Do smog advisories work? Results of an evaluation of the Canadian Smog Advisory Program

To determine the effectiveness of the Canadian Smog Advisory Program.

Telephone interviews covering perceptions, knowledge, recall of and response to advisories, and general views on their usefulness and effectiveness were conducted with 1,474 randomly selected individuals in four geographic areas. Multiple logistic regression was used to model advisory recall as a function of explanatory variables.

Recall of advisories was higher (72%; 95% CI 68-77%) when measured immediately following an advisory in southern New Brunswick. Recall was lower when measured at the end of the smog "season", and varied significantly between Toronto (46%; 42-51%), Haldimand-Norfolk (18%; 14-24%) and Vancouver (61%; 56-65%). Education and geographic area (urban versus rural) were the strongest explanatory variables in two final multiple logistic regression models. A minority of those who recalled an advisory reported taking action.

Smog advisories were partially successful in generating awareness, but only marginally effective in promoting action.