Revised Mortality Estimates Due to Air Pollution in Canada

Scientists worldwide have been estimating mortality and morbidity rates related to air pollution exposure for over a decade using complex scientific models.  Prior to 2002, based on the best estimates and scientific procedures of the day, the Government of Canada estimated that air pollution contributed to 5,000 premature deaths in Canada each year.  In 2002, however, researchers at Health Canada and Johns Hopkins University in the United States found problems in the statistical model used to derive such estimates.  Since then, improved software and analysis techniques have led to more accurate calculations. 

Scientists are now able to include both short and long-term health effects of air pollution in their calculations.  The estimates also assume background levels of air pollution, whereas previous estimates assumed no background levels of air pollution. This means that even if all human activities that contribute to air pollution, such as industry and vehicles were eliminated, air pollution levels would not drop to zero because natural sources such as forest fires, windblown dust and volcanoes would remain.

In analyzing data from eight cities across Canada (Quebec City, Montreal, Ottawa, Toronto, Hamilton, Windsor, Calgary and Vancouver), Health Canada estimates 5,900 deaths per year in these cities can be attributed to air pollution.

Air pollution continues to be a public health concern and is linked with illnesses such as asthma, heart disease and respiratory disease.  All of these carry a potential risk of death.

What is Health Canada and the Government of Canada doing to address air pollution and bring these numbers down?

• Health Canada continues research on the health effects of air pollution and the Government of Canada is taking action to improve air quality. 
• Health Canada and Environment Canada are working together with provincial and municipal governments, non-governmental organizations and other partners on the development of a health-based national air quality index.
• Health Canada researchers and scientists provide essential scientific support for many clean air initiatives, including regulations that protect and promote the health of Canadians.
• The Government of Canada's Clean Air Agenda commits money and resources for government, industry and communities to work together to improve air quality by addressing the following aspects: transportation, industry, transboundary pollution, monitoring and reporting, scientific research and public outreach.
• The Government of Canada is working with the provinces and territories to achieve environmental standards across the country.
• Canada has bilateral and international agreements to reduce transboundary sources of air pollution that affect Canadians and their environment. 
• Tangible results of the Clean Air Agenda include more air monitoring stations and public outreach programs, which means more Canadians are receiving vital information about air quality and their health, and are engaged in efforts to improve both.

Is air pollution getting better or worse in Canada?

The levels of some pollutants have declined dramatically over the last 20 to 30 years. However, concentrations of ground-level ozone (the harmful gas that’s produced when pollutants closest to the ground are baked in the sun), have not followed this trend, and in some areas have increased.

What can Canadians do to reduce the risks to their health from air pollution?

• Leave your car at home more often: walk, bike, rollerblade, take public transit or car pool.
• Heed air pollution advisories in your community and tailor your activities accordingly.
• Avoid or reduce strenuous outdoor activities when smog levels are high, especially during summer afternoons when ground-level ozone is at its peak.
• If you have a heart or lung condition, follow the advice of your health care professional about how to best manage your condition.

How do Health Canada’s mortality estimates compare to international figures?

The World Health Organization recently estimated that 800,000 deaths per year worldwide (1.4% of all deaths) could be attributed to urban outdoor air pollution.

How do the mortality estimates compare to the effects of other risk factors?

Health Canada estimates that more than 45,000 people in Canada died prematurely in 2004 due to tobacco use.  At least 1,000 of them were non-smokers.

For further information on mortality estimates, or to receive a copy of Health Canada’s peer-reviewed report, contact the Air Health Effects Division.