Pulmonary function and bronchial reactivity in human subjects with exposure to ozone and respirable sulfuric acid aerosol.

The effect of 0.3 ppm ozone with a subsequent exposure to 100 micrograms/m3 sulfuric acid aerosol was studied in 12 nonsmoking subjects to determine if preexposure to ozone would sensitize them to sulfuric acid aerosol. Pulmonary function and bronchial reactivity measurements were made after single and sequential exposures to these pollutants. No significant changes in pulmonary function or bronchial reactivity to methacholine were observed. However, a decrease in bronchial reactivity approaching significance occurred after the 4-h exposure to 100 micrograms/m3, 0.13 microns sulfuric acid aerosol. We conclude that there are no readily apparent risks from sequential exposures of nonsmokers to low concentrations of ozone and sulfuric acid aerosol during light-to-moderate exercise.