Some countries have adopted vehicular restriction in order to reduce air pollution levels. In São Paulo metropolitan region, the vehicle restriction was adopted from 1996 to 1998, in order to reduce air pollution, during wintertime. Since 1997, a similar project was implemented during the whole year in the central area of São Paulo in order to improve the urban traffic. This time series study was developed to investigate the relationship between daily levels of air pollutants (CO, NO2, SO2, PM10 and O3) and the daily numbers of elderly patients with upper respiratory infection diseases (URID) atended at the Clinics Hospital emergency room service of the University of São Paulo Medical School, during this period. Generalized adittive Poisson regression models were estimated and adjusted by seasonality (non-parametric smoother functions), weather (non-parametric smoother functions and linear terms), weekdays indicator, vehicular restriction indicator periods and the daily number of non respiratory admissions. The effects of air pollutants were estimated based on daily levels and 2 to 7 day moving average. Carbon monoxide (CO) and sulphor dioxide (SO2) were associated with URID and these correlations were resistant even with the inclusion of control variables. The vehicular restriction reduced the pollutants levels. However, no reduction in emergency room visits for URID was detected.
Air pollution; Aged respiratory tract infections; Time series
