Pulmonary Response to Ozone Exposures in Healthy Individuals Aged 55 Years or Greater

Abstract

Since minimal data are available regarding the pulmonary effects of ozone (O₃) in healthy individuals over the age of 55, this research was designed to determine if this group was at risk for pulmonary function changes when exposed to O₃ at ambient concentrations for one hour during intermittent exercise. Ten female and nine male subjects were exposed for 60 minutes in random order to one of the following O₃ concentrations: 0.0, 0.2, or 0.3 ppm. All exposures were administered through a rubber mouthpiece while the subject was either at rest or moderately exercising on a treadmill. The following pulmonary function tests (PFT) were recorded before exposure, and at periods immediately following and 20 minutes postexposure: total respiratory resistance (R_T), thoracic gas volume at functional residual capacity (FRC), and forced expiratory volume in one second (FEV₁). Baseline PFT mean values and air exposure PFT mean values were compared through the use of repeated measure two-way analysis of variance to detect any significant effect of exposure on these parameters. Following 60 minutes of exposure at light intermittent exercise, there were no statistically significant pulmonary functional changes observed in male subjects. However, in female subjects, a statistically significant increase in R_T was observed.