Canada ranks third in the world for air quality, according to new statistics compiled by the World Health Organization.
Estonia took first place, with the highest air quality in the world, followed by the African island nation of Mauritius. Canada tied with Australia for third place, with an annual average of 13 micrograms of PM10 particles per cubic meter.
Measuring 10 micrometers or less by definition, PM10 particles can do serious damage when they pass though the lungs into the bloodstream, increasing the risk of heart disease, lung cancer, asthma, and acute lower respiratory infections.
WHO guidelines advise a maximum of 20 micrograms per cubic meter, but their findings showed that some cities had as many as 300.
"Air pollution is a major environmental health issue and it is vital that we increase efforts to reduce the health burden it creates," said Dr Maria Neira, WHO Director for Public Health and Environment, in a statement.
"If we monitor and manage the environment properly we can significantly reduce the number of people suffering from respiratory and heart disease, and lung cancer."