Canada’s Air Pollutant Emissions Inventory Report: annex 2 part 7

A2.3 Recalculations

Emission recalculation is an essential practice in the maintenance of up-to-date and consistent trends in air pollutant emissions. Circumstances that warrant a change or refinement of data and/or methods include:

  • correction of errors detected by quality control procedures
  • incorporation of updates to activity data including changes to data sources
  • re-allocation of activites to different categories (which will affect sub-totals)
  • refinements of methodologies and emission factors
  • inclusion of categories previously not estimated (which improves inventory completeness)

Resubmissions of facility-reported data previously reported to the 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. 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 fuel combustion, residential fuel combustion, agricultural fuel use and construction fuel combustion sectors rely on the latest fuel use quantities from the Statistics Canada annual publication Report on Energy Supply and Demand in Canada (RESD) (Statistics Canada, RESD, n.d.).

The following in-house emissions estimates were recalculated for the 2018 edition of the APEI. Brief descriptions of the recalculations and the impacts on emission levels are provided in tables A2-13 to A2-19.

  • Oil and Gas Industry: Refined Petroleum Products Bulk Storage and Distribution; Natural Gas Distribution; Accidents and Equipment Failures; Disposal and Waste Treatment; Heavy Crude Oil Cold Production; Light/Medium Crude Oil Production; Natural Gas Production and Processing; Natural Gas Transmission and Storage; Oil Sands In-Situ Extraction; Petroleum Liquids Storage; Petroleum Liquids Transportation; Well Drilling/Servicing/Testing
  • Manufacturing: Bakeries; Wood Products
  • Transportation and Mobile Equipment: Marine Transportation; On-Road Vehicles; Off-Road Vehicles and Equipment
  • Agriculture: Animal Production; Crop Production; Fuel Use
  • Commercial/Residential/Institutional: Commercial and Institutional Fuel Combustion; Construction Fuel Combustion; Residential Fuel Combustion
  • Incineration and Waste: Waste Incineration; Landfills
  • Mercury in Products

For the purpose of tables A2-13 to A2-19, the term “significant” refers to changes greater than ±10% in emission levels.

Table A2-13:  Recalculations for Oil and Gas Industry
Sector/subsector Polluant(s) Description Impact on emissions
Refined Petroleum Products Bulk Storage and Distribution (under Downstream Oil and Gas Industry) VOCs For the period 2013 to 2017, some emissions previously allocated to petroleum refining are now reported in this category. Changes in allocation resulted in a maximum emission increase of about 1.3% in 2014.
Natural Gas Distribution (under Downstream Oil and Gas Industry) TPM, PM10, PM2.5, SOx, NOx, VOCs, CO Recalculations occurred from 2003 through 2016 as a result of updates to the reported NPRI data and improved allocation of NPRI data to the Oil and Gas Industry subsectors. This resulted in changes to emissions at the national level from 2003 through 2016 for CO (largest difference in 2004: +293.0 t, +15.7%), from 2003 through 2016 for NOx (largest difference in 2004: -46.0t, -24.0%), from 2015 through 2016 for SOx (largest difference in 2016: +0.1t, +12.2%), 2003 through 2016 for PM10 (largest difference in 2005: -11.4t, -33.8%), from 2004 through 2016 for TPM (largest difference in 2010: +0.2t, +19.3%). For VOC and PM2.5, this recalculation did not result in an emissions change greater than ±10%.
Accidents and Equipment Failures (under Upstream Oil and Gas Industry) VOCs Recalculations occurred from 2012 through 2016 as a result of updated activity data. (AER, AER Compliance Dashboard – Incidents, 2018; BCOGC, 2018; SK MOE, Saskatchewan upstream oil and gas IRIS incident report, 2018). The recalculations did not result in changes greater than ±10% for any pollutants in the impacted years.
Disposal and Waste Treatment (under Upstream Oil and Gas Industry) VOCs, CO Recalculations occurred from 2013 through 2016 as a result of updated activity data. (AER, Upstream petroleum industry flaring and venting report, 2018; AER, VPR6800 Supply and disposition of gas (economics), 2018; Statistics Canada, Table 25-10-0063-01, n.d.). The recalculations did not result in changes greater than ±10% for any of the pollutants.
Heavy Crude Oil Cold Production (under Upstream Oil and Gas Industry) VOCs Recalculations occurred from 2013 through 2016 as a result of updated activity data. (AER, Upstream petroleum industry flaring and venting report, 2018; AER, VPR6800 Supply and disposition of gas (economics), 2018; SK MOE, Saskatchewan fuel, flare and vent, 2018). The recalculations did not result in changes greater than ±10% for any of the pollutants.
Light Medium Crude Oil Production (under Upstream Oil and Gas Industry) TPM, PM10, PM2.5, SOx, NOx, VOCs, CO, NH3 Recalculations occurred from 2012 through 2016 as a result of updated activity data. (AER, Upstream petroleum industry flaring and venting report, 2018; AER, VPR6800 Supply and disposition of gas (economics), 2018; BC, 2018; SK MOE, Saskatchewan fuel, flare and vent, 2018). The recalculations did not result in changes greater than ±10% for any of the pollutants.
Natural Gas Production and Processing (under Upstream Oil and Gas Industry) SOx Recalculations occurred from 2006 through 2016 as a result of updates to the reported NPRI data and improved allocation of NPRI data to the Oil and Gas Industry subsectors. The recalculations did not result in changes greater than ±10% for any of the pollutants.
Natural Gas Transmission and Storage (under Upstream Oil and Gas Industry) TPM, PM10, PM2.5, SOx, NOx, VOCs, CO, NH3

Recalculations occurred from 2002 through 2016, as a result of updates to the reported NPRI data and the improved allocation of NPRI data to Oil and Gas Industry subsectors.

This resulted in changes to emissions at the national level from 2002 through 2016 for CO (largest difference in 2012: +733.6t, +15.6%), from 2002 through 2016 for NOx (largest difference in 2004: +3767.0t, 15.9%), from 2002 through 2016 for VOCs (largest difference in 2004: +262t, +20.4%), 2003 through 2016 for SOx (largest difference in 2010: +747.7t, +3621.0%), from 2002 through 2016 for PM2.5 (largest difference in 2003: +83.3t, +27.4%), from 2002 through 2016 for PM10 (largest difference in 2016: +25.5t, +28.8%), from 2002 through 2016 for TPM (largest difference in 2011: +84.8t, +91.3%). For NH3, this resulted in changes to 2016 emissions at the national level (+0.1t, +16.4%).
Oil Sands In-Situ Extraction (under Upstream Oil and Gas Industry) TPM, PM10, PM2.5, SOx, NOx, VOCs, CO, NH3, CD Recalculations occurred for the entire time series, from 1990 through 2016, as a result of updates to the reported NPRI data and improved allocation of NPRI data to the Oil and Gas Industry subsectors. This resulted in changes to emissions at the national level from 1990 through 2016 for TPM (largest difference in 2004: +59.2t, +26.7%), from 2002 through 2005 for Cd (largest difference in 2004: +37.2t, +284.4%), from 2002 through 2016 for SOx (largest difference in 2003: +536.2t, +10.4%).For all other pollutants, this recalculation did not result in an emissions change of greater than ±10%.
Petroleum Liquids Storage (under Upstream Oil and Gas Industry) VOCs Recalculations occurred from 2002 through 2016 as a result of updates to the reported NPRI data and improved allocation of NPRI data to the Oil and Gas Industry subsectors. The recalculations resulted in changes to VOC emissions from 2002 through 2016 (largest difference in 2005: 2940.2t, 150.9%).
Petroleum Liquids Transportation (under Upstream Oil and Gas Industry) TPM, PM10, PM2.5, SOx, NOx, VOCs, CO Recalculations occurred from 2012 through 2016 as a result of updates to the reported NPRI data. This resulted in changes to emissions at the national level from 2012 through 2016 for PM2.5 (largest difference in 2016: +5.2t, +73.9%), from 2012 through 2016 for PM10 (largest difference in 2016: +7.8t, +96.5%), from 2012 through 2016 for TPM (largest difference in 2016: +7.8t, +96.5%). For SOx, this resulted in emissions from 2012 through 2016 (i.e. no emissions estimates previously). For all other pollutants, this recalculation did not result in an emissions change of greater than ±10%.
Oil Sands Mining, Extraction and Upgrading (under Upstream Oil and Gas Industry) TPM, PM10, PM2.5, SOx, NOx, VOCs, CO, NH3, Pb, B(a)p, B(p)f, HCB, B(k)f, I(1,2,3-cd)p Recalculations occurred from 1996 through 2016 as a result of updates to the reported NPRI data and improved allocation of NPRI data to the Oil and Gas Industry subsectors. This resulted in changes to emissions at the national level from 1996 through 2005 for NH3 (largest difference in 1998: +674t, +68.9%), from 2002 through 2005 for Cd (largest difference in 2004: -16.0t,-32.5%), from 2000 through2005 for B(b)f (largest difference in 2005: -0.4t, -35.6%), from 2000 through 2005 for B(k)f (largest difference in 2005: -0.4t,-40.8%), from 2000 through 2005 for I(1,2,3-cd)p (largest difference -0.3t, -29.4%). For all other pollutants, this recalculation did not result in an emissions change of greater than ±10%.
Table A2-14:  Recalculations for Manifacturing
Sector/subsector Polluants Description Impact on emissions
Bakeries VOCs A new estimation methodology was implemented to align with that used by the Quebec Government. Updated population and bakeries activity data were used for 1990–2016 estimates.

The recalculations resulted in significant changes in emissions levels (> ±10%) for 1990–2016.

The recalculated emissions decreased by 10.9 kt or 69% in 2016 for VOCs.

Wood Products TPM, PM10, PM2.5, SOx, NOx, VOCs, CO, NH3, Pb, Cd, Hg, dioxins/furans, B(a)p, B(b)f, B(k)f, I(cd)p,

The recalculations were done using updated activity data provided by the Forestry Products and Fishery Acts Division from 1990 to 2016.

The recalculations resulted in changes in emission levels (> ±10%) for TPM; PM10 and PM2.5 from 2006 to 2016; NOx from 2004 to 2005; VOCs for 2005; CO for 2003; Pb for 2004; Cd from 2003 to 2004; dioxins/furans from 1990 to 2008 and 2011 to 2016; and B(a)p from 2002 to 2004.

Table A2-15:  Recalculations for Transportation and Mobile Equipment
Sector/subsector Polluant Fuel Description Impact on emissions
Marine Transportation B(a)p, B(b)f, B(k)f, I(cd)p, TPM, PM10, PM2.5, SOx, NOx, VOCs, CO, NH3, Pb, Cd, Hg, D/F Heavy Fuel Oil, Marine Diesel Oil, Marine Gasoline Oil Model updates from Marine Emissions Inventory Tool 2015, new interpolation for the years between 2010–2014 and new extrapolation to 2016.

The recalculations did not impact results for 1990.

The recalculations for 2016 resulted in significant changes in the emissions of B(a)p (+103% or +10kg), B(b)f (+103% or +19kg), B(k)f (+103% or +10kg), I(1,2,3-cd)p (+103% or +19kg), TPM (-17% or -940 t), PM10 (-17% or -900 t), PM2.5 (-17% or -830 t), SOx (-36% or -4.9 kt), NOx (-7% or -14 kt), VOCs (+13% or +0.95 kt), CO (-11% or -2.4 kt), NH3 (-10% or -30 t), Pb (+103 or +290 kg), Cd (-66% or -65 kg), Hg (-76% or -1.7 kg) and D/F (+103% or +10 kg).

On-Road Vehicles (includes the following sectors: Heavy-duty Diesel Vehicles, Heavy-duty Gasoline Vehicles, Heavy-duty LPG/NG Vehicles, Light-duty Diesel Trucks, Light-duty Diesel Vehicles, Light-duty Gasoline Trucks, Light-duty Gasoline Vehicles, Light-duty LPG/NG Vehicles, Light-duty LPG/NG Trucks, Motorcycles, Tire Wear and Brake Lining) all All transport fuels

Due to the inter-relationship between the On-road and Off-road sectors in terms of how total fuel use is normalized to the Report on Energy Supply and Demand (RESD), changes in methodology to any aspect of on-road or off-road will impact both sectors. Relative to the 2018 submission, for the 2019 submission the following methodology changes were implemented for on-road and off-road.

Change in assumed hours-of-use for snowmobiles for all year and all provinces/territories (ECCC, Off-road Equipment Analysis - Snowmobiles, 2018).

Change in estimated number of Diesel off-road vehicles/engines used in Oil Sands mining (ECCC, Off-road Equipment Analysis - Oil Sands Mining Equipment, 2018).

Change in estimated number of on-road vehicles in all territories for all years.

Change in the version of the RESD used for normalization.

The recalculations did not significantly impact results for 1990 or 2016.
Off-Road Vehicles and Equipment all All transport fuels

Due to the inter-relationship between the On-road and Off-road sectors in terms of how total fuel use is normalized to the Report on Energy Supply and Demand (RESD), changes in methodology to any aspect of on-road or off-road will impact both sectors. Relative to the 2018 submission, for the 2019 submission the following methodology changes were implemented for on-road and off-road.

Change in assumed hours-of-use for snowmobiles for all year and all provinces/territories (ECCC, Off-road Equipment Analysis - Snowmobiles, 2018).

Change in estimated number of Diesel off-road vehicles/engines used in Oil Sands mining. (ECCC, Off-road Equipment Analysis - Oil Sands Mining Equipment, 2018).

Change in estimated number of on-road vehicles in all territories for all years.

Change in the version of the RESD used for normalization.

The net result of methodology changes impact all pollutants for both On-road and Off-road sectors, for all years. However, changes are not large at the national level, with only VOC from off-road being a change greater than 10% in calendar years 1990 and 2016, relative to the 2018 submission estimates for those same calendar years for off-road. The 2019 submission shows a 10.2% (93 kt) decrease in VOC from off-road in calendar year 1990, compared with the 2018 submission. Similarly, the 2019 submission shows a 17.9% (28 kt) decrease in VOC from off-road in calendar year 2016, compared with the 2018 submission.

Table A2-16:  Recalculations for Agriculture
Sector/subsector Polluant Description Impact on emissions
Animal Production NH3 The methodology for estimating ammonia emissions from swine was updated. The previous methodology used per head emission factors fixed in time that varied only regionally. In the updated method, a variable time series of ammonia loss factors are applied to swine N excretion estimates and changes to manure management storage types that also change over time. Swine NH3 estimates are now responsive to changes in nitrogen excretion resulting from changes in animal weight, and changes in manure storage practices over time. Emissions of NH3 decreased slightly by 9.1 kt (-3%) in 1990, 15 kt (-4%) in 2005, and 17 kt (-6%%) in 2016.
Animal Production TPM, PM10, PM2.5 Integration of the 2016 census of agriculture and updates to annual Statistics Canada surveys, resulted in changes to activity data which impacted livestock populations and distribution of livestock on the landscape. The recalculations did not result in changes in emission levels of greater than 10% for any of the pollutants in 1990, 2005, or 2016.
Animal Production VOC The methodology for estimating emissions of non-methane volatile organic compounds (NMVOCs) for dairy cattle was updated from a Tier 1 method to a Tier 2 method. The new methodology incorporates the impact of feeding practices, especially silage content in feed, and changes in manure management practices, on VOC emissions. Emissions of VOCs from livestock increased by 9.5 kt (+10%) in 1990, 12 kt (+11%) in 2005, and 17 kt (+17%) in 2016.
Crop Production NH3 Changes in swine manure N excretion rates, and updates to livestock and crop activity data from the 2016 census of agriculture and annual Statistics Canada surveys, resulted in the redistribution of various synthetic N fertilizers among eco-districts and between perennial and annual crops. The recalculations did not result in changes in emission levels of greater than 10% for any of the pollutants in 1990, 2005, or 2016.
Crop Production TPM, PM10, PM2.5 Integration of the 2016 census of agriculture and updates to annual Statistics Canada surveys, resulted in changes to activity data including crop areas and tillage practices.

The recalculations did not result in changes in emission levels of greater than 10% for any of the pollutants in 1990 or 2005.

In 2016, emissions of TPM increased by 676 kt (+22%), PM10 increased by 258 kt (+20%), and PM2.5 increased by 67 kt (+22%)

Fuel Use TPM, PM10, PM2.5, SOx, NOx, VOCs, CO, NH3, Pb, Cd, Hg, dioxins/ furans, B(a)p, B(b)f, B(k)f, I(cd)p, HCB

The activity data have been updated to a more recent edition of the RESD.

The recalculations did not result in changes in emission levels for any of the pollutants in 1990.

For the year 2016, recalculation resulted in the following changes: 12% for NOx, 28% for Pb, 35% for VOC, 45% for Hg, 47% for CO, 52% for PM10, 56% for PM2.5, and 87% for TPM. The remaining pollutant emissions changed by less than ±10% in 2016.

Table A2-17:  Recalculations for Commercial/Residential/Institutional
Sector/subsector Polluant Description Impact on emissions
Commercial and Institutional Fuel Combustion

TPM, PM10, PM2.5, SOx, NOx, VOCs, CO, NH3, Pb, Cd, Hg, dioxins/furans, B(a)p, B(b)f, B(k)f, I(cd)p, HCB

The activity data have been updated to a more recent edition of the RESD.

The recalculations did not result in changes in emission levels for any of the pollutants in 1990.

For the year 2016, SOx changed by -24%, D/F changed by -46% and due to changes in fuel use, HCB emissions are estimated to be zero in 2016. The remaining pollutant emissions changed by less than ±10% in 2016.

Construction Fuel Combustion TPM, PM10, PM2.5, SOx, NOx, VOCs, CO, NH3, Pb, Cd, Hg, dioxins/furans, B(a)p, B(b)f, B(k)f, I(cd)p, HCB

The activity data have been updated to a more recent edition of the RESD.

The recalculations did not result in changes in emission levels of greater than 10% for any of the pollutants in 1990.

For the year 2016, D/F changed by -27%, VOC changed by -24%, NOx changed by -17%, CO changed by -16%, NH3 changed by -15%, B(a)p changed by -11%, and PM2.5 changed by -10%. The remaining pollutant emissions changed by less than ±10% in 2016.

Residential Fuel Combustion TPM, PM10, PM2.5, SOx, NOx, VOCs, CO, NH3, Pb, Cd, Hg, dioxins/furans, B(a)p, B(b)f, B(k)f, I(cd)p, HCB The activity data have been updated to a more recent edition of the RESD, and more detailed RESD data have been incorporated.

The recalculations did not result in changes in emission levels for any of the pollutants in 1990.

For the year 2016, HCB changed by 12%. The remaining pollutant emissions changed by less than ±10% in 2016.

Table A2-18:  Recalculations for Incineration and Waste Sources
Sector/subsector Polluant Description Impact on emissions
Waste Incineration Cd, CO, D/F, Hg, NH3, NOx, Pb, PM10, PM2.5, SOx, TPM, VOC

Changes affecting estimates include an update of sewage sludge incineration activity data for the complete 1990-2016 time series, using information collected in ECCC waste incineration surveys.

The recalculations resulted in no significant changes in emission levels for Waste Incineration.

Landfills (under Waste Treatment and Disposal)

VOCs, TPM, PM10, PM2.5

The amount of waste landfilled was adjusted across the time series using the best available waste disposal data. Additionally, landfill gas capture data was updated and corrections were made across the time series. The recalculations did not result in more then +/- 10% change for any pollutants in the years 1990 or 2016.
Table A2-19:  Recalculations for Mercury in Products
Sector/subsector Polluant Description Impact on emissions
Ore and Mineral Industries Hg The estimation methodologies for mercury in products have been updated from 2009 forward. In addition, recalculations have been done from 1990 to 2008 (when applicable) based on the updated methodologies. Please note that mercury in products Hg emissions are reconciled with point source emissions before publication.

In 1990, Hg changed by -36% or -323 kg. In 2016, Hg changed by -45% or -173 kg.

Manufacturing Hg The estimation methodologies for mercury in products have been updated from 2009 forward. Recalculations have not been done from 1990 to 2008 for this sector. Please note that mercury in products Hg emissions are reconciled with point source emissions before publication.

The recalculations were not done for 1990. In 2016, Hg changed by -16% or -3 kg.

Commercial / Residential / Institutional Hg

The estimation methodologies for mercury in products have been updated from 2009 forward. In addition, recalculations have been done from 1990 to 2008 (when applicable) based on the updated methodologies. Please note that mercury in products Hg emissions are reconciled with point source emissions before publication.

In 1990, Hg changed by 32% or 206 kg. In 2016, Hg changed by -17% or -61 kg.

Incineration and Waste Hg The estimation methodologies for mercury in products have been updated from 2009 forward. In addition, recalculations have been done from 1990 to 2008 (when applicable) based on the updated methodologies. Please note that mercury in products Hg emissions are reconciled with point source emissions before publication. In 1990, Hg changed by less than ±10% or 160 kg. In 2016, Hg changed by -82% or -821 kg.
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