Potentially toxic metals, source apportionment, meteorological impacts and health risks assessment of fine particulate matter (PM2.5) over Ilorin, Nigeria.

Air pollution is a growing global concern due to harmful constituents like potentially toxic metals (PTMs), which can attach to particles such as dust, soot, and secondary aerosols, increasing their toxicity. This study assessed the seasonal variation, source apportionment, meteorological patterns, and health risks associated with PTMs (V, Mn, Cd, Cr, Fe, Zn, Ni, As, Co, Cu, Pb) in PM₂.₅ over Ilorin, Nigeria. PM2.5 data for 2019 were obtained from the SPARTAN network at the University of Ilorin and processed for analysis. Results showed that PTM concentrations-particularly Fe, Zn, Cr, Pb, and Co, were significantly higher during the dry season. Cu and Cd also contributed to observed seasonal variations. PMF showed that the sources of pollutant were crustal, industrial sources, secondary inorganic, and biomass burning. EF showed that Cu, Pb, As had values that were between 10 and 100 indicating that they were from both crustal and anthropogenic sources. Cd and Zn had values of 953.27 and 217.87 respectively, which were greater than 100 indicating that they were from industrial sources. Finally, V, Cr, Mn, Fe, Co, had values of 6.05, 1.97, 2.47, 1.00, and 5.28 respectively, which indicates that they were majorly from crustal sources. The Health risk assessment (non-cancer risk) via inhalation revealed a high hazard index (HI = 99.12), mainly from Fe (66.48) and Zn (31.76). Monte Carlo simulation for cancer risk (CR) indicated Cr and As as the highest contributors via inhalation (7.06E-05 and 2.84E-06), while Ni posed the greatest risk via dermal exposure (3.20E-05). These findings highlight significant health concerns associated with airborne PTMs and the need for targeted air quality management, particularly during the dry season.