Fawole Olusegun G, Yusuf Najib, Sunmonu Lukman A, Obafaye Aderonke, Audu Dauda K, Onuorah Loretta, Olusegun Christiana F, Deme Abdoulaye, Senghor Habib
School of the Environment, Geography and Geosciences University of Portsmouth Portsmouth UK.
Department of Physics and Engineering Physics Obafemi Awolowo University Ile-Ife Nigeria.
Geohealth. 2022 Oct 1;6(10):e2022GH000597. doi: 10.1029/2022GH000597. eCollection 2022 Oct.
The emergence of COVID-19 brought with it panic and a sense of urgency causing governments to impose strict restrictions on human activities and vehicular movements. With anthropogenic emissions, especially waste management (domestic and municipal), 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 concentrations and size distribution of atmospheric aerosols and concentration of gaseous pollutants over West African subregion and seven major COVID-19 epicenters in the subregion. Satellite retrievals and reanalysis data sets were used to study the impact of the restrictions on Aerosol Optical Depth (AOD) and atmospheric concentrations NO, SO, CO, and O. The anomalies were computed for 2020 relative to 2017-2019 (the reference years). In 2020 relative to the reference years, for area-averaged AOD levels, there was a consequential mean percentage change between -6.7% ± 21.0% and 19.2% ± 27.9% in the epicenters and -10.1% ± 15.4% over the subregion. The levels of NO and SO 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 predominant sources of CO in major cities in the subregion.
新冠疫情的出现带来了恐慌和紧迫感，导致各国政府对人类活动和车辆通行实施严格限制。据认为，人为排放，尤其是废物管理（家庭和市政）、交通和工业活动，是造成环境空气污染的重要因素。本研究评估了这些限制措施对西非次区域以及该次区域七个主要新冠疫情中心大气气溶胶浓度和粒径分布以及气态污染物浓度的影响。利用卫星反演数据和再分析数据集研究了这些限制措施对气溶胶光学厚度（AOD）以及大气中一氧化氮、二氧化硫、一氧化碳和臭氧浓度的影响。计算了2020年相对于2017 - 2019年（参考年份）的异常情况。相对于参考年份，2020年，在各疫情中心，区域平均AOD水平的相应平均百分比变化在-6.7% ± 21.0%至19.2% ± 27.9%之间，在整个次区域为-10.1% ± 15.4%。疫情中心的一氧化氮和二氧化硫水平也大幅下降，尤其是在限制措施严格执行期间。然而，与参考年份相比，2020年大气中的一氧化碳和臭氧水平略有上升。这项研究表明，“一刀切”的政策无法降低空气污染物水平，而且交通和工业过程并非该次区域主要城市一氧化碳的主要来源。
