Hundreds of millions of city dwellers breathe air so polluted with chemicals, smoke and particles that it dramatically exceeds World Health Organization limits with major impacts on health and the environment.
A major study on the state of air pollution in 20 of Asia's key cities shows that while there have been improvements in achieving better air quality, air pollution still poses a threat to health and quality of life of many people.
The study led by the Stockholm Environment Institute's (SEI) centre at the University of York (UK) and the Clean Air Initiative for Asia Cities (CAI-Asia) is being published as Asian Environment Ministers hold the first governmental meeting on urban air quality in Asia on 1314 December in Yogyakarta, Indonesia as part of the Better Air Quality 2006 Workshop.
The World Health Organization estimates that 537,000 people in Southeast Asia and the Pacific die prematurely each year due to air pollution. The study found that there has been a general improvement in the ability of Asia cities to manage urban air quality since the 1990s. But air quality in the majority of the cities examined still exceeds international guidelines for the protection of human health for certain pollutants.
Concentrations of sulphur dioxide, the gas responsible for acid rain, have stabilized at a relative low level and rarely exceed health guidelines. However, the use of high sulphur fuel content in some countries may result in an increase in emissions.
Emissions of nitrogen dioxide and fine particulate matter, mainly from the transport sector, are of concern in all cities currently experiencing rapid motorization. In addition, tropospheric ozone, a main constituent of photochemical smog, will increase if motor vehicle use continues to rise.
The international collaborative effort was led by the Stockholm Environment Institute's (SEI) centre at the University of York (UK) and the Clean Air Initiative for Asia Cities (CAI-Asia) together with the Korea Environment Institute (KEI) (Seoul) and the United Nations Environment Programme (UNEP) (Nairobi). The study was funded by the Swedish International Development Co-operation Agency (Sida), the Korean Ministry of Environment and the Asian Development Bank (ADB).
The study examined the capability to manage air quality and collected air quality data for Bangkok, Beijing, Busan, Colombo, Dhaka, Hanoi, Ho Chi Minh City, Hong Kong, Jakarta, Kathmandu, Kolkata, Metro Manila, Mumbai, New Delhi, Seoul, Shanghai, Singapore, Surabaya, Taipei and Tokyo.
The assessment showed that while there are underlying similarities in the air pollution problems in each city, many differences still exist.
Bangkok, Seoul, Shanghai and Singapore, Taipei and Tokyo were identified as having excellent capacity to manage air quality. These cities have achieved major reductions in key emissions but still face the challenge of addressing moderate fine particulate pollution resulting from vehicles fumes.
Colombo, Ho Chi Minh City, Jakarta, Metro Manila and Mumbai were identified as having moderate capability in air quality management. They have achieved reductions in sulphur dioxide emissions but have the challenge of addressing transport-related emissions.
Dhaka, Hanoi, Surabaya and Kathmandu were identified has having limited capability to manage air quality. Air pollution data was limited for key pollutants. These cities have the challenge of improving air quality monitoring as well as further achieving reductions in emissions.
Dr Dieter Schwela, SEI, lead author, said: "Some cities have made tremendous progress in improving their air quality. However, more work needs to be done to address specific pollutants such as fine particulate matter which poses a real threat to human health."
"The study has shown that there is a great opportunity for those cities which need to develop further their air quality management capability to learn from cities such as Hong Kong and Tokyo that are further along the road to achieving better air quality."
The study's authors recommend further action is required to improve air quality in Asia's cities. These include:
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