Air quality categories
Air quality categories are used to make it easier to interpret air quality data by reducing the complexity associated with different pollutant concentration units and air quality guideline values.
Each air quality measurement from a monitoring station is assigned an air quality category rating based on comparison of the measurement value against the relevant air quality guideline. Five colour-coded air quality categories are used, being 'Good' (green), 'Fair' (yellow), 'Poor' (orange), 'Very Poor' (red) or 'Extremely Poor' (dark red). Values greater than the air quality guideline will be appear as ‘Poor’, ‘Very Poor’ or ‘Extremely Poor’.
- Good
- Fair
- Poor
- Very Poor
- Extremely Poor
- Not available
Each air quality category has associated health action level advice to assist you to understand how current pollutant levels might affect your health and general guidance on recommended preventative actions to take. At present this advice relates particularly to smoke and dust exposure (the most common causes of poor air quality in Queensland). Also, air quality guidelines for total suspended particles (TSP) and visibility relate to the aesthetic environment (dust nuisance or visibility loss), not human health.
Go to the live air data page to check the air quality categories, available every hour for South East Queensland, Toowoomba, Maryborough, Gladstone, Central Queensland, Mackay, Ayr, Townsville, Cairns and Mount Isa.
Go to the Smoke and dust health action levels page to view sensor data.
Defining the air quality categories
The tables below show the measurement ranges for each of the five air quality categories for individual pollutants, the averaging times for each pollutant, and the National Environment Protection (Ambient Air Quality) Measure (Air NEPM) standards, Environmental Protection (Air) Policy (Air EPP) objectives or hourly guidelines used to define these category ranges. The breakpoint between the ‘Fair’ and ‘Poor’ categories is the relevant air quality guideline value.
The 1-hour, 8-hour and 24-hour averaging times are for the most recent periods.
Air quality category ranges
| Air pollutant | Averaging period | Units | Guideline | GOOD | FAIR | POOR | VERY POOR | EXTREMELY POOR |
|---|---|---|---|---|---|---|---|---|
| Ozone O3 | 1 hour | ppm | 0.100 | 0.000 to 0.067 | 0.068 to 0.100 | 0.101 to 0.150 | 0.151 to 0.200 | 0.201 and above |
| 8 hour | ppm | 0.065 | 0.000 to 0.043 | 0.044 to 0.065 | 0.066 to 0.097 | 0.098 to 0.130 | 0.131 and above | |
| Nitrogen dioxide NO2 | 1 hour | ppm | 0.080 | 0.000 to 0.053 | 0.054 to 0.080 | 0.081 to 0.120 | 0.121 to 0.160 | 0.161 and above |
| 8 hour | ppm | 9.0 | 0.0 to 6.0 | 6.1 to 9.0 | 9.1 to 13.5 | 13.6 to 18.0 | 18.1 and above | |
| Sulfur dioxide SO2 | 1 hour | ppm | 0.075 | 0.000 to 0.050 | 0.051 to 0.0.75 | 0.076 to 0.113 | 0.114 to 0.150 | 0.151 and above |
| Particulate matter < 10µm PM10 | 1 hour | µg/m3 | 100 | 0.0 to 50.0 | 50.1 to 100.0 | 100.1 to 200.0 | 200.1 to 600.0 | 600.1 and above |
| 24 hour | µg/m3 | 50 | 0.0 to 25.0 | 25.1 to 50.0 | 50.1 to 100.0 | 100.1 to 300.0 | 300.1 and above | |
| Particulate matter < 2.5 µm PM2.5 | 1 hour | µg/m3 | 25 | 0.0 to 12.5 | 12.6 to 25.0 | 25.1 to 50.0 | 50.1 to 150.0 | 150.1 and above |
| 24 hour | µg/m3 | 20 | 0.0 to 10.0 | 10.0 to 20.0 | 20.1 to 40.0 | 40.1 to 120.0 | 120.1 and above | |
| TSP | 1 hour | µg/m3 | 250 | 0.0 to 125.0 | 125.1 to 250.0 | 250.1 to 500.0 | 500.1 to 1500.0 | 1500.1 and above |
| 24 hour | µg/m3 | 80 | 0.0 to 40.0 | 40.1 to 80.0 | 80.1 to 160.0 | 160.1 to 480.0 | 480.1 and above | |
| Visibility | 1 hour | Mm-1 | 235 | 0 to 118 | 118 to 235 | 236 to 470 | 471 to 1410 | 1411 and above |
Notes:
- For the relevant guideline value source, refer to the following tables
- ppm: parts per million
- µg/m3: micrograms per cubic metre
Air NEPM standards
Air NEPM standards are set to minimise the risk of adverse health impacts from exposure to air pollution. Air NEPM standards cover those pollutants typically used to assess ambient air quality.
| Pollutant | Air NEPM standard | Averaging time |
|---|---|---|
| Ozone | 0.065ppm | 8 hour |
| Nitrogen dioxide | 0.08ppm | 1 hour |
| Sulfur dioxide | 0.075ppm | 1 hour |
| Carbon monoxide | 9.0ppm | 8 hours |
| PM10 | 50µg/m3 | 24 hours |
| PM2.5 | 20µg/m3 | 24 hours |
Notes:
- ppm: parts per million
- µg/m3: micrograms per cubic metre
Air EPP objectives
In addition to adoption of the above Air NEPM standards for protection of human health, the Air EPP sets additional air quality objectives covering a range of environmental values, including human health and wellbeing, protecting the health and biodiversity of ecosystems, protecting the aesthetics of the environment, and protecting agricultural use of the environment.
The Air EPP visibility-reducing particles objective, designed to protect good visibility, is 20km, which means you would be able to see clearly for at least 20km.
| Pollutant | Air EPP objective | Averaging time |
|---|---|---|
| Visibility-reducing particles | 20km | 1 hour |
This goal is related to a light scattering coefficient value measured using a nephelometer. The degree of scattering is inversely proportional to the visibility. A scattering coefficient value of 235Mm-1 (235 inverse megametres) or less is equivalent to a visibility of 20km or more.
Hourly particle guidelines
| Pollutant | Guideline | Averaging time |
|---|---|---|
| Ozone | 0.100ppm # | 1 hour |
| PM10 | 100µg/m3 † | 1 hour |
| PM2.5 | 25µg/m3 ‡ | 1 hour |
| TSP | 250µg/m3 * | 1 hour |
Queensland reports hourly averages for ozone, PM2.5, PM10 and TSP (instead of an 8-hour or 24 hour running average) to provide guidance on what health protection actions to take in response to peak (hourly average) concentrations of these pollutants in the air.
Notes:
- ppm: parts per million
- µg/m3: micrograms per cubic metre
- # Air EPP hourly objective previously in force until August 2024 when replaced by the current 8-hour objective
- † interim hourly guideline adopted by the majority of Australian jurisdictions pending development of public health advice for PM10 by the Environmental Health Standing Committee (enHealth)
- ‡ enHealth guidance for public health agencies managing prolonged smoke events from landscape fires
- * Good practice guide for assessing and managing dust.
Related information
- View the current air quality in Queensland and current smoke and dust health action levels, with hourly updates from the statewide monitoring network.
- Watch the video to learn more about Queensland’s air quality monitoring network including how airborne particles, weather and pollution events can influence air quality.