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In this paper, we present results from the SAPALDIA study (Swiss Study on Air Pollution and Lung Diseases in Adults) regarding associations between lung function [forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1)], as assessed during the cross-sectional study in 1991, and average levels of NO2 exposure within the eight study communities. We distinguished average home outdoor exposure and average personal exposure to NO2 and obtained exposure estimates by computing regional averages of passive sampler measurements performed by a random subsample of SAPALDIA participants in 1993. Previous analyses had revealed associations between average lung function and average air pollution levels between communities. The present results show that such associations may also be seen within communities: a 10-micrograms per m3 increase in average home outdoor and personal exposure to NO2 between zones of residence of the same community was associated with a change in average FVC by -0.59% [95% confidence limits (CL) = 0.01, -1.19] and -0.74% (95% CL = -0.07, -1.41), respectively. These values, however, are smaller than the ones found for the corresponding associations between study communities: -1.67% (95% CL = -1.01, -2.33) and -2.93% (95% CL = -2.11, -3.75), respectively. The different magnitudes of these two types of associations might be explained by differences in spatial variation between various components of air pollution.

The effect of long-term exposure to air pollutants was studied in a cross-sectional population-based sample of adults (aged 18 to 60 yr; n = 9,651) residing in eight different areas in Switzerland. Standardized medical examination included questionnaire data, lung function tests, skin-prick testing, and end-expiratory CO concentration. The impact of annual means of air pollutants on FVC and FEV1 was tested (controlling for age and age squared, sex, height, weight, educational level, nationality, and workplace exposure). Analyses were done separately for healthy never-smokers, ex-smokers (controlling for pack-yr), for current smokers (controlling for cigarettes per day and pack-yr smoked), and for the whole population. Significant and consistent effects on FVC and FEV1 were found for NO2, SO2, and particulate matter < 10 microm (PM10) in all subgroups and in the total population, with PM10 showing the most consistent effect of a 3.4% change in FVC per 10 microg/m3. Results for ozone were less consistent. Atopy did not influence this relationship. The limited number of study areas and high intercorrelation between the pollutants make it difficult to assess the effect of one single pollutant. Our conclusion is that air pollution from fossil fuel combustion, which is the main source of air pollution with SO2, NO2, and PM10 in Switzerland, is associated with decrements in lung function parameters in this study.

The present overview summarizes data from the literature dealing with effects of air pollution on lung health in children. Special care was taken to critically review manuscripts which were published in peer reviewed international journals. In doing so, one realizes that the degree of air pollution is closely related to pulmonary problems of children. However, since single peak loads of polluted air might not be a sufficient indicator for long-term effects of contaminated air on human health, special care has to be taken to search for connections between air toxicity and data of epidemiology, physiology, and pathophysiology.

To investigate the effects of air pollution on the respiratory health of children, a study was undertaken in the southern part of Switzerland covering 312 school children who lived in two zones with significantly different concentrations of NO2. In the more urban area the mean NO2 measured over a period of 10 months was 36.2 +/- 9.5 micrograms/m3 (25 14-day values greater than 40) compared to the mean of the second, rural area of 26.2 +/- 10.4 micrograms/m3 (6 14-day values greater than 40). Respiratory health was evaluated by determination of bronchial reactivity to Carbachol in 5 diagnostic groups (healthy: 109; healthy with positive family history of atopy: 60; allergic but not asthma: 59; asthma: 55; and "unclear cough": 29) by the technique of group specific sampling. The study shows differences in the incidence of bronchial hyperreactivity in children (PD65 less than 900 micrograms Carbachol). Within the 5 diagnostic groups, however, this distinction was significant only in the group of healthy subjects (p less than 0.005). In the other diagnostic groups the influence of the various trigger factors such as respiratory tract infections, allergen exposure, parental smoking and (last but not least) drug treatment seems to be as important as that of air pollution.