Oladele F. Anjorin^1,, Mariam D. Solomon², Jaryum H. Kiri², Jonathan D. Dabak², Samuel Y. Gazuwa², Simon G. Mafulul², Raymond I. Daspan³, Elizabeth O. Okoh⁴, Isaac S. Laka⁵, Jane-Rose Onche², Isa S. Wuti²

Background: When stones are crushed, the finer dust gets airborne and escapes as fugitive emissions, constituting dust pollution problems in the vicinity with severe adverse effects on the ambient air quality and human health. Methodology: In this study, active sampling method was deployed to sample and obtain the ambient concentrations of CO, SO₂, H₂S and PM (of sizes 2.5 and 10 microns) in the fugitive emissions from selected manual stone crushing sites in North Central Nigeria. The trapped particles sampled were analysed for particulate-associated heavy metals such as Cd, Co, Cr, Cu, Pb, Mn, Ni, Fe, and Zn by Atomic Absorption Spectrometry (AAS). Principal Findings: The observed mean concentration of CO, SO₂ and H₂S sampled were 0.12 mg/m³, 0.06 mg/m³ and 0.004 mg/m³, respectively. The mean concentration of PM_2.5 was observed to be 26.5 µg/m³ (ranged from 8 µg/m³ to 70 µg/m³) which is about 76.7 % higher than the World Health Organization (WHO) air quality guidelines (15 µg/m³ for 24- mean for PM_2.5). The Mean concentration of PM₁₀ was observed to be 54.36 µg/m³ (ranged from 17 µg/m³ to 143 µg/m³) which is about 20.8 % higher than the World Health Organization (WHO) air quality guidelines (45 µg/m³ for 24-mean for PM₁₀). AAS analysis revealed that metal- bearing particulates have significant levels of the selected heavy metals except copper that was below detection limit: Cr, Mn, Fe, Pb, Zn, Ni, Cd and Co were respectively, 48.0 mg/m³, 82.0 mg/m³, 140.0 mg/m³, 202.0 mg/m³, 34.0 mg/m³, 1403.0 mg/m³, 21.0 mg/m³, 60.0 mg/m³. Conclusion: All the metals (Pb, Ni and Cd), classified by IARC as carcinogenic in humans (group 1) greatly exceeded on average the annual EU’s limits (500, 20, 6 and 5 ng/ m³ respectively).

fugitive emissions, stones, crushed, manual, ambient air, particles, gaseous pollutants