• healthsciences ON PULMONARY FUNCTION AND SYMPTOMS RESPONSES

Because of increased interest in an 8-h ozone (OJ) federal air quality standard, acute pulmonary function responses to prolonged square-wave OJ exposure between 0.08 and 0.12 ppm have been examined in several U.S. Environmental Protection Agency (EPA) chamber studies. A low-cost face-mask OJ exposure system was developed in this labo-ratory and found to produce closely similar pulmonary responses to those observed in prolonged exposures by U.S. EPA investigators. The primary purpose of the present study was to investigate the pulmonary function and subjective symptoms effects of 6.6-h square-wave exposure to 0.12 ppm OJ by these two methods using the same group of subjects. In addition, further investigation of pulmonary function and symptoms responses upon 6.6-h exposures to lower levels of OJ (0.04-0.08 ppm) were studied with the face-mask inhalation system. Thirty young adult subjects completed five 6.6-h exposures with six 50-min periods of exercise at an intensity requiring a minute ventilation rate (V E) of-20 Uminlm2 of body surface area, each followed by 10 min of rest, except fol/ow-ing 3 h when the rest period was lengthened for a lunch break. The total OJ doses for the chamber and face-mask exposures to 0.12 ppm OJ were not significantly differen