Oxidant and Acid Aerosol Exposure in Healthy Subjects and Subjects with Asthma

Research Report 70, November 1994

Part I: Effects of Oxidants, Combined with Sulfuric or Nitric Acid, on the Pulmonary Function of Adolescents with Asthma Jane Q. Koenig, David S.Covert, William E. Pierson, Quentin S. Hanley, Viviana Rebolledo, Karen Dumler, and Steve E. McKinney

Part II: Effects of Sequential Sulfuric Acid and Ozone Exposures on the Pulmonary Function of Healthy Subjects and Subjects with Asthma Mark J. Utell, Mark W. Frampton, Paul E. Morrow, Christopher Cox, Paul C. Levy, Donna M. Speers, and F. Raymond Gibb

In two separate studies, Drs. Koenig and Utell examined the effects of exposing healthy subjects and subjects with asthma to combined oxidant and acid pollutants. Each team of investigators conducted studies in which human volunteers received either combined or sequential exposures to oxidant gases and acid aerosols and standard pulmonary function tests were performed and symptoms were recorded. Dr. Koenig and colleagues exposed 28 adolescents with asthma to varying concentrations of ozone, nitrogen dioxide, and sulfuric acid for 90 minutes while the subject exercised intermittently; exposures to the different combinations of substances were separated by at least one week. Dr. Utell and colleagues examined the effects of sequential exposures to sulfuric acid and ozone on pulmonary function in 30 subjects with asthma and 30 healthy subjects between the ages of 18 and 45. Subjects were exposed first to either sulfuric acid or sodium chloride (as a control exposure) at a concentration of 100 µg/m3. Twenty-four hours later they were exposed to ozone for three hours, including intermittent exercise. Each two-day exposure protocol was separated from the next one by at least two weeks.