Identification and reduction of carcinogens in the respiratory environment

Epidemiological studies have implicated three factors in the overall increase of lung cancer--tobacco, especially cigarette smoking, urban pollution and, to a lesser extent, certain industrial respiratory environments. Some data were discussed on carcinogenic industrial inhalants, and on the possible effect of urban pollution. The reduction of pollution and that of specific environmental agents is stressed. Laboratory studies on the identification of carcinogens in cigarette smoke and their reduction toward the "less harmful cigarette" represent a part of this aspect.