Ambient ozone pollution at a coal chemical industry city in the border of Loess Plateau and Mu Us Desert: characteristics, sensitivity analysis and control strategies

Manfei Yin; Xin Zhang; Yunfeng Li; Kai Fan; Hong Li; Rui Gao; Jinjuan Li

doi:10.7717/peerj.11322

Ambient ozone pollution at a coal chemical industry city in the border of Loess Plateau and Mu Us Desert: characteristics, sensitivity analysis and control strategies

PeerJ. 2021 Apr 27:9:e11322. doi: 10.7717/peerj.11322. eCollection 2021.

Authors

Manfei Yin^{1

2}, Xin Zhang^{2

3}, Yunfeng Li^{2

3}, Kai Fan⁴, Hong Li², Rui Gao², Jinjuan Li¹

Affiliations

¹ College of Resource and Environment Engineering, Guizhou University, Guiyang, China.
² State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, China.
³ Environment Research Institute, Shandong University, Jinan, China.
⁴ Yulin Municipal Ecology and Environment Bureau, Yulin, China.

Abstract

In this study, ambient ozone (O₃) pollution characteristics and sensitivity analysis were carried out in Yulin, a city in the central area of the Loess Plateau during 2017 to 2019 summer. O₃ concentrations increased for 2017 to 2019. Correlation and statistics analysis indicated high temperature (T > 25 °C, low relative humidity (RH < 60%), and low wind speed (WS < 3 m/s) were favorable for O₃ formation and accumulation, and the O₃ pollution days (MDA8 O₃ > 160 µg/m³) were predominantly observed when the wind was traveling from the easterly and southerly. O₃ concentration in urban area of Yulin was higher than that in background. The pollution air masses from Fenwei Plain increase the level and duration of O₃ pollution. In order to clarify the formation mechanism and source of O₃, online measurements of volatile organic compounds (VOCs) were conducted from 7 July to 10 August in 2019. The average of VOCs concentration was 26 ± 12 ppbv, and large amounts of alkenes followed by aromatics, characteristic pollutants of the coal chemical industry, were detected in the ambient air. To further measure the sensitivity, the observation-based model (OBM) simulation was conducted. Empirical Kinetic Modeling Approach (EKMA) plot and relative incremental reactivity (RIR) value indicated Yulin located on VOCs-limited regime. That implied a slight decrease of NO_x may increase O₃ concentration. When the emission reduction ratio of anthropogenic VOCs/NO_x higher than 1:1, the O₃ will decrease. O₃ control strategies analysis shows that the O₃ targets of 5% and 10% O₃ concentration reductions are achievable through precursor control, but more effort is needed to reach the 30% and 40% reduction control targets.

Keywords: Characteristics; Coal chemistry; Loess Plateau; OBM simulation; Ozone; Sensitivity.

Grants and funding

This work was supported by the Fundamental Research Funds for Central Public Welfare Scientific Research Institutes of China, CRAES (No. 2019YSKY-012 and 2019YSKY-018), the National Key Research and Development Program of China (No. 2019YFC0214800), and the National Nature Science Foundation of China (No. 41907197). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.