Pollution characteristics and sources of environmentally persistent free radicals and oxidation potential in fine particulate matter related to city lockdown (CLD) in Xi'an, China

Dyussenova Ainur; Qingcai Chen; Yuqin Wang; Hao Li; Hao Lin; Xuying Ma; Xin Xu

doi:10.1016/j.envres.2022.112899

Pollution characteristics and sources of environmentally persistent free radicals and oxidation potential in fine particulate matter related to city lockdown (CLD) in Xi'an, China

Environ Res. 2022 Jul:210:112899. doi: 10.1016/j.envres.2022.112899. Epub 2022 Feb 14.

Authors

Dyussenova Ainur¹, Qingcai Chen², Yuqin Wang¹, Hao Li¹, Hao Lin¹, Xuying Ma³, Xin Xu⁴

Affiliations

¹ School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, China.
² School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an, 710021, China. Electronic address: chenqingcai@sust.edu.cn.
³ College of Geomatics, Xi'an University of Science and Technology, Xi'an, 710054, China.
⁴ Xi'an Institute for Innovative Earth Environment Research, Xi'an, 710061, China.

Abstract

The impact of COVID-19 control on air quality have been prevalent for the past two years, however few studies have explored the toxicity of atmospheric particulate matter during the epidemic control. Therefore, this research highlights the characteristics and sources of oxidative potential (OP) and the new health risk substances environmentally persistent free radicals (EPFRs) in comparison to city lockdown (CLD) with early days of 2019-2020. Daily particulate matter (PM_2.5) samples were collected from January 14 to February 3, 2020, with the same period during 2019 in Xi'an city. The results indicated that the average concentration of PM_2.5 decreased by 48% during CLD. Concentrations of other air pollutants and components, such as PM₁₀, NO₂, SO₂, WSIs, OC and EC were also decreased by 22%, 19%, 2%, 17%, 6%, and 4% respectively during the CLD, compared to the same period in 2019. Whereas only O₃ increased by 30% during CLD. The concentrations of EPFRs in PM_2.5 was considerably lower than in 2019, which decreased by 12% during CLD. However, the OP level was increased slightly during CLD. Moreover, both EPFRs/PM and DTTv/PM did not decrease or even increase significantly, manifesting that the toxicity of particulate matter has not been reduced by more gains during the CLD. Based on PMF analysis, during the epidemic period, the contribution of traffic emission is significantly reduced, while EPFRs and DTTv increased, which consist of significant O₃ and secondary aerosols. This research leads to able future research on human health effect of EPFRs and oxidative potential and can be also used to formulate the majors to control EPFRs and OP emissions, suggest the need for further studies on the secondary processing of EPFRs and OP during the lockdown period in Xi'an. .The COVID-19 lockdown had a significant impact on both social and economic aspects. The city lockdown, however, had a positive impact on the environment and improved air quality, however, no significant health benefits were observed in Xi'an, China.

Keywords: COVID-19; Environmentally persistent free radicals (EPFRs); Oxidation potential (OP); PM(2.5); Sources.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Air Pollutants* / analysis
Air Pollution* / analysis
COVID-19* / epidemiology
China
Communicable Disease Control
Environmental Monitoring / methods
Free Radicals / analysis
Humans
Particulate Matter / analysis

Substances

Air Pollutants
Free Radicals
Particulate Matter