Government of Ontario Ministry of the Environment
  | central site | feedback | search | français |

HOME | NEWS | PUBLICATIONS | AIR | LAND | WATER | GENERAL | CONTACT US
Air Quality Ontario | Reports and Forecasts | Weather Summary | Taking Action | Information | Historical Data | Smog Advisory Statistics | Pollutant Concentrations (New Feature)

Carbon Monoxide (CO)

What is carbon monoxide?

CO is a colourless, odourless and tasteless but poisonous gas produced primarily by incomplete burning of fossil fuels.

What are the sources of CO?

Approximately 85 per cent of the CO emitted in Ontario in 2006 came from the transportation sector. The remainder came from residential/miscellaneous (7 per cent), other industrial processes (5 per cent) and smelters/primary metals (3 per cent).

Ontario Carbon Monoxide Emissions by Sector
(Emissions from Point/Area/Transportation Sources, 2006 Estimates)
Pie Chart Category Percent
Carbon monoxide emissions by sectors (chart) Road Vehicles 45%
Other Transportation 40%
Residential/Miscellaneous 7%
Other Industrial Processes 5%
Smelters/Primary Metals 3%

Note: 2006 is the latest complete inventory. Emissions may be revised with updated source/sector information or emission estimation methodologies as they become available.

What are the effects of CO?

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 following table shows the health effects of different Air Quality Index levels caused by carbon monoxide.

Health effects of different Air Quality Index (AQI) levels caused by carbon monoxide
Category AQI Pollutant Concentration
Breakpoints (ppm)
Carbon Monoxide (CO)
Very Good Very Good 0 - 15
0 - 12
No health effects are expected in healthy people.
Very Good Good 16 - 31
13 - 22
No health effects are expected in healthy people.
Very Good Moderate 32 - 49
23 - 30*
Blood chemistry changes but no noticeable impairment.
Very Good Poor 50 - 99
31 - 49
Increased symptoms in smokers with heart disease.
Very Good Very Poor 100 or over
50 or over
Increasing symptoms in non-smokers with heart disease; blurred vision; some clumsiness.

* Ontario 1-hour AAQC for CO = 30 ppm

Note: ppm = parts per million.

For more information, see our list of publications.

Disclaimer


Maintained by the Government of Ontario

© Queen's Printer for Ontario, 2009 | Privacy Policy | Air Quality Ontario RSS Air Qualtiy Ontario XML

This information is provided as a public service, but we cannot guarantee that it is current or accurate.
Readers should verify the information before acting on it. Disclaimer