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[1] Atmospheric stability and many natural and anthropogenic sources lead to the accumulation of aerosols over southern Africa with potential climatic forcing consequences. A trajectory climatology for southern Africa shows that air circulates over the entire region for several days in an anticyclonic type pattern of flow concentrating aerosols and trace gases below 700 or 500 hPa. A long-term, time-resolved, sizefractionated aerosol monitoring site along the locus of one of the main transport routes was established at Ben Macdhui mountain in the eastern Cape ($30°S, 28°E). Chemical data collected from initial samples indicated that distinctive episodes of industrial-related emissions are detected at the site using inorganic fine sulfur as a unique tracer. In addition, two intensive sampling campaigns were undertaken to augment the long-term data set. Emissions from four sources influencing the aerosol content at Ben Macdhui were identified: aeolian dust or soil from the natural landscape, industry, biomass burning, and sea-salt emissions from the marine environment. The industrial aerosols were transported mostly in an anticyclonic recirculation pattern from the Highveld and had a distinct chemical signature. Some industrial emissions were transported from the east between the site and the east coast of South Africa.

South Africa has been identified as a source of industrial pollution that is significant at a global scale. This study was designed to provide quantitative information, by direct measurement, across northeastern South Africa, which includes the highly industrialised Mpumalanga Highveld. The specific aim of the study was to evaluate whether or not acidic atmospheric pollution poses a threat to soils, plants and water bodies of South Africa. To address this aim, a network of 37 passive sampling sites was established to measure monthly mean concentrations of near-surface SO(2), NO(2) and ozone. The area covered extended over the northern and eastern interior of South Africa while avoiding sources of local emissions such as towns, mines and highways. The field campaign was conducted between August 2005 and September 2007. Spatial distributions and temporal trends for these pollutant gases were assessed. Critical levels analysis comparisons were made against applicable air quality standards, guidelines and limits to evaluate the potential for adverse atmospheric pollution impacts on regional environments. The assessment indicates that only in the central source area of the South African industrial Highveld are some levels exceeded. In remote areas, including the sensitive forested regions of the Drakensberg escarpment, pollutant concentrations are below the critical thresholds for environmental damage.

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