Outdoor Air Pollution Environmental Exposures

Outdoor Air Pollution Environmental Exposures


Canadians are exposed to fine and ultrafine particles by breathing outdoor air containing emissions from any combustion source, including industrial processes, gasoline and diesel engine exhausts, fireplaces, furnaces, prescribed burning for forestry and agricultural purposes, and naturally-caused wildfires.[1]


CAREX Canada estimates of potential lifetime excess cancer risk for outdoor air pollution are unavailable at this time. According to the Canadian Population Attributable Risk of Cancer (ComPARe) study, 6.9%, or 1,700 lung cancer cases were due to exposure to PM2.5 in outdoor air in 2015[2]. The study estimates that over 3,000 lung cancer cases could be prevented between 2016 and 2042 if declining trends in PM2.5 continue.

Particulates in outdoor air are monitored by the National Air Pollution Surveillance (NAPS) network. In 2013, the annual average levels of PM2.5 was 7.3 µg/m3, and the annual peak 24-hour concentration was 20 µg/m3. Both of these values remained below the 2015 Canada Wide Standard.[1] Between 1985 and 2012, daily averages for PM10 remained below 10 µg/m3 in 44 of 49 different sites located across Canada. Higher levels of PM10 were found in large urban areas and near roadways.[3]

A search of Environment Canada’s National Pollutant Release Inventory (NPRI) yielded the following results on current potential for exposure to outdoor air pollution in Canada:


NPRI 2015[4]
Substance name: ‘PM – Total Particulate Matter’
‘PM10 – Particulate Matter ≤ 10 microns’
‘PM2.5 – Particulate Matter ≤ 2.5 microns’
All amounts released into environment (on-site release)
PM Type# of facilitiesQuantityIndustry
Total PM1,188327,251 tResource extraction and processing, manufacturing
PM103,142131,212 t
PM2.53,52148,780 t
t = tonne


This map shows predicted levels of PM2.5 in outdoor air at residential locations by health region in Canada as of 2011. The average (median) concentration of PM2.5 within the health regions measured in outdoor air for 2011 was 6.630 µg/m3, but concentrations of PM2.5 can be higher or lower than average in many locations. Concentrations should be compared to the applicable jurisdictional guidelines and standards for ambient air quality based on chronic, carcinogenic effects (or non-carcinogenic effects, if cancer is not the point of interest).

Predicted annual average particulate matter (PM2.5) concentrations in outdoor air at residential locations by health region, 2011

*Measured at the National Air Pollution Surveillance (NAPS) monitors in 2011
Methods and Data

Our Environmental Approach page includes documentation on our mapping methods.

Data sources and data quality for outdoor air pollution can be found in the PDF below.

Supplemental data – Outdoor Air Pollution [PDF]


1. Environment and Climate Change Canada. Ambient Levels of Fine Particulate Matter (2016)
2. Gogna P, Narain TA, O’Sullivan DE, Villeneuve PJ, Demers PA, Hystad P, Brenner DR, Friedenreich CM, King WD; ComPARe Study Team. “Estimates of the current and future burden of lung cancer attributable to PM2.5 in Canada“. Prev Med 2019; 122:91-99.
4. Environment and Climate Change Canada. National Pollutant Release Inventory (NPRI) Facility Search (Substance name: ‘Particulate matter’)

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