RESPIRATORY HEALTH AND LONG-TERM EXPOSURE TO AIR-POLLUTANTS IN SWISS SCHOOLCHILDREN

The impact of long-term exposure to air pollution on respiratory and a llergic symptoms and illnesses was assessed in a cross-sectional study of schoolchildren (ages 6 to 15 yr, n = 4,470) living in 10 different communities in Switzerland. Air pollution measurements (particulate m atter less than 10 mu m in diameter [PM(10)], nitrogen dioxide [NO2], sulfur dioxide [SO2], and ozone) and meteorologic data were collected in each community. Reported symptom rates of chronic cough, nocturnal dry cough, and bronchitis, adjusted for individual risk factors, were positively associated with PM(10), NO2, and SO2. The strongest relatio nship was observed for PM(10) (adjusted odds ratios for chronic cough, nocturnal dry cough, and bronchitis between the most and the least po lluted community for PM(10) were 3.07 [95% CI: 1.62 to 5.81], 2.88 [95 % CI: 1.69 to 4.89], and 2.17 [95% CI: 1.21 to 4.89], respectively). T he high correlation between the average concentrations of the pollutan ts makes the assessment of the relative importance of each pollutant d ifficult. No association between long-term exposure to air pollution a nd classic asthmatic and allergic symptoms and illnesses was found. Th ere was some indication that frequency of fog is a risk factor of chro nic cough and bronchitis, independent of air pollution. In conclusion, this study provides further evidence that rates of respiratory illnes ses and symptoms among children augment with increasing levels of air pollution even in countries like Switzerland with moderate average air pollution concentrations.