compared to other regions, alkenes are relatively more important for O₃ formation in the petrochemical industry area of Lanzhou, while aromatics are relatively less important. Generally, O₃ formation occurred in a VOC-limited regime in the morning and in a transitional regime in the afternoon. The response surface methodology (RSM) combined with a chemical box model was applied to obtain relationships between O₃ and its precursors and determine the most effective way to reduce the O₃ concentration. Reduction in the non-alkene concentration slightly affected the O₃ concentration. In contrast, the effect of nitrogen oxides (NO_x) was closely related to the alkene concentration, and NO_x concentration reduction could lead to an increase in the O₃ concentration when alkenes were abated to less than 80% of the present concentration. To mitigate O₃ pollution near the petrochemical industrial area of Lanzhou, reducing the alkene concentration, especially the C4 alkene concentration (1,3-butadiene, cis-2-butene, and trans-2-butene), was the fastest and most effective control strategy. The results of this study serve as a reference for O₃ pollution control in petrochemical industrial areas.

Keywords: Control strategy; Incremental reactivity; OH reactivity; Ozone pollution; Petrochemical industry.

MeSH terms

Air Pollutants* / analysis
Alkenes
China
Environmental Monitoring / methods
Ozone* / analysis
Volatile Organic Compounds* / analysis

Substances

Air Pollutants
Alkenes
Volatile Organic Compounds
Ozone