Acute effects of air pollution on respiratory health of 50-70 yr old adults

The aim of this study was to investigate the association between daily chan ges in respiratory health and air pollution in 489 adults, aged 50-70 yrs, with and without chronic respiratory symptoms, living in urban and nonurban areas in the Netherlands. Subjects were selected from the general population with a screening questio nnaire. During three consecutive winters starting in 1992/1993, peak expira tory flow (PEF) and respiratory symptoms were registered in a daily diary. Daily measurements of particles with a 50% cut-off aerodynamic diameter of 10 mu m (PM10), black smoke (BS), sulphate, sulphur dioxide (SO2) and nitro gen dioxide (NO2) were conducted. The difference in PM10, BS and sulphate c oncentrations between urban and nonurban areas was small, but there was mor e contrast in the concentrations of SO2 and NO2, In symptomatic subjects from urban areas, PM10, BS, sulphate and SO2 concen trations were associated with the prevalence of large decrements in morning PEF (>20% below the median). BS in particular was also associated with upp er respiratory symptoms (URS), The magnitude of the effect estimates was in the order of an 80% increase in PEF decrements and a 20% increase in URS f or a 40 mu g.m(-3) increase of the same day BS concentration. In symptomati c subjects from nonurban areas, no consistent associations between air poll ution and health indicators were observed. However, the differences in effe ct estimates between urban and nonurban symptomatic panels were small and n onsignificant. In nonsymptomatic adults from both areas, no consistent patt ern of associations with air pollution was found. In conclusion, air pollution effects were only found in symptomatic adults in the urban areas.