Air pollution and childhood asthma emergency hospital admissions: estimating intra-city regional variations.

In recent years childhood asthma has increased. Although the precipitants of childhood asthma are yet to be established possible contributing factors are local ambient air pollutants. This study aims to assess associations of regional ambient air pollutants on emergency department childhood asthma presentations across four regions of the city of Melbourne, Australia. Daily emergency department (ED) presentations for asthma in children were studied for the years 2000 and 2001. Estimates of local air pollutant levels were obtained using simulation modelling techniques. Generalized Additive Models were used to examine associations between combined local levels of air pollutants and childhood asthma ED presentations adjusting for seasonal variation, day of week effects, and meteorological variables. There was consistent associations between childhood ED asthma presentations and regional concentration of PM10, with a strongest association of RR = 1.17 (95% CI 1.05 to 1.31) in the central district of Melbourne. NO2 and Ozone was associated with increased childhood asthma ED presentations in the Western districts. This study suggests that regional concentrations of PM10 may have a significant effect on childhood asthma morbidity. In addition, ozone may play a role however, its effect may vary by geographical region.