Abstract
The South African electricity sector is known for its heavy reliance on coal. The aim of this study is to assess the impacts of increasing SO2, NO2 and PM emissions from the three return-to-service (RTS) power stations (Komati, Camden and Grootvlei), and the newly constructed Medupi and Kusile Power Stations on ambient air quality measured at the monitoring stations in the vicinities of these power stations. Trends in power station emissions were identified using the LINEST function on Microsoft Excel, and trends in ambient pollution concentrations were determined using Theil-Sen analysis. The correlation between the emissions and ambient pollution concentrations at nearby monitoring stations was determined with the Spearman partial rank correlation coefficient. Lastly, compliance of ambient pollution concentrations with the South Africa National Ambient Air Quality Standards was assessed. It is found that SO2 and NO2 emissions increased with the commissioning of the RTS power stations, and that there are no statistically significant increasing trends in ambient SO2 concentrations at Komati, Camden, Phola (near Kusile), Chicken Farm (near Kusile), Marapong (near Medupi) and Medupi monitoring stations; and no statistically significant increasing trends in ambient PM10 concentrations at Komati, Grootvlei and Medupi monitoring stations associated with the commissioning of the power stations. This is because the nearest power stations have very little influence on the ambient SO2 concentration (pollution roses show high SO2 concentrations from the directions of other coal-fired power stations), and ambient PM10 concentrations are significantly affected by low-level sources as opposed to power station emissions. It is only at Camden Monitoring Station where there are increases in PM10 concentrations from the direction of Camden Power Station, and at Grootvlei Monitoring Station where increasing SO2 concentrations are from the directions of Grootvlei and Lethabo power stations. There is no correlation between emissions at Komati, Camden and Kusile power stations and ambient SO2, NO2 and PM10 concentrations at the Komati, Camden, Chicken Farm and Phola monitoring stations. The wind roses show that SO2 concentrations are emanate from other power stations and not necessarily the nearest power station, while NO2 and PM10 concentrations are mainly from low-level sources. A strong, positive correlation exists only between SO2 emissions at Grootvlei Power Station and ambient SO2 concentrations at the Grootvlei Monitoring Station, and PM emissions at Medupi Power Station and ambient PM10 ambient concentrations at the Marapong and Medupi monitoring stations (although it is likely that the correlation at Medupi is related to construction and vehicle activity, and not emissions from Medupi Power Station). There is generally compliance with the ambient SO2 and NO2 standards at all the monitoring stations, but compliance with the 24-hour and annual PM10 standards was not achieved at ABSTRACT v | P a g e most monitoring stations. It is concluded that ambient air pollution in the areas of the monitoring stations is a cumulative effect of various pollution sources, including distant coal-fired power stations, rather than emanating from the nearby power station.
M.Sc. (Environmental Mangement)