The Air Quality Index (AQI) represents how clean the air is. A low AQI number means the quality of the air is better.

We collect data from the air quality monitoring stations in various scientific units. As the units, time frames and exposure standard are different for different pollutants this can make it hard to compare numbers in a meaningful way.

The AQI provides a number that easily compares the level between different pollutants, locations and time periods.

You can access data readings and AQI’s through the AQI table.

Air Quality Index calculations

The AQI is calculated using the following calculation:


From the calculation, a pollutant with an index value of 100 is at a concentration equal to an environmental standard level.

A site AQI is the highest AQI of any pollutant. A daily AQI is the highest site AQI recorded in a 24-hour period.

Air Quality Index and health risks

Each category in the AQI reflects a different level of health risk. Please see the table below for more information.

Description Air Quality Index Description of Potential Health Risks
Very Good
0-33 Air quality is considered good, and air pollution poses little or no risk.
34-66 Air quality is considered good, and air pollution poses little or no risk.
67-99 Air quality is acceptable. However, there may be a health concern for very sensitive people.
100-149 The air quality is unhealthy for sensitive groups, such as people with lung disease or heart disease. The general population is not likely to be affected.
Very Poor
150-199 Everyone may begin to experience health effects, especially those from sensitive groups.
200+ Everyone may experience health effects. In Canberra, the AQI only reaches this level during major bushfires or dust storms.


Page last updated on: 18 Oct 2018