Perspective on air pollution: the canadian scene.

Despite the large ratio of land mass to population, Canada has significant air pollution problems, some being due to our cold climate, the long arctic nights, and a mineral-based economy. Routes of intoxication include the respiration of polluted air and the secondary contamination of food and water. Although pollution is often measured in terms of industrial emissions, the physician must be concerned rather with the dose of pollutants to which the individual is exposed. The principal air pollutants, in terms of emitted tonnage, are carbon monoxide, sulfur dioxide, hydrocarbons, particulates, and oxides of nitrogen. Sources of these various materials are discussed.