Air Quality

Air quality describes the concentration of air pollutants in the air that we breathe. Air pollutants can become dangerous to human health if concentrations become elevated, especially for people who are sensitive to air pollution, such as the elderly, individual with respiratory illnesses and young children, or are exposed to pollutants 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.