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 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 Air NEPM standard, Air EPP objectives or hourly particle 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 | <0.067 | 0.067 - 0.100 | 0.101 - 0.150 | 0.151 - 0.200 | 0.201 and above |
| 8 hour | ppm | 0.065 | <0.043 | 0.043-0.065 | 0.066-0.097 | 0.098-0.130 | 0.131 and above | |
| Nitrogen dioxide NO2 | 1 hour | ppm | 0.080 | <0.053 | 0.053 - 0.080 | 0.081 - 0.120 | 0.121-0.160 | 0.161 and above |
| 8 hour | ppm | 9.0 | <6.0 | 6.0 - 9.0 | 9.1 - 13.5 | 13.6-18.0 | 18.1 and above | |
| Sulfur dioxide SO2 | 1 hour | ppm | 0.100 | <0.067 | 0.067 - 0.100 | 0.101 - 0.150 | 0.151-0.200 | 0.201 and above |
| Particulate matter < 10µm PM10 | 1 hour | µg/m3 | 100 | <50 | 50 - 100 | 100.1 - 200 | 200.1-600 | 600.1 and above |
| 24 hour | µg/m3 | 50 | <25 | 25 - 50 | 50.1 - 100 | 100.1-300 | 300.1 and above | |
| Particulate matter < 2.5 µm PM2.5 | 1 hour | µg/m3 | 50 | <25 | 25 - 50 | 50.1 - 100 | 100.1-300 | 300.1 and above |
| 24 hour | µg/m3 | 25 | <12.5 | 12.5 - 25 | 25.1 - 50 | 50.1-150 | 150.1 and above | |
| TSP | 1 hour | µg/m3 | 250 | <125 | 125 - 250 | 250.1 - 500 | 500.1-1500 | 1500.1 and above |
| 24 hour | µg/m3 | 80 | <40 | 40 - 80 | 80.1 - 160 | 160.1.-480 | 480.1 and above | |
| Visibility | 1 hour | Mm-1 | 235 | <118 | 118 - 235 | 236 - 470 | 471-1410 | 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 | 0.10ppm | 1 hour |
| Carbon monoxide | 9ppm | 8 hours |
| PM10 | 50µg/m3 | 24 hours |
| PM2.5 | 25µg/m3 | 24 hours |
Notes:
- ppm: parts per million
- µg/m3: micrograms per cubic metre
Air EPP objectives
The Air EPP sets 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.
| Pollutant | Air EPP objective | Averaging time |
|---|---|---|
| Ozone | 0.100ppm | 1 hour |
| Visibility-reducing particles | 20km | 1 hour |
The EPP Air 1 hour objective for ozone is used to provide guidance on health actions to take in response to peak (hourly) concentrations of ozone in the air.
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.
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 |
|---|---|---|
| PM10 | 100µg/m3 † | 1 hour |
| PM2.5 | 50 µg/m3 ‡ | 1 hour |
| TSP | 250µg/m3* | 1 hour |
Queensland is now reporting hourly averages for PM2.5, PM10 and TSP (instead of a 24 hour running average) to provide guidance on what health actions to take, based on the hourly average concentrations of particles in the air.
Notes:
- µg/m3: micrograms per cubic metre
- † interim guideline set at twice the enHealth breakpoint between the ‘Fair’ and ’Poor’ categories for PM2.5
- ‡ enHealth guidance for public health agencies managing prolonged smoke events from landscape fires
- * Good practice guide for assessing and managing dust.