Health Risk Assessment of Sulphur Dioxide Emissions From a Coal-Fired Power Plant In Botswana

Abstract

Background: Coal-fired power plants (CFPPs) are significant sources of sulphur dioxide (SO₂) emissions, which are linked to respiratory and cardiovascular health issues. This study assessed health risks from SO₂ emissions at the Morupule B Power Station (MBPS) in Palapye, Botswana, considering local meteorological and geographical conditions. Purpose: This research aimed to quantify SO₂ emissions from MBPS, model their dispersion using AERMOD, and assess associated health risks for vulnerable population subgroups (infants, children, and the elderly). Methods: SO₂ emission rates were calculated using standard molecular weight conversions and volumetric flow analysis. AERMOD was employed to predict ground-level SO₂ concentrations within a 20km × 20km domain using meteorological data from 2021-2023. Health risks were quantified using Hazard Quotients (HQ) based on the USEPA Health Risk Assessment Framework. Results: The maximum ground-level concentrations were 113.1 μg/m³ (hourly), 30.4 μg/m³ (daily), and 8.0 μg/m³ (annual), representing only 32.3%, 24.3%, and 16.0% of respective regulatory limits. Hazard Quotient analysis revealed all values remained well below 1.0 across all population groups, with the elderly showing slightly higher susceptibility (HQ values of 0.0734 for hourly, 0.0553 for daily, and 0.0363 for annual exposures). Predominant north- northeasterly winds effectively dispersed emissions away from major population centers. Conclusion: Current SO₂ emissions from MBPS pose minimal health risks to surrounding communities due to effective emission control technologies, favorable atmospheric dispersion conditions, and strategic facility location. The study demonstrates that coal-fired power generation can operate with limited public health impact when appropriate controls are implemented. These findings contribute valuable region-specific data to address research gaps regarding air quality management in sub-Saharan Africa.