International Comparison: Urban Air Quality

• Fine particulate matter
• Ground-level ozone
• Sulphur dioxide
• Nitrogen dioxide

Fine particulate matter

International urban areas with available data are compared with major Canadian cities to provide an overview of how Canadian urban air quality ranks internationally.^[1]

The Canadian urban areas included in this comparison have populations of over 1 million.

• In 2010, Vancouver had the lowest average annual fine particulate matter (PM_2.5) concentration both in Canada and among all the cities compared.
• Edmonton^[2] was the Canadian city with the highest average annual concentration of PM_2.5 in 2010, a level comparable to Chicago’s. 

Annual average concentrations of fine particulate matter for selected Canadian and international cities, 2010

Note: The fine particulate matter (PM_2.5) indicator is based on the annual average of 24-hour daily average concentrations. Cities with populations comparable to Canadian cities (urban populations of over 1 million) and available data are included in this analysis.
Source: Environment Canada (2012) National Air Pollution Surveillance (NAPS) program; the European Environment Agency (2012) AIRBASE; the United States Environmental Protection Agency (2012) Air Quality System (AQS) Data; and the Office of Environment and Heritage, New South Wales (2012)Air Quality Data Search.

Ground-level ozone

International urban areas with available data are compared with major Canadian cities to provide an overview of how Canadian urban air quality ranks internationally.^[3]

The Canadian urban areas included in this comparison have populations of over 1 million.

• In 2010, Vancouver had the lowest annual average concentration of ground-level ozone (O₃) in Canada and had almost the lowest among the compared cities.
• Ottawa/Gatineau had the highest O₃ concentration in Canada, with levels comparable to many urban areas of larger-sized populations.

Annual average concentrations of ground-level ozone for selected Canadian and international cities, 2010

Note: The ground-level ozone (O₃) indicator is based on the annual average of the 8-hour daily maximum concentrations. Cities with populations comparable to Canadian cities (urban populations of over 1 million) and available data are included in this analysis.
Source: Environment Canada (2012) The National Air Pollution Surveillance (NAPS) program; Canadian Air and Precipitation Monitoring Network (CAPMoN); the European Environment Agency (2012) AIRBASE; the United States Environmental Protection Agency (2012) Air Quality System (AQS) Data; and the Office of Environment and Heritage, New South Wales (2012) Air Quality Data Search.

Sulphur dioxide

International urban areas with available data are compared with major Canadian cities to provide an overview of how Canadian urban air quality ranks internationally.^[4]

The Canadian urban areas included in this comparison had populations of over 1 million.

• Ottawa/Gatineau had the lowest annual average sulphur dioxide (SO₂) concentration of all cities compared.
• Montréal had the highest SO₂ concentration in Canada, with levels comparable to other urban areas with similar-sized populations.

Annual average concentrations of sulphur dioxide for selected Canadian and international cities, 2010

Note: The sulphur dioxide (SO₂) indicators are based on the annual average of 24-hour daily average concentrations. Cities with populations comparable to Canadian cities (urban populations of over 1 million) with available data are included in this analysis.
Source: Environment Canada (2012) National Air Pollution Surveillance (NAPS) program; the European Environment Agency (2012) AIRBASE; the United States Environmental Protection Agency (2012) Air Quality System (AQS) Data; Andand the Office of Environment and Heritage, New South Wales (2012) Air Quality Data Search.

Nitrogen dioxide

International urban areas with available data are compared with major Canadian cities to provide an overview of how Canadian urban air quality ranks internationally.^[5]

The Canadian urban areas included in this comparison had populations of over 1 million.

• Ottawa/Gatineau was second behind Sydney, Australia for the lowest nitrogen dixoide (NO₂) concentration in all cities compared.
• Calgary had the highest NO₂ concentration in Canada, a level comparable to Phoenix, Arizona.

Annual average concentrations of nitrogen dioxide for selected Canadian and international cities, 2010

Note: The nitrogen dioxide (NO₂) indicators are based on the annual average of 24-hour daily average concentrations. Cities with populations comparable to Canadian cities (urban populations of over 1 million) with available data are included in this analysis.
Source: Environment Canada (2012) National Air Pollution Surveillance (NAPS) program; the European Environment Agency (2012) AIRBASE; the United States Environmental Protection Agency (2012) Air Quality System (AQS) Data; and the Office of Environment and Heritage, New South Wales (2012)Air Quality Data Search.

Related indicators

• Ambient Levels of Fine Particulate Matter
• Ambient Levels of Ground-Level Ozone
• Ambient Levels of Sulphur Dioxide
• Ambient Levels of Nitrogen Dioxide
• Ambient Levels of Volatile Organic Compounds

Other information

• Impacts of Air Pollution
• Environment Canada – Smog
• Outdoor air pollution in cities database (World Health Organization). This dataset includes concentrations of PM_2.5 and PM₁₀ by city and by country for 1100 cities in 91 countries. It reports that Canada ranks third for the lowest concentration of PM₁₀ and of PM_2.5. It also states that 20 Canadian cities are found in the top 25 for the lowest concentrations of PM₁₀ and of PM_2.5.

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[1] Caution must be taken when comparing air quality from different cities. Beyond population, other factors such as climate, geography, local emissions and transboundary pollution influence air pollution. Technical and methodological factors such as the type of monitoring equipment used, station location, and number of stations for one city can also influence the results of the comparison.

[2] Fine particulate matter (PM_2.5) monitors in Edmonton, Calgary and Montréal are based on newer technologies than those in other cities in Canada. These newer methods measure a portion (semi-volatile) of the PM_2.5 mass that was not captured by the older instruments. 

[3] Caution must be taken when comparing air quality from different cities. Beyond population, other factors such as climate, geography, local emissions and transboundary pollution influence air pollution. Technical and methodological factors such as the type of monitoring equipment used, station location and number of stations for one city can also influence the results of the comparison.

[4] Caution must be taken when comparing air quality from different cities. Beyond population, other factors such as climate, geography, local emissions and transboundary pollution influence air pollution. Technical and methodological factors such as the type of monitoring equipment used, station location, and number of stations for one city can also influence the results of the comparison.

[5] Caution must be taken when comparing air quality from different cities. Beyond population, other factors such as climate, geography, local emissions and transboundary pollution influence air pollution. Technical and methodological factors such as the type of monitoring equipment used, station location, and number of stations for one city can also influence the results of the comparison.