Air pollution and health in three urban communities.

A health study was conducted in three communities in the greater Montreal region; the first two were characterized by relatively high particulate and sulfur dioxide levels, respectively, and a third community without major industrial pollution. In each community, 300 men and women 45 to 64 yr of age were studied. Residents of the two more polluted communities exhibited a higher prevalence of respiratory symptoms and mean lung function evaluated by various tests was lower than in residents of the less polluted community. When intercity differences in age and smoking were accounted for, no statistically significant intercity differences in health status could be shown. Given the limitations of this study, the results provide no evidence to suggest that current Canadian standards for sulfur dioxide adequately protect human health as measured by the indices used in the study, for adults in the age range of 45 to 64 yr.