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Atmospheric pollution has emerged as a problem in most African countries only in the past few decades. Its severity and impacts are still largely unknown, although it is believed that vegetation, soils and water in some areas have been adversely affected by gaseous pollutants and acid rain.
The main sources of atmospheric pollution are bush fires, vehicle emissions, manufacturing, mining and industry. Major industrial sources include thermal power stations, copper smelters, ferro-alloy works, steel works, foundries, fertilizer plants, and pulp and paper mills. If the projected growth of demand for vehicular transport and electricity is to be met with current technologies, emissions from thermal power stations are projected to increase elevenfold and from vehicles fivefold by 2003 (World Bank 1992). The use of leaded fuel in vehicles is also a major concern. Lead pollution is worsened by the region's ageing vehicles, most of which are more than 15 years old. They are also said to emit five times more hydrocarbons and carbon monoxide, and four times more nitrogen oxides, than new ones (World Bank 1995c).
Air pollution is most significant in the more urbanized and industrialized countries of Northern and Southern Africa. In Southern Africa, air pollution is largely from thermal power stations. About 89 per cent of electricity generation in the SADC region is from coal, mostly produced in South Africa where it accounted for 97 per cent of total electricity generation in 1994 (Sivertsen and others 1995). As South African coal contains about 1 per cent sulphur, the country emits more sulphur dioxide than any other in the SADC region and is ranked as the 15th largest emitter of greenhouse gases in the world (USAID 1997). During 1990-91, South Africa contributed 66 per cent of all sulphur emissions in the SADC region, whereas Lesotho, Swaziland and Mozambique jointly contributed only 0.9 per cent (Sivertsen and others 1995). As this dependence on coal-based thermal power will persist for years, sulphur dioxide pollution will remain a problem unless measures are taken to reduce the levels of sulphur in coal or provide incentives for developing alternative energy sources such as hydropower, wind, geothermal and solar.
Mining is a major source of income and also of air pollution in Southern Africa. The mining industry employs more than 800 000 people, generates 60 per cent of foreign exchange earnings and contributes about 11 per cent of GDP in the SADC region (SADC 1992). Sulphur emissions from mining are estimated at one million tonnes per year and are a growing concern, particularly among people with respiratory problems (SADC 1992).
Indoor air pollution caused by the widespread use of biomass as a cooking fuel is also a major contributor to the high incidence of respiratory diseases because of the exposure to smoke and other pollutants in a confined space. In sub-Saharan Africa, biomass use is expected to provide nearly 80 per cent of the total energy used even in 2010. In Northern Africa, the corresponding figure is much lower (see pie charts); even in 1995, traditional fuel use was only some 3 per cent of the total (WRI, UNEP, UNDP and WB 1998).
In West Africa, the Harmattan winds often result in high atmospheric dust loading and poor visibility, and contribute to respiratory and other diseases. The continual build-up of mineral dust concentrations since the 1960s is likely to have a climatic impact through a land-atmosphere feedback mechanism (Ben Mohamed and Frangi 1986, Ben Mohamed 1985 and 1998).
Despite these problems, most African states have few or no specific air quality standards. City dwellers, in particular, are exposed to respiratory diseases such as asthma, bronchitis and emphysema as a result of industrial emissions and vehicle exhaust fumes (UNECA 1996). Heat islands in urban areas have also been shown to affect weather and local climate (Hewehy 1993).
Africa's emissions of the greenhouse gases that cause climate change are still low, estimated to be only 7 per cent of global emissions (World Bank 1998). Africa presently emits only 3.5 per cent of the world's total carbon dioxide. South Africa alone contributes 44 per cent of the region's emissions. Total carbon dioxide emissions in the region are expected to increase to 3.8 per cent of the world total by the year 2010 due to increased industrialization and urbanization (Energy Information Administration 1997). As they serve as a sink for carbon dioxide and mitigate greenhouse gas emissions, Africa's vast forest reserves play a key role in alleviating and balancing the emissions of the industrialized world. However, this crucial function is threatened by accelerating deforestation.
Climate change, resulting in sea-level rise and flooding or erosion of low-lying coastal areas and lagoons, will have serious adverse impacts on ecosystems, water resources, coastal zones and human settlements, particularly in the countries of Western and Central Africa, the Nile Delta and the Indian Ocean island states. Poverty makes many African peoples and countries particularly vulnerable to the impacts of climate change, especially in areas dependent on rain-fed agriculture. This vulnerability is increased by recurrent natural disasters such as drought, floods and cyclones. Increases in water stress and drought may also increase the incidence of vector-borne diseases and hunger. In 1998, the El Niño is thought to have been the cause of serious floods in Southern and Eastern Africa and exacerbated outbreaks of cholera, malaria and Rift Valley fever in Kenya and Somalia (CARE 1998).
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