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International Comparison of Urban Air Quality Indicators Data

Annual average concentrations of fine particulate matter for selected Canadian and international urban areas, 2011
Urban AreaAverage ambient concentration
(micrograms per cubic metre)
Urban area population
Sofia28.61 162 898
Warsaw28.02 726 829
Rome22.23 695 148
Brussels21.31 885 319
Lyon20.11 226 249
Berlin19.95 055 116
Barcelona19.04 440 629
Amsterdam17.91 482 287
Paris17.211 797 021
Hamburg16.73 209 759
Prague16.32 156 097
London15.07 668 300
Chicago14.009 522 434
Pittsburgh14.02 360 733
Madrid13.36 369 162
Houston13.26 177 035
Phoenix13.24 329 534
Milwaukee11.91 566 981
Washington11.85 860 342
Calgary10.91 309 200
Boston10.34 640 802
Montréal10.13 957 700
Edmonton8.61 230 100
Seattle8.53 552 157
Stockholm7.82 054 343
Denver7.62 645 209
Toronto6.55 941 500
Ottawa/Gatineau5.81 273 300
Sydney5.54 667 283
Vancouver4.12 363 700

Note: The fine particulate matter (PM2.5) indicator is based on the annual average of 24-hour daily average concentrations. International urban areas with populations comparable to Canadian urban areas (urban populations of over 1 million) and available data are included in this analysis.

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Annual average concentrations of ozone for selected Canadian and international urban areas, 2011
Urban AreaAverage ambient concentration
(parts per billion)
Urban area population
Denver51.12 645 209
Phoenix47.64 329 534
Pittsburgh40.22 360 733
Washington40.05 860 342
Athens39.94 113 979
Sofia39.51 162 898
Houston39.36 177 035
Chicago38.99 522 434
Madrid38.36 369 162
Milwaukee36.71 566 981
Rome36.23 695 148
Berlin34.95 055 116
Boston34.64 640 802
Stockholm34.52 054 343
Barcelona34.04 440 629
Lyon33.71 226 249
Toronto33.55 941 500
Calgary33.51 309 200
Prague33.52 156 097
Edmonton33.31 230 100
Warsaw33.22 726 829
Hamburg32.73 209 759
Ottawa/Gatineau32.71 273 300
Zürich31.71 160 687
Paris31.511 797 021
Montréal30.33 957 700
London28.37 668 300
Seattle28.23 552 157
Brussels27.51 885 319
Amsterdam27.11 482 287
Vancouver26.62 363 700
Bucharest17.21 942 254

Note: The ozone (O3) indicator is based on the annual average of the 8-hour daily maximum concentrations. International urban areas with populations comparable to Canadian urban areas (urban populations of over 1 million) and available data are included in this analysis.

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Annual average concentrations of sulphur dioxide for selected Canadian and international urban areas, 2011
Urban AreaAverage ambient concentration
(parts per billion)
Urban area population
Sofia5.71 162 898
Pittsburgh4.44 329 534
Bucharest4.11 942 254
Athens3.54 113 979
Washington2.65 860 342
Warsaw2.62 726 829
Chicago2.29 522 434
Hamburg1.93 209 759
Boston1.84 640 802
Prague1.42 156 097
Milwaukee1.41 566 981
Madrid1.46 369 162
Toronto1.45 941 500
Brussels1.21 885 319
London1.27 668 300
Houston1.26 177 035
Vancouver1.12 363 700
Montréal1.13 957 700
Seattle1.13 552 157
Edmonton1.11 230 100
Berlin1.05 055 116
Barcelona1.04 440 629
Lyon0.91 226 249
Zürich0.81 160 687
Paris0.511 797 021
Rome0.43 695 148
Ottawa/Gatineau0.21 273 300
Sydney0.04 667 283

Note: The sulphur dioxide (SO2) indicators are based on the annual average of 24-hour daily average concentrations. International urban areas with populations comparable to Canadian urban areas (urban populations of over 1 million) with available data are included in this analysis.

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Annual average concentrations of nitrogen dioxide for selected Canadian and international urban areas, 2011
Urban AreaAverage ambient concentration
(parts per billion)
Urban area population
Rome28.43 695 148
Barcelona22.04 440 629
London21.87 668 300
Paris21.011 797 021
Lyon20.01 226 249
Madrid19.86 369 162
Chicago19.79 522 434
Brussels19.51 885 319
Denver19.32 645 209
Amsterdam19.31 482 287
Athens19.34 113 979
Zürich18.51 160 687
Phoenix17.94 329 534
Sofia17.41 162 898
Stockholm17.42 054 343
Prague17.12 156 097
Bucharest16.31 942 254
Toronto15.05 941 500
Berlin15.05 055 116
Boston14.24 640 802
Edmonton14.11 230 100
Calgary13.71 309 200
Hamburg13.33 209 759
Warsaw12.92 726 829
Washington12.85 860 342
Milwaukee11.51 566 981
Montréal11.53 957 700
Pittsburgh11.32 360 733
Vancouver10.72 363 700
Houston9.16 177 035
Sydney8.04 667 283
Ottawa/Gatineau7.11 273 300

Note: The nitrogen dioxide (NO2) indicators are based on the annual average of 24-hour daily average concentrations. International urban areas with populations comparable to Canadian urban areas (urban populations of over 1 million) with available data are included in this analysis.

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