Pulmonary function and symptom responses after 6. 6-hour exposure to 0. 12 ppm ozone with moderate exercise
Episodes occasionally occur when ambient ozone (O/sub 3/) levels remain at or near 0.12 ppm for more than 6 h. Small decrements in lung function have been reported following 2-h exposures to 0.12 ppm O/sub 3/. For short exposures to higher O/sub 3/ concentrations, lung function decrements are a function of exposure duration. Thus, we investigated the hypothesis that prolonged exposure to 0.12 ppm O/sub 3/ would result in progressively larger changes in respiratory function and symptoms over time. Ten nonsmoking males were exposed once to clean air and once to 0.12 ppm O/sub 3/ for 6.6 h. Exposures consisted of six 50-min exercise periods, each followed by 10-min rest and measurement; a 35-min lunch period followed by the third exercise period. Exercise ventilation averaged approximately 40 L/min. Forced expiratory and inspiratory spirometry and respiratory symptoms were measured prior to exposure and after each exercise. Airway reactivity to methacholine was determined after each exposure. After correcting for the air exposures, FEV 1.0 was found to decrease linearly during the O/sub 3/ exposure and was decreased by an average of 13.0 percent at the end of exposure. Decreases in FVC and FEF24-75% were also linear and averaged 8.3 and 17.4 percent, respectively, at the end of exposure. On forced inspiratory tests, the FIVC and FIV05 were decreased 12.6 and 20.7 percent, respectively. Increases in the symptom ratings of cough and pain on deep inspiration were observed with O/sub 3/ exposure but not with clean air. Airway reactivity to methacholine was approximately doubled following O/sub 3/ exposure.
- Research Organization:
- Environmental Monitoring and Services, Inc., Chapel Hill, NC (USA)
- OSTI ID:
- 5284577
- Journal Information:
- J. Air Pollut. Control Assoc.; (United States), Journal Name: J. Air Pollut. Control Assoc.; (United States) Vol. 38:1; ISSN JPCAA
- Country of Publication:
- United States
- Language:
- English
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