THE EFFECT OF THE URBAN AMBIENT AIR-POLLUTION MIX ON DAILY MORTALITY-RATES IN 11 CANADIAN CITIES

Objective: Determine the risk of premature mortality due to the urban ambient air pollution mix in Canada. Methods: The number of daily deat hs for non-accidental causes were obtained in 11 cities from 1980 to 1 991 and linked to concentrations of ambient gaseous air pollutants usi ng relative risk regression models for longitudinal count data. Result s: Nitrogen dioxide had the largest effect on mortality with a 4.1% in creased risk (p<0.01), followed by ozone at 1.8% (p<0.01), sulphur dio xide at 1.4% (p<0.01), and carbon monoxide at 0.9% (p=0.04) in multipl e pollutant regression models. A 0.4% reduction in premature mortality was attributed to achieving a sulphur content of gasoline of 30 ppm i n five Canadian cities, a risk reduction 12 times greater than previou sly reported. Conclusions: Ambient air pollution generated from the bu rning of fossil fuels is a risk factor for premature mortality in 11 C anadian cities.