Spatiotemporal Assessment of Particulate and Gaseous Air Pollutants in Northwestern Nigeria (2000–2024) Using Satellite-Derived Datasets

Abstract

Atmospheric pollution remains a persistent environmental and public health challenge in Northwestern Nigeria, driven by rapid urbanization, biomass burning, and industrial growth. This study assessed the spatial and temporal distribution of five key pollutants: Particulate Matter (PM₂.₅), Aerosol Optical Depth (AOD), Nitrogen Dioxide (NO₂), Carbon Monoxide (CO), and Ozone across the region over a 24 year period from 2000 to 2024. Monthly satellite derived datasets were obtained from NASA’s Giovanni platform using MERRA 2 and OMI/Aura products with spatial resolutions ranging from 0.25 degrees to 1.0 degree and a monthly temporal scale. Geographic Information System (GIS) softwarewas applied to generate mean concentration maps, while temporal trends were analyzed using statistical tools. Results revealed significant spatial disparities in pollutant concentrations, with hotspots in urban and industrial areas such as Kaduna, Kano, and Kebbi, and lower levels in rural northern states including Sokoto and Katsina. Seasonal variations were evident, with higher pollution levels during the dry Harmattan months. Although some pollutants, particularly PM₂.₅ and NO₂, showed slight declines in recent years, air quality remains a pressing concern. The study concludes that sustained exposure to harmful pollutants poses risks to public health, especially in urban centers, underscoring the need for targeted policy action, cleaner energy adoption, and improved monitoring systems. Future research should focus on assessing the direct health impacts of long term exposure through epidemiological studies.