General preventive measures against carcinogenic exposure in the external environment.

Different measures are used to prevent unacceptable carcinogenic exposure from different sources in the external environment, be it accumulated carcinogens from previous pollution, exposure related to life-style, and exposure related to living standards and the organization of the community as a whole. A precondition for goal-directed prevention is knowledge of exposures to carcinogens and measures to minimize or substitute carcinogens in products and in emissions. One of the most significant sources of carcinogens in the outdoor air in many Western countries is the traffic, especially diesel-powered vehicles. Necessary preventive measures include restriction of carcinogenic exhaust from the individual vehicle, plans for the community to diminish transportation needs, as well as to changing the usual behaviour of the individual. Unlike exposure to carcinogens in the surrounding air, exposure to accumulated carcinogens in ground-water and in soil at polluted sites may be diminished by the pattern of use. International aspects are involved in for instance minimizing the risk of getting skin cancer from sunlight. Besides protecting vulnerable individuals there should be a global preservation of the ozone layer. Lowering the risk of long transported air pollution, like radioactivity from accidents at nuclear power stations, demands international efforts to increase safety measures and information about accidents.