Integrated assessment of strategies to reduce air pollution in the Vaal Triangle Priority Area, South Africa

South Africa currently faces a serious problem of air pollution in its cities. The approach used to manage air quality has not yet met the desired outcomes. In this study, potential mitigation options for ambient PM2.5 in the Vaal Triangle Airshed Priority Area (VTAPA)—one of the most industrialised regions in South Africa—were explored using the GAINS (Greenhouse Gas and Air Pollution Interactions and Synergies) model. Based on projections of economic activities and population, changes in PM2.5 concentrations were quantified, applying different assumptions on application rates of end-of-pipe control technologies for key emission sources of PM2.5 and its precursor gases NOx and SO2. Ambient PM2.5 concentrations were used to estimate the potential human health benefits of emission reductions. Our findings reveal that PM2.5 concentrations for the VTAPA will not reach recommended air quality limits by 2035 under the current legislation. By introducing stringent controls, emissions will be reduced by more than half, and national air quality standards are attained. Trajectories show that implementation costs in the alternative scenario will nearly be twice as high as those for the current policies. Analysis using the GAINS model has demonstrated the value of assessing the multiple dimensions of air pollution through applying an integrated approach to provide evidence-based support for policy decision-making