Canada’s Air Pollutant Emissions Inventory Report 2022: chapter 2.11

2.11 Polycyclic aromatic hydrocarbons

The APEI reports emissions of four polycyclic aromatic hydrocarbons (PAHs): benzo(a)pyrene (B(a)p), benzo(b)fluoranthene (B(b)f), benzo(k)fluoranthene (B(k)f) and indeno[1,2,3-cd]pyrene (I(cd)p). The analysis presented here is based on the aggregate total of all four substances. In 2020, 60 t of PAHs were emitted in Canada (Table 2–13), with 84% (50 t) attributed to Commercial/Residential/Institutional sources. This is almost entirely due to Home Firewood Burning, this sector being the largest contributor to PAH emissions since 2004, with 83% (50 t) of total 2020 emissions. Transportation and Mobile Equipment was the next largest source, contributing 12% (7.3 t) of PAH emissions in 2020.

From 1990 to 2020, PAH emissions decreased by 80% (234 t) (Figure 2–11), primarily owing to emission reductions in the Aluminium Industry and Iron and Steel Industry sectors of almost 100% each (109 t and 79 t, respectively). Emissions from Aluminium Industry experienced a large drop in PAH emissions from 2008 to 2016 owing to process improvements and the progressive phase-out of old Söderberg aluminium production technologies (ECCC, 2014). Emissions of these four types of PAHs from Iron and Steel Industry dropped significantly earlier in the time series, from 1993 to 2006, and emissions remained small through 2020. Reductions here are a result of effective emission controls on coke ovens and coke by-product plants (EC, 2001).

Within Commercial/Residential/Institutional sources, Home Firewood Burning contributed to the downward trend across the 1990-2020 time series, with a decrease in emissions of 29% (20 t) owing to a 28% reduction in wood consumption and the adoption of more efficient wood combustion equipment. Between the years 2019 and 2020, Home Firewood Burning experienced a PAH emission decrease of 8.4% (4.6 t) attributed to reduced wood consumption. PAH emissions from Transportation and Mobile Equipment have decreased across the time series owing to increasingly stringent engine and vehicle regulations.Footnote 8

The most significant changes in PAH emissions from 1990 to 2020 include:

Figure 2–11: Trends in Canadian polycyclic aromatic hydrocarbons emissions (1990 to 2020)

Figure 2-11 (See long description below)
Long description for Figure 2–11

Figure 2–11 is a stacked area graph displaying the five major contributors to national PAH trends. They are the following: Aluminium Industry, Iron and Steel Industry, Light-Duty Gasoline Trucks and Vehicles, Other, and Home Firewood Burning. The figure shows that the contribution of Home Firewood Burning was almost constant during the period, whereas emissions from Aluminium and Iron and Steel Industries significantly decreased between 1990 and 2020. The following table displays the contributions (t) for the years 1990 to 2020.

Figure 2–11: Trends in Canadian polycyclic aromatic hydrocarbons emissions (1990 to 2020) (t)
Section 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 2019 2020
Aluminium Industry 109 90 89 89 88 87 87 86 86 85 84 84 59 63 41 45 51 41 41 27 21 22 23 31 23 4.9 0.10 0.13 0.19 0.14 0.08
Home Firewood Burning 70 71 75 75 74 72 74 74 59 58 59 51 50 47 51 52 52 61 62 63 57 61 58 66 68 67 64 65 62 54 50
Iron and Steel Industry 80 80 82 86 61 46 32 19 24 30 11 7.3 7.9 8.3 3.7 4.6 0.34 0.44 0.46 0.58 0.72 0.68 0.74 0.55 0.40 0.40 0.44 0.39 0.40 0.37 0.37
Light-Duty Gasoline Trucks and Vehicles 15 15 15 15 15 14 14 14 14 13 13 13 12 11 10 8.9 8.2 8.1 8.4 7.3 7.0 6.3 6.0 5.9 5.5 5.3 5.5 5.5 5.6 5.6 4.8
Other 20 21 16 20 19 19 15 12 12 10 10 10 11 15 10 8.6 9.8 7.2 8.2 8.6 6.8 6.1 6.3 5.2 7.6 6.5 6.0 5.0 4.5 5.1 4.7

Table 2–13: National summary of annual polycyclic aromatic hydrocarbons emissions

Notes:
Totals may not add up due to rounding.
0.00 Indicates emissions were truncated due to rounding.
- Indicates no emissions

Ore and Mineral Industries (kg)
Sector 1990 2000 2005 2015 2016 2017 2018 2019 2020
Sub-total 190 000 95 000 50 000 5 400 690 550 620 540 470
Aluminium Industry 110 000 84 000 45 000 4 900 100 130 190 140 83
Asphalt Paving Industry 14 14 15 12 11 12 12 11 11
Cement and Concrete Industry 17 13 19 2.8 0.23 0.62 0.34 0.26 0.18
Foundries 0.00 0.00 - - - - - - -
Iron and Steel Industry 80 000 11 000 4 600 400 440 390 400 370 370
Iron Ore Pelletizing - - - 20 20 21 18 20 8.6
Mineral Products Industry - - - - - - - - -
Mining and Rock Quarrying - - - 110 110 0.00 0.00 0.00 0.00
Non-Ferrous Mining and Smelting Industry 1.9 2.8 0.33 0.32 0.30 0.33 0.33 0.34 0.20
Oil and Gas Industry (kg)
Sector 1990 2000 2005 2015 2016 2017 2018 2019 2020
Sub-total 150 95 46 24 20 18 22 470 520
Downstream Oil and Gas Industry 150 92 43 19 14 13 14 14 57
Upstream Oil and Gas Industry 2.3 3.3 2.3 4.8 5.8 4.5 7.9 450 460
Electric Power Generation (Utilities) (kg)
Sector 1990 2000 2005 2015 2016 2017 2018 2019 2020
Sub-total 370 360 240 6.1 6.8 6.5 0.00 0.00 0.00
Coal 240 240 240 - - - - - -
Diesel - - - - - - - - -
Natural Gas 2.9 2.3 0.23 0.00 0.00 0.00 0.00 0.00 0.00
Waste Materials - - - - - - - - -
Other (Electric Power Generation) 130 110 - 6.0 6.8 6.5 - - -
Manufacturing (kg)
Sector 1990 2000 2005 2015 2016 2017 2018 2019 2020
Sub-total 320 310 300 130 120 140 130 150 160
Abrasives Manufacturing - - - - - - - - -
Bakeries - - - - - - - - -
Biofuel Production - - - - - - - - -
Chemicals Industry 0.60 24 29 25 25 25 24 24 23
Electronics 0.00 0.00 - - - - - - -
Food Preparation - - - - - - - - -
Glass Manufacturing 0.00 0.00 - - - - - - -
Grain Industry - - - - - - - - -
Metal Fabrication 1.1 1.1 8.3 - - - - - -
Plastics Manufacturing - 0.00 - - - - - - -
Pulp and Paper Industry 110 130 190 100 89 110 100 120 130
Textiles - - - - - - - - -
Vehicle Manufacturing (Engines, Parts, Assembly, Painting) 0.00 0.24 - 0.00 0.00 0.00 0.00 0.00 0.00
Wood Products 210 150 72 8.6 7.9 6.0 6.0 5.4 4.8
Other (Manufacturing) - 0.00 2.2 - - - - - -
Transportation and Mobile Equipment (kg)
Sector 1990 2000 2005 2015 2016 2017 2018 2019 2020
Sub-total 24 000 20 000 1 000 7 800 8 100 8 200 8 300 8 400 7 300
Air Transportation (LTO) 12 6.8 5.4 5.8 5.7 5.8 6.2 6.2 3.9
Domestic Marine Navigation, Fishing and Military 68 77 84 34 35 36 39 43 41
Heavy-Duty Diesel Vehicles 910 990 1 200 610 600 630 660 650 620
Heavy-Duty Gasoline Vehicles 6 200 4 300 4 200 1 800 1 900 1 900 1 900 1 900 1 800
Heavy-Duty LPG/NG Vehicles 1 100 1 300 330 2.5 3.5 6.7 6.7 6.2 6.4
Light-Duty Diesel Trucks 2.1 2.7 2.8 1.8 1.9 2.3 2.5 2.5 2.2
Light-Duty Diesel Vehicles 7.8 5.4 3.4 2.4 2.2 2.2 2.1 2.1 1.8
Light-Duty Gasoline Trucks 4 500 5 400 3 800 2 800 3 000 3 000 3 100 3 300 2 900
Light-Duty Gasoline Vehicles 11 000 7 600 5 000 2 500 2 500 2 500 2 400 2 400 1 900
Light-Duty LPG/NG Trucks 380 170 80 0.85 0.93 1.1 1.1 1.1 0.66
Light-Duty LPG/NG Vehicles 47 25 12 0.00 0.00 0.058 0.058 0.055 0.00
Motorcycles 39 38 42 37 40 41 41 41 34
Off-Road Diesel Vehicles and Equipment  - - - - - - - - -
Off-Road Gasoline/LPG/NG Vehicles and Equipment - - - - - - - - -
Rail Transportation 63 59 58 34 31 33 36 36 33
Tire Wear and Brake Lining - - - - - - - - -
Agriculture (kg)
Sector 1990 2000 2005 2015 2016 2017 2018 2019 2020
Sub-total 0.32 0.31 0.21 0.21 0.23 0.22 0.23 0.23 0.21
Animal Production - - - - - - - - -
Crop Production - - - - - - - - -
Agricultural Fuel Combustion 0.32 0.31 0.21 0.21 0.23 0.22 0.23 0.23 0.21
Commercial/Residential/Institutional (kg)
Sector 1990 2000 2005 2015 2016 2017 2018 2019 2020
Sub-total 70 000 59 000 53 000 67 000 64 000 65 000 62 000 54 000 50 000
Commercial and Institutional Fuel Combustion 2.6 3.1 2.9 2.3 2.3 2.3 2.4 2.5 2.4
Commercial Cooking  100 110 120 110 110 110 110 110 110
Construction Fuel Combustion  0.45 0.19 0.41 0.28 0.22 0.23 0.22 0.25 0.33
Home Firewood Burning  70 000 59 000 52 000 67 000 64 000 65 000 62 000 54 000 50 000
Human - - - - - - - - -
Marine Cargo Handling  - - - - - - - - -
Residential Fuel Combustion 5.3 4.6 4.3 3.3 3.0 3.0 3.2 3.0 2.7
Service Stations - - - - - - - - -
Other (Miscellaneous) - - - - - - - - -
Incineration and Waste (kg)
Sector 1990 2000 2005 2015 2016 2017 2018 2019 2020
Sub-total 490 530 610 640 660 660 670 680 690
Crematoriums 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Waste Incineration 490 530 610 640 660 660 670 680 690
Waste Treatment and Disposal - - - 0.00 0.00 0.00 0.00 0.00 0.00
Paints and Solvents (kg)
Sector 1990 2000 2005 2015 2016 2017 2018 2019 2020
Sub-total - - - - - - - - -
Dry Cleaning - - - - - - - - -
General Solvent Use - - - - - - - - -
Printing - - - - - - - - -
Surface Coatings - - - - - - - - -
Dust (kg)
Sector 1990 2000 2005 2015 2016 2017 2018 2019 2020
Sub-total - - - - - - - - -
Coal Transportation - - - - - - - - -
Construction Operations - - - - - - - - -
Mine Tailings - - - - - - - - -
Paved Roads - - - - - - - - -
Unpaved Roads - - - - - - - - -
Fires (kg)
Sector 1990 2000 2005 2015 2016 2017 2018 2019 2020
Sub-total 9 800 2 000 1 200 2 900 2 400 1 400 820 870 700
Prescribed Burning 9 800 2 000 1 200 2 900 2 400 1 400 820 870 700
Structural Fires - - - - - - - - -
Totals (kg)
Sector 1990 2000 2005 2015 2016 2017 2018 2019 2020
Ore and Mineral Industry 190 000 95 000 50 000 5 400 690 550 620 540 470
Oil and Gas Industry 150 95 46 24 20 18 22 470 520
Electric Power Generation (Utilities) 370 360 240 6.1 6.8 6.5 0.00 0.00 0.00
Manufacturing 320 310 300 130 120 140 130 150 160
Transportation and Mobile Equipment 24 000 20 000 1 000 7 800 8 100 8 200 8 300 8 400 7 300
Agriculture 0.32 0.31 0.21 0.21 0.23 0.22 0.23 0.23 0.21
Commercial/Residential/Institutional 70 000 59 000 53 000 67 000 64 000 65 000 62 000 54 000 50 000
Incineration and Waste 490 530 610 640 660 660 670 680 690
Paints and Solvents - - - - - - - - -
Dust - - - - - - - - -
Fires 9 800 2 000 1 200 2 900 2 400 1 400 820 870 700
Grand Total 290 000 180 000 120 000 84 000 76 000 76 000 72 000 66 000 60 000

Note:
Refer to Annex 4.4 for more information on international marine navigation and air transportation reporting emissions.

Other emissions estimated in the APEI (kg)
Sector 1990 2000 2005 2015 2016 2017 2018 2019 2020
Domestic Air Transportation (Cruise) 5.5 4.4 3.1 3.0 3.0 3.1 3.3 3.3 1.9
International Air Transportation (Cruise) 3.1 3.0 2.3 2.0 2.1 2.2 2.3 2.4 0.94
International Marine Navigation 52 72 83 68 67 65 65 69 60

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