Abstract
Gauteng is the economic hub of the country and the most populous province with a population of approximately 15 million people. It contains the megacity conurbation of Tshwane-Johannesburg-Ekurhuleni. Its domain is at the centre of three areas declared as priority areas for air quality management Urban form describes the physical characteristics of an urban area including its shape, size and configuration and can affect air quality levels. In this paper, two urban form metrices were assessed which are the centrality index and urban compactness for the city of Johannesburg. Johannesburg has numerous patches dispersed around its Central Business District (CBD) which leads to vehicles having to travel a long distance to reach the CBD and more tail pipe emissions. The city has a low compactness index which is associated with slow and inefficient driving that leads to more emissions. Also, the inner city of Johannesburg has a grid-block street type that leads to numerous stops and goes and high emissions. The distance to the city's CBD from the surrounding urban patches is long and vehicles have to travel a distance to reach the city centre leading to increased tailpipe emissions. The city has a low compactness index which is associated with slow and inefficient driving that increases emissions. Also, the inner city of Johannesburg has a grid-block street type that leads to numerous stops and goes resulting in high emissions. Landcover was overlaid data with PM2.5 concentrations derived from ambient air quality monitoring stations, socioeconomic regression model and remote sensing to evaluate the association of different land cover with PM2.5 concentrations. Based on the findings, there is no clear evidence suggesting an association between specific land covers and PM2.5 concentrations. For this association to be properly assessed a land use regression model should be developed.