Ambient Air Quality on the South African Highveld
The South African interior plateau, known as the Highveld, is the most heavily industrialised region in southern Africa. Rich mineral resources (particularly gold, platinum and coal) have resulted in large urban and industrial developments being sited in the region. Air pollution is derived from low-level sources such as vehicles, domestic coal combustion and mines, and elevated sources including stacks of metallurgical and petrochemical industries and coal-fired power plants. Air quality is controlled by the meteorology of the region, which is characterised by strong temperature inversions at night and highly convective conditions during the day. Local emissions do not only affect air quality in the immediate vicinity of the sources, but have been observed to impact on surrounding countries and oceans due to long-range transport. In turn, emissions from industries and biomass burning in tropical Africa affect the Highveld. The status quo of air quality in the region will be presented, based on air quality and deposition monitoring and modelling conducted in the region. Insights into atmospheric chemistry and transport on the Highveld will be given. Challenges for air quality related to the developing nature of the South African economy and the implementation of the new air quality legislation will be discussed.