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OZONE CONCENTRATION-PULMONARY RESPONSE RELATIONSHIPS FOR 6.6 HOUR EXPOSURES WITH 5 HOURS OF MODERATE EXERCISE TO 0.08, 0.10 AND 0.12 PPM
Citation:
Horstman, D., L. Folinsbee, P. Ives, S. Salaam, AND W. McDonnell. OZONE CONCENTRATION-PULMONARY RESPONSE RELATIONSHIPS FOR 6.6 HOUR EXPOSURES WITH 5 HOURS OF MODERATE EXERCISE TO 0.08, 0.10 AND 0.12 PPM. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-90/487 (NTIS PB91191486).
Description:
The magnitudes of pulmonary responses we previously observed (1) following 6.6-h exposures to 0.12 ppm ozone (O3) suggested that responses would also occur with similar exposures at lower O3 concentrations. he objective of this study was to determine the extent of pulmonary function decrements, respiratory discomfort, and increased airway reactivity to methacholine induced exposure to O1 below 0.12 ppm. eparate 6.6-h chamber exposures to 0.00, 0.08, 0.10, and 0.12 ppm O3 included six 50-min periods of moderate exercise (VE = 39 L/min, HY = 115 bpm, and VO2 = 1.5 L/min). ach exercise period was followed by 10 min of rest. 5-min lunch break was included midway through the exposure. lthough not intended as an exact simulation, the overall duration, intensity, and metabolic requirements of the exercise performed were representative of a day of moderate to heavy work or play. reexposure FEV, averaged 4.39 L, and essentially no change (+0.03 L) occurred with exposure to 0.00 ppm O3. ignificant decreases (p < 0.01) of -0.31, -0.30, and -0.54 L were observed with exposures to 0.08, 0.10, and 0.12 ppm, respectively. he provocative dose of methacholine required to increase airway resistance by 100% (PD100) was 58 cumulative inhalation units (CIU) following exposure to 0.00 ppm and was significantly reduced (p < 0.01) to 37 CIU at 0.08, 31 CIU at 0.10, and 26 CIU at 0.12 ppm O3; reductions in PD100 are considered indicative of increases in on specific airway responsiveness. e conclude that exposure to O3 at levels often found in ambient air while engaged in activity representative of a typical day of moderate to heavy work or play induced clinically meaningful pulmonary responses.