Cytologic respiratory changes in workers exposed to air pollution and cigarette smoking.

Sputum specimens taken at random from 420 of 2,500 sweepers of Naples (369 male smokers, at least ten filter cigarettes daily for a minimum of ten years, and 51 male controls, nonsmokers) have been investigated. In the smokers group, 220 cases (59.6\%) with nonspecific chronic inflammatory disease, 54 cases (14.6\%) with regular squamous metaplasia, 13 (3.5\%) with atypical squamous metaplasia, and one case (0.3\%) of presumed carcinoma in situ have been identified. In the control group, 17 cases (35.3\%) of nonspecific chronic inflammatory processes with occasional regular squamous metaplasia were the only found pathology. Based upon their results, the authors have been unable to demonstrate that air pollution may enhance the smoking effect on the respiratory tract.