Asthma and air pollutants: a time series study *

SummaryObjectiveTo estimate the risk of hospitalization for asthma in children after exposure to air pollutants in a medium-sized city in Southeast Brazil.MethodsAn ecological time series study was carried out with hospitalization data for asthma in children under 10 years of age living in São José dos Campos, SP, Brazil, and concentrations of particulate matter with aerodynamic diameter < 10 microns, sulfur dioxide, and ozone; data were also obtained on relative humidity and temperatures. Pearson's coefficient correlation was used for the study variables. To estimate the association between hospitalizations due to asthma and air pollutants, Poisson regression generalized additive models were built, according to lags of up to seven days.ResultsThere was a strong correlation between hospitalizations and the pollutants particulate matter and sulfur dioxide. Exposure to particulate matter and sulfur dioxide were associated with significant relative risks of 1.01 to 1.04 of hospitalization due to asthma on the same day and within three days after exposure. Increases in the concentrations of these pollutants increase the risk of hospitalization between 8% and 19%.ConclusionThere is evidence of the effect of air pollutants on asthma hospitalization in a medium-sized city in Southeast Brazil.