Canada’s Air Pollutant Emissions Inventory Report 2025: annex 3

Recalculations

Emission recalculation is an essential practice in the maintenance of up-to-date and consistent trends in air pollutant emissions. The Air Pollutant Emissions Inventory (APEI) is continuously updated with improved estimation methodologies, activity data and more recent and appropriate emission factors. As new information and data become available, previous estimates are updated and recalculated to ensure a consistent and comparable trend in emissions. Circumstances that warrant a change or refinement of data and/or methods include the:

Resubmissions of facility-reported data previously reported to the National Pollutant Release Inventory (NPRI) can also result in revised historical estimates. Generally, these recalculations by facilities are completed for only a few years in their historical emissions.

In contrast, new activity data are incorporated into the in-house estimates as they become available, and these updates are reflected in the trends on an ongoing basis. Table 3–1 in Chapter 3 shows which sources are estimated using facility reported data and/or in-house methods. Updated trends, based on updated facility-reported data and in-house estimates, are published on a yearly basis. For example, the calculation of emissions from commercial, residential, agricultural and construction fuel combustion sources rely on the latest fuel use quantities from the Statistics Canada annual publication Report on Energy Supply and Demand in Canada (RESD) (Statistics Canada, n.d.).

A3.1 Recalculations in this Air Pollutant Emissions Inventory Edition

The following pollutants were not significantly recalculated (net emissions change <2%) between the 2024 and 2025 editions of the APEI with negligible impacts on the time series trend lines:

The following pollutants had notable recalculations between the 2024 and 2025 editions of the APEI (in order of recalculation importance):

These recalculations are presented in Figure A3–1 to Figure A3–6, all at the national level.

Recalculations to PAHs emissions (Figure A3–1) are primarily attributed to incorporating a new emission factor from a Canadian residential wood combustion study. This study better reflects significant advancements made in stove designs and control strategies over the last several years, as well as Canadian practices in firewood burning. The new study is available online on the Government of Canada Open Data PortalFootnote 1 .

Figure A3–1 Recalculations to Polycyclic Aromatic Hydrocarbons (PAHs)

Figure A3–1 Recalculations to Polycyclic Aromatic Hydrocarbons (PAHs)
Long description for Figure A3-1

Figure A3-1: Recalculations to Polycyclic Aromatic Hydrocarbons (PAHs)

Figure A3-1 is a line graph comparing changes in polycyclic aromatic hydrocarbons (PAHs) emissions (1990-2023) between the 2024 and 2025 editions of the APEI. PAHs emissions have followed a similar trend for both the previous and current editions, decreasing sharply between 1990 and 2004 and then stabilizing while slightly continuing to decrease from 2005 to 2023. The figure is accompanied by a table presenting changes in PAHs emissions in tonnes as well as in percentage between the 2024 and 2025 editions of the APEI. The first table in this description is the one appearing on the graph. The second table in this description represents the two lines of the graph, i.e., the emissions of PAHs in tonnes for the 2024 and 2025 editions of the APEI.

Year Change in PAH Emissions (tonnes) Change in PAH Emissions (%)
1990 -39 -14%
1991 -39 -15%
1992 -42 -16%
1993 -42 -15%
1994 -41 -17%
1995 -40 -18%
1996 -41 -20%
1997 -41 -21%
1998 -34 -18%
1999 -33 -18%
2000 -34 -20%
2001 -30 -19%
2002 -29 -22%
2003 -28 -20%
2004 -30 -28%
2005 -31 -28%
2006 -31 -27%
2007 -36 -33%
2008 -37 -33%
2009 -38 -38%
2010 -34 -39%
2011 -37 -41%
2012 -35 -40%
2013 -40 -39%
2014 -41 -42%
2015 -42 -53%
2016 -40 -56%
2017 -40 -57%
2018 -37 -56%
2019 -32 -54%
2020 -30 -56%
2021 -30 -59%
2022 -32 -58%
Year PAH Emissions (tonnes) 2024 APEI PAH Emissions (tonnes) 2025 APEI
1990 282 243
1991 264 224
1992 264 223
1993 273 231
1994 245 203
1995 228 188
1996 212 171
1997 195 153
1998 185 151
1999 187 154
2000 167 134
2001 155 125
2002 131 102
2003 136 108
2004 107 77
2005 112 81
2006 114 83
2007 111 75
2008 113 76
2009 100 62
2010 86 52
2011 90 53
2012 89 53
2013 102 62
2014 99 58
2015 79 37
2016 71 31
2017 70 30
2018 66 29
2019 59 27
2020 54 23
2021 52 21
2022 55 23
2023 NIL 20

Recalculations to NOx and dioxins and furans emissions (Figure A3–2 and Figure A3–3 respectively) are mainly attributed to new data received to determine emissions from the Domestic Marine Navigation, Fishing and Military sector. Dioxins and furans emissions recalculations are also attributed to changes in activity data used to calculate landfill emissions. Specifically, a reduction in the amount of landfill gas flared resulted in a decrease in dioxins and furans emissions from landfills.

Figure A3–2 Recalculations to Nitrogen Oxides (NOx)

Figure A3–2 Recalculations to Nitrogen Oxides (NOx)
Long description for Figure A3-2

Figure A3-2: Recalculations to Nitrogen Oxides (NOx)

Figure A3-2 is a line graph comparing changes in nitrogen oxides (NOx) emissions (1990-2023) between the 2024 and 2025 editions of the APEI. NOx emissions have followed a similar trend for both the previous and current editions. From 1990 to 1997, emissions increased and then decreased drastically from 1999 to 2020. Emissions have since plateaued. The figure is accompanied by a table presenting changes in NOx emissions in kilotonnes as well as in percentage between the 2024 and 2025 editions of the APEI. The first table in this description is the one appearing on the graph. The second table in this description represents the two lines of the graph, i.e., the emissions of NOx in kilotonnes for the 2024 and 2025 editions of the APEI.

Year Change in NOx Emissions (kilotonnes) Change in NOx Emissions (%)
1990 -15 -0.7%
1991 -10 -0.4%
1992 -15 -0.7%
1993 -15 -0.7%
1994 -14 -0.6%
1995 -9 -0.3%
1996 -9 -0.3%
1997 -9 -0.3%
1998 -8 -0.3%
1999 -13 -0.5%
2000 -15 -0.6%
2001 -13 -0.5%
2002 -7 -0.3%
2003 -8 -0.3%
2004 -8 -0.3%
2005 -8 -0.3%
2006 -10 -0.5%
2007 -15 -0.7%
2008 -21 -1.0%
2009 -19 -1.0%
2010 -11 -0.6%
2011 -19 -1.1%
2012 -21 -1.2%
2013 -16 -1.0%
2014 -14 -0.9%
2015 -12 -0.8%
2016 -14 -0.9%
2017 -29 -2.0%
2018 -16 -1.1%
2019 -36 -2.5%
2020 -54 -4.1%
2021 -67 -5.1%
2022 -71 -5.4%
Year NOx Emissions (kilotonnes) 2024 APEI NOx Emissions (kilotonnes) 2025 APEI
1990 2,251 2,236
1991 2,186 2,176
1992 2,250 2,235
1993 2,334 2,319
1994 2,483 2,469
1995 2,551 2,542
1996 2,624 2,615
1997 2,736 2,727
1998 2,749 2,741
1999 2,757 2,744
2000 2,708 2,693
2001 2,581 2,568
2002 2,544 2,536
2003 2,511 2,503
2004 2,362 2,355
2005 2,266 2,259
2006 2,111 2,101
2007 2,103 2,088
2008 2,022 2,001
2009 1,891 1,872
2010 1,896 1,885
2011 1,804 1,785
2012 1,695 1,675
2013 1,651 1,635
2014 1,611 1,597
2015 1,544 1,532
2016 1,469 1,455
2017 1,492 1,462
2018 1,454 1,438
2019 1,433 1,397
2020 1,305 1,251
2021 1,308 1,242
2022 1,303 1,232
2023 0 1,228

Figure A3–3 Recalculations to Dioxins and Furans

Figure A3–3 Recalculations to Dioxins and Furans
Long description for Figure A3-3

Figure A3-3: Recalculations to Dioxins and Furans

Figure A3-3 is a line graph comparing changes in dioxins and furans emissions (1990-2023) between the 2024 and 2025 editions of the APEI. Dioxins and furans emissions have followed a similar trend for both the previous and current editions, being stable from 1990 to 1997, then decreasing slowly until 2003, followed by a sharp decrease until 2012. Since then, emissions have plateaued. The figure is accompanied by a table presenting changes in dioxins and furans emissions in grams of toxicity equivalent (gTEQ) as well as in percentage between the 2024 and 2025 editions of the APEI. The first table in this description is the one appearing on the graph. The second table in this description represents the two lines of the graph, i.e., the emissions of dioxins and furans in gTEQ for the 2024 and 2025 editions of the APEI.

Year Change in D/F Emissions (gTEQ) Change in D/F Emissions (%)
1990 -0.1 -0.1%
1991 -0.2 -0.1%
1992 -0.5 -0.2%
1993 -0.5 -0.2%
1994 -0.5 -0.2%
1995 -0.3 -0.1%
1996 0.2 0.1%
1997 0.8 0.3%
1998 0.9 0.4%
1999 1.0 0.5%
2000 1.0 0.4%
2001 0.4 0.2%
2002 0.4 0.2%
2003 0.1 0.1%
2004 -0.1 -0.1%
2005 -0.3 -0.2%
2006 -0.1 0.0%
2007 -0.2 -0.1%
2008 -0.1 -0.1%
2009 -0.8 -0.7%
2010 -0.8 -0.7%
2011 -1.6 -1.9%
2012 -2.1 -2.6%
2013 -2.2 -2.9%
2014 -2.3 -2.9%
2015 -2.5 -3.0%
2016 -2.9 -3.6%
2017 -2.9 -3.5%
2018 -3.0 -3.8%
2019 -3.4 -4.0%
2020 -3.3 -4.3%
2021 -3.9 -4.6%
2022 -4.1 -5.0%
Year D/F Emissions (gTEQ) 2024 APEI D/F Emissions (gTEQ) 2025 APEI
1990 233 233
1991 242 242
1992 250 250
1993 253 252
1994 253 252
1995 245 245
1996 243 243
1997 246 247
1998 234 235
1999 224 225
2000 230 231
2001 221 221
2002 217 217
2003 217 218
2004 194 194
2005 170 170
2006 153 153
2007 144 143
2008 132 132
2009 122 121
2010 118 118
2011 87 86
2012 80 78
2013 78 76
2014 81 79
2015 83 81
2016 80 78
2017 83 80
2018 80 77
2019 85 82
2020 77 73
2021 83 79
2022 80 76
2023 NIL 77

Recalculations to PM10 and TPM emissions (Figure A3–4 and Figure A3–5 respectively) are largely attributed to changes in the Dust category. The main contributor for this category being the change in activity data (traffic counts) used as input to the road dust model. Another contributor is the incorporation of a new emission factor from a Canadian study to calculate emissions from the residential wood combustion sector (see PAHs recalculations section for more details).

Figure A3–4 Recalculations to Particulate Matter less than or equal to 10 Microns in Diameter (PM10)

Figure A3–4 Recalculations to Particulate Matter less than or equal to 10 Microns in Diameter (PM10)
Long description for Figure A3-4

Figure A3-4: Recalculations to particulate matter less than or equal to 10 microns in diameter (PM10)

Figure A3-4 is a line graph comparing changes in emissions of particulate matter less than or equal to 10 microns in diameter (PM10) (1990-2023) between the 2024 and 2025 editions of the APEI. PM10 emissions have followed a similar trend for both the previous and current submissions, increasing overall between 1990 and 2023. From 1990 to 2006, PM10 emissions are relatively stable and then increase more significantly between 2006 and 2013. Emissions continue to increase slightly until 2019, undergo a significant decrease in 2020, and then increase again until 2023. The figure is accompanied by a table presenting changes in PM10 emissions in kilotonnes as well as in percentage between the 2024 and 2025 editions of the APEI. The first table in this description is the one appearing on the graph. The second table in this description represents the two lines of the graph, i.e., the emissions of PM10 in kilotonnes for the 2024 and 2025 editions of the APEI.

Year Change in PM10 Emissions (kilotonnes) Change in PM10 Emissions (%)
1990 -182 -2.7%
1991 -156 -2.4%
1992 -152 -2.3%
1993 -173 -2.6%
1994 -181 -2.7%
1995 -190 -2.8%
1996 -129 -1.9%
1997 -112 -1.6%
1998 -77 -1.1%
1999 -102 -1.5%
2000 -77 -1.1%
2001 -53 -0.8%
2002 -49 -0.7%
2003 -45 -0.7%
2004 -50 -0.7%
2005 -46 -0.7%
2006 -31 -0.5%
2007 -33 -0.5%
2008 -24 -0.3%
2009 -20 -0.3%
2010 -21 -0.3%
2011 -11 -0.1%
2012 -4.9 -0.1%
2013 -2.7 0.0%
2014 6.0 0.1%
2015 15 0.2%
2016 1.5 0.0%
2017 -16 -0.2%
2018 25 0.3%
2019 -63 -0.8%
2020 -67 -0.9%
2021 214 2.9%
2022 264 3.5%
Year PM10 Emissions (kilotonnes) 2024 APEI PM10 Emissions (kilotonnes) 2025 APEI
1990 6,709 6,528
1991 6,518 6,361
1992 6,481 6,329
1993 6,546 6,373
1994 6,760 6,579
1995 6,791 6,601
1996 6,768 6,639
1997 6,972 6,860
1998 6,954 6,876
1999 6,965 6,863
2000 6,917 6,840
2001 7,050 6,997
2002 6,836 6,787
2003 6,847 6,802
2004 6,795 6,746
2005 6,855 6,809
2006 6,729 6,698
2007 6,927 6,894
2008 7,085 7,061
2009 6,985 6,965
2010 7,174 7,154
2011 7,267 7,257
2012 7,583 7,578
2013 7,790 7,787
2014 7,809 7,815
2015 7,684 7,699
2016 7,476 7,477
2017 7,661 7,645
2018 7,934 7,959
2019 8,156 8,093
2020 7,347 7,279
2021 7,488 7,702
2022 7,555 7,819
2023 NIL 8,172

Figure A3–5 Recalculations to Total Particulate Matter (TPM)

Figure A3–5 Recalculations to Total Particulate Matter (TPM)
Long description for Figure A3-5

Figure A3-5: Recalculations to total particulate matter (TPM)
Figure A3-5 is a line graph comparing changes in total particulate matter (TPM) emissions (1990-2023) between the 2024 and 2025 editions of the APEI. TPM emissions have followed a similar trend for both the previous and current submissions, increasing overall between 1990 and 2023. From 1990 to 2006, TPM emissions are relatively stable and then increase significantly between 2006 and 2013. Emissions continue to increase slightly until 2019, undergo a significant decrease in 2020, and then increase again until 2023. The figure is accompanied by a table presenting changes in TPM emissions in kilotonnes as well as in percentage between the 2024 and 2025 editions of the APEI. The first table in this description is the one appearing on the graph. The second table in this description represents the two lines of the graph, i.e., the emissions of TPM in kilotonnes for the 2024 and 2025 editions of the APEI.

Year Change in TPM Emissions (kt) Change in TPM Emissions (%)
1990 -788 -3.8%
1991 -693 -3.4%
1992 -693 -3.4%
1993 -800 -3.9%
1994 -856 -4.1%
1995 -908 -4.3%
1996 -667 -3.1%
1997 -592 -2.7%
1998 -449 -2.0%
1999 -541 -2.5%
2000 -445 -2.1%
2001 -385 -1.7%
2002 -370 -1.7%
2003 -359 -1.7%
2004 -373 -1.7%
2005 -351 -1.6%
2006 -307 -1.4%
2007 -328 -1.5%
2008 -304 -1.4%
2009 -305 -1.4%
2010 -311 -1.4%
2011 -271 -1.2%
2012 -270 -1.1%
2013 -267 -1.1%
2014 -232 -0.9%
2015 -217 -0.9%
2016 -275 -1.1%
2017 -369 -1.5%
2018 -230 -0.9%
2019 -544 -2.1%
2020 -500 -2.1%
2021 713 2.9%
2022 800 3.3%
Year TPM Emissions (kilotonnes) 2024 APEI TPM Emissions (kilotonnes) 2025 APEI
1990 20,764 19,976
1991 20,153 19,461
1992 20,126 19,433
1993 20,319 19,520
1994 21,113 20,257
1995 21,354 20,445
1996 21,256 20,589
1997 21,953 21,361
1998 21,939 21,490
1999 21,783 21,242
2000 21,549 21,105
2001 22,155 21,770
2002 21,606 21,237
2003 21,585 21,226
2004 21,425 21,052
2005 21,512 21,161
2006 21,202 20,896
2007 21,893 21,565
2008 22,500 22,195
2009 22,307 22,002
2010 22,929 22,618
2011 23,165 22,894
2012 24,387 24,117
2013 25,129 24,862
2014 25,046 24,814
2015 24,731 24,514
2016 23,992 23,717
2017 24,734 24,365
2018 25,814 25,584
2019 26,540 25,996
2020 23,690 23,190
2021 24,233 24,947
2022 24,530 25,330
2023 NIL 26,804

Recalculations to VOCs (Figure A3–6) are primarily attributed to incorporating a new emission factor from a Canadian study to calculate emissions from the residential wood combustion sector (see PAHs recalculations section for more details) as well as the refinement of the activity data used to determine the contribution of general solvent use.

Figure A3–6 Recalculations to Volatile Organic Compounds (VOCs)

Figure A3–6 Recalculations to Volatile Organic Compounds (VOCs)
Long description for Figure A3-6

Figure A3-6: Recalculations to Volatile Organic Compounds (VOCs)

Figure A3-6 is a line graph comparing changes in emissions of volatile organic compounds (VOCs) (1990-2023) between the 2024 and 2025 editions of the APEI. Overall, VOCs emissions have followed a similar trend for both the previous and current editions, with emissions in 2023 being lower than those in 1990. From 1990 to 1996, emissions increased and then decreased drastically from 1998 to 2020. Emissions have since plateaued. The figure is accompanied by a table presenting changes in VOCs emissions in kilotonnes as well as in percentage between the 2024 and 2025 editions of the APEI. The first table in this description is the one appearing on the graph. The second table in this description represents the two lines of the graph, i.e., the emissions of VOCs in kilotonnes for the 2024 and 2025 editions of the APEI.

Year Change in VOC Emissions (kilotonnes) Change in VOCs Emissions (%)
1990 -87 -3.8%
1991 -87 -3.8%
1992 -89 -3.9%
1993 -89 -3.7%
1994 -85 -3.5%
1995 -83 -3.3%
1996 -84 -3.3%
1997 -82 -3.2%
1998 -68 -2.6%
1999 -65 -2.6%
2000 -64 -2.6%
2001 -58 -2.4%
2002 -43 -1.8%
2003 -38 -1.6%
2004 -37 -1.6%
2005 -37 -1.6%
2006 -40 -1.8%
2007 -44 -2.1%
2008 -42 -2.1%
2009 -39 -2.1%
2010 -31 -1.7%
2011 -31 -1.8%
2012 -26.3 -1.5%
2013 -26.4 -1.5%
2014 -23.5 -1.3%
2015 -19 -1.1%
2016 -14.5 -0.9%
2017 -14 -0.8%
2018 -24 -1.5%
2019 -36 -2.3%
2020 -37 -2.7%
2021 -33 -2.4%
2022 -40 -2.8%
Year VOC Emissions (kilotonnes) 2024 APEI VOC Emissions (kilotonnes) 2025 APEI
1990 2,287 2,200
1991 2,263 2,176
1992 2,295 2,206
1993 2,388 2,299
1994 2,450 2,365
1995 2,512 2,429
1996 2,564 2,480
1997 2,558 2,476
1998 2,561 2,493
1999 2,520 2,455
2000 2,513 2,448
2001 2,435 2,377
2002 2,415 2,372
2003 2,356 2,318
2004 2,283 2,246
2005 2,293 2,256
2006 2,169 2,129
2007 2,104 2,059
2008 2,019 1,977
2009 1,870 1,832
2010 1,839 1,809
2011 1,768 1,737
2012 1,779 1,753
2013 1,812 1,785
2014 1,811 1,787
2015 1,710 1,691
2016 1,604 1,589
2017 1,596 1,582
2018 1,626 1,602
2019 1,579 1,543
2020 1,393 1,355
2021 1,405 1,372
2022 1,407 1,367
2023 NIL 1,368

Refer to Annex 2 and Canada’s Air Pollutant Emissions Inventory Methodology Document available on the Government of Canada Open Data PortalFootnote 2  for additional information on methodologies.

A3.2 Considerations for Future Editions of this Inventory

Further refinements and recalculations to the emission estimates are anticipated for subsequent editions of the APEI. An example of a suggested planned improvement is the refinement of the road Dust traffic-distribution model to include a variable (evolving) road network and, provincial and territorial specific total kilometers driven. This improvement is anticipated resulting in significant downward revisions to unpaved road dust particulate matter emission estimates by approximately 70% for the 2026 APEI.

Please contact apei-iepa@ec.gc.ca for more information on any methodological update or recalculations.

References

Statistics Canada. No date. Report on energy supply and demand in Canada (Annual), Catalogue No. 57 003 X.

Page details

2025-03-14