THE AIR-QUALITY IN DANISH URBAN AREAS

The Danish air pollution abatement is based by and large on emission c ontrol. Since the ratification of the international sulfur protocol of 1985, there has been a continuous tightening of the permissible sulfu r content in fuels and of the maximum emissions from power plants. As a consequence, the total annual emission of sulfur dioxide (SO2) has b een reduced from 450,000 tons in the seventies to 180,000 tons in 1990 . This has had a pronounced effect on the SO2 levels in Danish urban a reas. Thus, in Copenhagen, the yearly averages have fallen to about 25 %. For nitrogen oxides emitted from the power plants, similar regulati ons are in force. With this legislation, the most important and crucia l source of air pollution in Danish urban areas is road traffic. The c ontribution of nitrogen oxides from national traffic accounts for near ly half the total Danish emission and is increasing steadily; this is consistent with an observed increase of nitrogen oxides in ambient air . The permissible levels of lead in petrol has been reduced drasticall y. After an introduction of reduced tax on lead-free petrol, it now ac counts for more than two-thirds of the total consumption. As a result, the concentration of lead in urban ambient air has been reduced to le ss than one-sixth. The introduction of 3-way catalytic converters from October 1990 will result in reductions in the emission of a series of pollutants, e.g., lead, volatile organic compounds, carbon monoxide. and nitrogen oxides. In 1980, a Danish air quality monitoring program was established as a cooperative effort between the authorities, the G overnment, the counties, the municipalities, and the Greater Copenhage n Council. Subsequently, the program has been revised with greater emp hasis on air pollution from traffic. The network now includes monitori ng of gasses and particulates, generally at curb side. The effects of planned traffic regulations and measures taken are evaluated by use of air quality models. Only a few studies of the relations between air p ollution and health have been carried out in Denmark, but even the fai rly modest levels appear to have some impact on sensitive groups, e.g. , children and asthmatics.