title: Duration of pulmonary function adaptation to ozone in humans.
abstract: The duration of pulmonary function adaptation subsequent to cessation of a 5-day repeated ozone (O3) exposure was studied in 24 nonsmoking human subjects. A three-week, 3 hr/day study was conducted. The subjects received filtered air on Week 1 and 0.4 ppm O3 on Week 2. During Week 3, 13 subjects were re-exposed to O3 on Friday and 11 were re-exposed to O3 on Tuesday. Spirometric measurements (FVC and FEV1) and bronchial reactivity to methacholine showed adaptation within 2-3 days of the repeated daily exposures (Week 2). Although the duration of adaptation seen with bronchial reactivity appears longer than 7-days, the FVC and FEV1 clearly demonstrated complete loss of adaptation by 7 days, with a trend toward significance by 4 days. We conclude, therefore, the loss of ozone adaptation in pulmonary function is a gradual phenomenon lasting less than 7 days following cessation of repeated daily exposures.
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008168:Lung / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008688:Methacholine Compounds / Q000494:pharmacology; D008875:Middle Aged; D010126:Ozone; D013147:Spirometry; D013997:Time Factors; D014797:Vital Capacity
chemical_list: D008688:Methacholine Compounds; D010126:Ozone