What do the air quality categories mean?

In 2021, the AirRater categories were updated to be compatible with a new Australian system.

In November 2020, the Commonwealth Environmental Health Standing Committee (enHealth) agreed that all States and Territories would introduce hourly average air quality data for particles in addition to the traditional 24-hour averages that are the basis of daily air quality standards. This makes the states more easily comparable to one another, and makes it easier to understand air pollution levels for wide-scale, multi-state extreme events, such as we saw in summer 2019-20.

AirRater displays air quality readings in either ‘near real-time’ (almost instant) or as an ‘hourly average’ (the average of the reading in the previous hour). This is a reading of particulate matter, or PM, measured as PM2.5 (where 2.5 is the size in microns, or µg, of the particulate matter) PM2.5 readings are measured per cubic metre, giving us units of µg/m3. The higher the PM2.5 reading, the worse the air quality.

What are AirRater’s air quality categories?          

Air pollution (PM2.5  µg/m3)AirRater (from 2021)New enHealthPrevious AirRater  
0 to 9GoodGoodGood
10 to 24Fairly goodGoodFair
25 to 49Fairly poorFairPoor
50 to 99PoorPoorPoor
100 to 299Very poorVery poorVery poor (to 249)
300+Extremely poorExtremely poorTerrible (250+)

Why are AirRater’s new air quality categories different to the enHealth air quality categories?

AirRater supports people sensitive to air pollution to manage their health, both through day-to-day changes and during rare and extreme smoke events.

People who use AirRater have told us that they value having a heads up when air pollution starts increasing above usual background conditions, because many people experience symptoms well before air quality becomes obviously poor.

The AirRater system is useful for people who experience seasonally poor air quality which might not have extreme spikes in pollution but still has serious impacts on the health of some people. This includes, for example, areas affected by winter woodsmoke.

In contrast, the new enHealth air quality categories are designed for consistent communication during periods of very severe air pollution, especially during events like bushfires or dust storms.

To ensure national consistency of air quality information during extreme air pollution events, the AirRater categories for PM2.5 concentrations above 50 µg/m3 are identical to the new enHealth system.