The "urban factor" and lung cancer: cigarette smoking or air pollution?

Data are presented which suggest that cigarette smoking, and to a lesser degree, urban pollution as indexed by benzo[a]pyrene are etiologic factors in the causation of lung cancer. The dose--response relationship to benzo[a]pyrene to lung cancer death rate in the urban community was estimated by using data on lung cancer deaths among coke oven workers. It appears to be an excess of 2--5 mumg/m3 of benzo[a]pyrene per 100,000 population, suggesting that a lifetime community exposure to benzo[a]pyrene on a continuing basis may have a greater impact on lung deaths in the community than that considered by the Royal College of Physicians.