Monitoring and Mapping of Atmospheric Concentration of Carbon Monoxide, Sulphur Dioxide, and Nitrogen Dioxide from 2019 - 2022 in Benin City, Southern Nigeria

Abstract

This study presents a comprehensive monitoring and mapping assessment of the atmospheric concentrations of carbon monoxide (CO), sulphur dioxide (SO₂), and nitrogen dioxide (NO₂) from 2019 - 2022 in Benin City, Southern Nigeria using Google Earth Engine (GEE) and Sentinel 5P (S5P) TROPOMI satellite data. To extract the pollution map, all satellite datasets were imported into GEE, and pollutant results were obtained through JavaScript coding. The spatial map showed that the highest annual concentration of CO was recorded in 2020 as 0.0554 mol/m², the highest annual concentration of SO₂ was recorded in 2020 as 0.0000866 mol/m², and the highest annual concentration of NO₂ was recorded in 2021 as 0.0000797 mol/m². For CO, a paired sample t-test revealed that there was a significant difference in 2019 compared to 2020, but not in 2020 compared to 2021. The years 2021 and 2022 did not significantly differ from one another either. There was no significant difference in SO₂ across the years. For NO₂, there was a significant difference between 2019 and 2020, and also a significant difference between 2020 and 2021, but no significant difference between 2021 and 2022. This study finds that the COVID-19 lockdown protocol was loosely implemented in Benin City, as the results from this study did not effectively correlate with those of other studies. The study also finds the efficacy of S5P in monitoring and mapping the concentrations of CO, SO₂, and NO₂ in Benin City, laying the groundwork for future research using Sentinel 5P