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In the past quarter of a century, atmospheric pollution increased significantly in much of the region, largely as a result of escalating energy consumption due to economic growth and greater use of motor vehicles. The use of poor quality fuels with a high sulphur content such as coal, inefficient methods of energy production and use, traffic congestion, poor automobile and road conditions, leaded fuel and inappropriate mining methods have exacerbated the situation. Forest fires are also contributing significantly to air pollution. Significant health threats also exist from the use of low-quality traditional solid fuels, such as wood, crop residues and dung, for cooking and heating in lower-income urban households and rural areas.
Per capita commercial energy use more than doubled in most parts of the region between 1975 and 1995 (see graph). In 1995, the region accounted for 26.8 per cent of the world's commercial energy consumption. While global energy consumption fell by 1 per cent per year between 1990 and 1993, Asia's energy consumption grew by 6.2 per cent a year (ADB 1997). Fossil fuels now account for about 80 per cent of energy generation in the region, with coal accounting for about 40 per cent. The region also accounted for about 41 per cent of global coal consumption in 1993 (EIA 1995).
With the increase in the use of relatively high carbon content fuels such as coal and oil, emissions of CO2 also increased fast - at twice the average world rate of 2.6 per cent a year during 1975-95 (CDIAC 1998). Since the 1970s, industrial emissions of CO2 have grown 60 per cent faster in Asia than anywhere else (ADB 1997). China and Japan are the first and second largest CO2 emitters respectively in the region (WRI, UNEP, UNDP and WB 1998). However, CO2 emissions per capita are low, little more than than half the world average (see graph) and only 11.2 per cent of the level in North America in 1995. Past land clearing has also contributed a significant proportion of CO2 emissions in some countries.
Sulphur dioxide emissions in Asia increased from 11.25 million tonnes of sulphur equivalent in 1970 to 20 million tonnes in 1986 - at least four times the rate of any other region (Hameed and Dignon 1992). Nitrogen oxide (NOx) emissions from fossil fuel combustion increased by about 70 per cent (Hameed and Dignon 1992). However, total emissions were significantly less than those of North America and Europe during the same period.
The severity of air pollution varies considerably across Asia. Even major urban areas of Australia, where the concentration of air pollutants is generally low, occasionally experience levels of pollution that exceed air quality goals (Commonwealth of Australia 1996, NSW EPA 1997).
Two of Asia's giant economies, China and India, rely heavily on coal. Ninety per cent of China's 18 million tonnes of SO2 emitted into the atmosphere annually come from coal burning (State Planning Commission 1997). Overall, Asian emissions of SO2 are at least 50 per cent higher than those of North America, Africa and Latin America (ADB 1997). Three of Asia's 11 megacities (see table) exceed WHO guidelines for acceptable SO2 levels (WHO and UNEP 1992).
With increasing SO2 emissions, acidification is an emerging issue. The most sensitive areas are in south China, the southeast of Thailand, Cambodia and south Viet Nam (Hettelingh and others 1995). On the other hand, there is no evidence of significant acid deposition in Australia, which is not subjected to emissions from neighbouring countries and where fossil fuels have a low sulphur content (Commonwealth of Australia 1996).
Transportation contributes the largest share of air pollutants to the urban environment. The total number of registered vehicles in the region in 1996 was about 127 million, 4.24 per cent more than in the previous year (International Road Federation 1997). In Seoul, car ownership doubled in a single year between 1991 and 1992 (Ministry of Environment, Republic of Korea, 1990 and 1995). Lead pollution is a particular problem in megacities of Southeast Asia. The introduction of unleaded fuels is reducing average lead levels, although the rate of decline is slower in Asia than elsewhere.
Ten of Asia's 11 megacities exceed WHO guidelines for particulate matter by a factor of at least three (WHO and UNEP 1992). Levels of smoke and dust, a major cause of respiratory diseases, are generally twice the world average and more than five times as high as in industrial countries and Latin America (ADB 1997). Recent forest fires in Indonesia are a further, notorious source of air particulates (see box).
Recent studies show that smoke and dust particles can significantly damage human health. According to WHO estimates, Bangladesh, India, Nepal and Indonesia together account for about 40 per cent of the global mortality in young children caused by pneumonia (WHO 1993). In China, smoke and small particles from burning coal cause more than 50 000 premature deaths and 400 000 new cases of chronic bronchitis a year in 11 of its large cities (World Bank 1997a). The negative impacts of domestic burning of solid fuels are not confined to developing countries. Winter air pollution, mostly from coal and wood-burning fires in private homes, is a persistent problem in New Zealand (New Zealand Ministry for the Environment 1997).
Some countries have managed to gain partial control over air quality deterioration. During the past two decades, Japan successfully reduced emissions of SO2, NOx and CO through technological innovation, institutional development, and cooperation by all levels of government and industry. SO2 emissions, for instance, decreased nearly 40 per cent between 1974 and 1987 (WRI, UNEP and UNDP 1992). Similar air pollution problems in the Republic of Korea have been reduced since the 1980s by increasing the use of low-sulphur oil and liquified natural gas (Government of Republic of Korea 1998).
Demand for primary energy in Asia is expected to double every 12 years while the world average is every 28 years. High carbon-content fuels are likely to continue to dominate the region's energy market. Coal will remain the fuel of choice throughout much of the region, because of its abundance and easy availability, especially in China, India and Mongolia, and demand is projected to increase by 6.5 per cent a year (World Bank 1997c).
By the year 2000, SO2 emissions from coal burning in Asia are expected to surpass the emissions of North America and Europe combined (World Bank 1997a) and, if current trends in economic development continue without effective SO2 control measures, will more than triple within the next 12 years. This is likely to result in a significant increase in acid deposition problems, especially within East Asia. The Korean peninsula will be seriously affected by cross-border acid rain. Mongolia may receive acid rain from its north-western border with Russia. In addition, urban air pollution will be aggravated by increasing emissions from transport. A study of Nepal, for instance, estimates that total emissions will increase fivefold by 2013, about two-thirds of which are likely to come from the transport sector (Shrestha and others 1996).
While the region's contribution to the greenhouse effect and total world emissions of atmospheric pollutants are currently limited, both are increasing fast. Air quality is proving detrimental to human health in many parts of the region. These trends are likely to continue.
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