Preliminary Measurements of Aerosol Concentration and Composition in Palapye, Botswana

Atmospheric aerosols have known impacts on the earth’s radiative balance and human health. Due to the sparseness of aerosol measurements in some regions of the world, many estimates of climate and health impacts rely on satellite observations of aerosol optical depth or model estimates of aerosol concentrations. However, these estimates require validation from in situ observations of surface concentration, composition, and aerosol optical depth.

In rapidly developing nations, new access to technology such as electricity, gas or diesel automobiles, and propane cookstoves are quickly changing the emissions and the resulting concentrations and optical properties of that region’s aerosols. Botswana is a medium-sized nation in the Southern Africa region that is characterized by savanna and desert. Historically, dust and biomass burning from solid fuel use and agricultural burns have dominated this regions aerosol sources, but population growth and rapid modernization are likely changing the aerosol concentrations and types in the region. To better quantify aerosol concentration and composition in this region, a five-week study was conducted at the Botswana International University of Science and Technology (BIUST) in Palapye, Botswana. We conducted filter-based PM2.5, time-resolved optically based PM2.5, and aerosol optical depth measurements using a custom-design low-cost sensor. Additionally, we conducted black carbon optical measurements using an Aethlabs MicroAeth AE51 aethalometer, and passive measurements of gas-phase ammonia. We will present these data, and what the implications are for air quality in Palapye, as well as to motivate future research in this under-studied part of the world.

We acknowledge the support from the National Science Foundation under grant number OISE-1559308