Air Quality - Ozone (O3)

Edmonton’s air quality is assessed continuously through air quality monitoring stations and measures yearly average concentrations. Monitoring air quality and climate pollutants helps us understand and reduce negative impacts on people, buildings, infrastructure and the natural environment.

Ground-level ozone (O3) is a colourless, odourless gas that contributes to smog. Ozone is formed through a chemical reaction, when nitrogen oxides (NOx) and volatile organic compounds (VOCs)  mix with sunlight. Ozone is also a short-lived climate pollutant and contributes to climate change.

Some air pollutant levels decreased in the Edmonton Region in 2020, likely due to reduced emissions from fewer transportation trips during the pandemic. These reductions were not expected to be sustained as transportation patterns returned to pre-pandemic levels, and starting in 2021, some air pollutant levels increased. 

The provincial government provides an Air Quality Health Index (AQHI) that relates air quality outside to health, using a scale from 1 to 10. The lower the number, the lower the risk. The index is based on PM2.5, ozone (O3), sulphur dioxide (SO2), nitrogen dioxide (NO2) and other pollutants.