Canadian Environmental Indicators?Air Quality looks at the state of air quality in Canada and examines air quality regulations. The study examines long-term monitoring data from Environment Canada?s National Air Pollution Surveillance network on five major air pollutants regularly cited as posing health risks to Canadians: ground-level ozone, particulate matter, nitrogen dioxide, sulfur dioxide, and carbon monoxide. The study also examines the air quality standards and regulatory mechanisms already in force in Canada to determine whether local air quality is getting better or worse, and how it compares to the clean-air targets in place across the country.