Airborne fine particles pollution and health risks estimates

In this paper the results of the analyses of health risks associated with PM10 and PM2.5 are discussed, which have been made by the WHO and by a recent Italian multicentric epidemiological study in 8 cities. The distribution of PM10 and PM2.5 levels in the various cities are also considered. WHO estimates of short-term relative risk of daily mortality were 1.0074 and 1.015, by 10 microg/m3 increase respectively of PM10 and of PM2.5. Long-term risk estimates of mortality for the same increase of PM10 and PM2.5 were respectively 1.10 and 1.14, whereas more recent evaluations have indicated a value of 1.07 for PM2.5. The Italian meta-analysis study was concentrated on short-term effects associated to PM10. The effect estimate on mortality was an increase of 1.17%. The short-term effects indicated by the Italian study appeared greater than those estimated by WHO, but the confidence intervals (0.44%-2.06%) included the value of 0.74%. The hypothesis of a greater risk in Italy for the same increase of PM10 deserves further examination. The available mean concentration levels of PM10 in Italy showed an acceptable agreement, even if they were produced by different bodies. Mean yearly concentration of PM10 in the major Italian cities resulted about 50 microg/m3, range 30 microg/m3 to less than 70 microg/m3 since the first '90 up to 2001. Very few data are available on PM2.5, with the exception of Rome where mean annual levels resulted near 28 microg/m3, with 24 h averages ranging from 5 to 101 microg/m3.