Proximity to two main sources of industrial outdoor air pollution and emergency department visits for childhood asthma in Edmonton, Canada.

OBJECTIVE: Children are recognized to be more susceptible than healthy adults to the effects of air pollution; however, relatively few Canadian studies of children have focused on industrial emissions. We conducted a spatial cross-sectional study to explore associations between emergency department (ED) visits for childhood asthma and residential proximity to two industrial sources of air pollution (coal-fired power plant and petrochemical industry) in Edmonton, Canada.

METHODS: Using administrative health care data for Alberta between 2004 and 2010, we conducted a spatial analysis of disease clusters of count data around these two industrial sources. The distance from children's place of residence to these industrial sources was determined by using the six-character postal code from the children's ED visit. Clusters of cases were identified at the census dissemination area. Negative binomial multivariable spatial regression was used to estimate the risks of clusters in relation to the distance to these industrial sources.

RESULTS: The relative risk of ED visits for asthma, calculated using a spatial scan test for events, was 10.4 (p value <0.01) within the power plant area when compared with the outside area. In addition, there was an inverse association of the distance to the power plant (coefficient = -0.01 per km) with asthma visits when multivariable models were used. No asthma clusters were identified around the petrochemical industrial area.

CONCLUSION: Our analyses revealed that there was a cluster of ED visits for asthma among children who lived near the coal-fired power plant just outside Edmonton.