The status of air quality in Kampala city, Uganda 2017-2019: Results from the Eastern Africa GEOHealth Hub using a high-tech reference monitor (Beta Attenuation Monitor 1022)

Abstract

Introduction: Ambient air pollution (AP), particularly from fine particulate matter <2.5 micrometers in aerodynamic diameter (PM2.5) is a big public health problem especially in low and middle-income countries. Because of apparent high population growth rate (3%) and economic development in Uganda, ambient AP appears to be rising. As such, we are monitoring ambient PM2.5 concentrations in Kampala City in a series of studies about the effect of AP on health. This work is part of research and training objectives of the Global Environmental and Occupational Health (GEOHealth) Hub for Eastern Africa. Methods: Using a Beta Attenuation Monitor (BAM) 1022, we prospectively measured ambient PM2.5 concentration for 2 years. This equipment was installed at Makerere University School of Public Health building rooftop (about 15 meters high). The BAM 1022 generated real-time data on PM2.5, relative humidity and ambient temperature. Results: For the last two years (October 2017 to September 2019), the annual mean of PM2.5 concentrations were 41.3µg/m3 and 39.2µg/m3 respectively. Our two-year data consistently show that dry seasons (January, February, June, July and August) have higher monthly mean PM2.5 concentrations (46.6µg/m3) compared to the wet seasons of March, April, May, September-, October, November and December (35.7µg/m3). We observed that for two years the highest PM2.5 concentration in typical day was between 06.00hrs and 10.00hrs (peak being at 08.00hrs -PM2.5 61.3µg/m3). However, nights were more polluted between 19.00hrs to 04.00hrs (peak being at 23.00hrs (PM2.5 71.2 µg/m3). Further, when we divided the day (07.00hrs-18.00hrs) and night (19.00-06.00hrs), the average PM2.5 concentrations for the two years were 34.5µg/m3 and 46.9µg/m3 respectively.Conclusion: Ambient AP is higher in the dry season. Besides, there is more PM2.5 concentration at night compared to daytime. These results present an opportunity for further studies on AP and its effect on health using hospital mortality and morbidity data.