Canada’s Air Pollutant Emissions Inventory Report: chapter 2.3

2.3  Nitrogen oxides (NOx)

Approximately 1.8 Mt of NOx were released in Canada in 2017 (Table 2–5). Transportation and mobile equipment was the largest contributor, accounting for 52% (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 32% (562 kt) of total NOx emissions. The oil and gas industry accounted for 27% (481 kt) of total NOx emissions in 2017, with the upstream oil and gas industry accounting for nearly all of the national total (464 kt). Electric power generation (utilities) contributed 8% (146 kt) of total NOx emissions, with coal-fired generation contributing 6% (110 kt) of the national total. The remaining 13% of NOx emissions were distributed across multiple sources.

From 1990 to 2017, national NOx emissions decreased by 26% (631 kt) (Figure 2–3). A significant driver of this trend was the consistent reduction in emissions from light-duty gasoline trucks and vehicles across the entire time series, 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 2017. 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 in marine transportation, respectively.

The most significant changes in NOx emissions from 1990 to 2017 include:

  • transportation and mobile equipment: decrease of 35% (494 kt), of which:
    • off-road diesel vehicles and equipment: decrease of 59% (197 kt)
    • light-duty gasoline trucks and vehicles: decrease of 51% (176 kt)
    • marine transportation: increase of 38% (53 kt)
    • heavy-duty diesel vehicles: decrease of 20% (60 kt)
  • electric power generation (utilities): decrease of 43% (111 kt), of which:
    • coal: decrease of 46% (96 kt)
  • oil and gas industry: increase of 39% (135 kt), of which:
    • upstream oil and gas industry: increase of 49% (153 kt)
    • downstream oil and gas industry: decrease of 51% (18 kt)

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 2017.

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
Sector 1 - Upstream Oil and Gas Industry 310 310 320 350 380 400 410 460 470 490 430 420 420 460 400 400 400 430 440 440 430 450 440 450 460 460 450 460
Sector 2 - Heavy-Duty Diesel Vehicles 290 250 240 240 250 250 280 330 370 410 410 400 390 380 380 410 380 370 360 320 320 330 300 290 260 240 230 230
Sector 3 - Marine Transportation 140 140 150 150 160 160 170 170 180 180 190 190 200 200 210 210 210 210 210 210 210 200 200 200 200 200 190 190
Sector 4 - Other 1700 1600 1700 1700 1800 1800 1800 1900 1900 1900 1900 1800 1700 1600 1600 1400 1300 1300 1200 1100 1200 1100 1000 1000 1000 920 880 890

Table 2-5:  National summary of annual NOx emissions

Ore and Mineral Industries (tonnes)
Sector 1990 2000 2005 2012 2013 2014 2015 2016 2017
Sub-total 110 000 99 000 98 000 77 000 71 000 72 000 71 000 68 000 76 000
Aluminium Industry 1 600 1 300 2 000 1 400 1 300 1 100 1 100 1 200 1 200
Asphalt Paving Industry 1 200 1 100 1 200 1 100 1 000 1 200 1 200 1 100 1 100
Cement and Concrete Industry 43 000 45 000 54 000 36 000 32 000 31 000 35 000 32 000 34 000
Foundries 490 640 540 140 140 140 140 140 140
Iron and Steel Industry 19 000 16 000 13 000 12 000 11 000 12 000 11 000 11 000 11 000
Iron Ore Industry 10 000 10 000 380 760 1 500 1 600 1 200 1 300 1 700
Mineral Products Industry 1 300 560 1 100 260 300 310 290 300 290
Mining and Rock Quarrying 25 000 21 000 24 000 25 000 22 000 23 000 20 000 19 000 25 000
Non-Ferrous Mining and Smelting Industry 4 300 3 800 1 800 1 500 1 600 1 600 1 600 1 900 1 800
Oil and Gas Industry (tonnes)
Sector 1990 2000 2005 2012 2013 2014 2015 2016 2017
Sub-total 350 000 460 000 430 000 460 000 460 000 480 000 480 000 470 000 480 000
Downstream Oil and Gas Industry 35 000 30 000 31 000 19 000 18 000 17 000 17 000 17 000 17 000
Upstream Oil and Gas Industry 310 000 430 000 400 000 440 000 450 000 460 000 460 000 450 000 460 000
Electric Power Generation (Utilities) (tonnes)
Sector 1990 2000 2005 2012 2013 2014 2015 2016 2017
Sub-total 260 000 330 000 250 000 170 000 160 000 170 000 150 000 150 000 150 000
Coal 210 000 230 000 190 000 130 000 120 000 130 000 110 000 120 000 110 000
Diesel 3 000 8 200 8 300 9 300 9 500 10 000 11 000 10 000 9 800
Natural Gas 20 000 65 000 38 000 22 000 21 000 19 000 17 000 17 000 16 000
Waste Materials 45 520 240 300 190 170 210 360 390
Other (Electric Power Generation) 28 000 28 000 21 000 10 000 8 300 10 000 11 000 10 000 10 000
Manufacturing (tonnes)
Sector 1990 2000 2005 2012 2013 2014 2015 2016 2017
Sub-total 190 000 170 000 140 000 69 000 70 000 69 000 69 000 68 000 69 000
Abrasives Manufacturing 240 90 74 no emissions (-) - - - - -
Bakeries 4.0 4.0 - 0.86 1.1 1.0 0.89 0.89 0.95
Biofuel Production - - - 18 18 17 18 16 18
Chemicals Industry 41 000 47 000 37 000 24 000 22 000 21 000 23 000 22 000 23 000
Electronics 150 160 71 - - - - 0.01 -
Food Preparation 2 400 2 900 3 300 1 600 1 700 1 700 1 800 1 700 1 900
Glass Manufacturing 7 000 7 400 6 100 900 920 890 920 780 780
Grain Industry 1 400 1 300 1 600 1 000 950 1 000 780 760 1 100
Metal Fabrication 5 900 9 000 1 200 280 220 240 320 350 280
Plastics Manufacturing 880 810 100 41 0.95 0.91 9.0 11 13
Pulp and Paper Industry 72 000 49 000 45 000 29 000 31 000 30 000 30 000 29 000 30 000
Textiles 120 170 110 30 33 33 8.2 7.8 7.8
Vehicle Manufacturing (Engines, Parts, Assembly, Painting) 2 500 3 500 1 500 550 630 610 650 610 600
Wood Products 17 000 21 000 18 000 10 000 11 000 11 000 11 000 11 000 11 000
Other (Manufacturing) 33 000 30 000 22 000 1 300 1 200 1 200 1 100 1 200 1 200
Transportation and Mobile Equipment (tonnes)
Sector 1990 2000 2005 2012 2013 2014 2015 2016 2017
Sub-total 1 400 000 1 800 000 1 400 000 1 100 000 1 100 000 1 000 000 960 000 910 000 920 000
Air Transportation 52 000 64 000 68 000 69 000 73 000 72 000 75 000 78 000 81 000
Heavy-Duty Diesel Vehicles 290 000 410 000 410 000 300 000 290 000 260 000 240 000 230 000 230 000
Heavy-Duty Gasoline Vehicles 60 000 82 000 60 000 44 000 44 000 37 000 35 000 37 000 37 000
Heavy-Duty LPG/NG Vehicles 15 000 34 000 4 500 220 110 59 61 80 140
Light-Duty Diesel Trucks 790 1 500 2 100 1 200 1 200 1 300 1 400 1 600 1 700
Light-Duty Diesel Vehicles 2 200 2 200 1 200 980 990 940 920 860 830
Light-Duty Gasoline Trucks 97 000 190 000 130 000 82 000 77 000 70 000 68 000 72 000 73 000
Light-Duty Gasoline Vehicles 200 000 220 000 120 000 60 000 57 000 50 000 46 000 46 000 44 000
Light-Duty LPG/NG Trucks 7 500 5 900 2 900 84 43 31 27 29 34
Light-Duty LPG/NG Vehicles 820 740 280  2.6   1.1 0.81 0.73   0.89 1.2
Marine Transportation 140 000 190 000 210 000 200 000 200 000 200 000 200 000 190 000 190 000
Motorcycles 320 440 530 630 630 620 640 680 680
Off-road Diesel Vehicles and Equipment 330 000 360 000 280 000 190 000 190 000 170 000 170 000 130 000 140 000
Off-road Gasoline/LPG/CNG Vehicles and Equipment 53 000 37 000 28 000 29 000 28 000 30 000 30 000 29 000 30 000
Rail Transportation 160 000 150 000 130 000 120 000 110 000 110 000 98 000 91 000 91 000
Tire Wear and Brake Lining no emissions (-) - - - - - - - -
Agriculture (tonnes)
Sector 1990 2000 2005 2012 2013 2014 2015 2016 2017
Sub-total 2 100 2 200 2 100 4 400 4 400 4 600 4 100 4 200 4 100
Animal Production no emissions (-) - - - - - - - -
Crop Production - - - - - - - - -
Fuel Use 2 100 2 200 2 100 4 400 4 400 4 600 4 100 4 200 4 100
Commercial / Residential / Institutional (tonnes)
Sector 1990 2000 2005 2012 2013 2014 2015 2016 2017
Sub-total 87 000 90 000 86 000 80 000 80 000 83 000 80 000 77 000 79 000
Cigarette Smoking no emissions (-) - - - - - - - -
Commercial and Institutional Fuel Combustion 23 000 30 000 30 000 25 000 25 000 27 000 26 000 26 000 27 000
Commercial Cooking - - - - - - - - -
Construction Fuel Combustion 3 900 2 000 2 700 2 900 2 600 2 500 2 500 2 600 2 700
Home Firewood Burning 25 000 23 000 19 000 20 000 20 000 20 000 20 000 20 000 20 000
Human - - - - - - - - -
Marine Cargo Handling 0.20 0.06 - - 29 31 26 24 28
Residential Fuel Combustion 35 000 35 000 35 000 32 000 33 000 34 000 32 000 29 000 30 000
Service Stations - - - - - - - - -
Other (Commercial / Residential / Institutional) - - - - - - - - -
Incineration and Waste (tonnes)
Sector 1990 2000 2005 2012 2013 2014 2015 2016 2017
Sub-total 7 900 8 000 9 300 4 400 4 800 4 500 4 400 4 400 5 400
Crematoriums 8.3 12 15 18 19 21 21 22 23
Waste Incineration 2 500 2 800 3 700 2 900 2 900 2 600 2 400 2 500 2 500
Waste Treatment and Disposal 5 400 5 100 5 700 1 600 1 900 1 900 2 000 2 000 2 900
Paints and Solvents (tonnes)
Sector 1990 2000 2005 2012 2013 2014 2015 2016 2017
Sub-total 110 120 130 23 23 23 23 23 17
Dry Cleaning 1.1 1.6 no emissions (-) - - - - - -
General Solvent Use - - - - - - - - -
Printing 110 120 130 23 23 23 23 23 17
Surface Coatings 0.12 0.12 - - - - - - -
Dust (tonnes)
Sector 1990 2000 2005 2012 2013 2014 2015 2016 2017
Sub-total - - - - - - - - -
Coal Transportation - - - - - - - - -
Construction Operations - - - - - - - - -
Mine Tailings - - - - - - - - -
Paved Roads - - - - - - - - -
Unpaved Roads - - - - - - - - -
Fires (tonnes)
Sector 1990 2000 2005 2012 2013 2014 2015 2016 2017
Sub-total 7 500 1 400 890 1 500 650 2 600 2 000 1 700 990
Prescribed Forest Burning 7 400 1 400 850 1 500 610 2 600 2 000 1 600 970
Structural Fires 49 39 35 39 36 28 26 26 27
Totals (tonnes)
Source 1990 2000 2005 2012 2013 2014 2015 2016 2017
Ore and Mineral Industries 110 000 99 000 98 000 77 000 71 000 72 000 71 000 68 000 76 000
Oil and Gas Industry 350 000 460 000 430 000 460 000 460 000 480 000 480 000 470 000 480 000
Electric Power Generation (Utilities) 260 000 330 000 250 000 170 000 160 000 170 000 150 000 150 000 150 000
Manufacturing 190 000 170 000 140 000 69 000 70 000 69 000 69 000 68 000 69 000
Transportation and Mobile Equipment 1 400 000 1 800 000 1 400 000 1 100 000 1 100 000 1 000 000 960 000 910 000 920 000
Agriculture 2 100 2 200 2 100 4 400 4 400 4 600 4 100 4 200 4 100
Commercial / Residential / Institutional 87 000 90 000 86 000 80 000 80 000 83 000 80 000 77 000 79 000
Incineration and Waste 7 900 8 000 9 300 4 400 4 800 4 500 4 400 4 500 5 400
Paints and Solvents 110 120 130 23 23 23 23 23 17
Dust no emissions (-) - - - - - - - -
Fires 7 500 1 400 890 1 500 650 2 600 2 000 1 700 990
Grand Total 2 400 000 2 900 000 2 500 000 2 000 000 1 900 000 1 900 000 1 800 000 1 800 000 1 800 000

Notes:

Totals may not add up due to rounding.

- Indicates no emissions

0.00 Indicates emissions truncated due to rounding

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