Air Quality Health Index

The Air Quality Health Index (AQHI) is a public information tool that helps Canadians protect their health on a daily basis from the negative effects of air pollution. This tool has been developed by Health Canada and Environment Canada, in collaboration with the provinces and key health and environment stakeholders.

In British Columbia, the Air Quality Health Index is available to more than 80 per cent of the population.

What is it?

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.

The AQHI 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.

Flag scale

The Air Quality Health Index is updated several times a day and shares four primary things;

  1. A number from 1 to 10+ indicating the air quality. 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 AQHI reading (Low, Moderate, High or Very High Health Risk).
  3. Health messages customized to each category for both the general population and “at risk” population.
  4. Current AQHI readings and forecast values for later today, tonight and tomorrow.

The Air Quality Health Index is designed to give you this information in one place along with some suggestions on how you might adjust your activity levels depending on your individual health risk from air pollution.

How is a community’s AQHI calculated?

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

  • Ozone (O3) at ground level
  • Fine Particulate Matter also known as PM2.5 and PM10. These are microscopic solid or liquid particles.
  • Nitrogen Dioxide (NO2)

What is the scale for the AQHI?

The Air Quality Health Index is measured on a scale ranging from 1 to 10+. The AQHI values are also grouped into health risk categories, shown below. These categories help people identify risk levels.

  • 1-3 Low health risk
  • 4-6 Moderate health risk
  • 7-10 High health risk
  • 10+ Very high health risk

Each day, your school’s air quality flag page will tell you the AQHI reading for your location. To check the AQHI in your community outside of school, visit