Indoor air quality in rural Southwestern Uganda: particulate matter, heavy metals and carbon monoxide in kitchens using charcoal fuel in Mbarara Municipality

Abstract

The use of biomass energy over open fires in sub-Saharan Africa is rampant yet it is associated with air pollution. Information on the contribution of common biomass like charcoal to indoor air pollution in Uganda is scarce; therefore, kitchen-indoor air in charcoal fueled kitchens was characterized for fine particulate matter (PM2.5), heavy metals and carbon monoxide content in Mbarara Municipality Western Uganda. PM2.5 was measured using University of California Berkeley Particle and Temperature Sensor (UCB-PATS), heavy metals were determined using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and carbon monoxide was measured using a portable, battery-operated, data-logging Drager Pac 7000. In the kitchens assessed, the mean 24-h concentration for PM2.5 was 0.449 mg/m3 in the wet season and 0.526 mg/m3 in the dry season; CO was 41.52 ppm, and all concentrations were higher than the World Health Organization 24-h Air Quality Guideline for PM2.5 of 0.024 mg/m3 and CO of 6.340 ppm. Heavy metals in particulate matter were in concentration ranges of 1.012–9.820 μg/m3 Fe, 0.012–0.092 μg/m3 Cr, 0.060–10.750 μg/m3 Zn, 0.048–0.300 μg/m3 Cu, 0.004–0.052 μg/m3 Pb and ND—0.004 μg/m3 Cd. All mean metal concentrations were lower than recommended exposure levels by EPA although chronic exposure is a risk to health. Kitchen ventilation and size were found to significantly influence indoor pollutant levels; charcoal fuel significantly contributed to indoor air pollution and is therefore a risk factor to human health.