The ETS (Edmonton Transit System) Electronic Billboard at South Campus Transit Center, with Foote Field in the background. The 6:07 at the center of the billboard is the time, but the “2- Low Risk” at the bottom of the sign is the air quality.
The ETS Electronic Billboards, which can be found at all major transit centers, display lots of different information on the weather and other subjects. This includes the time (“6:07”, at the center of the billboard), and the current air quality (“2- Low Risk”, at the bottom of the billboard). Air quality, which measures how much pollution is in the air, is usually displayed on the AQHI (Air Quality Health Index) scale. The AQHI scale goes from 1-10. A low AQHI like 1 or 2 means that air quality is good, and that air pollution health risk is low. A high AQHI like 9 or 10 means air quality is bad, and that air pollution health risk is high.
Environment Canada says people should avoid exercising outside when air quality is bad. This is even more important for children, older people, and people with heart or breathing problems.
For more information about the AQHI, and to get your local AQHI forecast, see the Environment Canada website at https://www.canada.ca/en/environment-climate-change/services/air-quality-health-index.html