Air pollution and hospital admissions for respiratory conditions in Rome, Italy

Most of the evidence regarding the association between particulate air poll ution and emergency room visits or hospital admissions for respiratory cond itions and asthma comes from the USA. European time-series analyses have su ggested that gaseous air pollutants are important determinants of acute hos pitalization for respiratory conditions, at least as important as particula te mass. The association between daily mean levels of suspended particles a nd gaseous pollutants (sulphur dioxide, nitrogen dioxide, carbon monoxide, ozone) was examined. The daily emergency hospital admissions for respirator y conditions in the metropolitan area of Rome during 1995 - 1997,were also recorded. Daily counts of hospital admissions for total respiratory conditions (43 ad missions .day(-1)), acute respiratory infections including pneumonia (18.da y(-1)), chronic obstructive pulmonary disease (COPD) (13.day(-1)), and asth ma (4.5.day(-1)) among residents of all ages and among children (0-14 yrs) were analysed, The generalized additive models included spline smooth funct ions of the day of study, mean temperature, mean humidity, influenza epidem ics, and indicator variables for day of the week and holidays, Total respiratory admissions were significantly associated with same-da, le vel of NO2 (2.5%, increase per interquartile range (IQR) change, 22.3 mug.m (-3)) and CO (2.8% increase per IQR, 1.5 mg.m(-3)). No effect was found for particulate matter and SO2, whereas O-3 was associated with admissions onl y among children (lag 1, 5.5%, increase per IQR, 23.9 mug.m(3)). The effect of NO2 was stronger on acute respirator!, infections (lag 0, 4.0% increase ) and on asthma among children (lag 1, 10.7% increase). The admissions for all ages for asthma and CORD were associated only with same-day level of CO (5.5% and 4.3% increase, respectively). Multipollutant models confirmed th e role of CO on all respiratory admissions, including asthma and COPD, and that of NO2 on acute respiratory infections, Among children, O-3 remained a strong indicator of acute respiratory infections, Carbon monoxide and photochetnical pollutants (nitrogen dioxide, ozone) app ear to he determinants of acute respiratory conditions in Rome, Since carbo n monoxide and nitrogen dioxide are good indicators of combustion products from traffic related sources, the detected effect may be due to unmeasured fine and ultrafine particles.