An integrated systems approach towards air quality management in the Vaal Triangle Priority Area
Abstract
The quality of air breathed in South Africa is of great concern, especially in the industrialised region of the Vaal Triangle where particulate matter (PM) concentrations are high. Long term exposure to PM is associated with serious adverse health impacts, including respiratory illnesses, cardiovascular morbidity and premature mortality. Rapid urbanisation combined with industrialisation, increase in vehicle ownership and continual use of coal and wood as primary domestic energy carriers have contributed to the deterioration of air quality in the Vaal Triangle Airshed Priority Area (VTAPA). Despite the establishment of an air quality management plan and implementation of mitigation measures, the current approach to managing air quality in the VTAPA has not produced the desired outcomes. PM levels still remain well above national ambient air standards. This is in part due to a lack of implementation oversight and allocation of resources. Financial restrictions have also made a contribution; with the current economic performance of South Africa, more cost-efficient strategies are required to manage air pollution in the VTAPA.
Air quality management is multidisciplinary in nature. An approach that examines different pollutant emissions, their contributions to atmospheric concentrations, potential control measures and their associated costs in an integrated system is therefore required. For this reason, an integrated approach to air quality management was performed for this study in order to identify alternative policy interventions that will reduce air pollution with minimal costs to the South African economy.
Monitoring is a key component of air quality management. However, the number of air quality monitoring stations distributed in the VTAPA is inadequate to capture the full-scale variability of pollutants. Adding more stations to the current monitoring network will require substantial financial resources. The paper “Evaluating the potential of remote sensing imagery in mapping ground-level fine particulate matter (PM2.5) for the Vaal Triangle Priority Area” (Chapter 4) in this study, seeks to examine the potential of satellite remote sensing, a cheaper and more spatially descriptive alternative, in monitoring PM2.5 across the VTAPA. The satellite remote sensing method was able to identify PM2.5 concentration clusters consistent with known source emission regions in the VTAPA. Temporal analysis of PM2.5 using the satellite remote sensing technique shows that concentrations are still above national ambient air standards. For satellite remote sensing to be effectively exploited as a tool for air quality monitoring in unmonitored regions in the VTAPA, further research on improving the precision and accuracy of satellite-retrieved PM2.5 is necessary.
Source apportionment is an important process during the initial phase and review stage of air quality management as it helps in identifying the sources that need to be prioritised for control. The paper “Updated PM10-2.5 and PM2.5 source apportionment for the Vaal Triangle air pollution priority area, South Africa” (Chapter 5) in this study, identified the main sources contributing to PM loading in the VTAPA using the receptor modelling technique. It was found that although the VTAPA is a highly industrialised region, localised sources may have a greater impact on PM loading in low-income settlements. Source contributions varied across low-income settlements, and it is recommended that individual plans will need to be designed to manage air quality in these areas. Decision-makers will need to prioritise dust, industry, domestic coal burning, wood and biomass combustion sources in the new air quality management plan for the VTAPA.
The paper “Integrated assessment of strategies to reduce air pollution in the Vaal Triangle Priority Area, South Africa” (Chapter 6) in this study, uses the GAINS model to integrate data on pollutant emissions, their contributions to atmospheric concentrations, potential control measures and their associated costs so as to devise a management strategy that effectively reduces PM levels in the VTAPA to within national acceptable standards. Comparisons between the current and alternate management strategy showed that significant air quality improvements would not take place in the medium term if the policy interventions that are presently there for the VTAPA were to continue. Implementation of more stringent controls will lower emissions by more than half, and decrease concentrations to within recommended air quality limits. The negative health impacts from PM exposure are likely to be drastically reduced in the near future if a stricter approach is adopted. However, operational costs for this alternative management strategy will almost be doubled in comparison to the current approach.
This study makes an important contribution to the current body of knowledge by identifying a more cost-effective approach to air quality management in the VTAPA. It is recommended that future studies should include climate change policies in order to identify air pollution reduction measures that have the co-benefit of reducing greenhouse gas emissions.