Air Quality Health Index classroom kit, grades 5 and 6, environment: chapter 9


D. Air Quality Health Index

One window opened to get fresh air

Since people cannot necessarily see poor air quality, Environment Canada and Health Canada created an index to help Canadians make decisions about exposure to air pollution. This is called the Air Quality Health Index (AQHI).

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

The AQHI includes three (3) pollutants that can be in the air in urban or rural areas at any time of year:

  • Particulate matter (PM2.5),
  • Ground-level ozone (O3), and
  • Nitrogen dioxide (NO2).

How to use the AQHI

Look at the number and colour of the AQHI in the daily forecast on Environment Canada’s weather website. It gives hourly AQHI readings and maximum forecasted values for today, tonight, and tomorrow.

The AQHI goes from 1 to 10. The higher the number, the greater the health risk from air pollution (e.g. Low, Moderate, High, or Very High Health Risk). It is helpful because it tells Canadians if the current air quality is ideal for outdoor activities or if they need to consider reducing the intensity of these outdoor activities. It even has direct health information for children and other groups at risk. By using the AQHI, you can protect your health, have an active lifestyle and reduce air pollution - all at the same time! After all, the best way not to be exposed to air pollution is not to make air pollution.

1 to 10+ graduated colored scale (from pale blue to red)
Health Risk Messages
Health Risk AQHI Health Messages
  At Risk Population General Population
Low 1-3 Enjoy your usual outdoor activities. Ideal air quality for outdoor activities.
Moderate 4-6 Consider reducing or rescheduling strenuous activities outdoors if you are experiencing symptoms. No need to modify your usual outdoor activities unless you experience symptoms such as coughing or throat irritation.
High 7-10 Reduce or reschedule strenuous activities outdoors. Children and the elderly should also take it easy. Consider reducing or rescheduling strenuous activities outdoors if you experience symptoms such as coughing and throat irritation.
Very High Above 10 Avoid strenuous activities outdoors. Children and the elderly should also avoid outdoor physical exertion. Reduce or reschedule strenuous activities outdoors, especially if you experience symptoms such as coughing and throat irritation.

More information about the AQHI is available online.

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  • Why are children considered an at-risk group?
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