Canada’s Air Pollutant Emissions Inventory Report 2025: annex 4
Submission to the United Nations Economic Commission for Europe
Canada reports on atmospheric emissions of air pollutants to the United Nations Economic Commission for Europe (UNECE) through the European Monitoring and Evaluation Programme (EMEP) Centre on Emission Inventories and Projections (CEIP)Footnote 1 pursuant to the 1979 Convention on Long-range Transboundary Air Pollution (CLRTAP) of the UNECE and its associated protocols. Canada's annual official submission to the UNECE comprises an air pollutant dataset, the Nomenclature for Reporting (NFR) tables, submitted by February 15 and its accompanied report by March 15. The CLRTAP has been supplemented by a number of protocols, the most active being the Gothenburg, Heavy Metals, and Persistent Organic Pollutants (POPs) protocols. Canada has ratified all of the protocols except for the 1991 Protocol on Volatile Organic Compounds (VOCs). The requirements under that Protocol are obsolete given that Canada now has commitments on VOCs under the Gothenburg Protocol.
A4.1 Canada’s Air Pollution Emissions Relative to International Commitments
This edition of the Canada’s Air Pollutant Emissions Inventory (APEI) indicates that all international commitments relative to air pollution emissions continue to be met. Table A4–1 lists the atmospheric pollutants and associated protocols under the CLRTAP along with the corresponding emission reduction targets or ceilings and the current situation in relation to those protocols (compared with the latest data year).
Table A4–1: Canada’s Air Pollutant Emissions in Relation to Protocols under the Convention on Long-Range Transboundary Air Pollution
| Pollutant | Protocols under the CLRTAP | Protocol obligation | Target met | Current situation (2023 emissions) |
|---|---|---|---|---|
| PM2.5 | 1999 Gothenburg Protocol (as amended in 2012) |
25% emission reduction from 2005 levels by 2020 and beyonda | Since 2016 | 21% under the emissions reduction commitment |
| SO2 | 1999 Gothenburg Protocol (as amended in 2012) | 55% emission reduction from 2005 levels by 2020 and beyond | Since 2018 | 36% under the emissions reduction commitment |
| SO2 | 1999 Gothenburg Protocol | 2010 emissions ceiling of 1.45 megatonnes (Mt) | Since 2009 | 58% under the emissions ceiling |
| SO2 | 1994 Oslo Protocol | Maintain emissions in the regional Sulphur Oxides Management Area (SOMA)b 46% below 1980 | Since 1990 | 86% under the emissions ceiling of 1.8Mt |
| SO2 | 1985 Helsinki Protocol | Reduction of emissions by at least 30% from 1980 levels by 1993 | Since 1990 | 81% under the emissions ceiling of 3.3 Mt |
| NOx | 1999 Gothenburg Protocol (as amended in 2012) | 35% emission reduction from 2005 levels by 2020 and beyond | Since 2016 | 16% under the emissions reduction commitment |
| NOx | 1999 Gothenburg Protocol | 2010 emissions ceiling of 2.25 Mt | Since 2006 | 45% under the emissions ceiling |
| NOx | 1988 Sofia Protocol | Stabilize (not exceed) 1987 emission level by 1994 | Since 1990 | 56% under the emissions ceiling of 2.8 Mt |
| VOCs | 1999 Gothenburg Protocol (as amended in 2012) | 20% emission reduction from 2005 levels by 2020 and beyond | Since 2011 | 24% under the emissions reduction commitment |
| VOCs | 1999 Gothenburg Protocol | 2010 emissions ceiling of 2.1 Mt | Since 2008 | 35% under the emissions ceiling |
| NH3 | 1999 Gothenburg Protocol | Emission reporting | Since established | Yearly reporting |
| Pb | 1998 Aarhus Protocol on Heavy Metals | 50% emission reduction of 1990 levels by 2011 | Since 2002 | 82% under the emissions ceiling of 511 tonnes |
| Cd | 1998 Aarhus Protocol on Heavy Metals | 50% emission reduction of 1990 levels by 2011 | Since 2007 | 89% under the emissions ceiling of 41 tonnes |
| Hg | 1998 Aarhus Protocol on Heavy Metals | 50% emission reduction of 1990 levels by 2011 | Since 1995 | 81% under the emissions ceiling of 17 tonnes |
| Dioxins and furans | 1998 Aarhus Protocol on POPs | Stabilize (not exceed) 1990 emission levels | Since 1999 | 67% under the emissions ceiling of 233 gTEQ |
| PAHs B(a)p | 1998 Aarhus Protocol on POPs | Stabilize (not exceed) 1990 emission levels | Since 1991 | 90% under the emissions level |
| PAHs B(b)f | 1998 Aarhus Protocol on POPs | Stabilize (not exceed) 1990 emission levels | Since 1991 | 92% under the emissions level |
| PAHs B(k)f | 1998 Aarhus Protocol on POPs | Stabilize (not exceed) 1990 emission levels | Since 1991 | 95% under the emissions level |
| PAHs I(cd)p | 1998 Aarhus Protocol on POPs | Stabilize (not exceed) 1990 emission levels | Since 1991 | 89% under the emissions level |
| HCB | 1998 Aarhus Protocol on POPs | Stabilize (not exceed) 1990 emission levels | Since 2003 | 88% under the emissions ceiling of 39 kg |
Notes:
- This commitment excludes road dust, construction operations and crop production emission sources.
- The SOMA covers the provinces of Nova Scotia, Prince Edward Island, New Brunswick and parts of Quebec and Ontario.
Table A4–1 shows that all commitments were met between 1990 and 2018, and that they continue to be met, with the latest one to be met being for the emissions reduction of sulphur oxides (SOx). Specifically, for the most recent protocol under the CLRTAP (1999 Gothenburg Protocol, as amended in 2012):
- Emissions of fine particulate matter (particulate matter less than or equal to 2.5 microns in diameter [PM2.5]) decreased from most sources with the notable exceptions of dust sources (not from combustion) such as construction operations and roads; Canada’s emission reduction commitment for PM2.5Footnote 2 excludes these two sources along with crop production. Emissions of PM2.5 were 1.4 megatonnes (Mt) in 2023, but excluding these three sources, they were 21% lower than the 2020 reduction commitment of the amended Gothenburg Protocol of 2012.
- Emissions of sulphur oxides (SOx) were 0.60 megatonnes (Mt) in 2023, which is 36% below the 0.9 Mt commitment as per the amended Gothenburg Protocol of 2012.
- Emissions of nitrogen oxides (NOx) were 1.2 Mt in 2023, which is 16% below the 1.5 Mt commitment as per the amended Gothenburg Protocol of 2012.
- Emissions of non-methane VOCs (NMVOCs)Footnote 3 were 1.4 Mt in 2023, which is 24% below the 1.8 Mt commitment as per the amended Gothenburg Protocol of 2012.
A4.2 Overview of the United Nations Economic Commission for Europe Reporting Template
The UNECE NFR categories correspond to the sectors described in the EMEP/EEA Air Pollutant Emission Inventory Guidebook (EEA, 2023). In addition to providing technical guidance for developing inventory methodologies, the EMEP/EEA guidebook includes instructions for attributing sectoral emissions to NFR codes.
Whereas the APEI report groups emissions by sectors (e.g., pulp and paper industry), the emissions in the UNECE are grouped by process and combustion sources. For example, the pulp and paper industry within the APEI includes both combustion and process emissions. The combustion component is mapped to NFR sector 1A2d (Stationary combustion in manufacturing industries and construction: Pulp, Paper and Print). The process component is mapped to NFR sector 2H1 (Pulp and paper industry).
Table A4–2 illustrates the structure of the UNECE reporting template. The template, last revised November 18, 2019, can be found in its entirety on the CEIP website.Footnote 4 Canada’s NFR tables annual submission can be found on the CEIP website as well.Footnote 5
Table A4–2: Excerpt from United Nations Economic Commission for Europe Nomenclature for Reporting Template for 2025
| NFR aggregation for gridding and LPS (GNFR) |
NFR sectors to be reported NFR Code | NFR sectors to be reported Long name | Main pollutants (from 1990) NOx (as NO2) (kt) |
Main pollutants (from 1990) NMVOC (kt) |
Main pollutants (from 1990) SOx (as SO2) (kt) |
Main pollutants (from 1990) NH3 (kt) |
Particulate matter (from 2000) PM2.5 (kt) |
Particulate matter (from 2000) PM10 (kt) |
Particulate matter (from 2000) TSP (kt) |
Particulate matter (from 2000) BC (kt) |
Other (from 1990) CO (kt) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| A_PublicPower | 1 A 1 a | Public electricity and heat production | NIL | NIL | NIL | NIL | NIL | NIL | NIL | NIL | NIL |
| B_Industry | 1 A 1 b | Petroleum refining | NIL | NIL | NIL | NIL | NIL | NIL | NIL | NIL | NIL |
| B_Industry | 1 A 1 c | Manufacture of solid fuels and other energy industries | NIL | NIL | NIL | NIL | NIL | NIL | NIL | NIL | NIL |
| B_Industry | 1 A 2 a | Stationary combustion in manufacturing industries and construction: Iron and steel | NIL | NIL | NIL | NIL | NIL | NIL | NIL | NIL | NIL |
| B_Industry | 1 A 2 b | Stationary combustion in manufacturing industries and construction: Non-ferrous metals | NIL | NIL | NIL | NIL | NIL | NIL | NIL | NIL | NIL |
| B_Industry | 1 A 2 c | Stationary combustion in manufacturing industries and construction: Chemicals | NIL | NIL | NIL | NIL | NIL | NIL | NIL | NIL | NIL |
| B_Industry | 1 A 2 d | Stationary combustion in manufacturing industries and construction: Pulp, Paper and Print | NIL | NIL | NIL | NIL | NIL | NIL | NIL | NIL | NIL |
| B_Industry | 1 A 2 e | Stationary combustion in manufacturing industries and construction: Food processing, beverages and tobacco | NIL | NIL | NIL | NIL | NIL | NIL | NIL | NIL | NIL |
| B_Industry | 1 A 2 f | Stationary combustion in manufacturing industries and construction: Non-metallic minerals | NIL | NIL | NIL | NIL | NIL | NIL | NIL | NIL | NIL |
| I_Offroad | 1 A 2 g vii | Mobile combustion in manufacturing industries and construction: (please specify in your IIR) | NIL | NIL | NIL | NIL | NIL | NIL | NIL | NIL | NIL |
| B_Industry | 1 A 2 g viii | Stationary combustion in manufacturing industries and construction: Other (please specify in your IIR) | NIL | NIL | NIL | NIL | NIL | NIL | NIL | NIL | NIL |
Notes:
BC = black carbon
GNFR = Gridded nomenclature for reporting
IIR = Informative Inventory Report, which is equivalent to Air Pollutant Emissions Inventory Report and Black Carbon Report in Canada
LPS = Large point source
NMVOC = Non-methane volatile organic compounds (refer to Annex 1 for more information)
TSP = Total suspended particles (equivalent to TPM in this report)
A4.3 Mapping of Air Pollutant Emission Inventory Emissions to the United Nations Economic Commission for Europe’s Nomenclature for Reporting Categories
The mapping of APEI sector emissions to UNECE NFR categories involves dividing the sector emissions into their combustion and process components. Whereas certain sectors contribute solely a process component (in the case of road dust) or combustion component (in the case of the transport sector), the majority of sectoral emissions are distributed over both components. In most sectors, this is accomplished using a split ratio, which, apart from a small number of exceptions, is assigned to a particular subsector and pollutant. For example, in the oil sands mining, extraction and upgrading subsector, a portion of the emissions are attributed to combustion and are accounted in manufacture of solid fuels and other energy industries, while another portion is attributed to the process emissions and are compiled in the fugitive emissions oil as illustrated in Table A4–3. The only exception for that subsector is ammonia (NH3), where all emissions are attributed to combustion activities. Finally, some in-house estimation methodologies produce detailed emissions by sources, and emissions are assigned directly to the appropriate combustion or process NFR code.
Table A4–3: Example of Subsector Mapping to a United Nations Economic Commission for Europe’s Nomenclature for Reporting Category
| APEI subsector | UNECE NFR category Combustion | UNECE NFR category Process | Pollutant | Split ratios (w/w)a Combustion | Split ratios (w/w)a Process |
|---|---|---|---|---|---|
| Oil Sands Mining, Extraction and Upgrading | 1A1c: Manufacture of solid fuels and other energy industries | 1B2ai: Fugitive emissions oil: Exploration, production, transport | B(a)p | 0.998 | 0.002 |
| Oil Sands Mining, Extraction and Upgrading | 1A1c: Manufacture of solid fuels and other energy industries | 1B2ai: Fugitive emissions oil: Exploration, production, transport | B(b)f | 0.834 | 0.166 |
| Oil Sands Mining, Extraction and Upgrading | 1A1c: Manufacture of solid fuels and other energy industries | 1B2ai: Fugitive emissions oil: Exploration, production, transport | B(k)f | 0.998 | 0.002 |
| Oil Sands Mining, Extraction and Upgrading | 1A1c: Manufacture of solid fuels and other energy industries | 1B2ai: Fugitive emissions oil: Exploration, production, transport | Cd | 0.970 | 0.030 |
| Oil Sands Mining, Extraction and Upgrading | 1A1c: Manufacture of solid fuels and other energy industries | 1B2ai: Fugitive emissions oil: Exploration, production, transport | CO | 0.947 | 0.053 |
| Oil Sands Mining, Extraction and Upgrading | 1A1c: Manufacture of solid fuels and other energy industries | 1B2ai: Fugitive emissions oil: Exploration, production, transport | Hg | 0.969 | 0.031 |
| Oil Sands Mining, Extraction and Upgrading | 1A1c: Manufacture of solid fuels and other energy industries | 1B2ai: Fugitive emissions oil: Exploration, production, transport | I(1,2,3-cd)p | 0.999 | 0.001 |
| Oil Sands Mining, Extraction and Upgrading | 1A1c: Manufacture of solid fuels and other energy industries | 1B2ai: Fugitive emissions oil: Exploration, production, transport | NH3 | 1.000 | 0.000 |
| Oil Sands Mining, Extraction and Upgrading | 1A1c: Manufacture of solid fuels and other energy industries | 1B2ai: Fugitive emissions oil: Exploration, production, transport | NOX | 0.996 | 0.004 |
| Oil Sands Mining, Extraction and Upgrading | 1A1c: Manufacture of solid fuels and other energy industries | 1B2ai: Fugitive emissions oil: Exploration, production, transport | Pb | 0.990 | 0.010 |
| Oil Sands Mining, Extraction and Upgrading | 1A1c: Manufacture of solid fuels and other energy industries | 1B2ai: Fugitive emissions oil: Exploration, production, transport | PM10 | 0.442 | 0.558 |
| Oil Sands Mining, Extraction and Upgrading | 1A1c: Manufacture of solid fuels and other energy industries | 1B2ai: Fugitive emissions oil: Exploration, production, transport | PM2.5 | 0.646 | 0.354 |
| Oil Sands Mining, Extraction and Upgrading | 1A1c: Manufacture of solid fuels and other energy industries | 1B2ai: Fugitive emissions oil: Exploration, production, transport | SOX | 0.998 | 0.002 |
| Oil Sands Mining, Extraction and Upgrading | 1A1c: Manufacture of solid fuels and other energy industries | 1B2ai: Fugitive emissions oil: Exploration, production, transport | TPM | 0.293 | 0.707 |
| Oil Sands Mining, Extraction and Upgrading | 1A1c: Manufacture of solid fuels and other energy industries | 1B2ai: Fugitive emissions oil: Exploration, production, transport | VOC | 0.113 | 0.887 |
Notes:
w/w = weight by weight (mass fraction)
a. Data sources: ECCC (2017)
A4.4 Reporting International Marine Navigation and Air Transportation Emissions
The APEI reports marine and aviation differently than NFR tables. While the overall total of emissions for these sectors are the same, the allocation into different categories is different.
The NFR table has five categories for marine: 1A3dii – National navigation (shipping), 1A4ciii – Agriculture/Forestry/Fishing: National fishing, 1A3di(i) – International maritime navigation, 1A3di(ii) – International inland waterways, and 1A5b – Other, Mobile (including military, land based and recreational boats). The APEI report includes all emissions occurring from domestic marine navigation (1A3dii), fishing vessels (1A4ciii) and military vessels (1A5b) in one category as those emissions contribute to Canada’s national total. International marine navigation (excluding fishing and military operations) is reported in a separate table in the APEI report and the NFR table, as those emissions do not contribute to Canada’s national total. This is consistent with international reporting requirements. No values are reported under 1A3di(ii) – International inland waterways.
Similarly, the NFR table has five categories for aviation: 1A3ai(i) – International aviation landing/take-offs (LTO) (civil), 1A3ai(ii) – International aviation cruise (civil), 1A3aii(i) – Domestic aviation LTO (civil), 1A3aii(ii) – Domestic aviation cruise (civil), and 1A5b – Other, Mobile (including military, land based and recreational boats). The APEI report includes all emissions occurring from civil LTO cycles—1A3ai(i) and 1A3aii(i)—and military flights (1A5b) in one category as those emissions contribute to Canada’s national total. The emissions attributed to the cruise phase for civil flights are reported separately in the APEI report and the NFR table, as those emissions do not contribute to Canada’s national total. This is consistent with international reporting requirements.
References
[ECCC] Environment and Climate Change Canada. 2017. An Inventory of GHG, CAC and Other Priority Emissions by the Canadian Oil Sands Industry: 2003 to 2015. Prepared by Clearstone Engineering Ltd.
[EEA] European Environment Agency. 2023. EMEP/EEA air pollutant emission inventory guidebook 2023. Technical guidance to prepare national emissions inventories. Luxembourg: Publications Office of the European Union Technical Report No. 06/2023
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