Air pollution and daily mortality in Turin, 1991-1996

A time series study was carried out to assess the relationship between the air pollutants measured by the air quality monitoring network and daily mortality in Turin, Italy. We used TSP, SO2, NO2, O3, and CO concentrations measured from 1-1-1991 to 31-12-1996 at three stations of the city network, chosen to represent different, typical circumstances of exposure to air pollution in the town. The analysis was performed by robust Poisson regression model including loss smoothing functions to allow for long-time trend, seasons, temperature and relative humidity. Dummy variables for the days of the week and holidays were also included. The relative risk of death for a unit increase in the pollutant concentration either during the same day (lag 0) in the previous ones (lag up to 5) was computed. The unit increase was 50 micrograms/m3 for TSP, SO2, NO2, O3, and 2 mg/m3 for CO. The average daily number of deaths for natural causes was 21. The relative risks for total mortality were 1.04 for TSP (lag 1), 1.10 for SO2 (lag 2), 1.06 for NO2 (lag 1), 1.01 for O3 (lag 0), 1.03 for CO (lag 1). The relative risks were 1.05 for TSP (lag 0), 1.12 for SO2 (lag 2), 1.07 for NO2 (lag 1), 1.03 for O3 (lag 0), 1.03 for CO (lag 1) for cardiovascular mortality, and 1.08 for TSP (lag 2), 1.20 for SO2 (lag 2), 1.12 for NO2 (lag 2), 1.03 for O3 (lag 2), 1.05 for CO (lag 2) for respiratory mortality.