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Pulmonary responses of healthy young adults exposed to 0.06 and 0.08 ppm ozone
Citation:
DEVLIN, R. B., C. S. KIM, H. R. KEHRL, M. HAZUCHA, N. ALEXIS, J. C. LAY, A. G. RAPPOLD, J. Brown, D. B. PEDEN, AND D. DIAZ SANCHEZ. Pulmonary responses of healthy young adults exposed to 0.06 and 0.08 ppm ozone. Presented at Health Effects Institute (HEI) Annual Conference, Alexandria, VA, April 25 - 27, 2010.
Impact/Purpose:
This poster represents pulmonary changes in human volunteers exposed to 0.06 ppm ozone
Description:
Background. Previous studies have shown small but significant decreases in spirometric lung function in healthy young adults exposed to 0.08 ppm ozone. It is unclear, however, if such effects may are seen at concentrations below 0.08 ppm. Methods. A group of 30 healthy young adults (men and women in equal number, age = 18-35 years) was exposed to 0.0 (filtered air), 0.06 and 0.08 ppm ozone for 6.6 hours while undergoing moderate exercise in a tightly controlled environmental chamber. Spirometric lung function (e.g., FEV l and FVC) was measured immediately before, during and after exposure. Induced sputum samples were obtained at least 24 hour before exposure (baseline sample) and in the morning following the 6.6 hour exposure to 0.08 ppm ozone. The samples were assayed for markers of inflammation including differential cell counts and pro-inflammatory cytokines. Changes in lung function and symptom scores with ozone exposures were compared with those with filtered air exposure. Results. Exposure of participants to both 0.08 and 0.06 ppm ozone resulted in small, but significant, decreases in FEV 1 and FVC compared with exposure to filtered air. There were no differences in both FEV 1 and FVC responses between males vs. females. The mean symptom score was greater vs. filtered air only after completion of 0.08 ppm exposure. Neutrophils, monocytes and dendritic cells recovered from sputum were significantly increased after 0.08 ppm exposure, as were IL-6, IL-8, IL-12p70 and TNFa. This cohort is part of a larger study in which we will ascertain whether individuals carrying the null GSTMI allele are more responsive to ozone than those carrying the wild type allele. The entire study will have a total of 60 individuals exposed to 0.06 ppm (30 wild type, 30 GSTM1 null). In addition to lung function, induced sputum is being performed on these participants to determine if exposure to 0.06 ppm ozone causes pulmonary inflammation. Conclusions. Exposure of healthy young adults to levels of ozone at or below the current standard causes small but significant decrements in lung function. Additionally, this is the first study to report inflammation measured in cells and fluid recovered by induced sputum (as opposed to bronchoalveolar lavage) in individuals exposed to 0.08 ppm ozone. This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.