Health effects of urban air pollution. Special consideration of areas at 1,500 m and above.

Urban air pollution, when sufficiently severe, can cause death in humans; these deaths occur preponderantly among those with increased susceptibility. Pollution--carbon monoxide and oxidants in particular--is capable of aggravating preexisting chronic heart and lung diseases. Pollution and tobacco (especially cigarette) smoke act synergistically in a causative role in chronic bronchitis and in an aggravating role in emphysema. Susceptibility to the effects of urban air pollution varies widely, with the most susceptible being fetuses, the newborn, the elderly, the infirm, those with chronic heart and lung diseases, and those who smoke. The carbon monoxide standards for sea level are probably too lenient for an altitude of 1,500 m and above. Using a broad definition of health, which takes into account concepts such as quality of life and social and mental well-being, few metropolitan residents would deny that their health is compromised by air that is malodorous, that irritates mucous membranes, and that obscures beautiful scenery.