Chicago Air Pollution Study

Abstract

A study was done to determine whether a dose-effect relationship exists between levels of pollution as measured by SO2 and acute morbidity from respiratory disease in patients with chronic bronchopulmonary disease. For this purpose a Registry of 561 patients with chronic bronchopulmonary disease was established. A graded pulmonary disease classification was developed, based on severity of symptoms; a daily personal pollution index was estimated for each patient, based on SO2 levels in his square mile of employment and residence; and a daily calendar was maintained to record acute respiratory illness. In patients age 55 and over with grade 3 and 4 bronchitis, an increase in the acute morbidity rate was found in association with increased levels of SO2. This increase in illness rate was recorded for the day of exposure and more consistently for the day following exposure.