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Impacts of COVID-19 restrictions on regional and local air quality across selected West African cities
  • +6
  • Olusegun Gabriel Fawole,
  • Najib Yusuf,
  • Lukman Niyi Sunmonu,
  • Aderonke Adekemi Obafaye,
  • Dauda Kashim Audu,
  • Loretta Onuorah,
  • Christiana Funmilola Olusegun,
  • Abdoulaye Deme,
  • Habib Senghor
Olusegun Gabriel Fawole
Obafemi Awolowo University, Obafemi Awolowo University

Corresponding Author:[email protected]

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Najib Yusuf
Centre for Atmospheric Research, Centre for Atmospheric Research
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Lukman Niyi Sunmonu
Obafemi Awolowo University, Obafemi Awolowo University
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Aderonke Adekemi Obafaye
Centre for Atmospheric Research, Centre for Atmospheric Research
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Dauda Kashim Audu
Centre for Atmospheric Research, National Space Research and Development Agency, Centre for Atmospheric Research, National Space Research and Development Agency
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Loretta Onuorah
Godfrey Okoye University,Enugu, Godfrey Okoye University,Enugu
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Christiana Funmilola Olusegun
Centre for Atmospheric Research National Space Research and Development Agency, Centre for Atmospheric Research National Space Research and Development Agency
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Abdoulaye Deme
UFR Sciences Appliquees et Technologie (SAT),, UFR Sciences Appliquees et Technologie (SAT),
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Habib Senghor
Senegalese National Agency of Civil Aviation and Meteorology, Senegalese National Agency of Civil Aviation and Meteorology
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Abstract

The emergence of COVID-19 brought panic and a sense of urgency causing governments to impose strict restrictions on human and vehicular movement. With anthropogenic emissions, especially traffic and industrial activities, said to be a significant contributor to ambient air pollution, this study assessed the impacts of the imposed restrictions on the atmospheric concentrations and size distribution of atmospheric aerosols and gaseous pollutants over West African sub-region and seven major COVID-19 epicenters in the sub-region. Satellite retrievals and reanalysis datasets were used to study the impact of the restrictions on Aerosol Optical Depth (AOD) and atmospheric concentrations NO2, SO2, CO and O3. These anomalies were computed for 2020 relative to 2017-2019 (the reference years). In 2020 relative to the reference years, there was a significant reduction of between 0.5±24.6 – 13.7±30.3% and 5.9±17.1% in area-averaged AOD levels at the epicenters and over the sub-region, respectively. The levels of NO2 and SO2 also reduced substantially at the epicenters, especially during the periods when the restrictions were highly enforced. However, the atmospheric levels of CO and ozone increased slightly in 2020 compared to the reference years. This study shows that “a one cap fits all” policy cannot reduced the level of air pollutants and that traffic and industrial processes are not the major sources of CO in major cities in the sub-region. Although not available, ground-based measurements would have given a clearer and better picture of the anomalies observed with the dataset used in this study which are on a coarser spatial resolution.