Short-term variation in air pollution and in average lung function among never-smokers. The Swiss Study on Air Pollution and Lung Diseases in Adults (SAPALDIA).

The present analysis was directed at investigating associations between short-term variations in air pollutant levels (NO2, total suspended particulates [TSP], O3) and cross-sectional lung function (FVC, FEV1, and forced expiratory flow at 25% to 75% of FVC [FEF25-75]) within a random sample of 3,912 adult never-smokers from eight areas of Switzerland (i.e., participants in the Swiss Study on Air Pollution and Lung Diseases in Adults [SAPALDIA] cross-sectional study, 1991). Within each local data set, the logarithms of FVC, FEV1, and FEF25-75 were regressed against the 24-h-means of NO2 and TSP and the 8-h mean of O3 (10:00 A.M. to 6:00 P.M.) on the examination day, with control for subjects' sex, age, height and weight, seasonal fluctuations and weekly cycles and meteorologic factors. On average, a 10-microg/m3 increment in the daily level of NO2, TSP, and O3 was associated with decrements in FEV1 of 0.67% (95% confidence interval [CI]: 0.13% to 1.21%), 0.46% (95% CI: 0.14% to 0.78%), and 0.51% (95% CI: 0.13% to 0.88%), respectively. Moreover, 10-microg/m3 increments in NO2 and TSP were associated with decrements in FVC of 0.73% (95% CI: 0.22% to 1.23%) and 0.36% (95% CI: 0.06% to 0.66%), respectively, and a 10-microg/m3 increment in O(3) was associated with a decrement in FEF25-75 of 1.04% (95% CI: 0.22% to 1.85%). Our results suggest that FVC, FEV1, and FEF25-75 vary with the daily level of NO2, TSP, and O3, but that these measures of lung function do not allow separation of the effects of particulates from those of NO2.