Air Quality - PM2.5

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.

Particulate matter (PM) is made up of airborne particles in solid or liquid form and is a major component of smog. There are two types of PM: primary and secondary. 

Primary PM is emitted directly into the atmosphere from sources like smokestacks, exhaust pipes, wind-blown soils or vehicle traffic on a dirt road. Secondary PM is formed through chemical and physical reactions involving sulphur oxides (SOx) and nitrogen oxides (NOx) and can appear as smog, acid rain, industrial emissions and in the smoke from wildfires.

Particulate matter exists in different sizes but the most concerning to human health are those with a diameter of less than 2.5 micrometres (PM2.5).

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 standards are part of a national Air Quality Management System to better protect human health and the environment. In October, 2012, the Canadian Council of Ministers of the Environment (CCME) agreed to the new CAAQS for fine particulate matter (PM2.5).  Levels are represented by the colours green, yellow, orange, and red, indicating lowest to highest levels of concentration.

The levels apply the 3-year average of the annual average of the daily concentrations.

The Alberta 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.

The Air Quality Health Index also enables a breakdown of emission type by station. The Edmonton region has in some years exceeded air quality standards and is currently in the “Orange” management level of the Canadian Ambient Air Quality Standards for particulate matter. Being at an Orange management level means that the airzone needs to improve air quality using early and ongoing actions for continuous improvement. This response is led by the Provincial Government, and the City of Edmonton works in collaboration with other partners in the airshed to develop and implement these responses.