PM 2.5 chemical composition in Cape Town, South Africa

Numerous health outcomes have been attributed to PM2.5 exposure, even at low concentrations, from studies in developed countries. There is a lack of studies in Africa that reported on PM2.5, PM2.5 absorbance (soot), BC, UV-PM (organic carbon) and trace element concentrations and their health effects. PM2.5 samples were collected over 24 h and every third day at an urban background site in Cape Town during 18 April 2017 to 16 April 2018. The mean PM2.5 concentration was 13 µg.m−3 (range: 1.2-39 µg.m−3). PM2.5 concentrations exceeded the yearly World Health Organization (WHO) air quality guideline (5 µg.m−3). The daily WHO guideline (15 µg.m−3) was exceeded on 38 occasions during the 121-day study period. The mean soot, black carbon and organic carbon concentrations were 1.4 m−1 x 10−5, 2.5 µg.m−3 and 2.4 µg.m−3, respectively. Eight trace elements (Ca, Cl, Fe, K, S, Si, Ti and Zn) were detected with high signal to noise ratios. The observed exposure levels at this urban background site, if believed to be experienced across the city, may pose a risk to human health.