Canada’s Air Pollutant Emissions Inventory Report 2025: 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 2023, 20 t of PAHs were emitted in Canada (Table 2–13), with 84% (17 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, with 84% (17 t) of 2023 total emissions. Transportation and Mobile Equipment was the next largest source, contributing 11% (2.2 t) of PAH emissions in 2023.
From 1990 to 2023, PAH emissions decreased by 92% (223 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 the Aluminium Industry experienced a large decrease 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 the Iron and Steel Industry dropped significantly earlier in the time series, from 1993 to 2006, and emissions remained small through 2023. 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 to 2023 time series. PAH emissions from Home Firewood Burning fluctuate from year to year, but have resulted in an overall decrease in emissions of 45% (14 t). This decrease is owed to a 32% reduction in wood consumption and the adoption of more efficient wood combustion equipment.
The most significant changes in PAH emissions from 1990 to 2023 include:
- Ore and Mineral Industries: decrease of almost 100% (188 t), with:
- Aluminium Industry: decrease of almost 100% (109 t)
- Iron and Steel Industry: decrease of almost 100% (79 t)
- Commercial/Residential/Institutional sources: decrease of 45% (14 t)
- Home Firewood Burning: decrease of 45% (14 t)
Figure 2–11: Trends in Canadian Polycyclic Aromatic Hydrocarbons Emissions (1990 to 2023)
Long description for Figure 2-11
Figure 2–11: Trends in Canadian Polycyclic Aromatic Hydrocarbon Emissions for 1990 to 2023.
Figure 2–11 is a stacked area graph displaying the five major contributors to national polycyclic aromatic hydrocarbon trends. They are the following: Aluminium Industry, Iron and Steel Industry, Other, Light-Duty Gasoline Trucks and Vehicles, 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 2023. The following table displays the contributions (t) for the years 1990 to 2023.
| 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 | 2019 | 2020 | 2021 | 2022 | 2023 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Home Firewood Burning | 31 | 31 | 33 | 33 | 32 | 32 | 33 | 32 | 26 | 25 | 25 | 22 | 21 | 20 | 21 | 22 | 21 | 25 | 25 | 25 | 23 | 24 | 23 | 26 | 26 | 26 | 25 | 25 | 25 | 23 | 19 | 17 | 18 | 17 |
| Light-Duty Gasoline Trucks and Vehicles | 8.4 | 7.9 | 7.8 | 8.1 | 8.4 | 8.0 | 7.9 | 7.6 | 7.4 | 7.2 | 6.8 | 6.4 | 6.0 | 5.5 | 5.2 | 4.6 | 4.2 | 4.0 | 3.6 | 3.4 | 3.1 | 2.2 | 2.0 | 2.0 | 1.9 | 1.8 | 1.8 | 1.7 | 1.7 | 1.7 | 1.5 | 1.5 | 1.5 | 1.5 |
| Other | 15 | 15 | 11 | 15 | 14 | 15 | 11 | 8.2 | 7.9 | 7.0 | 6.3 | 5.9 | 7.4 | 11.8 | 6.2 | 5.3 | 6.7 | 4.3 | 5.5 | 6.0 | 4.2 | 4.4 | 4.4 | 3.3 | 6.0 | 4.8 | 4.0 | 2.8 | 2.2 | 2.6 | 2.3 | 2.3 | 2.7 | 1.4 |
| Iron and Steel Industry | 80 | 80 | 82 | 86 | 61 | 46 | 32 | 19 | 24 | 30 | 11 | 7.3 | 8.0 | 8.3 | 3.8 | 4.6 | 0.3 | 0.4 | 0.5 | 0.6 | 0.7 | 0.7 | 0.7 | 0.5 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | 0.3 |
| 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 | 0.1 | 0.1 | 0.2 | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 |
Table 2–13: National Summary of Annual Polycyclic Aromatic Hydrocarbons Emissions
| Source | 1990 | 2000 | 2005 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 |
|---|---|---|---|---|---|---|---|---|---|
| Ore and Mineral Industries | 190,000 | 95,000 | 50,000 | 620 | 540 | 470 | 470 | 500 | 400 |
| Aluminium Industry (Ore and Mineral Industries) | 110,000 | 84,000 | 45,000 | 190 | 140 | 83 | 89 | 89 | 72 |
| Iron and Steel Industry (Ore and Mineral Industries) | 80,000 | 11,000 | 4,600 | 400 | 370 | 370 | 370 | 400 | 310 |
| Other Ore and Mineral Industries Sectors (Ore and Mineral Industries) | 33 | 30 | 42 | 30 | 31 | 19 | 12 | 10 | 10 |
| Oil and Gas Industry | 150 | 95 | 46 | 22 | 470 | 470 | 480 | 55 | 61 |
| Electric Power Generation (Utilities) | 370 | 360 | 240 | 0.00 | 0.00 | 0.00 | 6.5 | 5.1 | 5.9 |
| Manufacturing | 320 | 310 | 290 | 140 | 150 | 160 | 120 | 120 | 210 |
| Transportation And Mobile Equipment | 12,000 | 10,000 | 7,800 | 2,700 | 2,600 | 2,300 | 2,300 | 2,200 | 2,200 |
| Heavy-Duty Diesel Vehicles (Transportation And Mobile Equipment) | 2,200 | 2,300 | 2,400 | 600 | 520 | 460 | 450 | 400 | 390 |
| Heavy-Duty Gasoline Vehicles (Transportation And Mobile Equipment) | 1,300 | 880 | 660 | 260 | 260 | 230 | 210 | 180 | 190 |
| Light-Duty Gasoline Trucks (Transportation And Mobile Equipment) | 2,700 | 3,000 | 2,200 | 1,100 | 1,100 | 970 | 990 | 970 | 1,000 |
| Light-Duty Gasoline Vehicles (Transportation And Mobile Equipment) | 5,700 | 3,800 | 2,400 | 630 | 610 | 490 | 500 | 490 | 480 |
| Other Transportation and Mobile Equipment Sectors (Transportation And Mobile Equipment) | 480 | 220 | 230 | 150 | 150 | 120 | 120 | 120 | 130 |
| Agriculture | 0.32 | 0.31 | 0.21 | 0.23 | 0.23 | 0.21 | 0.20 | 0.21 | 0.20 |
| Commercial/Residential/Institutional | 31,000 | 25,000 | 22,000 | 25,000 | 23,000 | 19,000 | 17,000 | 18,000 | 17,000 |
| Home Firewood Burning (Commercial/Residential/Institutional) | 31,000 | 25,000 | 22,000 | 25,000 | 23,000 | 19,000 | 17,000 | 18,000 | 17,000 |
| Other Commercial/Residential/Institutional Sectors (Commercial/Residential/Institutional) | 110 | 120 | 130 | 120 | 120 | 120 | 120 | 120 | 120 |
| Incineration and Waste | 34 | 35 | 39 | 38 | 37 | 37 | 36 | 36 | 37 |
| Paints and Solvents | NA | NA | NA | NA | NA | NA | NA | NA | NA |
| Dust | NA | NA | NA | NA | NA | NA | NA | NA | NA |
| Fires | 9,800 | 2,000 | 1,200 | 820 | 870 | 700 | 700 | 1,600 | 290 |
| Grand Total | 240,000 | 130,000 | 81,000 | 29,000 | 27,000 | 23,000 | 21,000 | 23,000 | 20,000 |
Notes:
Totals may not add up due to rounding.
0.00 Indicates emissions were truncated due to rounding.
NA Indicates no emissions.
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