[Acute Effects of the Natural Atmospheric Ozone Exposure on Lung Function of Clinically Normal Smokers and Non-smokers]

The influence of moderate ambient ozone exposure on spirometric lung function and bronchial responsiveness was analyzed in 13 healthy adult nonsmokers and 11 asymptomatic smokers. The study was divided into an initial investigation at low atmospheric ozone concentrations of about 80 (range 68-102) micrograms/m3 and a subsequent similar testing at moderately elevated ozone concentrations above 140 (range 145-205) micrograms/m3. Overall there was a slight but significant impairment in forced expiratory volumes (p less than 0.002) at elevated compared with low ozone concentrations. Furthermore, a significant increase in bronchial responsiveness was shown, with a decrease in threshold dose for inhaled metacholine to produce a 50% fall in specific airway conductance (p less than 0.02). In both smokers and nonsmokers there was a similar change in lung function at ambient ozone concentrations, with more pronounced bronchial irritation in the smokers group. It is concluded that even moderately elevated ambient ozone concentrations can induce slight but significant ventilatory obstruction and an obvious increase in bronchial responsiveness in healthy adults. Although the minor impairment of lung function did not cause manifest acute respiratory problems, it still reduced maximal physical ventilation capacity. The results further support the assumption that air pollution may act as a primary trigger in the development of obstructive airway disease.