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 indices, available every hour for South East Queensland, South West Queensland, Gladstone, Mackay, Moranbah, Bowen, Townsville 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 periodUnitsGuidelineGOODFAIRPOOR VERY POOR EXTREMELY POOR
1 hour ppm 0.100 <0.070 0.070 - 0.100 0.101 - 0.150 0.151 - 0.200 0.201 and above
 8 hourppm0.065<0.0430.043-0.0650.066-0.0970.098-0.1300.131 and above
Nitrogen dioxide
1 hour ppm 0.080 <0.053

0.053 - 0.080

0.081 - 0.120 0.121-0.160

0.161 and above

Carbon monoxide

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
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
< 10 µm 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


  • 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


  • 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
Ozone0.100ppm1 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 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 Air EPP objective 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.