Geospatial Assessment of Waste Disposal Site's Impact on Air Quality in Sokoto Metropolis, Nigeria

Rapid urban expansion and inadequate waste management in northern Nigerian cities have increased open dumping and burning of waste. This is contributing significantly to air pollution and related health risks in the region. This study assessed the impact of waste disposal sites on air quality in Sokoto metropolis using a geospatial analytical approach. Forty-nine (49) active waste disposal sites were identified and mapped. Air quality parameters, including particulate matter (PM₂.₅ and PM₁₀) were analyzed. Secondary datasets included administrative boundaries from the Office of the Surveyor General of the Federation, road and water body data from OpenStreetMap, and population data from WorldPop. The data were processed and analysed in ArcGIS 10.8. The results show that distribution of waste disposal site were clustered in the central and north-eastern areas of the metropolis (ratio = 0.818, z = –2.438, p = 0.015). Air quality results showed elevated particulate matter levels around several waste disposal sites, with concentrations decreasing with distance from the sites. Hazard zonation maps generated through Multi-Criteria Decision Analysis (MCDA) indicated predominantly moderate-risk zones, with localised high-risk areas near active waste disposal sites. Population overlay analysis revealed that about 90% of residents in the metropolis live in moderate to high exposure zones. The findings demonstrate that waste disposal practices contribute to localised air quality degradation and increased environmental risk. The study recommends improved waste management systems, enforcement of buffer regulations, and adoption of GIS-based planning to support sustainable urban environmental management.