Environmental ozone field study on pulmonary and subjective responses of assumed risk groups.

Lung function parameters (measured with a body plethysmograph) and subjective votes on irritations of eyes or airways were taken from subjects belonging to four assumed ozone risk groups and one control group (40 subjects each: senior citizens, juvenile asthmatics, forestry workers, athletes, and clerks). Every subject was examined on 8 days both in the morning and in the afternoon. The intention was to obtain an equal distribution of measuring days with elevated and low ozone concentrations, respectively, for each subject. On average the ozone concentrations reached 0.070 ppm on "ozone days" [maximum concentration 0.112 ppm for clerks (outdoors), 0.100 ppm for senior citizens, 0.091 for juvenile asthmatics, 0.086 ppm for athletes, and 0.077 ppm for forestry workers] and 0.028 ppm on "control days" (minimum 0.001 ppm). The results show no relevant ozone effect for the group with the lowest ventilation rate (senior citizens) and only marginal reductions of respiratory flows and volumes for athletes. Pulmonary decrements of juvenile asthmatics on ozone days were small but larger than those documented in the literature for healthy children. Forestry workers and clerks had significantly higher airway resistances on ozone days, although having been exposed to the lowest ozone concentrations of all groups. Thus, on days with moderately elevated levels of ozone in the environment it is assumed that ozone itself has a minor influence on pulmonary responses compared to that of other constituents of the air in certain locations like in forests or indoors on these days. These could be reaction products of ozone with motor tool exhausts in the case of forestry workers or substances originating from ozone deposition on the surfaces of the offices.