Atmospheric fine particulate matter (PM_2.5) in Bloemfontein, South Africa

Indoor and outdoor pollution has become a worldwide problem; it impacts both the environment and human health. Research-driven air pollution assessment studies were done in some of the larger South African cities like Cape Town and Pretoria, but almost none in the Free State province. The purpose of the present study was to determine PM2.5 levels and its chemical components over a period of more than one year in the Free State capital, Bloemfontein. Particulate matter was collected on PFTE filters, which were then analysed gravimetrically, by smoke stain reflectometry and X-ray fluorescence. The average PM2.5 concentration for the study period was 11 μg/m3, which exceeded the World Health Organization (WHO) annual guideline limit (5 μg/m3), but not the annual South African National Ambient Air Quality Standard (20 μg/m3). The daily WHO guideline (15 μg/m3) was exceeded on 28 days, but not the daily South African standard (40 μg/m3). The average soot concentration was 1.2 μg/m3. The five most abundant trace elements detected in the PM2.5 filter samples were K, Ca, Si, S and Fe.