Canada’s Air Pollutant Emissions Inventory Report 2020: chapter 2.3

2.3 Nitrogen oxides (NOx)

Approximately 1.8 Mt of NOx were released in Canada in 2018 (Table 2–5). Transportation and mobile equipment was the largest contributor, accounting for 51% (0.9 Mt) of total NOx emissions. Within this source category, heavy-duty diesel vehicles, marine transportation, and off-road diesel vehicles and equipment were the largest emitters, collectively contributing 34% (602 kt) of total NOx emissions. The oil and gas industry accounted for 27% (486 kt) of total NOx emissions in 2018, with the upstream oil and gas industry accounting for nearly all of the oil and gas industry total (470 kt). Electric power generation (utilities) contributed 7% (129 kt) of total NOx emissions, with coal-fired generation contributing 5% (92 kt) of the national total. The remaining 15% of NOx emissions were distributed across multiple sources.

From 1990 to 2018, national NOx emissions decreased by 25% (601 kt) (Figure 2–3). A significant driver of this trend was the decrease in emissions from light-duty gasoline trucks and vehicles, as a result of increasingly stringent vehicle regulations. Emissions from off-road diesel vehicles and equipment and heavy-duty diesel vehicles increased at the beginning of the time series and decreased after 2000 and 2005, respectively. Within electric power generation (utilities), coal contributed to the downward trend across the time series, with a gradual decrease in emissions from 1998 to 2018. Finally, the upstream oil and gas industry and marine transportation are the only major contributors to NOx emissions that experienced an increase in emissions across the time series. This increase is attributed to expansion and growth in the oil and gas industry and an increase in marine activity.

The most significant changes in NOx emissions from 1990 to 2018 include:

Figure 2–3: Major contributors to national NOx trends

Figure 2-3 (See long description below)
Long description for Figure 2–3

Figure 2–3 is a stacked area graph displaying the four major contributors to national NOx trends. The four contributors are the following: Heavy-Duty Diesel Vehicles, Marine Transportation, Upstream Oil and Gas Industry, and Other. The following table displays the contributions (kt) for the years 1990 to 2018.

Figure 2–3: Major contributors to national NOx trends (kt)
Sector 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018
Sector 1 - Upstream Oil and Gas Industry 311 306 325 349 380 399 413 456 470 486 429 422 421 464 396 400 404 428 439 436 432 446 442 447 460 461 454 464 470
Sector 2 - Heavy-Duty Diesel Vehicles 293 254 239 238 251 254 280 327 368 406 414 403 386 384 378 408 384 371 356 324 325 325 303 288 264 239 232 244 257
Sector 3 - Marine Transportation 140 144 148 152 156 160 165 171 176 181 187 192 196 201 206 211 210 209 208 207 206 203 201 198 196 193 192 192 191
Sector 4 - Other 1 625 1 582 1 615 1 643 1 713 1 747 1 772 1 819 1 805 1 811 1 828 1 712 1 676 1 590 1 524 1 391 1 261 1 257 1 190 1 100 1 121 1 054 969 936 905 863 818 848 850

Table 2–5: National summary of annual NOx emissions

Ore and Mineral Industries (tonnes)
Sector 1990 2000 2005 2013 2014 2015 2016 2017 2018
Sub-total 100 000 99 000 110 000 83 000 82 000 81 000 78 000 86 000 82 000
Aluminium Industry 1 600 1 300 2 000 1 300 1 100 1 100 1 200 1 200 1 200
Asphalt Paving Industry 1 200 1 100 1 200 1 000 1 200 910 890 840 840
Cement and Concrete Industry 43 000 45 000 54 000 32 000 31 000 35 000 32 000 34 000 36 000
Foundries 490 640 540 140 140 140 140 140 140
Iron and Steel Industry 19 000 16 000 13 000 11 000 12 000 11 000 11 000 11 000 11 000
Iron Ore Industry 10 000 10 000 9 800 13 000 12 000 12 000 11 000 12 000 9 900
Mineral Products Industry 1 300 560 1 100 300 310 290 300 290 240
Mining and Rock Quarrying 24 000 20 000 23 000 22 000 23 000 20 000 19 000 25 000 22 000
Non-Ferrous Mining and Smelting Industry 4 300 3 800 1 800 1 600 1 600 1 600 1 900 1 800 1 600
Oil and Gas Industry (tonnes)
Sector 1990 2000 2005 2013 2014 2015 2016 2017 2018
Sub-total 350 000 460 000 430 000 460 000 480 000 480 000 470 000 480 000 490 000
Downstream Oil and Gas Industry 35 000 30 000 31 000 18 000 17 000 17 000 17 000 17 000 16 000
Upstream Oil and Gas Industry 310 000 430 000 400 000 450 000 460 000 460 000 450 000 460 000 470 000
Electric Power Generation (Utilities) (tonnes)
Sector 1990 2000 2005 2013 2014 2015 2016 2017 2018
Sub-total 260 000 330 000 250 000 160 000 170 000 150 000 150 000 150 000 130 000
Coal 210 000 230 000 190 000 120 000 130 000 110 000 120 000 110 000 92 000
Diesel 3 100 8 300 8 500 8 600 9 200 9 900 9 100 8 900 9 800
Natural Gas 20 000 65 000 38 000 21 000 19 000 17 000 17 000 16 000 18 000
Waste Materials 45 200 88 52 94 110 220 260 200
Other (Electric Power Generation) 28 000 28 000 21 000 8 000 10 000 11 000 10 000 9 700 9 000
Manufacturing (tonnes)
Sector 1990 2000 2005 2013 2014 2015 2016 2017 2018
Sub-total 190 000 170 000 140 000 70 000 69 000 69 000 69 000 70 000 69 000
Abrasives Manufacturing 240 90 74 -* - - - - -
Bakeries 4.0 4.0 - 1.1 1.0 0.89 0.89 0.95 -
Biofuel Production - - - 33 41 18 16 18 -
Chemicals Industry 41 000 47 000 37 000 23 000 22 000 23 000 23 000 23 000 25 000
Electronics 150 160 71 - - - 0.01 - -
Food Preparation 2 400 2 900 3 300 1 700 1 700 1 800 1 700 1 900 1 900
Glass Manufacturing 7 000 7 400 6 100 920 890 920 780 780 770
Grain Industry 1 400 1 300 1 600 950 1 000 780 760 1 100 820
Metal Fabrication 5 900 9 000 1 200 370 360 470 490 420 440
Plastics Manufacturing 880 810 100 0.95 0.91 9.0 11 13 18
Pulp and Paper Industry 72 000 49 000 45 000 31 000 30 000 30 000 29 000 30 000 29 000
Textiles 120 170 110 33 33 8.2 7.8 7.8 7.7
Vehicle Manufacturing (Engines, Parts, Assembly, Painting) 2 500 3 500 1 500 630 610 650 610 600 660
Wood Products 18 000 22 000 19 000 11 000 12 000 11 000 12 000 11 000 11 000
Other (Manufacturing) 33 000 30 000 22 000 620 580 480 510 560 680
Transportation and Mobile Equipment (tonnes)
Sector 1990 2000 2005 2013 2014 2015 2016 2017 2018
Sub-total 1 400 000 1 700 000 1 400 000 1 000 000 940 000 890 000 840 000 880 000 910 000
Air Transportation 6 700 6 700 6 700 6 400 6 100 6 300 6 500 6 800 7 300
Heavy-duty Diesel Vehicles 290 000 410 000 410 000 290 000 260 000 240 000 230 000 240 000 260 000
Heavy-duty Gasoline Vehicles 60 000 82 000 60 000 44 000 37 000 35 000 37 000 37 000 38 000
Heavy-duty LPG/NG Vehicles 15 000 34 000 4 500 110 59 61 80 140 140
Light-duty Diesel Trucks 790 1 500 2 100 1 200 1 300 1 400 1 600 1 800 2 000
Light-duty Diesel Vehicles 2 200 2 200 1 200 990 940 920 860 860 830
Light-duty Gasoline Trucks 97 000 190 000 130 000 77 000 70 000 68 000 72 000 74 000 78 000
Light-duty Gasoline Vehicles 200 000 220 000 120 000 57 000 50 000 46 000 46 000 45 000 45 000
Light-duty LPG/NG Trucks 7 500 5 900 2 900 43 31 27 29 34 34
Light-duty LPG/NG Vehicles 820 740 280 1.1 0.81 0.73 0.89 1.2 1.2
Marine Transportation 140 000 190 000 210 000 200 000 200 000 190 000 190 000 190 000 190 000
Motorcycles 320 440 530 630 620 640 680 700 720
Off-road Diesel Vehicles and Equipment 330 000 360 000 280 000 190 000 170 000 170 000 130 000 140 000 150 000
Off-road Gasoline/LPG/NG Vehicles and Equipment 53 000 37 000 28 000 28 000 30 000 30 000 29 000 30 000 31 000
Rail Transportation 160 000 150 000 130 000 110 000 110 000 98 000 88 000 100 000 100 000
Tire Wear and Brake Lining -* - - - - - - - -
Agriculture (tonnes)
Sector 1990 2000 2005 2013 2014 2015 2016 2017 2018
Sub-total 2 100 2 200 2 100 4 400 4 600 4 100 4 200 4 200 4 100
Animal Production -* - - - - - - - -
Crop Production - - - - - - - - -
Fuel Use 2 100 2 200 2 100 4 400 4 600 4 100 4 200 4 200 4 100
Commercial / Residential / Institutional (tonnes)
Sector 1990 2000 2005 2013 2014 2015 2016 2017 2018
Sub-total 87 000 90 000 86 000 80 000 83 000 80 000 77 000 79 000 83 000
Cigarette Smoking1 -* - - - - - - - -
Commercial and Institutional Fuel Combustion 23 000 30 000 30 000 25 000 27 000 26 000 26 000 27 000 28 000
Commercial Cooking - - - - - - - - -
Construction Fuel Combustion 3 900 2 000 2 700 2 600 2 500 2 500 2 600 2 700 2 800
Home Firewood Burning 25 000 23 000 19 000 20 000 20 000 20 000 20 000 20 000 19 000
Human1 - - - - - - - - -
Marine Cargo Handling 0.20 0.06 - 29 31 47 24 28 26
Residential Fuel Combustion 35 000 35 000 35 000 33 000 34 000 32 000 29 000 30 000 33 000
Service Stations - - - - - - - - -
Other (Miscellaneous) - - - - - - - - -
Incineration and Waste (tonnes)
Sector 1990 2000 2005 2013 2014 2015 2016 2017 2018
Sub-total 7 900 7 600 9 000 4 500 4 200 4 200 4 200 5 200 4 400
Crematoriums 8.2 12 15 19 21 21 22 23 23
Waste Incineration 2 500 2 500 4 000 2 700 2 400 2 400 2 400 2 400 2 300
Waste Treatment and Disposal 5 400 5 100 5 000 1 800 1 800 1 900 1 800 2 700 2 100
Paints and Solvents (tonnes)
Sector 1990 2000 2005 2013 2014 2015 2016 2017 2018
Sub-total -* - 35 23 23 23 23 17 15
Dry Cleaning - - - - - - - - -
General Solvent Use - - - - - - - - -
Printing - - 35 23 23 23 23 17 15
Surface Coatings - - - - - - - - -
Dust (tonnes)
Sector 1990 2000 2005 2013 2014 2015 2016 2017 2018
Sub-total -* - - - - - - - -
Coal Transportation - - - - - - - - -
Construction Operations - - - - - - - - -
Mine Tailings - - - - - - - - -
Paved Roads - - - - - - - - -
Unpaved Roads - - - - - - - - -
Fires (tonnes)
Sector 1990 2000 2005 2013 2014 2015 2016 2017 2018
Sub-total 7 500 1 400 890 650 2 600 2 000 1 700 990 500
Prescribed Burning 7 400 1 400 850 610 2 600 2 000 1 600 970 470
Structural Fires 49 39 35 36 28 27 27 27 27
Totals (tonnes)
Sector 1990 2000 2005 2013 2014 2015 2016 2017 2018
Ore and Mineral Industries 100 000 99 000 110 000 83 000 82 000 81 000 78 000 86 000 82 000
Oil and Gas Industry 350 000 460 000 430 000 460 000 480 000 480 000 470 000 480 000 490 000
Electric Power Generation (Utilities) 260 000 330 000 250 000 160 000 170 000 150 000 150 000 150 000 130 000
Manufacturing 190 000 170 000 140 000 70 000 69 000 69 000 69 000 70 000 69 000
Transportation and Mobile Equipment 1 400 000 1 700 000 1 400 000 1 000 000 940 000 890 000 840 000 880 000 910 000
Agriculture 2 100 2 200 2 100 4 400 4 600 4 100 4 200 4 200 4 100
Commercial / Residential / Institutional 87 000 90 000 86 000 80 000 83 000 80 000 77 000 79 000 83 000
Incineration and Waste 7 900 7 600 9 000 4 500 4 200 4 200 4 200 5 200 4 400
Paints and Solvents -* - 35 23 23 23 23 17 15
Dust - - - - - - - - -
Fires 7 500 1 400 890 650 2 600 2 000 1 700 990 500
Grand Total 2 400 000 2 900 000 2 400 000 1 900 000 1 800 000 1 800 000 1 700 000 1 700 000 1 800 000

Notes:

Totals may not add up due to rounding.

1. Cigarette Smoking as well as Infant Diapered Waste (which is included within the Human sector) are being considered for removal from future inventories. If you have any questions, please contact us at ec.iepa-apei.ec@canada.ca or 1-877-877-8375.

* - = no emission

0.00 Indicates emissions truncated due to rounding

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