The air quality index (AQI) is an index for reporting daily and hourly air quality. It is an indication of how clean or polluted the air is in areas across NSW.

The AQI is a quick and easy tool to inform you about:
  • Air pollution levels at your nearest monitoring site or region
  • Specific information for people more at risk from exposure to short-term air pollution
  • Simple steps to take to protect yourself

The AQI does not provide guidance on the effects of long-term exposure to air pollution.

The NSW Office of Environment and Heritage (OEH) is responsible for air quality monitoring in NSW and issuing the AQI. Check today’s air Quality Index at: 

What does the air quality index mean?

When you look at the AQI at your nearest monitoring site or in you region, you will see the display of a colour depending on the air quality measured. The meanings of the different colours are explained in the table below. The AQI will help you understand the current level of air quality and provide information on how to reduce your risk of exposure to air pollution if necessary
AQI What action should people take?
Enjoy activities
Enjoy activities
People unusually sensitive to air pollution:
Plan strenuous outdoor activities when air quality is better
Sensitive Groups: Cut back or reschedule strenuous outdoor activities
Sensitive groups: Avoid strenuous outdoor activities
Everyone: Cut back or reschedule strenuous outdoor activities
Sensitive groups: Avoid all outdoor physical activities
Everyone: Significantly cut back on outdoor physical activities

Details on susceptible groups can be found in the section on ‘Who is affected by air pollution’.

Each colour category in the AQI corresponds to a different level of health risk:

Very Good and Good: 
  • AQI value 0 - 66
  • Air quality is considered good, and air pollution poses little or no risk
  • AQI value 67 – 99
  • Air quality is acceptable. However, there may be a health concern for very susceptible people.
  • AQI value 100 – 149
  • Air quality could be a problem for susceptible people. For example, people with lung disease are at greater risk from exposure to ozone, while people with either lung disease or heart disease are at greater risk from exposure to particle pollution. The general population is not likely to be affected when the AQI is in this range.
Very Poor:
  • AQI value 150 – 200
  • Everyone may begin to experience health effects. People from susceptible groups may experience more serious health effects.
  • AQI value > 200
  • Everyone may experience more serious health effects. In Sydney, the AQI only reaches this level during major bushfires or dust storms.

What is an air pollution health alert?

Every day at 4pm, the NSW Office of Environment and Heritage (OEH) issues a forecast for the next day’s air quality index. If the predicted AQI is 100 or more (poor, very poor, or hazardous) an air pollution health alert will be issued.
Information provided in air pollution health alerts: 
  • Poor AQI: targeting information to the groups known to be sensitive to that type of pollution. The alert provides advice to watch for symptoms, have reliever medicine nearby, and seek medical advice if symptoms get worse even after using reliever medication and resting. The alert also states whether remaining indoors will help to reduce exposure.
  • Very poor or hazardous AQI: targeting everyone. Advice for sensitive groups as in poor AQI, but additionally it includes advice on staying indoors and limiting exercise.

You can subscribe to air pollution health alerts via the following website: 

To learn more about how to best avoid symptoms from exposure to air pollution, visit our section ‘Simple steps to protect your health’. To learn more about air quality index, please see our air quality fact sheet section.