A comprehensive study of air quality in urban, low-income areas of South Africa

Abstract

Multi-year ambient air quality data from 4 networks (19 sites) in Gauteng have been analyzed, in addition to data from intensive indoor and outdoor air quality monitoring in a small township in Mpumalanga province. PM10 concentrations in township areas are 56% higher than in developed residential areas and 78% higher than in industrial areas as an annual average, with PM10 in townships 63 and 136% higher than developed residential and industrial areas, respectively, in winter (June, July, August). Monthly PM10 and PM2.5 concentrations reach annual maxima during winter at all sites except in industrial areas. Diurnal profiles of PM10 and PM2.5 display maxima during morning (06:00-09:00 LT) and evening (17:00-22:00 LT) at nearly every site - especially during winter - and underscore the importance of domestic burning as a major source of primary particles. Multi-year averages indicate that evening maxima at some township sites average in excess of 400 μg m-3. These results from the urban/industrial Gauteng area quantitatively confirm previous studies suggesting that the lowest-income populations of South Africa experience the poorest air quality, and demonstrate that domestic burning results in frequent exposure to high concentrations of particulate pollution in the region comprising the cities of Johannesburg and Tshwane. Results from intensive township monitoring suggest that indoor air quality is closely related to indoor/outdoor temperature gradients and fuel usage, but that ambient air quality is a disconnected system controlled by local meteorology in addition to overall domestic emissions