Outdoor Air Pollution
Calculating lifetime excess cancer risk requires an estimate of intake and a cancer potency factor. No published cancer potency factors for inhalation of particulate air pollution are available from Health Canada, the California Office of Environmental Health Hazard Assessment (OEHHA), or the US Environmental Protection Agency (US EPA). An estimate of lifetime excess cancer risk for inhalation of diesel engine exhaust, which is a source of particulate air pollution, is available.
Particulates 2.5 µm in diameter or less (PM2.5) are most often associated with adverse health effects. Particles of this size can be inhaled deeply into the lungs and a wide range of known or suspected carcinogens may be adhered to them. PM2.5 is measured in outdoor air by National Air Pollution Surveillance monitors, and several Canadian studies have measured levels in indoor air.
Comparison of Measured Concentration of PM2.5 in Outdoor and Indoor Air in Canada
Provincial Tables & Maps
|Maps||Provincial Estimates||Predicting Concentrations|
This map shows predicted levels of PM2.5in outdoor air at residential locations in Canada in 2011.
Scroll down for provincial and territorial maps.
New Brunswick, Prince Edward Island, Nova Scotia
Newfoundland and Labrador
Yukon, Northwest Territories, Nunavut
The average concentration of PM2.5 measured in outdoor air in 2011 was 6.9 µg/m3, but concentrations of PM2.5 can be higher or lower than average in many locations. We used a model to predict annual average concentrations of PM2.5 in outdoor air at residential locations for the year 2011 in order to calculate the the number of people in each exposure level by province or territory.
The tables below show provincial populations by concentration levels (either annual average or number of times above/below the national average).
Concentrations of fine particulates (PM2.5) in outdoor air were predicted for residential locations in 2011 using levels measured at National Air Pollution Surveillance (NAPS) monitors and estimates of concentrations from known emitters. Residential locations are represented by the geographic coordinates for all street blocks in Canada in 2011, as provided by Statistics Canada.
Setting the Background Level
The background concentration is assigned using measured levels from National Air Pollution Surveillance (NAPS) monitors using the following rules:
Identifying Dispersion Gradients for Roads, Rails, Large Industries and Airports
1. Smargiassi A, Baldwin M, Pilger C, Dugandzic R, Brauer M. 2005. Small-scale spatial variability of particle concentrations and traffic levels in Montreal: a pilot study. Sci Total Environ 338(3):243-251.
2. Beckerman B, Jerrett M, Brook JR, Verma DK, Arain MA, Finkelstein MM. (2008). Correlation of nitrogen dioxide with other traffic pollutants near a major expressway. Atmos Environ 42(2):275-290.
3. Hitchins J, Morawska L, Wolff R, Gilbert D. 2000. Concentrations of submicrometre particles from vehicle emissions near a major road. Atmos Environ 34(1):51-59.
4. Roorda-Knape MC, Janssen NAH, De Hartog JJ, Van Vliet PHN, Harssema H, Brunekreef B. 1998. Air pollution from traffic in city districts near major motorways. Atmos Environ 32(11):1921-1930.
5. Tiitta P, RRaunemma T, Tissari J, Yli-Tuomi T, Leskinen A, Kikkonen J, et al. 2002. Measurements and modeling of PM2.5 concentrations near a major road in Kuopio, Finland. Atmos Environ 36(25):4057-4068.
Applying the Dispersion Gradients to Residential Locations
Check here periodically for information on identified trends in measured levels or factors related to exposure, if available.
|Outdoor Air||Indoor Air|
We assume PM2.5 is present at these levels in all outdoor air, although concentrations may vary from one location to another. Maps of estimated concentrations above and below the average level reported here are provided in the Provincial Tables and Maps section.
We assume PM2.5 is present at these levels in all indoor air, although concentrations may vary from one location to another.
Allen R.W., Leckie S., Millar G., Brauer M. 2009. The impact of woode stove technology upgrades on indoor residential air quality. Atmospheric Environment, 43(37) : 5908-5915.
Brown K.W., Sarnat J.A., Suh H.H., Coull B.A., Spengler J.D., Koutrakis P. 2008. Ambient site, home outdoor and home indoor particulate concentrations as proxies of personal exposures. Journal of Environmental Monitoring, 10(9): 1041-1051.
Heroux M.E., Clark N., Van Ryswyk K., Mallick R., Gilbert N.L., Harrison I., Rispler K., Wang D., Anastassopoulos A., Guay M., MacNeill M., Wheeler, A. J. 2010. Predictors of Indoor Air Concentrations in Smoking and Non-Smoking Residences. International Journal of Environmental Research and Public Health, 7(8): 3080-3099.
Hystad P.W. 2007. Modeling residential fine particulate matter infiltration: implications for exposure assessment. Masters of Science Thesis, Department of Geography, University of Victoria, BC, Canada.
Kim D., Sass-Kortsak A., Purdham J.T., Dales R.E., Brook J.R. 2006. Associations between personal exposures and fixed-site ambient measurements of fine particulate matter, nitrogen dioxide, and carbon monoxide in Toronto, Canada. Journal of Exposure Science and Environmental Epidemiology, 16(2): 172-183.
Loo C.K.J., Foty R.G., Wheeler A.J., Miller D.J., Evans G., Stieb D.M., Dell S.D. 2010. Do questions reflecting indoor air pollutant exposure from a questionnaire predict direct measure of exposure in owner-occupied houses? Int. J. Environ. Res. Public Health, 7: 3270-3297.
Miller J.D., Dugandzic R., Frescura A-M, Salares V. 2007. Indoor- and outdoor-derived contaminants in urban and rural homes in Ottawa, Ontario, Canada. Journal of Air & Waste Management Association, 57(3): 297-302.
Raaschou-Nielsen O., Hermansen M.N., Loland L., Buchvald F., Pipper C.B., Sørensen M., Loft S., Bisgaard H. 2010. Long-term exposure to indoor air pollution and wheezing symptoms in infants. Indoor Air, 20: 159-167.
Wheeler A.J., Wallace L.A., Kearney J., Van Ryswyk K., You H., Kulka R., Brook J.R., Xu X. 2011. Personal, indoor, and outdoor concentrations of fine and ultrafine particles using continuous monitors in multiple residences. Aerosol Science and Technology, 45: 1078-1089.
Only publicly available data were used to determine average and maximum concentrations in outdoor and indoor air.
No systematic method for measuring data quality was possible, so we provide the following assessments of how well the data used may represent the actual Canadian average levels. Quality is rated higher when there are data from a number of Canadian monitors, or from Canadian studies that show results similar to other comparable studies. Quality is rated lower when data from few monitors or studies were available, and lowest when estimates are based on non-Canadian data. Others may rate data quality differently.