ELECTRONIC ARTICLE |

* Department of Epidemiology and Community Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
Air Health Effects Division, Health Canada, Ottawa, Ontario, Canada
Objectives.The purpose of this study was to examine the association between ambient air pollution and hospitalization for respiratory infections among children who were younger than 15 years in Toronto during a 4-year period (19982001).
Methods.Exposures averaged during periods that varied from 1 to 7 days were used to assess the effects of air pollutants, including thoracic particulate matter (PM10), fine (PM2.5) and coarse (PM102.5) particulate matter, carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), and ozone (O3), on hospitalization for respiratory infections. A case-crossover design was used to calculate odds ratios for the hospitalization adjusted for daily weather conditions with an incremented exposure corresponding to the interquartile range in air pollution exposures.
Results.When particulate matter and gaseous pollutants were mutually taken into account, the effect remained pronounced for PM102.5 in both boys and girls. The adjusted odds ratio for 6-day average exposure to PM102.5 with an increment of 6.5 µg/m3 was 1.15 (95% confidence interval: 1.021.30) for boys and 1.18 (95% confidence interval: 1.011.36) for girls. The effect also remained for PM10 in boys and for NO2 in girls. PM2.5, CO, SO2, and O3 showed no significant effects on hospitalization for respiratory infection in both genders when other pollutants were taken into consideration.
Conclusion.Our study suggested a detrimental effect of relatively low levels of ambient particulate matter and gaseous pollutants, especially coarse particulate matter and NO2, on hospitalization for respiratory infections in children.
Key Words: air pollution coarse particulate matter gaseous pollutants hospitalization for respiratory infection case-crossover analysis risk assessment
Abbreviations: CO, carbon monoxide SO2, sulfur dioxide NO2, nitrogen dioxide O3, ozone PM10, thoracic particulate matter <10 µm in aerodynamic diameter PM2.5, fine particulate matter <2.5 µm in aerodynamic diameter TEOM, tapered element oscillating microbalance PM102.5, coarse particulate matter between 2.5 and 10 µm in aerodynamic diameter OR, odds ratio CI, confidence interval TSP, total suspended particles