Dispersion of PM and VOC pollutants from open burning of municipal solid wastes on host communities: emission inventory estimation and dispersion modelling study

Abstract

The emissions from open burning of municipal solid wastes (MSWs) are very harmful. Owing to the scarcity of information on the impact of open burning of MSW on the onsite workers and the population within the vicinity of the Sokoto-Aiyekale dump site in Ilorin, Kwara State, this study focused on examining the impact of open burning of solid waste at the dump site on its host communities. The criteria air pollutants (CAPs) such as particulate matter (PM) and volatile organic compounds (VOCs) were determined using the emission factor approach. Deposition gauges were deployed at selected sampling spots to collect particulates which were characterized for heavy metal concentrations for the wet and dry seasons using energy dispersive X-ray fluorescence (EDXRF). The seasonal deposition fluxes, the deposition velocities and the scavenging ratios of the elements were estimated. The ground level concentrations of each of the CAPs within a 15 km radius were predicted using the AERMOD software (Version 8.2.0). The results showed that the emission inventory for PM and VOCs is in the range of 2200.5–2481.1 and 5913.9–6668.0 tons per annum between 2016 and 2020, respectively. Fourteen elements (Fe, Au, Ag, Pd, Rh, Cd, Zn, In, Sn, Cu, Mn, Ti, Ru, and S) were identified from the deposition study, with Fe having the highest concentration of 67 512.8 and 73 845.5 μg m⁻³ in the wet and dry seasons, respectively. The wet and dry deposition fluxes ranged from 7.32 to 11.46 and 38.83 to 88.8 g per m² per month, respectively. Deposition velocities of the trace metals were in the range of 0.0000528–0.00075444 and 0.0003377–0.0048183 m s⁻¹ in the wet and dry seasons, respectively. The average 1, 8, 24 h, and annual concentrations were 16 175, 6634, 3190 and 409 μg m⁻³ for PM and 20 959, 7000, 3700 and 418 μg m⁻³ for VOCs, respectively. This research shows that open burning of solid wastes is characterized by harmful gaseous emissions and heavy metals with potential adverse effects on receptor communities. These findings will serve as baseline information for environmental protection agencies.