Respiratory symptoms, spirometry, and oxidant air pollution in nonsmoking adults.

Comparison of 197 nonsmokers (Seventh Day Adventists) residing in the San Gabriel Valley (high oxidant) with 244 living in San Diego area (similar pollution but with lower oxidant) is discussed. Study was conducted in winter when differences between the two areas were negligible and thus when irreversible effects could be detected. Some unusual findings included: an unexpectedly low chronic bronchitis prevalence rate of 1.77% as compared with the general population, a greater prevalence of chronic bronchitis in women in both areas (not significant), and no effect of socio-economic status. Comparison of pulmonary function using VC, FEV, MEF, peak flow, time constant, and FVC showed no differences between the two groups. The annual mean oxidant level is about the same in both areas and may have influenced spirometric values more than oxidant peaks. Also, these tests may not have been sufficiently sensitive.