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Outdoor Air Pollution: One of the leading causes of death globally

A new international study led by scientists at Health Canada has shed new light on the impact of air pollution on human mortality.

The research estimates that almost nine million people around the world die prematurely every year because of outdoor air pollution. This is more than double the previous estimates, making outdoor air pollution one of the leading causes of premature death globally. Its impact on life expectancy is now comparable to poor diets and cigarette smoking. 

Air pollution can be made up of many different things, including something called fine particulate matter. These are small particles that come from different sources like forest fires, agricultural and residential wood burning, power plants, motor vehicles, airplanes, volcanic eruptions and dust storms. The particles are tiny – less than 3% of the diameter of a human hair – and can remain suspended in the air for long periods of time. High concentrations of particulates in the air can result in poor air quality and air pollution.

When there is fine particulate matter in the air, it can enter our lungs when we breathe. Long-term exposure to high levels can lead to heart and lung disease.

For this new study, Health Canada researchers Richard Burnett and Mieczysław (Mietek) Szyszkowicz brought together 15 research groups from around the world to estimate the number of deaths due to particulate matter exposure in 195 countries, including Canada.

According to senior research scientist Richard Burnett, this represents the largest international collaboration among researchers studying the health effects of long-term exposure to outdoor air pollution.

“The advances in knowledge made by this study were only possible with the cooperation of more than 50 researchers in Canada, the United States, Europe, and Asia,” said Burnett.

The researchers used new mathematical risk models and refined methods to calculate the new estimates. Governments and policy makers around the world can use this information to draw connections between changes in outdoor air pollution and health risks. The study concludes that efforts to improve air quality could have significantly greater health benefits for their citizens than previously thought. This is particularly true in countries with the highest air pollution concentrations such as India or China.

“Future research will focus on identifying the most significant pollution sources causing these health effects,” said Burnett. “This information is critical to developing the most effective strategies to improve air quality that result in the largest public health benefits.” 

Children, older adults and those who are suffering from lung or heart disease are particularly vulnerable to the effects of fine particles in the air. Visit to learn about air contaminants and the health effects of poor air quality and what you can do to improve air quality.

Reference: The study, titled “Global Mortality and Long-Term Ambient Exposure to Fine Particulate Matter: a New Relative Risk Estimator”, is published and available online in the Proceedings of the National Academy of Science.

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