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 deaths for non-accidental causes were obtained in 11 cities from 1980 to 1991 and linked to concentrations of ambient gaseous air pollutants using relative risk regression models for longitudinal count data.

RESULTS

Nitrogen dioxide had the largest effect on mortality with a 4.1% increased risk (p < 0.01), followed by ozone at 1.8% (p < 0.01), sulphur dioxide at 1.4% (p < 0.01), and carbon monoxide at 0.9% (p = 0.04) in multiple pollutant regression models. A 0.4% reduction in premature mortality was attributed to achieving a sulphur content of gasoline of 30 ppm in five Canadian cities, a risk reduction 12 times greater than previously reported.

CONCLUSIONS

Ambient air pollution generated from the burning of fossil fuels is a risk factor for premature mortality in 11 Canadian cities.