Except for such isolated statements little consideration has been given to air pollution as an etiologic factor in disease. Until recently the chief concern of the medical sciences has related to investigating and dealing with biological factors in disease causation. Recognition of the role of air pollution as more than a nuisance developed with the findings among industrial workers of diseases secondary to inhaling large concentrations of air pollutants, such as byssinosis in cotton workers,2 silicosis' and pneumoconiosis4 in foundry workers and coal miners, and farmer's lung5 in farmers, to name a few. Bronchogenic carcinoma was found to occur with abnormally high frequency in workers exposed to uranium," nickel,7 and chromate dusts8 while an unusually high incidence of mesotheliomas and lung cancer was noted to occur in asbestos workers.9 An even greater incidence of carcinoma was noted among those workers who smoked cigarettes.
Additional impetus was given to consideration of