Relationship between pediatric hospital admissions for respiratory diseases and air pollution (PM10 and TSP) in Milan during the first semester 2007 and first semester 2008

The trend was analysed of hospital admissions to the Department of Pediatrics, San Paolo Hospital, Milan, Italy, with respect to respiratory diseases and daily levels of TSP (Total Suspended Particulate) and PM 10 (Particulate Matter < 10 μm), and a comparison was made between the first semester of 2007 and 2008. Since January 1, 2008, a municipal order was introduced (ECOPASS pollution charge), reducing vehicular traffic towards the city center. Respiratory disorders included the following: asthma or asthma like disorders; upper respiratory illness (pharyngitis, rhinitis, otitis), lower respiratory illness (bronchitits, bronchiolitis and pneumonia). The following results were obtained: there were 241 days (64,8%) with at least one hospital admission vs 122 (35,2%) with no hospital admission. Daily concentration of TSP significandy differed (p=0,03) between days with or without admission, whereas the difference between PM10 concentrations was not significant. The trend of hospital admissions was significantly different in days with both TSP and PM10 concentrations exceeding 60 μg/m3 (p < 0,05). In total, there were 226 admissions during the 1st semester 2007 vs 214 in the 1st semester 2008. The mean duration of hospitalization was also reduced (5,1 vs 4,5 days) (p = 0,009). The daily mean concentration of TSP was 48 ± 17,8 during 2007 vs 35,6 ± 17,5 during 2008 (p < 0,01). Present data support the hypothesis, that exposure to air pollutants causes detrimental effects on children respiratory health. The observed improval could be due to meteorological reasons, but also to the introduction of ECOPASS, which determined a reduction of vehicular traffic. Present data, even if preliminary, seem to suggest that even a modest reduction of pollutant concentration can have beneficial effects on children's respiratory health.