The Multi-Time Scale Changes in Air Pollutant Concentrations and Its Mechanism before and during the COVID-19 Periods: A Case Study from Guiyang, Guizhou Province

The lockdown during the coronavirus disease 2019 (COVID-19) pandemic provides a scarce opportunity to assess the efficiency of air pollution mitigation. Herein, the monitoring data of air pollutants were thoroughly analyzed together with meteorological parameters to explore the impact of human activ...

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Autores principales: Zhihua Su, Xin Li, Yunlong Liu, Bing Deng
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Publicado: MDPI AG 2021
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spelling oai:doaj.org-article:59af328deada481bae8498185d888f8a2021-11-25T16:45:30ZThe Multi-Time Scale Changes in Air Pollutant Concentrations and Its Mechanism before and during the COVID-19 Periods: A Case Study from Guiyang, Guizhou Province10.3390/atmos121114902073-4433https://doaj.org/article/59af328deada481bae8498185d888f8a2021-11-01T00:00:00Zhttps://www.mdpi.com/2073-4433/12/11/1490https://doaj.org/toc/2073-4433The lockdown during the coronavirus disease 2019 (COVID-19) pandemic provides a scarce opportunity to assess the efficiency of air pollution mitigation. Herein, the monitoring data of air pollutants were thoroughly analyzed together with meteorological parameters to explore the impact of human activity on the multi-time scale changes of air pollutant concentrations in Guiyang city, located in Southwest China. The results show that the COVID-19 lockdown had different effects on the criteria air pollutants, i.e., PM<sub>2.5</sub> (diameter ≤ 2.5 μm), PM<sub>10</sub> (diameter ≤ 10 μm), sulfur dioxide (SO<sub>2</sub>), nitrogen dioxide (NO<sub>2</sub>), carbon monoxide (CO), and ozone (O<sub>3</sub>) concentrations. The lockdown caused a significant drop in NO<sub>2</sub> concentration. During the first-level lockdown period, the NO<sub>2</sub> concentration declined sharply by 8.41 μg·m<sup>−3</sup> (45.68%). The decrease in NO concentration caused the “titration effect” to weaken, leading to a sharp increase in O<sub>3</sub> concentration. Although human activities resumed partially and the “titration effect” enhanced certainly during the second-level lockdown period, the meteorological conditions became more conducive to the formation of O<sub>3</sub> by photochemical reactions. Atmosphere oxidation was enhanced to promote the generation of secondary aerosols through gas–particle transitions, thus compensating for the reduced primary emission of PM<sub>2.5</sub>. The implication of this study is that the appropriate air pollution control policies must be initiated to suppress the secondary generation of both PM<sub>2.5</sub> and O<sub>3</sub>.Zhihua SuXin LiYunlong LiuBing DengMDPI AGarticlecoronavirus disease 2019 (COVID-19)lockdownatmospheric pollutantsmeteorological conditionssecondary aerosol formationGuiyangMeteorology. ClimatologyQC851-999ENAtmosphere, Vol 12, Iss 1490, p 1490 (2021)
institution DOAJ
collection DOAJ
language EN
topic coronavirus disease 2019 (COVID-19)
lockdown
atmospheric pollutants
meteorological conditions
secondary aerosol formation
Guiyang
Meteorology. Climatology
QC851-999
spellingShingle coronavirus disease 2019 (COVID-19)
lockdown
atmospheric pollutants
meteorological conditions
secondary aerosol formation
Guiyang
Meteorology. Climatology
QC851-999
Zhihua Su
Xin Li
Yunlong Liu
Bing Deng
The Multi-Time Scale Changes in Air Pollutant Concentrations and Its Mechanism before and during the COVID-19 Periods: A Case Study from Guiyang, Guizhou Province
description The lockdown during the coronavirus disease 2019 (COVID-19) pandemic provides a scarce opportunity to assess the efficiency of air pollution mitigation. Herein, the monitoring data of air pollutants were thoroughly analyzed together with meteorological parameters to explore the impact of human activity on the multi-time scale changes of air pollutant concentrations in Guiyang city, located in Southwest China. The results show that the COVID-19 lockdown had different effects on the criteria air pollutants, i.e., PM<sub>2.5</sub> (diameter ≤ 2.5 μm), PM<sub>10</sub> (diameter ≤ 10 μm), sulfur dioxide (SO<sub>2</sub>), nitrogen dioxide (NO<sub>2</sub>), carbon monoxide (CO), and ozone (O<sub>3</sub>) concentrations. The lockdown caused a significant drop in NO<sub>2</sub> concentration. During the first-level lockdown period, the NO<sub>2</sub> concentration declined sharply by 8.41 μg·m<sup>−3</sup> (45.68%). The decrease in NO concentration caused the “titration effect” to weaken, leading to a sharp increase in O<sub>3</sub> concentration. Although human activities resumed partially and the “titration effect” enhanced certainly during the second-level lockdown period, the meteorological conditions became more conducive to the formation of O<sub>3</sub> by photochemical reactions. Atmosphere oxidation was enhanced to promote the generation of secondary aerosols through gas–particle transitions, thus compensating for the reduced primary emission of PM<sub>2.5</sub>. The implication of this study is that the appropriate air pollution control policies must be initiated to suppress the secondary generation of both PM<sub>2.5</sub> and O<sub>3</sub>.
format article
author Zhihua Su
Xin Li
Yunlong Liu
Bing Deng
author_facet Zhihua Su
Xin Li
Yunlong Liu
Bing Deng
author_sort Zhihua Su
title The Multi-Time Scale Changes in Air Pollutant Concentrations and Its Mechanism before and during the COVID-19 Periods: A Case Study from Guiyang, Guizhou Province
title_short The Multi-Time Scale Changes in Air Pollutant Concentrations and Its Mechanism before and during the COVID-19 Periods: A Case Study from Guiyang, Guizhou Province
title_full The Multi-Time Scale Changes in Air Pollutant Concentrations and Its Mechanism before and during the COVID-19 Periods: A Case Study from Guiyang, Guizhou Province
title_fullStr The Multi-Time Scale Changes in Air Pollutant Concentrations and Its Mechanism before and during the COVID-19 Periods: A Case Study from Guiyang, Guizhou Province
title_full_unstemmed The Multi-Time Scale Changes in Air Pollutant Concentrations and Its Mechanism before and during the COVID-19 Periods: A Case Study from Guiyang, Guizhou Province
title_sort multi-time scale changes in air pollutant concentrations and its mechanism before and during the covid-19 periods: a case study from guiyang, guizhou province
publisher MDPI AG
publishDate 2021
url https://doaj.org/article/59af328deada481bae8498185d888f8a
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