Carbon monoxide
Health effects
Measurement of carbon monoxide
Carbon monoxide is a colourless, odourless gas. It is formed when substances containing carbon are burned with an insufficient supply of air.
Carbon monoxide pollution. Photo: DERM
The combustion of fuels such as petrol, gas, coal and wood generate emissions of carbon monoxide. We burn coal to generate energy and electricity for our homes. Gas and wood can be used for cooking and heating in appliances like stoves and barbecues.
Motor vehicles are the main source of carbon monoxide pollution in urban areas. The motor vehicles we drive operate on petrol, diesel, or gas. Car exhaust emissions contain carbon monoxide from incomplete burning of fuel in the engine.
Emissions of carbon monoxide from motor vehicle usage in south-east Queensland has been estimated at 328,700 tonnes, or 83 percent of the total estimated carbon monoxide emissions for the region (South East Queensland Regional Air Quality Strategy, 1999).
Health effects
Carbon monoxide can have serious health impacts on humans and animals. When inhaled, the carbon monoxide bonds to the haemoglobin in the blood (and becomes carboxyhaemoglobin) in place of oxygen and is carried through the blood stream. This reduces the oxygen-carrying capacity of the red blood cells and decreases the supply of oxygen to tissues and organs, especially the heart and brain. This can be a serious problem for people with cardiovascular disease. Most people in the community need to be exposed to a level of 200 ppm for several hours before they start to feel effects. Carboxyhaemoglobin formation is reversible when the person is no longer exposed to carbon monoxide.
Air Quality standard
Air quality standards and goals for pollutants such as carbon monoxide have been set by governments, health and environment organisations around the world.
In Queensland the Environmental Protection (Air) Policy goal for carbon monoxide is a maximum of 8ppm for an 8 hour period. It has been set to protect sensitive members of the community from feeling any health effects from carbon monoxide levels. Carbon monoxide concentrations in the ambient (outdoor) air are measured for south-east Queensland against the EPP(Air) goal and are well below 8ppm.
Although ambient carbon monoxide levels in urban residential areas are unlikely to cause significant health effects, indoor sources such as poorly ventilated gas appliances and wood heaters could pose a risk to human health.
Measurement of carbon monoxide
Carbon monoxide absorbs infrared radiation at wavelengths near 4.7 microns. Infrared radiation is passed through a cell containing ambient air. The degree of absorption is a measure of the amount of carbon monoxide. A gas filter correlation technique incorporated in the instrument minimises interference from other gases that absorb infrared radiation, ensuring that the instrument responds specifically to carbon monoxide.
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Last updated: 07 April 2006