Assessment of Harmattan-Driven PM2.5 Pollution Episodes and Associated Public Health Risks in Kebbi State, Nigeria

The Harmattan season heightens the risk of respiratory infections, cardiovascular complications, and other pollution-related morbidities.This paper examines thirty years (November to March 1994-2024) of Harmattan-induced PM2.5 pollution episodes in Kebbi State, Nigeria.The study used satellite-derived aerosol datasets and GIS-based modelling.MERRA-2, MODIS MAIAC, and Sentinel-5P products were processed using ArcGIS to generate Harmattan-season PM2.5 composites.The data were analyzed using Air Quality Index (AQI) classifications (U.S. EPA standards).Perceived human health risks were evaluated using Hazard Quotient (HQ), Exposure Dose Intake (EDI), and Lifetime Cancer Risk (LCR).Line graph was used to depict decadal concentrations of PM2.5 and ANOVA was used to assess the variation of PM2.5 across the LGAs.Results show persistently elevated PM2.5 levels across the 30-year period, with decadal averages ranging from 98.38 to 101.03 µg/m³ values that exceed WHO 24-hour limits by more than sixfold.AQI ratings were predominantly in the Unhealthy to Very Unhealthy categories, indicating heightened exposure risks for both sensitive groups and the general population.Spatial analysis revealed uniformly high PM2.5 concentrations across all 21 Local Government Areas, demonstrating the overwhelming influence of large-scale Saharan dust intrusions during Harmattan rather than localized emissions.Health-risk findings indicate HQ values far above safe thresholds (HQ > 1), EDI values between 3.12-4.07µg/kg-day, and LCR values surpassing U.S. EPA acceptable cancer-risk ranges, confirming significant non-carcinogenic and carcinogenic risks from chronic PM2.5 exposure.These outcomes underscore the urgent need for enhanced air-quality monitoring, dust mitigation measures, and targeted public health interventions in northern Nigeria.