Health effects of urban air pollutants. Guideline values and conditions in Sweden

Abstract The level of sulphur dioxide in cities has declined in many countries, and in Sweden it hardly constitutes a health problem any more. The level of nitrogen dioxide, on the contrary, has not declined. The guideline value for nitrogen dioxide is exceeded in areas with high traffic density, and may be close to the level where asthmatics could be affected. The guideline value for carbon monoxide can also be exceeded in such places and give symptoms in persons with heart and lung diseases. Levels of ozone are enhanced in the southern part of Sweden during summertime and are periodically in the range where irritation symptoms can be expected. Generally, there is an increased lung cancer incidence in cities compared to rural areas. In Sweden, it has been estimated that about 100 lung cancer cases annually may be attributed to air pollutants. Lead has been emitted in high amounts in urban areas due to the use of leaded gasoline. The blood lead levels are now declining in the population of Sweden due to reduced emissions, and are generally well below the levels where damage to the developing brain in children may occur. Environmental objectives have been set up for Sweden aiming at reductions of air pollutants by different means. If fulfilled, these plans will lead to reduced air pollutant concentrations in urban areas, which will reduce the risk for health effects in the general population.