Air pollution and emergency room visits due to chronic lower respiratory diseases in the elderly: an ecological time-series study in São Paulo, Brazil.

The objective of this study was to investigate the effect of daily air pollution levels (carbon monoxide, nitrogen dioxide, ozone, sulfur dioxide, and particulate matter with an aerodynamic profile < or = 10 microns) on morbidity by using the daily number of emergency room visits due to chronic lower respiratory disease (CLRD) in people older than 64 years of age in the city of São Paulo, Brazil, from 1996 to 1998. Generalized additive Poisson regression models adjusted for long-time trend and weather (nonparametric functions), weekdays (dummy variable), and daily number of nonrespiratory admissions were adopted. Ozone and sulfur dioxide were the pollutants statistically associated with CLRD visits. Interquartile range increases in the 6-day moving average of sulfur dioxide (11.82 micrograms/m3) and in the 4-day moving average of ozone(35.87 micrograms/m3) increased CLRD emergency room visits in 18% and 14%, respectively. These results reinforce the idea that air pollution may promote adverse health effects in the elderly.