Ozone level effect on respiratory illness: an investigation of emergency department visits

This project examined the relationship of daily ozone (O3) levels to the number of respiratory-related emergency department (ED) visits. The confounding effects of temperature, humidity, mold, and pollen counts were examined, as were the effects of day of the week on numbers of ED visits. The design is a time-series relating concurrently measured variables that are repeatedly measured over time. Respiratory-related ED visits at three hospitals in a southern city were examined. Visits were analyzed separately for pediatric, adult, and geriatric patients. A significant association was found between elevated O3 levels and respiratory-related visits for adults. The same association was not found for pediatric or geriatric ED visits. Days with higher ozone were accompanied by higher numbers of adults going to the emergency department because of respiratory complaints. However, the effect was not large and does not appear to hold for pediatric or geriatric ED visits.