Archived: Air Pollutant Emission Inventory report: annex 2 - inventory development: 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, and
- inclusion of categories previously not estimated (which improves inventory completeness)
Recalculations of facility-reported data previously reported to the NPRI facilities submit 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 1991-2017).
Emissions in the following in-house 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 A2-21.
- Ore and mineral industries: asphalt paving; rock, sand and gravel; and silica production
- 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 storage; oil sands in-situ extraction and processing; petroleum liquids storage; petroleum liquids transportation; and well drilling/servicing/testing
- Manufacturing: bakeries
- Transportation and mobile equipment: marine transportation; on-road vehicles; and off-road vehicles and equipment
- Agriculture: animal production; fertilizer application and fuel use
- Commercial/Residential/Institutional: cigarette smoking; commercial and institutional fuel combustion; construction fuel combustion; human; residential fuel combustion; service stations and other miscellaneous sources
- Incineration and waste sources: landfills; residential waste burning
- Paints and solvents: dry cleaning; general solvent use; printing and surface coatings
- Dust: residential construction, coal transportation
- Fires: prescribed forest burning
For the purpose of tables A2-13 to A2-21, the term “significant” refers to changes greater than ±10% in emission levels.
| Sector/subsector | Polluants | Description | Impact on emissions |
|---|---|---|---|
| Asphalt paving | TPM, PM10, PM2.5, SOx, NOx, VOCs, CO, Pb, Cd, Hg, dioxins/furans, B(a)p, B(b)f, B(k)f, I(cd)p, HCB | The activity data have been updated from a more recent RESD, which including some of historical data (2005 to 2015). | The recalculations resulted in no significant changes in emission levels (± >10%) for 1990. The recalculations resulted in the following changes in 2015 at the national level: -12% (-58 t) for SOx., |
| Cement and concrete | TPM, PM10, PM2.5, Pb and Cd. | The recalculations were done using updated population and cement activity data since 2005, up to 2015. | No changes in emission levels occurred for 1990. For 2015, estimates for all pollutants decreased by 1.6% (TPM 0.7 kt; PM10 0.2 kt; PM2.5 0.1 kt; Pb 1.7 kg; Cd 0.02 kg). |
| Rock, sand and gravel (under mining and rock quarrying) | TPM, PM10, PM2.5 | Recalculations of emission estimates for 1990 to 2015 were due to changes in emission factors. Emission factors are now taken from the EMEP/EEA 2013 Guidebook’s Tier 1 emission factors for Quarrying and mining of minerals other than coal. Activity level data for the complete time series was updated to reflect the most recent information from NRCan. |
The methodology and activity level data updates resulted in decreases to the particulate matter in-house estimates. In 1990, the significant changes at the national level were -23% (2.8 kt) for TPM ; -34%(630 t) for PM2.5; and --23%(1.4 kt) for PM10. The recalculations resulted in changes in emission levels of less than ±10% for 2015. |
| Silica production (under mining and rock quarrying) | TPM, PM10, PM2.5 | Emissions were recalculated to incorporate updated annual mineral production data for 2015 and updated population data for 2012 to 2015. | The recalculations resulted in changes in emission levels of less than ±10% for 2012 and 2015. |
| Sector/subsector | Polluants | Description | Impact on emissions |
|---|---|---|---|
| Refined petroleum products bulk storage and distribution (under downstream oil and gas industry) | VOCs | Recalculations occurred for the entire time series because of updated activity data. In addition, for the period 1990 to 2005, some emissions previously allocated to petroleum refining are now reported in this category. | The recalculations resulted in an approximately 1% decrease in emissions for 2015. Changes in allocation resulted in an emission increase of about 20% in 1990. |
| Natural gas distribution (under downstream oil and gas industry) | TPM, PM10, PM2.5, SOx, NOx, VOCs, CO | Recalculations occurred from 1996 through 2015 as a result of changes made to the allocation of NPRI data to Oil and Gas subsectors. | For 2015, on a national level, the allocation changes resulted in significant changes to TPM, PM10 and PM2.5 (-11 t or -86%), SOx (-29 t or -98%), NOx (-4.2 kt or -97%), VOCs (-0.2 kt or -39%), and CO (-4.3 kt or -97%). |
| Accidents and equipment failures (under upstream oil and gas industry) | VOCs | Recalculations occurred from 2001 through 2015 as a result of updated activity data being made available (AER 2017e, BCOGC 2017, CNLOPB 2017e, MB 2017, SK MOE 2017d). | 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) | TPM, PM10, PM2.5, SOx, NOx, VOCs, CO, NH3 | Recalculations occurred from 2001 thru 2015 as a result of updated activity data being made available (AER 2017a, AER 2017d, Statistics Canada d). | The recalculations did not result in changes greater than ±10% for any of the pollutants in 2015. |
| Heavy crude oil cold production (under upstream oil and gas industry) | TPM, PM10, PM2.5, SOx, NOx, VOCs, CO, NH3 | New activity data was used to estimate emissions from reported venting, flaring and fuel combustion. This resulted in recalculations to emissions from 2001 to 2015 (AER 2017a, AER 2017d, SK MOE 2017c). | The new activity data resulted in significant changes to 2015 emissions at the national level for TPM, PM10 and PM2.5 (+254 t or +94%), SOx (+821 t or 51%), NOx (+2.3 kt or +20%), CO (+3.4 kt or +23%), and NH3 (+7.5 t or 20%). The recalculations did not result in changes greater than ±10% for VOCs in 2015. |
| Light/medium crude oil production (under upstream oil and gas industry) | TPM, PM10, PM2.5, SOx, NOx, VOCs, CO, NH3 | New activity data was used to estimate emissions from reported venting, flaring and fuel combustion. This resulted in recalculations to emissions from 2001 to 2015 (AER 2017a, AER 2017d, BC 2017, SK MOE 2017c). | The new activity data resulted in significant changes to 2015 emissions at the national level for TPM, PM10 and PM2.5 (+662 t or +25%), NOx (+5.4 kt or +15%), CO (+7.9 kt or +17%), and NH3 (+1.9 t or 13%). The recalculations did not result in changes greater than ±10% for SOx or VOCs in 2015. |
| Natural gas production and processing (under upstream oil and gas industry) | TPM, PM10, PM2.5, SOx, NOx, VOCs, CO, NH3 | New activity data was used to estimate emissions from reported venting, flaring and fuel combustion. This resulted in recalculations to emissions from 2001 to 2015 (AER 2017a, AER 2017b, AER 2017d, BC 2017, SK MOE 2017c, Statistics Canada c) | The new activity data resulted in significant changes to 2015 emissions at the national level for TPM, PM10 and PM2.5 (+381 t or +17%), and SOx (+20.3 kt or +21%). The recalculations did not result in changes greater than ±10% for any other pollutants in 2015. |
| Natural gas transmission and storage (under upstream oil and gas industry) | TPM, PM10, PM2.5, SOx, NOx, VOCs, CO, NH3 | Recalculations occurred for the entire time series, from 1990 through 2015, as a result of changes made to the allocation of NPRI data to Oil and Gas subsectors. | The allocation changes resulted in significant changes to 2015 national level emissions for SOx (+3.1 t or 15%), NOx (+2.4 kt or +14%), VOCs (+153 t or +22%), CO (+1.0 kt or +19%), and NH3 (+0.6 t or 325%). The recalculations resulted in changes in 2015 emission levels of less than ±10% for TPM, PM10 and PM2.5. |
| Oil sands in-situ extraction and processing (under upstream oil and gas industry) | TPM, PM10, PM2.5, SOx, NOx, VOCs, CO, NH3 | New activity data was used to estimate emissions from reported venting and flaring for well testing. This resulted in recalculations to emissions from 2001 to 2015 (AER 2017a, AER 2017b). | The new activity data resulted in significant changes to 2015 emissions at the national level for TPM, PM10 and PM2.5 (+341 t or +50%). The recalculations did not result in changes greater than ±10% for any other pollutants in 2015. |
| Petroleum liquids storage (under upstream oil and gas industry) | TPM, PM10, PM2.5, NOx, VOCs | Changes were made to the method used to allocate NPRI facilities to Oil and Gas subsectors. In addition, changes were made to the PM Distribution ratios (see Table A2-23) | The recalculations resulted in significant changes to 2015 emissions at the national level for TPM (+4.3 t or 47%), PM10 (+5.3 t or +66%), PM2.5 (+3.6 t or +48%), and NOx (+25 t or +66%). The recalculations did not result in changes greater than ±10% for any other pollutants in 2015. |
| Petroleum liquids transportation (under upstream oil and gas industry) | TPM, PM10, PM2.5, SOx, NOx, VOCs, CO | Recalculations occurred from 1990 thru 2015 as a result of updated activity data being made available (Statistics Canada d). | The recalculations resulted in significant changes to 2015 emissions at the national level for TPM (+1.7 t or 26%), PM10 (+1.9 t or +29%), PM2.5 (+0.9 t or +14%), NOx (-0.1 t or -12%), and CO (-0.3 t or -12%). The recalculations did not result in changes greater than ±10% for VOCs or SOx in 2015. |
| Well drilling/servicing/testing (under upstream oil and gas industry) | TPM, PM10, PM2.5, SOx, NOx, VOCs, CO | New activity data was used to estimate emissions from reported venting and flaring for well testing. This resulted in recalculations to emissions from 2001 to 2015 (AER 2017a, CAPP 2017). | The new activity data resulted in significant changes to 2015 emissions at the national level for TPM, PM10 and PM2.5 (+34 t or +15%), SOx (+4.5 kt or +69%), NOx (+17 t or +12%), and CO (+95 t or +15%). The recalculations did not result in changes greater than ±10% for VOCs in 2015. |
| Sector/subsector | Polluants | Description | Impact on emissions |
|---|---|---|---|
| Bakeries | VOCs | Updated bread and bakery product manufacturing data from 2000 forward. Also performed 2015 estimates (Statistics Canada e,f,g). | There were no changes in the emission levels of VOC for 1990 since population data was not updated previous to 2000. Emissions from bakeries increased by 4.8 kt for the year 2015 (a significant increase for our in-house calculations of 52%). |
| Sector/subsector | Polluants | Fuel | Description | Impact on emissions |
|---|---|---|---|---|
| Marine transportation | B(a)p, B(b)f, B(k)f, I(1,2,3-cd)p, NOx, SOx, VOC | Heavy Fuel Oil, Marine Diesel Oil, Marine Gasoline Oil | Model updates from Marine Emissions Inventory Tool 2015, new interpolation for the years between 2015 and 2020. | The recalculations did not impact results for 1990. The recalculations for 2015 resulted in significant changes in the emissions of B(a)p (-41% or -3kg), B(b)f (-41% or -5kg), B(k)f (-41% or -3kg), I(1,2,3-cd)p (-41% or -5kg), NOx (-12% or -26kt), SOx (+24% or +3kt) and VOCs (-41% or -3kt). The recalculations did not result in changes in emission levels of greater than 10% for any of the other pollutants in 2015 |
| On-road Vehicles (Includes the following sectors: Heavy-duty diesel vehicles, Heavy-duty gasoline trucks, Heavy-duty LPG/NG vehicles, Light-duty diesel trucks, Light-duty diesel vehicles, Light-duty gasoline trucks, Light-duty gasoline vehicles, Light-duty LPG/CNG vehicles, Light-duty LPG/CNG trucks, Motorcycles, Tire Wear & Brake Lining) | - | All transport fuels | Environment and Climate Change Canada (ECCC) aligns estimates of on- and off-road fuel use with fuel data in the RESD. The activity data have been updated to a more recent edition of the RESD. | The recalculations did not significantly impact results for 1990 or 2015. |
| Off-road vehicles and equipment | CO, VOCs, NH3 | All transport fuels | Environment and Climate Change Canada (ECCC) aligns estimates of on- and off-road fuel use with fuel data in the RESD. The activity data have been updated to a more recent edition of the RESD. | The recalculations for 1990 resulted in significant changes in the emissions of CO (+27% or +771kt), NH3 (+18% or +68t), and VOCs (+29% or +264kt). The recalculations for 2015 resulted in significant changes in the emissions of VOC (+11% or +20kt). |
| Sector/subsector | Polluants | Description | Impact on emissions |
|---|---|---|---|
| Animal production | NH3 | The methodology for estimating ammonia emissions from dairy cattle 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 dairy cattle N excretion estimates and changes to manure management storage types that also change over time . Dairy NH3 estimates now accurately reflect changes in emissions associated with changes in milk production, taking into account changes in manure storage practices and dietary N intake over time. | Emissions of NH3 increased slightly by 9.8 kt (3%) in 1990, 7.8 kt (2%) in 2005, and 4.9 kt (2%) in 2015. |
| Fertilizer application (under crop production) | NH3 | Changes in Dairy manure N excretion rates allocation of manure N between perennial and annual crops, and crop N recommendation rates resulted in the redistribution of various synthetic N fertilizers among eco-districts and between perennial and annual crops. | The recalculations resulted in an increase in ammonia emissions of 1.9 kt for 1990, 1.2 kt for 2005, and 1.7 kt for 2015, with a relative change of less than 3%. |
| 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, in addition to incorporating more detailed RESD data. | The recalculations did not result in changes in emission levels of greater than 10% for any of the pollutants in 1990. For the year 2015, recalculation resulted in the following changes: -12% for Hg, -13% for Cd, 55% for B(a)p, -26% for SOx, -19% for TPM, -17% for PM10 and -10% for PM25. The rest of the pollutant emissions changed by less than ±10% in 2015. |
| Sector/subsector | Polluants | Description | Impact on emissions |
|---|---|---|---|
| Cigarette smoking | TPM, PM10, PM2.5, VOCs, CO, NH3, Pb, Cd, Hg, dioxins/furans, B(a)p, B(b)f, B(k)f | Updated population data by province and territory were incorporated for the years 2012 to 2015. | The recalculations resulted in changes of less than ±10% in 2012 and -10% for all pollutants in 2015. |
| Commercial and institutionnel 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, in addition to incorporating more detailed RESD data. | The recalculations did not result in changes in emission levels of greater than 10% for any of the pollutants in 1990. For the year 2015, SOx changed by -20% and HCB was reported where it wasn’t in previous years. The rest of the pollutant emissions changed by less than ±10% in 2015. |
| 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, in addition to incorporating more detailed RESD data. | The recalculations did not result in changes in emission levels of greater than 10% for any of the pollutants in 1990. For the year 2015, Pb changed by 25%, D/F changed by 203%, B(a)p changed by 49%, B(a)f changed by 53%, B(k)f changed by 53%, I(1,2,3-cd)p changed by 43%, CO changed by 72%, VOC changed by 170%, SOx changed by 77%, NOx changed by 78%, TPM changed by 41%, PM10 changed by 41%, PM2.5 changed by 39%, and NH3 changed by 65%. The rest of the pollutant emissions changed by less than ±10% in 2015 |
| Human | NH3 | Infant-diapered waste emissions were moved from Other Miscellaneous Sources to the Human sector to better categorize this emission source within the inventory. Updated population data by province and territory were incorporated for the years 2012 to 2015 for both infant diapered waste and respiration and perspiration. |
The recalculations and re-categorization of emissions resulted in changes in NH3 emission levels of less than ±10% in 1990, 2012 and 2015. |
| 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, in addition to incorporating more detailed RESD data. | The recalculations did not result in changes in emission levels of greater than 10% for any of the pollutants in 1990. For the year 2015, SOx changed by 92% and HCB was reported where it wasn’t in previous years. The rest of the pollutant emissions changed by less than ±10% in 2015. |
| Service stations | VOCs | Refined petroleum products retail: The estimation methodology for service stations has been changed from a growth factor approach to use of emission factors from U.S. EPA AP-42. The emissions from refuelling on-road vehicles have been removed as they are already included in on-road estimates for recalculation purposes. Off-road refuelling: The activity data have been updated to a more recent edition of the RESD. On-road refuelling Quantification of the impact of the new methodology for estimates of emissions from refuelling of on-road vehicles cannot be calculated because emissions from this source were not calculated separately in the previous estimation methods. The recalculations of VOC emissions related to refuelling of on-road vehicles estimates are included in Table A2-16 for on-road vehicles. |
Refined petroleum products retail: The recalculations did not result in changes greater than ±10% for any of the pollutants in 1990 and 2015. Off-road refuelling: The recalculations resulted in a 59% (8502 t) increase in VOC estimates for 1990, and a 56% (3954 t) increase in VOC estimates for 2015. |
| Other miscellaneous sources | NH3 | Infant-diapered waste emissions were moved from Other Miscellaneous Sources to the Human sector to better categorize this emission source within the inventory. | The recalculations resulted in changes in NH3 emission levels of -100% (-21 t) in both 1990 and 2015. |
| Sector/subsector | Polluants | Description | Impact on emissions |
|---|---|---|---|
| Landfills (under waste treatment and disposal) | TPM, PM10, PM2.5, VOCs, Hg | Changes affecting both PM and VOC estimates include replacement of a 13th order polynomial equation with linear interpolation for a data gap 1991 to 1997, and corrections to export and incineration activity data. Additionally, historical landfill data (1941 to 1990) was corrected using updated population data and per capita generation rates. Additional changes affecting VOC estimates include updated parameters in the FOD model, specifically updating DOCf factor from 0.6 to 0.5, and updating the oxidation factor from 0 to 0.1 (IPCC, 2006). |
VOCs changed by -31% (‑2046 t) and -40% (-3018 t) in 1990 and 2015, respectively. PM emissions did not change more than ±10%. |
| Residential waste burning (under waste incineration) | TPM, PM10, PM2.5, SOx, NOx, VOCs, CO, NH3, Hg, dioxins/furans, B(a)p, B(b)f, B(k)f, I(cd)p, HCB | The 2014 and 2015 emission estimates were recalculated based on updated population data (Statistics Canada a). | The recalculations resulted in no significant changes in emission levels (± >10%) for 2014 and 2015. |
| Sector/subsector | Polluants | Description | Impact on emissions |
|---|---|---|---|
| Dry cleaning, general solvent use, printing, surface coatings | VOCs | Projected estimates of national total solvent use for the year 2015 were recalculated using updated macroeconomic growth ratios. | The recalculations resulted in changes in the 2015 emission levels of less than ±10% in all solvent use sectors. |
| Sector/subsector | Polluants | Description | Impact on emissions |
|---|---|---|---|
| Residential construction (under construction operations) | TPM, PM10, PM2.5 | Emission estimates for the provinces were recalculated using: updated housing starts data for 2012 to 2016 (Statistics Canada t), average provincial soil silt contents weighted by the areas of highest residential construction1, and annual average lengths of construction by dwelling type and by province for 1990 to 2016 (CMHC 2017). Emission estimates for the territories (YT and NT) were recalculated using the same estimation methodology as the provinces. Average territorial-level silt contents, new housing starts data and annual average lengths of construction by dwelling type at the national level were incorporated. |
The recalculations resulted in significant changes in emission levels for 1990. Emissions of TPM, PM10 and PM2.5 all increased by 99% or by 11 kt, 3 kt and 1 kt, respectively. The recalculations for 2015 also resulted in significant changes in TPM (+162% or +33 kt), PM10 (+162% or +10 kt) and PM2.5 (+162% or +2 kt) emissions. |
| Coal transportation |
TPM, PM10, PM2.5 | The estimation methodology for Coal Transportation dust has been changed from a growth factor approach that started from data-points of the years 2004 and 2005 (in-house, using NRCan Coal Production statistics, following method of Cope and Bhattacharyya 2001) to using the method employed by Cope and Bhattacharyya for the entire time-series. The updated method also drew on a new data source for coal mine production and coal imports (Statistics Canada 2017a; Statistics Canada 2017b) | Emissions of TPM, and PM10 decreased by 12.5% in 1990 (0.22 kt for TPM and 0.11 kt for PM10). Emissions of TPM and PM10 increased by 21.2% in 2015 (0.21 kt for TPM, 0.10 kt for PM10). PM2.5 emissions had significant changes because of an error in the previous methods. The PM2.5 emissions increased by 64.8% in 1990 (0.12 kt) and increased by 517% in 2015 (0.20 kt). |
1 Flemming, C. 2017. Personal communication (email from Flemming C to Reza K, Environment and Climate Change Canada, dated July 20, 2017). AFOLU Section, Pollutant Inventories and Reporting Division, Environment and Climate Change Canada.
Page details
- Date modified: