Air Quality

Air quality describes the level of air pollutants in a certain area. Air pollutants can become dangerous to human health if people are sensitive to elevated levels of pollutants or are exposed to them for extended periods. To reduce risks, people need to know when pollutants are present and in what concentrations.

Environment Canada scientists assess air quality by collecting and analyzing samples taken from near ground level. Pollutant levels are affected by such factors as emissions sources, weather conditions and topography. Building on their expertise in weather prediction, Environment Canada scientists have developed complex computer models that now provide air quality forecasts for major centres in Canada. 

This section provides daily and long-term forecasts of air quality, including levels of smog and ground-level ozone.

Canadian Environmental Sustainability Indicators 2008

Environmental indicators provide a simple way to convey complex information and track progress on the environment, much like economic indicators such as the gross domestic product, the consumer price index and the unemployment rate do for the economy. This fourth annual release of CESI results presents the most timely and consistent information available on three environmental issues important to Canadians: clean air, clean water and greenhouse gas emissions.