Air pollution and emergency room visits due to pneumonia and influenza in São Paulo, Brazil

Abstract

OBJECTIVE: A time series was developed to investigate the effect of air pollution levels on morbidity due to respiratory diseases such as pneumonia and influenza among elderly people from 1996 to 1998. METHODS: Daily data on emergency room visits was collected at the university clinics hospital in São Paulo, Brazil. Daily levels of CO, NO2, O3, SO2 and PM10 were obtained from the State Environmental Agency. Daily measures of temperature and relative humidity were obtained from the Institute of Astronomy and Geophysics of the University of São Paulo. Generalized additive Poisson regression models were used to assess the relationship between pneumonia and influenza and air pollution, using the number of emergency room visits as dependent variable and the average daily levels of each pollutant as independent variables. The models were estimated and adjusted by seasonality (non-parametric function), weather, weekdays, motor vehicle circulation curbs periods and daily numbers of non-respiratory hospital admissions. RESULTS: The pollutants O3 and SO2 showed a statistical association with pneumonia and influenza. These associations remained robust when control variables were included. An interquartile range for O3 (38.80 mug/m³) and SO2 (15.05 mu g/m³) increased in 8.07% and 14.5%, respectively, the number of emergency room visits due to pneumonia and influenza. CONCLUSION: The study results suggest that air pollution in the city of São Paulo may promote adverse health effects in elderly people.