Air pollutants

Carbon monoxide (CO)

What is carbon monoxide?

Carbon monoxide is a colourless, odourless gas formed when substances containing carbon (fuels such as petrol, gas, coal and wood) are burned with a low supply of air.

What are the sources and contributors of carbon monoxide?

CO is produced both by natural processes (such as volcanic activity) and by human activity. Motor vehicles are the main source of CO in Auckland. Vehicle exhaust emissions contain CO from the incomplete burning of fuel in the engine. CO emissions are much greater in cold weather because vehicles require more fuel to start at cold temperatures.

Inside homes, CO is emitted from natural gas fuelled hot water heaters and home heating systems.

Carbon Monoxide Pie Chart

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What are the effects of carbon monoxide?

CO interferes with the blood's ability to carry, absorb and circulate oxygen around the body, especially to the heart and brain. High levels of CO can affect people with heart conditions such as angina, and can impair coordination and attention.

Although CO 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 our health.

Standards/guidelines for carbon monoxide

An air quality target of 30mg/m3 for a one hour average and 10mg/m3 for an eight hour average for CO.

View CO trends in Auckland.