Canada’s Air Pollutant Emissions Inventory Report 2025: chapter 2.2
2.2 Sulphur Oxides
In 2023, 608 kt of sulphur oxides (SOx) were emitted in Canada (Table 2–4). The Oil and Gas Industry was the largest contributor, accounting for 44% (264 kt) of national emissions. Approximately 86% (227 kt) of the emissions from this source were attributed to the Upstream Oil and Gas Industry sector. Ore and Mineral Industries was the second-largest source of SOx, accounting for 28% (168 kt) of total SOx emissions, mostly attributable to the Aluminium Industry sector at 11% (66 kt) and the Non-Ferrous Refining and Smelting Industry sector at 9.6% (59 kt) of the national total. Electric Power Generation (Utilities) also accounted for 22% (135 kt) of total SOx emissions, mostly attributable to coal-electric power generation at 20% (124 kt) of the national total.
Overall, SOx emissions decreased by 80% (2.4 Mt) between 1990 and 2023 (Figure 2–2). Reductions in emissions from the Ore and Mineral Industries, and in particular the Non-Ferrous Refining and Smelting Industry sector, were the largest driver of this downward trend, particularly in the early 1990s, and again from 2008 to 2023. The decrease since 2008 can be attributed to the preparation and implementation of pollution prevention plans by facilities, the installation of new technology or processes at facilities, the closure of four major smelters in Manitoba, Ontario, Quebec, and New Brunswick, and facilities achieving Base Level Industrial Emissions Requirements (BLIERs) through environmental performance agreements (ECCC, 2017, 2018a).
Emissions from Electric Power Generation (Utilities) decreased significantly from 2003 to 2023, primarily owing to the adoption of emissions control equipment on older coal units, and more recently, a decrease in coal consumption and closure of coal-fired power plants; resulting in a decrease of 77% (406 kt) of coal-electric power generation emissions during that period. Installation of pollution control equipment, switching to low sulphur heavy fuel oil and closure of generating stations burning heavy fuel oil also contributed 77% of the reduction in emissions in this sector between 2003 and 2023.
SOx emissions from the Oil and Gas Industry exhibited an overall downward trend since the mid-1990s. Emissions from the Upstream Oil and Gas Industry have gradually declined throughout the time series due to the implementation of better emission control technologies, particularly in the Oil Sands Mining, Extraction and Upgrading and Natural Gas Production and Processing subsectors. Improvements to SOx emissions mitigation technologies have similarly contributed to significant reductions in the Downstream Oil and Gas Industry, where Petroleum Refining emissions have decreased by 83 kt (69%) since 1990. Despite improved emissions controls SOx emissions from the Upstream Oil and Gas Industry gradually increased between 2016 and 2023. This recent trend is driven by a 34% increase in crude bitumen production, as well as increased flaring at natural gas production and processing facilities as part of growing efforts to reduce methane (CH4) emissions from venting. From 2020 to 2023, the Oil and Gas Industry experienced a 8.5% increase (21 kt) in SOx emissions, including a 7.6 kt (14%) increase from Oil Sands Mining, Extraction, and Upgrading, a 6.4 kt (33%) increase from Oil Sands In-Situ Extraction, and a 6.6 kt (6.0%) increase from Natural Gas production and Processing.
Emissions of SOx were 71% below 2005 levels. The main emission sources that contributed to these trends and the explanations for those decreases are similar to the ones between 1990 and 2023 that were previously explained.
The most significant changes in SOx emissions from 1990 to 2023 include:
- Ore and Mineral Industries: decrease of 89% (1.3 Mt), with:
- Non-Ferrous Refining and Smelting Industry: decrease of 95% (1.2 Mt)
- Electric Power Generation (Utilities): decrease of 78% (484 kt), with:
- Coal: decrease of 76% (390 kt)
- Oil and Gas Industry: decrease of 51% (271 kt), with:
- Upstream Oil and Gas Industry: decrease of 44% (179 kt)
- Downstream Oil and Gas Industry: decrease of 71% (92 kt)
The most significant changes in SOx emissions from 2005 to 2023 include:
- Ore and Mineral Industries: decrease of 80% (691 kt), with:
- Non-Ferrous Refining and Smelting Industry: decrease of 91% (618 kt)
- Electric Power Generation (Utilities): decrease of 74% (387 kt), with:
- Coal: decrease of 73% (337 kt)
- Oil and Gas Industry: decrease of 43% (198 kt), with:
- Upstream Oil and Gas Industry: decrease of 35% (122 kt)
- Downstream Oil and Gas Industry: decrease of 67% (75 kt)
Figure 2–2: Trends in Canadian SOx Emissions (1990 to 2023)
Long description for Figure 2-2
Figure 2–2: Trends in Canadian Sulphur Oxides Emissions for 1990 to 2023.
Figure 2–2 is a stacked area graph displaying the four major contributors to national sulphur oxides trends. They are the following: Non-Ferrous Refining and Smelting Industry, Coal (Electric Power Generation), Other and Upstream Oil and Gas Industry. The figure shows an important decrease in emissions between 1990 and 2023. The following table displays the contributions (kt) 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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Upstream Oil and Gas Industry | 406 | 402 | 427 | 434 | 464 | 445 | 437 | 395 | 378 | 383 | 377 | 368 | 350 | 355 | 348 | 349 | 329 | 317 | 298 | 298 | 279 | 272 | 276 | 260 | 235 | 216 | 196 | 207 | 212 | 214 | 207 | 217 | 229 | 227 |
| Other | 824 | 774 | 763 | 800 | 751 | 723 | 739 | 739 | 702 | 664 | 657 | 655 | 634 | 664 | 663 | 608 | 464 | 438 | 392 | 339 | 319 | 308 | 291 | 267 | 254 | 238 | 240 | 234 | 236 | 226 | 197 | 208 | 208 | 198 |
| Coal (Electric Power Generation) | 515 | 506 | 518 | 464 | 489 | 458 | 465 | 510 | 518 | 512 | 535 | 535 | 535 | 530 | 493 | 462 | 441 | 474 | 411 | 369 | 322 | 286 | 278 | 272 | 260 | 242 | 243 | 236 | 212 | 198 | 161 | 157 | 143 | 124 |
| Non-Ferrous Refining and Smelting Industry | 1,265 | 1,113 | 967 | 889 | 673 | 883 | 872 | 816 | 826 | 765 | 760 | 753 | 749 | 648 | 705 | 677 | 661 | 617 | 565 | 396 | 370 | 333 | 342 | 370 | 373 | 365 | 359 | 266 | 140 | 70 | 85 | 57 | 73 | 59 |
Table 2–4: National Summary of Annual SOx Emissions
| Source | 1990 | 2000 | 2005 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 |
|---|---|---|---|---|---|---|---|---|---|
| Ore and Mineral Industries | 1,500,000 | 920,000 | 860,000 | 260,000 | 180,000 | 200,000 | 160,000 | 180,000 | 170,000 |
| Aluminium Industry (Ore and Mineral Industries) | 31,000 | 48,000 | 63,000 | 61,000 | 57,000 | 62,000 | 59,000 | 53,000 | 66,000 |
| Asphalt Paving Industry (Ore and Mineral Industries) | 740 | 650 | 720 | 640 | 570 | 530 | 580 | 520 | 530 |
| Cement and Concrete Industry (Ore and Mineral Industries) | 48,000 | 45,000 | 54,000 | 25,000 | 23,000 | 20,000 | 19,000 | 20,000 | 14,000 |
| Foundries (Ore and Mineral Industries) | 1,800 | 1,900 | 1,700 | 23 | 22 | 21 | 2.2 | 2.1 | 1.8 |
| Iron and Steel Industry (Ore and Mineral Industries) | 37,000 | 30,000 | 31,000 | 20,000 | 20,000 | 15,000 | 14,000 | 16,000 | 17,000 |
| Iron Ore Pelletizing (Ore and Mineral Industries) | 15,000 | 16,000 | 18,000 | 9,700 | 11,000 | 10,000 | 9,700 | 9,500 | 9,000 |
| Mineral Products Industry (Ore and Mineral Industries) | 1,500 | 1,100 | 2,100 | 750 | 720 | 690 | 810 | 590 | 620 |
| Mining and Rock Quarrying (Ore and Mineral Industries) | 83,000 | 15,000 | 12,000 | 1,600 | 1,500 | 1,700 | 1,700 | 1,900 | 2,000 |
| Non—Ferrous Refining and Smelting Industry (Ore and Mineral Industries) | 1,300,000 | 760,000 | 680,000 | 140,000 | 70,000 | 85,000 | 57,000 | 73,000 | 59,000 |
| Oil and Gas Industry | 540,000 | 510,000 | 460,000 | 270,000 | 270,000 | 240,000 | 260,000 | 280,000 | 260,000 |
| Downstream Oil and Gas Industry (Oil and Gas Industry) | 130,000 | 140,000 | 110,000 | 53,000 | 53,000 | 37,000 | 46,000 | 48,000 | 38,000 |
| Upstream Oil and Gas Industry (Oil and Gas Industry) | 410,000 | 380,000 | 350,000 | 210,000 | 210,000 | 210,000 | 220,000 | 230,000 | 230,000 |
| Electric Power Generation (Utilities) | 620,000 | 620,000 | 520,000 | 220,000 | 210,000 | 170,000 | 170,000 | 150,000 | 130,000 |
| Coal (Electric Power Generation (Utilities)) | 510,000 | 530,000 | 460,000 | 210,000 | 200,000 | 160,000 | 160,000 | 140,000 | 120,000 |
| Diesel (Electric Power Generation (Utilities)) | 430 | 440 | 330 | 37 | 37 | 37 | 13 | 33 | 59 |
| Landfill Gas (Electric Power Generation (Utilities)) | 0.76 | 15 | NA | 92 | 88 | 11 | 7.2 | 6.5 | 6.5 |
| Natural Gas (Electric Power Generation (Utilities)) | 29,000 | 21,000 | 19,000 | 1,400 | 1,100 | 770 | 3,600 | 2,100 | 1,300 |
| Other (Electric Power Generation) (Electric Power Generation (Utilities)) | 74,000 | 63,000 | 41,000 | 6,700 | 6,400 | 6,500 | 8,400 | 8,800 | 9,000 |
| Manufacturing | 230,000 | 150,000 | 140,000 | 44,000 | 41,000 | 35,000 | 39,000 | 38,000 | 34,000 |
| Chemicals Industry (Manufacturing) | 38,000 | 31,000 | 36,000 | 20,000 | 18,000 | 15,000 | 18,000 | 19,000 | 17,000 |
| Pulp and Paper Industry (Manufacturing) | 140,000 | 78,000 | 66,000 | 22,000 | 20,000 | 19,000 | 18,000 | 17,000 | 15,000 |
| Other Manufacturing Sectors (Manufacturing) | 49,000 | 44,000 | 43,000 | 2,500 | 2,600 | 2,200 | 2,700 | 2,800 | 2,300 |
| Transportation and Mobile Equipment | 97,000 | 90,000 | 70,000 | 6,300 | 5,700 | 2,200 | 2,200 | 2,800 | 2,400 |
| Agriculture | 2,200 | 1,500 | 2,900 | 240 | 220 | 190 | 160 | 170 | 170 |
| Commercial/Residential/Institutional | 47,000 | 33,000 | 33,000 | 2,900 | 3,000 | 2,600 | 2,400 | 2,500 | 2,000 |
| Incineration And Waste | 1,300 | 1,900 | 1,800 | 2,200 | 2,100 | 2,400 | 2,100 | 2,100 | 1,800 |
| Paints and Solvents | NA | NA | 0.00 | NA | NA | NA | NA | NA | NA |
| Dust | NA | NA | NA | NA | NA | NA | NA | NA | NA |
| Fires | 180 | 28 | 18 | 12 | 15 | 11 | 10 | 24 | 4.2 |
| Grand Total | 3,000,000 | 2,300,000 | 2,100,000 | 800,000 | 710,000 | 650,000 | 640,000 | 650,000 | 610,000 |
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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