Carbon monoxide (CO) is a clear, odourless gas. Smoke and exhaust fumes often contain carbon monoxide.
Carbon monoxide is a common air pollutant. In Victoria, carbon monoxide levels are normally low in the outside air and not harmful to human health. We measure carbon monoxide at some of our air monitoring sites.
Health effects of carbon monoxide
Carbon monoxide can affect your health. However, you’re very unlikely to experience high carbon monoxide levels in the outside air. High levels can happen in enclosed spaces inside. For example, due to a faulty gas heater in your living room.
You can experience serious symptoms from breathing in high levels of carbon monoxide. Unborn babies and people with heart conditions are at greatest risk.
High levels of carbon monoxide can cause ‘flu-like’ symptoms, including:
- headaches
- tiredness
- dizziness
- nausea.
High carbon monoxide levels can sometimes cause unconsciousness or even death.
Sources of carbon monoxide
Carbon monoxide forms when materials don’t burn completely. Sources of carbon monoxide can include:
- burning fossil fuels like natural gas, petrol, coal and oil
- wood smoke
- car and truck exhausts
- faulty gas heaters, BBQs, ovens, and cooktops.
Carbon monoxide on EPA AirWatch
We show carbon monoxide data on EPA AirWatch using air quality categories.
| Air quality category | Carbon monoxide (parts per million) averaged over 1 hour |
|---|---|
| Good | Less than 30 |
| Fair | Doesn't apply |
| Poor | 30–70 |
| Very poor | Doesn't apply |
| Extremely poor |
More than 70 |
Read more about air quality
Vehicle emissions and air quality
Reviewed 16 March 2021
