A spatial approach to assessing PM 2.5 exposure level of a brickmaking community in South Africa

Globally, particulate matter with aerodynamic diameter of 2.5 µm or less poses a significant threat to human health. The first step in quantifying human health impacts caused by exposure to PM2.5 pollution is exposure assessment. Population-weighted exposure level (PWEL) estimation is one of the methods that provides a more precise exposure assessment since it incorporates the spatiotemporal distribution of population into pollution concentration estimate. In this study, PM2.5 exposure levels in the local communities around brickmaking industries (BMIs) were investigated, using the population census data of the study area and one-year data from nine PM2.5 monitoring stations installed in and around the brickmaking industries. The observed PM2.5 data was spatially interpolated using inverse distance weight (IDW). The PM2.5 levels across the study area was classified based on the World Health Organization interim target (IT) guidelines and the South African National ambient air quality standard (NAAQS). Annual PM2.5 population weighted exposure level of 27.6 µg/m3 was estimated for the study area. However, seasonal exposure levels of 28.9, 37.6, 26.5 and 20.7 µg/m3 were estimated for autumn, winter, spring and summer seasons, respectively. This implies that local communities around the brick kiln in the Vhembe District are exposed to high levels of PM2.5, especially in winter. The PM2.5 levels in the brickmaking industries as well as its other sources in the Vhembe District, therefore, need to be lowered. Findings from population exposure level to pollutants can provide valuable database for formulating policies and recommendations on exposure reduction and public health protection.