CO is a colourless, odourless and tasteless but poisonous gas produced primarily by incomplete burning of fossil fuels.
Approximately 87% of the CO emitted in Ontario in 2012 came from the transportation sectors. The remainder came from miscellaneous/residential (7%), other CO industrial sources (3%) and smelters/primary metals (3%).
|Other CO Industrial Sources||3%|
Note: 2012 is the latest complete inventory. Emissions may be revised with updated source/sector information or emission estimation methodologies as they become available.
CO enters the blood stream and reduces oxygen delivery to the organs and tissues. People with heart disease are particularly sensitive. Exposure to high levels is linked with impairment of vision, work capacity, learning ability and performance of difficult tasks.
The Ontario Ambient Air Quality Criteria (AAQC) for 1-hour average CO concentrations is 30 parts per million (ppm), which has been incorporated into Ontario’s Air Quality Health Index to better protect Ontarians. For more information on how the Air Quality Health Index has been modified for reporting in Ontario, please visit the Frequently Asked Questions.