| To address the lack of research on the pulmonary health effects of ozone (O3) and fine particulate matter (PM2.5) on individuals who recreate in the Great Smoky Mountains National Park and to replicate a study performed at Mt. Washington, NH, an observational study of adult day hikers of the Charlies Bunion trail was conducted on 71 days during the fall of 2002 and summer of 2003.; An improved exposure assessment method for ambient O3 and PM2.5 was developed using commercially-available analytical instrumentation that could be adapted for use in a relatively remote location such as the GSMNP. A UV-absorption based monitor was used to measure ozone concentrations, and a beta attenuation based monitor was used to measure PM2.5 mass concentrations. Health outcomes were assessed using pulmonary function tests (spirometry). Volunteer hikers were asked to perform pre- and post-hike spirometry, and ambient O3, PM2.5, temperature, and relative humidity were monitored during their hike.; Of the 817 hikers who participated, 354 (43%) met inclusion criteria (nonsmokers and no use of bronchodilators within 48 hours) and gave acceptable and reproducible spirometry. For these 354 hikers, the post-hike percentage change in FVC, FEV1, FVC/FEV1, PEF, and FEF25-75% were calculated and regressed separately against each pollutant concentration (ozone or particulate matter), adjusting for age, gender, hours hiked, smoking status, history of asthma or wheeze, hike load, reaching the summit, and temperature. There were no significant associations of acute changes in pulmonary function with either pollutant.; Finally, a high rate of spirometric test failure was observed, leading to concerns of potential selection bias in the epidemiologic analyses. To address this issue, the association between respiratory health status and spirometric test failure was examined using a cross-sectional analysis. The prevalence odds ratio for spirometric test failure, comparing those with self-reported respiratory symptoms to those without symptoms and adjusted for test session, gender age, body mass index, and technician skill, was 1.43 (95% CI: 0.78-2.09). For those with self-reported history of respiratory or cardiovascular illness, the adjusted prevalence odds ratio for spirometric test failure was 0.68 (95% CI: 0.38-0.99). |
