Atmospheric pollution and chronic chest disease.

The author reviews possible relationships between chronic bronchitis and air pollution, drawing attention to the difference in incidence of chronic bronchitis between England and Canada, and the recent increase in mortality from respiratory diseases in Canada.Neither air pollution nor smoking habits can fully account for these phenomena. Dr. Shephard describes methods of measuring pollution and concludes that Toronto is intrinsically as dirty as other cities of comparable size, and that although there have been substantial decreases of smoke over the past decade, levels of gaseous acid have shown little improvement. Urban/rural comparisons suggest that high concentrations of pollutants can double the prevalence of chronic bronchitis; however, the effect is much less obvious if comparisons are restricted to non-smokers of comparable social status. Longitudinal surveys suggest a worsening of condition in bronchitics during periods of intense pollution. Justification for air pollution control programs lies more in the prevention of damage to buildings and beauty then in a specific effect upon human health.