to evaluate the relationship between air pollution and hospital admissions in 25 Italian cities that took part in the EpiAir (Epidemiological surveillance of air pollution effects among Italian cities) project.study of time series with case-crossover methodology, with adjustment for meteorological and time-dependent variables. The association air pollution hospitalisation was analyzed in each of the 25 cities involved in the study; the overall estimates of effect were obtained subsequently by means of a meta-analysis. The pollutants considered were PM10, PM2.5 (in 13 cities only), NO2 and ozone (O3); this last pollutant restricted to the summer season (April-September).the study has analyzed 2,246,448 urgent hospital admissions for non-accidental diseases in 25 Italian cities during the period 2006- 2010; 10 out of 25 cities took part also in the first phase of the project (2001-2005).urgent hospital admissions for cardiac, cerebrovascular and respiratory diseases, for all age groups, were considered. The respiratory hospital admissions were analysed also for the 0-14-year subgroup. Percentage increases risk of hospitalization associated with increments of 10 μg/m(3) and interquartile range (IQR) of the concentration of each pollutant were calculated.reported results were related to an increment of 10 μg/m(3) of air pollutant. The percent increase for PM10 for cardiac causes was 0.34\% at lag 0 (95\%CI 0.04-0.63), for respiratory causes 0.75\% at lag 0-5 (95\%CI 0.25-1.25). For PM2.5, the percent increase for respiratory causes was 1.23\% at lag 0- 5 (95\%CI 0.58-1.88). For NO2, the percent increase for cardiac causes was 0.57\% at lag 0 (95\%CI 0.13-1.02); 1.29\% at lag 0-5 (95\%CI 0.52-2.06) for respiratory causes. Ozone (O3) did not turned out to be positively associated neither with cardiac nor with respiratory causes as noted in the previous period (2001-2005).the results of the study confirm an association between PM10, PM2.5, and NO2 on hospital admissions among 25 Italian cities. No positive associations for ozone was noted in this period.
