Emission Flux and Dispersion Analysis of Particulate Matter (PM10) from Mining and Industrial Areas in Rusizi District-Rwanda

Industrial and mining operations are classified as the primary sources of particulate matter (PM10) that pose substantial health and environmental risks, with much attention when situated in or near residential areas. The absence of a standardized approach for quantifying air pollutant fluxes in mining areas has been identified as a research gap, particularly given the increasing rate of mining extraction, especially in developing countries. This study used the AERMOD air pollutants dispersion model to analyze PM10 dispersion from the CIMERWA Cement Plant and adjacent mining sites in Rusizi District, Rwanda, throughout 2022. We developed methods to quantify PM10 horizontal and vertical fluxes and their emission rates within the framework of dispersion analysis. Results indicate high concentrations of PM10 in the vicinity of mining areas, with daily, hourly, monthly, and annual maximum mean ground-level concentrations of 158.86 µg m−3, 92.87 µg m−3, 46.15 µg m−3, and 27.65 µg m−3, respectively. Wind erosion, with a daily horizontal speed of 0.66 m s−1 and shear speed of 0.03 m s−1, contributes to a daily mean horizontal flux of 8.50 µg m−2 s−1 and vertical flux of 0.4 µg m−2 s−1 of PM10. Dispersion maps analysis highlights residents' exposure to significant levels of PM10 depicted with 28 discrete receptors in all directions. The circulation of polluted windy air masses substantially impacts regional air quality. The findings offer evidence-based recommendations for strategic mitigation measures targeted at residents, policymakers, stakeholders, and urban planners to address air quality issues arising from industrial mining activities.