Heavy ozone pollution episodes in urban Beijing during the early summertime from 2014 to 2017: Implications for control strategy

Xin Zhang; Hong Li; Xuezhong Wang; Yujie Zhang; Fang Bi; Zhenhai Wu; Yuhong Liu; Hao Zhang; Rui Gao; Likun Xue; Qingzhu Zhang; Yizhen Chen; Fahe Chai; Wenxing Wang

doi:10.1016/j.envpol.2021.117162

Heavy ozone pollution episodes in urban Beijing during the early summertime from 2014 to 2017: Implications for control strategy

Environ Pollut. 2021 Sep 15:285:117162. doi: 10.1016/j.envpol.2021.117162. Epub 2021 Apr 27.

Authors

Xin Zhang¹, Hong Li², Xuezhong Wang³, Yujie Zhang³, Fang Bi³, Zhenhai Wu³, Yuhong Liu⁴, Hao Zhang³, Rui Gao³, Likun Xue⁴, Qingzhu Zhang⁴, Yizhen Chen³, Fahe Chai³, Wenxing Wang¹

Affiliations

¹ Environment Research Institute, Shandong University, Qingdao, 266237, China; State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
² State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China. Electronic address: [email protected].
³ State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
⁴ Environment Research Institute, Shandong University, Qingdao, 266237, China.

PMID: 33965854
DOI: 10.1016/j.envpol.2021.117162

Abstract

Ground-level ozone (O₃) has become the principal air pollutant in Beijing during recent summers. In this context, an investigation of ambient concentrations and variation characteristics of O₃ and its precursors in May and June from 2014 to 2017 in a typical urban area of Beijing was carried out, and the formation sensitivity and different causes of heavy O₃ pollution (HOP, daily maximum 8-h O₃ (MDA8h O₃)>124 ppbv) were analyzed. The results showed that the monthly assessment values of the O₃ concentrations (the 90^th percentile MDA8h O₃ within one month) were highest in May or June from 2014 to 2017, and the values presented an overall increasing trend. During this period, the number of O₃ pollution days (MDA8h O₃ > 75 ppbv) also showed an increasing trend. During the HOP episodes, the concentrations of volatile organic compounds (VOCs), nitrogen oxides (NO_X), and carbon monoxide (CO) were higher than their respective mean values in May and June, and the meteorological conditions were more conducive to atmospheric photochemical reactions. The HOP episodes were mainly caused by local photochemical formation. From 2014 to 2017, O₃ formation during the HOP episodes shifted from VOC and NO_X mixed-limited to VOC-limited conditions, and O₃ formation was most sensitive to anthropogenic VOCs. Six categories of VOC sources were identified, among which vehicular exhaust contributed the most to anthropogenic VOCs. The VOC concentrations and OFPs of anthropogenic sources have decreased significantly in recent years, indicating that VOC control measures have been effective in Beijing. Nevertheless, NO_X concentrations did not show an evident decreasing trend in the same period. Therefore, more attention should be devoted to O₃ pollution control in May and June; control measure adjustments are needed according to the changes in O₃ precursors, and coordinated control of VOCs and NO_X should be strengthened in long-term planning.

Keywords: Beijing; Formation sensitivity; Heavy ozone pollution episodes; Precursor control; Source apportionment.

MeSH terms

Air Pollutants* / analysis
Air Pollution*
Beijing
Environmental Monitoring
Ozone* / analysis
Photochemical Processes
Volatile Organic Compounds* / analysis

Substances

Air Pollutants
Volatile Organic Compounds
Ozone