Environmental carcinogens in the city air and lung cancer incidence.

Possible contribution of polycyclic hydrocarbons, trace metals, and gaseous pollutants to the incidence of lung cancer in the urban populations has been considered, including the role of carcinogens in the cigarette smoke. A long-term plan has been proposed for the epidemiological studies and control of urban lung cancer incidence. A comparative assessment of lung cancer mortality rate for occupational, urban, and rural exposure to levels of benzo(a)pyrene typical of these environments is presented.