Air Pollutant Emission Inventory report: annex 2 - inventory development: part 1

A2.1 Overview of the compilation process

The process of compiling emission estimates for the Air Pollutant Emission Inventory (APEI) consists of developing in-house estimates, categorizing facility-reported data, and where necessary, reconciling the in-house estimates and the facility-reported data in a central database (Figure A2-1).

First, facility-reported data are compiled with the extraction of National Pollutant Release Inventory (NPRI) facility and emissions data from the verified NPRI database. New facilities are identified in the extracted data and classified among the APEI sector and subsector categories according to the nature of their activities. A quality control process is performed on the point source data prior to its inclusion in the APEI. A summary of this quality control process is presented in Chapter 4. A list of the facility-reported data is then produced and transferred to a central APEI database.

Figure A2-1: overview of the annual APEI compilation process

Figure A2-1: Overview of the Annual APEI Compilation Process
Long description for figure A2-1

Figure A2-1: This flowchart provides an overview of Canada’s annual Air Pollutant Emissions Inventory (APEI) compilation process. Facility-reported data from the National Pollutant Release Inventory (NPRI) are compiled with in-house estimates. New facilities are identified in the NPRI and classified among the APEI sector and subsector categories according to the nature of their activities. Next, imputation of unreported particulate matter (PM)-size fractions is performed and a list of the final facility-reported data is produced and transferred to a central database.

While the facility-reported data are compiled, the in-house estimates are calculated. In-house estimates first involves collection and analysis of the latest emission factors and activity data and/or database-driven-emissions models, followed by calculation of the emission estimates.

The next step in the process is elimination of double-counting of emissions between the in-house estimates and facility-reported data by a process of reconciliation. Once the calculated in-house estimates have been transferred to the central database, these estimates are reconciled with the facility-reported data by using an automated database utility. Reconciliation of the in-house estimates for solvent use and Hg emissions with the facility-reported data is carried out separately, and then transferred to the central database.

The final steps in the compilation process involve aggregation of the final facility-reported data and reconciled in-house estimates in the central database to produce draft emissions summaries for quality assurance/quality control and consultation purposes. Any identified issues are addressed and the central database is updated. Final emissions summaries are then produced and the final emissions database is used to fulfill Canada’s international and domestic reporting obligations.

In-house estimates are based on documented estimation methodologies, periodically reviewed and updated through literature searches, the collection and analysis of recent emission factors and activity data, and comparisons with alternative sources of information. Improvements to methods or data are implemented as appropriate, and estimates may be recalculated for part of or across the entire time series. Updated estimates are calculated using new and/or updated activity data. Calculations are typically performed in spreadsheets or database-driven emission models.

The next step in the compilation process is the elimination of any double-counting of emissions between the in-house estimates and facility-reported data  by a process of reconciliation. Reconciliation of the in-house estimates with the facility-reported data is required for sectors or subsectors when both in-house and facility-reported estimates exist (Table A2-1). For 2016, reconciliation was performed for the asphalt paving industry and about 20 other source categories. More information on reconciliation is available in section A2.5.1.

The final steps in the compilation process involve aggregating all reconciled data in the central database to produce draft emissions summaries for quality assurance/control and consultation purposes. The final emissions database is also used to generate emissions tables and figures which in turn fulfill Canada’s international and domestic reporting obligations.

A2.2 In-house estimates

The compilation of in-house estimates relies on information such as production data or activity levels for each sector. Calculations of in-house estimates are based on the latest data available at the time of compilation. When possible, the data are updated the each year.

Table A2-1 lists the sectors and subsectors of the APEI for which emissions are based on in-house estimates and provides the activity data year on which the 2016 in-house estimate is based.  

The in-house emissions estimation methodologies and emission models used in Canada are generally based on those developed by the United States Environmental Protection Agency (U.S. EPA) adapted to utilize Canadian data, thereby accounting for differences in climate, fuels, technologies and practices. Methods used in Canada’s APEI are therefore generally consistent with those used in the United States or those recommended in the European emission inventory guidebook (EMEP/EEA 2013).

Tables A2-2 through A2-12 summarize, for each source category, the estimation methodologies for the entire time series. For each source category, these tables provide a short description of:

  • the emission sources and pollutants covered;
  • the general inventory approach; and
  • references for the activity data, emission factors and/or emission models.

Table A2-1: 2016 Air Pollutant Emissions Inventory (APEI)

Ore and mineral industry
Sector Subsector Facility-reported data (NPRI)Table A2-1 Notea In-house estimates (estimated by ECCC) Activity data used for in-house estimates
Aluminium industry Alumina (bauxite refining) X - -
Aluminium industry Primary aluminium smelting and refining X - -
Aluminium industry Secondary aluminum (includes recycling) X - -
Asphalt paving industry - X X 2015
Cement and concrete industry Cement manufacture X - -
Cement and concrete industry Concrete batching and products X X 2016
Cement and concrete industry Gypsum product manufacturing X - -
Cement and concrete industry Lime manufacture X - -
Foundries Die casting X - -
Foundries Ferrous foundries X X 2011
Foundries Non-ferrous foundries X - -
Iron and steel industries Primary (blast furnace and DRI) X - -
Iron and steel industries Secondary (electric arc furnaces) X X -
Iron and steel industries Steel recycling X X -
Iron and steel industries Other (iron and steel industries) - X 2006
Iron ore industry Iron ore mining X - -
Iron ore industry Pelletizing X - -
Mineral products industry Clay products X - -
Mineral products industry Brick products X - -
Mineral products industry Other mineral products X - -
Mining and rock quarrying Coal mining industry X - -
Mining and rock quarrying Metal mining X - -
Mining and rock quarrying Potash X - -
Mining and rock quarrying Rock, sand and gravel X X 2015
Mining and rock quarrying Silica production - X 2016
Mining and rock quarrying Other minerals X - -
Non-ferrous mining and smelting industry Primary Ni, Cu, Zn, Pb X - -
Non-ferrous mining and smelting industry Secondary Pb, Cu X - -
Non-ferrous mining and smelting industry Other metals X - -
Oil and gas industry
Sector Subsector Facility-reported data (NPRI)Table A2-1 Notea In-house estimates (estimated by ECCC) Activity data used for in-house estimates
Downstream oil and gas industry Petroleum refining X - -
Downstream oil and gas industry Refined petroleum products bulk storage and distribution X X 2016
Downstream oil and gas industry Refined petroleum product pipelines X X 2015
Downstream oil and gas industry Natural gas distribution X - -
Downstream oil and gas industry Other downstream petroleum industry X - -
Upstream oil and gas industry Accidents and equipment failures - X 2016
Upstream oil and gas industry Disposal and waste treatment - X 2016
Upstream oil and gas industry Heavy crude oil cold production - X 2016
Upstream oil and gas industry Light medium crude oil productionTable A2-1 Noteb X X 2016
Upstream oil and gas industry Natural gas production and processingTable A2-1 Notec X X 2016
Upstream oil and gas industry Natural gas transmission X X 2015
Upstream oil and gas industry Oil sands in-situ extraction and processing X X 2016
Upstream oil and gas industry Oil sands mining, extraction and upgrading X - -
Upstream oil and gas industry Petroleum liquids storage X - -
Upstream oil and gas industry Petroleum liquids transportation - X 2016
Upstream oil and gas industry Well drilling/servicing/testing  - X 2016
Electric power generation (utilities)
Sector Subsector Facility-reported data (NPRI)Table A2-1 Notea In-house estimates (estimated by ECCC) Activity data used for in-house estimates
Coal - X - -
Diesel - X - -
Natural gas - X - -
Waste materials - X - -
Other electric power generation - X - -
Manufacturing
Sector Subsector Facility-reported data (NPRI)Table A2-1 Notea In-house estimates (estimated by ECCC) Activity data used for in-house estimates
Abrasives manufacture - X    
Bakeries - X X 2016
Biofuel production - X - -
Chemicals industry Chemical manufacture X - -
Chemicals industry Fertilizer production X - -
Chemicals industry Paint and varnish manufacturing X -  
Chemicals industry Petrochemical industry X - -
Chemicals industry Plastics and synthetic resins fabrication X - -
Chemicals industry Other chemical industries X - -
Electronics - X X 2015
Food preparation - X - -
Glass manufacture - X - -
Grain industries Grain processing X X 2016
Grain industries Warehousing and storage - - -
Metal fabrication - X - -
Plastics manufacture - X - -
Pulp and paper industry Pulp and paper industry X X 2006
Pulp and paper industry Converted paper product manufacturing X - -
Textiles - X - -
Vehicle manufacture (engines, parts, assembly, painting) - X - -
Wood productsd Panel board mills X X 2014
Wood productsd Sawmills X X 2014
Wood productsd Other wood products X - -
Other manufacturing industries - X X 2011
Transportation and mobile equipment
Sector Subsector Facility-reported data (NPRI)Table A2-1 Notea In-house estimates (estimated by ECCC) Activity data used for in-house estimates
Air transportation - - X 2016
Heavy-duty diesel vehicles - - X 2015
Heavy-duty gasoline vehicles - - X 2015
Heavy-duty LPG/NG vehicles - - X 2015
Light-duty diesel trucks - - X 2015
Light-duty diesel vehicles - - X 2015
Light-duty gasoline trucks - - X 2015
Light-duty gasoline vehicles - - X 2015
Light-duty LPG/NG trucks - - X 2015
Light-duty LPG/NG vehicles - - X 2015
Marine transportation - - X 2015
Motorcycles - - X 2016
Off-road diesel vehicles and equipment - - X 2013
Off-road gasoline/LPG/CNG vehicles and equipment - - X 2013
Rail transportation - - X 2016
Tire wear and brake lining - - X 2015
Agriculture
Sector Subsector Facility-reported data (NPRI)Table A2-1 Notea In-house estimates (estimated by ECCC) Activity data used for in-house estimates
Animal production - - X 2016
Crop production Fertilizer application - X 2016
Crop production Harvesting - X 2016
Crop production Tillage practices - X 2016
Crop production Wind erosion - X 2016
Fuel use - X X 2014
Commercial, residential and institutional
Sector Subsector Facility-reported data (NPRI)Table A2-1 Notea In-house estimates (estimated by ECCC) Activity data used for in-house estimates
Cigarette smoking - - X 2015
Commercial and institutional fuel combustion - X X 2015
Commercial cooking - - X 2016
Construction fuel combustion - - X 2014
Home firewood burning - - X 2015
Humane - - X 2016
Marine cargo handling - X - -
Residential fuel combustion - - X 2014
Service stations - - X 2015
Other miscellaneous sourcesf - - X 2015
Incineration and waste
Sector Subsector Facility-reported data (NPRI)Table A2-1 Notea In-house estimates (estimated by ECCC) Activity data used for in-house estimates
Crematoriums - X X 2015
Waste incineration Industrial and commercial incineration - X 2011
Waste incineration Municipal incineration X X 2011
Waste incineration Residential waste burning - X 2016
Waste incineration Other incineration and utilities - X 2009
Waste treatment and disposal Landfills X X 2014
Waste treatment and disposal Water and sewage treatment X - -
Waste treatment and disposal Specialized waste treatment and remediation X - -
Waste treatment and disposal Biological treatment of waste X - -
Waste treatment and disposal Waste sorting and transfer X - -
Paints and solvents
Sector Subsector Facility-reported data (NPRI)Table A2-1 Notea In-house estimates (estimated by ECCC) Activity data used for in-house estimates
Dry cleaning - X X 2016
General solvent use - - X 2016
Printing - X X 2016
Surface coatings - X X 2016
Dust
Sector Subsector Facility-reported data (NPRI)Table A2-1 Notea In-house estimates (estimated by ECCC) Activity data used for in-house estimates
Coal transportation - - X 2015
Construction operations - - X 2012
Mine tailings - - X 2006
Paved roads - - X 2002
Unpaved roads - X X 2002
Fires
Sector Subsector Facility-reported data (NPRI)Table A2-1 Notea In-house estimates (estimated by ECCC) Activity data used for in-house estimates
Prescribed forest burning - - X 2015
Structural fires - - X 2016
Mercury
Sector Subsector Facility-reported data (NPRI)Table A2-1 Notea In-house estimates (estimated by ECCC) Activity data used for in-house estimates
Mercury in productsTable A2-1 Noteg - - X 2008

Notes

X: denotes yes

a All facility-reported data were obtained from the NPRI Reporting Year 2016.

b Facility-reported data consists of facilities located in Atlantic Canada. For other provinces, it consists of in-house estimates.

c Facility-reported data consists of facilities located in Atlantic Canada and SO2 emissions from Alberta's natural gas processing facilities.

d In-house estimates for Wood Products were estimated by the Forestry Products group of the Environmental Stewardship Branch at ECCC. All other in-house estimates were estimated by PIRD.

e Ammonia emissions from infant diapered waste, which were previously reported under Other Miscellaneous Sources, are now reported under the Human sector.

f Emissions reported under Other Miscellaneous Sources are from breakage, transport and recycling of mercury-containing products. Products include: automotive mercury switches, batteries, dental amalgams, fluorescent lamps, fungicides, measurement and control devices, non-fluorescent lamps, switches and relays, thermometers, thermostats and tire balancers.

g Emissions from Hg-containing products were calculated as a separate inventory. Emissions are reported under many sectors such as Iron and Steel Industries, Municipal Incineration, Human, Other Miscellaneous Sources and Landfills. All in-house estimates for Hg in product emissions continues to be estimated and reported under these sectors.

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