About the Air Quality Health Index

What is the Air Quality Health Index (AQHI)?

Kids Group

The Air Quality Health Index or "AQHI" is a scale designed to help you understand what the air quality around you means to your health.

It is a health protection tool that is designed to help you make decisions to protect your health by limiting short-term exposure to air pollution and adjusting your activity levels during increased levels of air pollution. It also provides advice on how you can improve the quality of the air you breathe.

This index pays particular attention to people who are sensitive to air pollution and provides them with advice on how to protect their health during air quality levels associated with low, moderate, high and very high health risks.

The AQHI communicates four primary things;

  1. It measures the air quality in relation to your health on a scale from 1 to 10.  The higher the number, the greater the health risk associated with the air quality.  When the amount of air pollution is very high, the number will be reported as 10+. 
  2. A category that describes the level of health risk associated with the index reading (e.g. Low, Moderate, High, or Very High Health Risk).
  3. Health messages customized to each category for both the general population and the ‘at risk’ population.
  4. Current hourly AQHI readings and maximum forecast values for today, tonight, tomorrow and the next day.

The AQHI is designed to give you this information along with some suggestions on how you might adjust your activity levels depending on your individual health risk from air pollution.  Follow this guide on how to use the AQHI.

How is the AQHI calculated?

The AQHI is calculated based on the relative risks of a combination of common air pollutants that is known to harm human health.  These pollutants are:

  • Ozone (O3) at ground level,
  • Particulate Matter (PM2.5/PM10) and
  • Nitrogen Dioxide (NO2).

What is the scale for the AQHI?

The AQHI is measured on a scale ranging from 1-10+. The AQHI index values are grouped into health risk categories as shown below. These categories help you to easily and quickly identify your level of risk.

Air Quality Health Index scale colour bar.
  • 1-3  Low health risk
  • 4-6  Moderate health risk
  • 7-10  High health risk
  • 10 +  Very high health risk

More information on the scale and the AQHI categories.

How can I find out about the air quality in my community?

At-risk Group

To find your local AQHI, visit Your Local AQHI Conditions.

If you reside outside the AQHI community areas, please contact your local public health office, Ministry of Environment, or local lung and asthma association chapters for available local resources on air quality and your health.

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