Canada’s Air Pollutant Emissions Inventory Report 2022: chapter 3

Air pollutant emissions inventory development

The Air Pollutant Emissions Inventory (APEI) is a comprehensive and detailed inventory of air pollutant emissions in Canada, developed using two types of information:

The APEI is developed using many sources of information, procedures and emission estimation models. Emissions data reported by individual facilities to Environment and Climate Change Canada’s (ECCC’s) National Pollutant Release Inventory (NPRI) are supplemented with documented, science-based estimation tools to quantify total emissions. Together, these data sources provide a comprehensive overview of pollutant emissions across Canada. A framework has been developed that makes use of the best available data, while ensuring no double counting or omissions. This chapter presents information about the inventory development process.

3.1 Overview of inventory development

The process of developing comprehensive emission estimates for the APEI is presented in Figure 3–1. It consists of categorizing facility-reported data (section 3.2), calculating in-house estimates (section 3.3), and reconciling the facility-reported data and the in-house estimates in a database, where necessary (section 3.4), followed by compiling and reporting the results (section 3.5). Quality control (section 3.6) is performed throughout the inventory development process. Every year, the whole time series (from 1990 to the latest year) is estimated and continuous improvement often results in revisions to previously published estimates, called recalculations (section 3.7).

Facility-reported emissions

As a first step, 17 pollutants reported in the APEI are extracted from the NPRI verified database, which contains facility-reported data. New facilities are identified in the extracted data and classified within the APEI according to the nature of their activities. This step results in a compiled database containing all facility-reported emissions used in the air pollutant emissions inventory report.

More information on facility-reported emissions is presented in section 3.2.

In-house emission estimates

In-house estimates are based on documented estimation methodologies which are 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. Updated estimates are calculated using new or updated activity data. Where possible, inventory estimates calculated in-house use the most rigorous (highest-tier) methods. However, owing to practical limitations, the exhaustive development of all emissions categories is not possible. In these cases, estimates are generally calculated using activity data and emission factors following relatively basic (lower-tier) methodologies. Calculations are performed in spreadsheets (Excel), relational databases (MS Access and SQL server), using computational scripts (R and Python), and may include spatial data quantified using geographic information systems software (GIS-ArcGIS and QGIS).

More information on in-house estimates can be found in section 3.3.

Reconciliation

The next step in the compilation process is eliminating any double counting of emissions between the in-house estimates and the facility-reported data through a process of reconciliation. Table 3–1 illustratesthe origin of the emissions for each sector and subsector: facility-reported data, in-house calculated data or a combination of both, for the latest available year. The origin of the emissions can change depending on the year. Reconciliation of in-house estimates with facility-reported data is required for sectors or subsectors where both in-house and facility-reported estimates exist. For 2020, reconciliation was performed for 30 sectors.

More information on reconciliation is available in section 3.4.

Compilation and reporting

The final steps in the development process involve compiling all reconciled data within a final database and generating the results. The final database houses all APEI data and is the source of data for all APEI-related products, including:

More information on compilation and reporting is available in section 3.5.

Figure 3–1: Overview of the annual air pollutant emissions inventory compilation process

Figure 3–1 section-3.2 section-3.3 section-3.4 Database Open Data Table Online Search Tool UNECE Submission section-3.5

Long description for Figure 3–1

Figure 3–1 is a flow chart displaying an overview of Canada’s annual Air Pollutant Emissions Inventory compilation process. In this figure, there are two big boxes side by side at the top; the big box on the left describes Facility-Reported Emissions process and the big box on the right describes In-House Emission process. More details on Facility-Reported Emissions can be found in section 3.2 and more details on In-House Emissions Estimates can be found in section 3.3.

Within the big box on the top left, there are several small boxes and circles with arrows indicating the steps and order of the steps to describe the Facility-Reported Emissions process. The first circle is the National Pollutant Release Inventory (NPRI) database (Facility-Reported Data). From that circle, an arrow points to the next step: the Extraction of the 17 Pollutants Needed for Reporting box. Another arrow points from there to the box New Facilities Categorized into Appropriate Sectors and Subsectors. An arrow points from there to a circle representing the Facility Data for the Air Pollutant Inventory Database. From this database, a two-way arrow is used to point to the Particulate Matter Corrections box.

In the big box on the top right-hand side of this figure, in the first circle is Activity Data and Emissions Factors. From there, one arrow splits off to the left, Tier 1 is written on the arrow, and leads to Calculation of In-House Estimates. Another arrow splits off to the right, Tier 2 and Tier 3 is written on the arrow, and leads to Emissions Models, which then has another arrow leading to Calculation of In-House Estimates.

Both, the big top left box and the big top right box then merge into the Reconciliation step. More details on the reconciliation steps are provided in section 3.4. From there, an arrow points from Reconciliation to a circle representing the Air Pollutant Inventory Database. From there, four arrows split off to four reporting steps in boxes: from left to right they read – Emissions Tables and Figures for Report, Open Data Tables, Online Research Tool, and the last box: Projections, Air Quality Modeling, Canadian Environmental Sustainability Indicators (CESI) Indicators and Canada-U.S. Air Quality Agreement. Reconciliation step is also directly connected to the United Nations Economic Commission for Europe (UNECE) Submission Reporting step box, which is not directly linked to the Air Pollutant Inventory Database. More details on the compilation and reporting steps are provided in section 3.5.

Table 3–1: Origin of 2020 air pollutant emissions estimates by inventory category

Note:
x = yes

Ore and Mineral Industries
Sector Subsector Facility-reported dataa In-house estimatesb Activity data used for in-house estimates
Aluminium Industry Alumina (Bauxite Refining) x - -
Aluminium Industry Primary Aluminium Smelting and Refining x - -
Aluminium Industry Secondary Aluminium Production (Includes Recycling) x - -
Asphalt paving Industry - x x 2020
Cement and Concrete Industry Cement Manufacturing x - -
Cement and Concrete Industry Concrete Batching and Products x x 2020
Cement and Concrete Industry Gypsum Product Manufacturing x - -
Cement and Concrete Industry Lime Manufacturing x - -
Foundries Die Casting x - -
Foundries Ferrous Foundries x x 2020
Foundries Non-ferrous Foundries x - -
Iron and Steel Industry Primary (Blast Furnace and DRI) x - -
Iron and Steel Industry Secondary (Electric Arc Furnaces) x x 2020 (Hg in Products)
Iron and Steel Industry Steel Recycling x x 2020 (Hg in Products)
Iron Ore Industry Iron Ore Mining x - -
Iron Ore Industry Pelletizing x - -
Mineral Products Industry Brick Products x - -
Mineral Products Industry Clay Products x - -
Mineral Products Industry Other (Mineral Products Industry) 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 2020
Mining and Rock Quarrying Silica Production - x 2020
Mining and Rock Quarrying Limestone x - -
Mining and Rock Quarrying Other (Mining and Rock Quarrying) x - -
Non-Ferrous Refining and Smelting Industry Primary Ni, Cu, Zn, Pb x - -
Non-Ferrous Refining and Smelting Industry Secondary Pb, Cu x - -
Oil and Gas Industry
Sector Subsector Facility-reported dataa In-house estimatesb 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 2020
Downstream Oil and Gas Industry Refined Petroleum Product Pipelines x - -
Downstream Oil and Gas Industry Natural Gas Distribution x x 2020
Downstream Oil and Gas Industry Other (Downstream Oil and Gas Industry) x - -
Upstream Oil and Gas Industry Accidents and Equipment Failures - x 2020
Upstream Oil and Gas Industry Disposal and Waste Treatment - x 2020
Upstream Oil and Gas Industry Heavy Crude Oil Cold Production - x 2020
Upstream Oil and Gas Industry Light/Medium Crude Oil Productionc x x 2020
Upstream Oil and Gas Industry Natural Gas Production and Processingd x x 2020
Upstream Oil and Gas Industry Natural Gas Transmission and Storage x x 2020
Upstream Oil and Gas Industry Oil Sands In-Situ Extraction x x 2020
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 2020
Upstream Oil and Gas Industry Well Drilling/Servicing/Testing - x 2020
Electric Power Generation (Utilities)
Sector Subsector Facility-reported dataa In-house estimatesb 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 dataa In-house estimatesb Activity data used for in-house estimates
Abrasives Manufacturing - x - -
Bakeries - x x 2020
Biofuel Production - x - -
Chemicals Industry Chemical Manufacturing x - -
Chemicals Industry Cleaning Compound Manufacturing 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 Industry) x - -
Electronics - x x 2020 (Hg in Products)
Food Preparation - x - -
Glass Manufacturing - x - -
Grain Industry Grain Processing x x 2020
Grain Industry Warehousing and Storage x - 2020
Metal Fabrication - x - -
Plastics Manufacturing - x - -
Pulp and Paper Industry Converted Paper Product Manufacturing x -
-
Pulp and Paper Industry Pulp and Paper Product Manufacturing x - -
Textiles - x - -
Vehicle Manufacture (Engines, Parts, Assembly, Painting) - x - -
Wood Productse Panel Board Mills x x 2020
Wood Products Sawmills x x 2020
Wood Products Other (Wood Products) x - -
Other (Manufacturing) - x - -
Transportation and Mobile Equipment
Sector Subsector Facility-reported dataa In-house estimatesb Activity data used for in-house estimates
Air Transportation (LTO) - - x 2020
Domestic Marine Navigation, Fishing and Military - - x 2020
Heavy-duty Diesel Vehicles - - x 2020
Heavy-duty Gasoline Vehicles - - x 2020
Heavy-duty LPG/NG Vehicles - - x 2020
Light-duty Diesel Trucks - - x 2020
Light-duty Diesel Vehicles - - x 2020
Light-duty Gasoline Trucks - - x 2020
Light-duty Gasoline Vehicles - - x 2020
Light-duty LPG/NG Trucks - - x 2020
Light-duty LPG/NG Vehicles - - x 2020
Motorcycles - - x 2020
Off-road Diesel Vehicles and Equipment - - x 2020
Off-road Gasoline/LPG/NG Vehicles and Equipment - - x 2020
Rail Transportation - - x 2020
Tire Wear-and Brake Lining - - x 2020
Agriculture
Sector Subsector Facility-reported dataa In-house estimatesb Activity data used for in-house estimates
Agricultural Fuel Combustion - x x 2020
Animal Production - - x 2020
Crop Production Harvesting - x 2020
Crop Production Inorganic Fertilizer Application - x 2020
Crop Production Sewage Sludge Application - x 2020
Crop Production Tillage Practices - x 2020
Crop Production Wind Erosion - x 2020
Commercial / Residential / Institutional
Sector Subsector Facility-reported dataa In-house estimatesb Activity data used for in-house estimates
Commercial and Institutional Fuel Combustion - x x 2020
Commercial Cooking - - x 2019
Construction Fuel Combustion - - x 2020
Home Firewood Burning - - x 2019
Humanf - - x 2020
Marine Cargo Handling - x - -
Residential Fuel Combustion - - x 2020
Service Stations - - x 2019
Other (Miscellaneous)g - - x 2020
Incineration and Waste
Sector Subsector Facility-reported dataa In-house estimatesb Activity data used for in-house estimates
Crematoriums - x x 2020
Waste Incineration Hazardous Waste Incineration x x 2020
Waste Incineration Medical Waste Incineration x x 2020
Waste Incineration Municipal Incineration x x 2020
Waste Incineration Residential Waste Burningg - x 2020
Waste Incineration Sewage Sludge Incineration - x 2020
Waste Incineration Other (Waste Incineration) x - -
Waste Treatment and Disposal Biological Treatment of Waste x - 2018-2020 (based on availability)
Waste Treatment and Disposal Landfills x x 2020
Waste Treatment and Disposal Municipal Wastewater Treatment and Discharge x - -
Waste Treatment and Disposal Specialized Waste Treatment and Remediation x - -
Waste Treatment and Disposal Waste Sorting and Transfer x - -
Paints and Solvents
Sector Subsector Facility-reported dataa In-house estimatesb Activity data used for in-house estimates
Dry Cleaning - x x 2020
General Solvent Use - - x 2020
Printing - x x 2020
Surface Coatings - x x 2020
Dust
Sector Subsector Facility-reported dataa In-house estimatesb Activity data used for in-house estimates
Coal Transportation - - x 2020
Construction Operations - - x 2012
Mine Tailings - - x 2018
Paved Roads - - x 2020
Unpaved Roads - x x 2020
Fires
Sector Subsector Facility-reported dataa In-house estimatesb Activity data used for in-house estimates
Prescribed Burning - - x 2020
Structural Fires - - x 2017
Mercury
Sector Subsector Facility-reported dataa In-house estimatesb Activity data used for in-house estimates
Mercury in products h - - x 2020

Notes:
a. Based on the most recent facility-reported data from NPRI.
b. Estimated by ECCC.
c. Facility-reported data consists of facilities located in Atlantic Canada. For other provinces, it consists of in-house estimates.
d. Facility-reported data consists of facilities located in Atlantic Canada and SO2 emissions from Alberta's natural gas processing facilities.
e. 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.
f. Emissions reported under Other (Miscellaneous) are from breakage, transport and recycling of mercury-containing products using the Hg in Products methodology. 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. Hg in Products estimates for Residential Waste Burning are not estimated after 2008 as a result of the updates for the Hg in Products models.
h. Emissions from Hg-containing products were calculated as a separate inventory. Emissions are reported under many sectors such as Iron and Steel Industry, Municipal Incineration, Human, Other (Miscellaneous) and Landfills. All in-house estimates for Hg in Products emissions continue to be estimated and reported under these sectors.

3.2 Facility-reported emissions data

Facility-reported emissions data generally refer to any stationary sources that emit pollutants through stacks or other equipment at specific locations. The major source of facility-reported data is the NPRI, Canada’s legislated, publicly accessible inventory of pollutant releases (to air, water and land), disposals and transfers for recycling. The NPRI has provided facility-reported data on the 17 pollutants included in the APEI for  industrial and commercial facilities since 2002, for 10 of those 17 pollutants (polycyclic aromatic hydrocarbons [PAHs], heavy metals, dioxins and furans, hexachlorobenze [HCB] since 2000, ammonia since 1995 and the three heavy metals (Pd, Cd and Hg) since 1993. Prior to 2002, facility-level emissions for the criteria air contaminants (CACs ) were collected and compiled by provincial, territorial and regional environmental authorities across Canada and provided to ECCC for inclusion in the APEI. 

Facility-reported data from the NPRI are used in the APEI without modifications, except when 1) data quality issues are detected and not addressed during the quality control exercise, or 2) adjustments to particulate matter (PM) emissions are necessary to respect their size fraction. The NPRI reporting requirements and thresholds vary by pollutant and, in some cases, by industry. Details on these reporting requirements and thresholds are available on ECCC’s website in the National Pollutant Release Inventory section.  

A distinction has been made between reporting facilities and non-reporting facilities. Reporting facilities meet the threshold required to report to the NPRI, while non-reporting facilities do not meet the threshold owing to their size or emission levels. Some facilities may be required to report emissions of certain pollutants only. Therefore, emissions from the non-reporting facilities or of non-reported pollutants must be estimated in-house to ensure complete coverage.

Historically (e.g., for the years 1985, 1990, 1995 and 2000), facility-reported data were primarily provided by provinces and territories. In some cases, additional information was calculated to fill in intervening years or to update the original submissions. Trends for the intervening years were interpolated. The compilation of emissions for 2001 to 2005 occurred during a transition to the use of emissions data reported to the NPRI as the major source of industrial emissions. In general, facility-reported data from the NPRI and data provided by provinces and territories were used for years 2002, 2004 and 2005, and interpolation was used for 2001 and 2003.

Since 2005, information on facility-reported data has originated mainly from the NPRI, with limited data obtained from some provincial governments on selected sources that are not reported to the NPRI.

The NPRI groups substances into five parts, as listed below. Each part has its own reporting thresholds or triggers for mandatory reporting.

Table 3–2 shows the 17 air pollutants reported in the APEI and their NPRI reporting thresholds. No VOC data collected under Part 5 are used in the APEI.

Notes:
MPO = Manufactured, processed or otherwise used
NA = Not applicable

Table 3–2: National Pollutant Release Inventory air pollutant reporting thresholds
Substance National Pollutant Release Inventory part # (threshold category) Mass threshold Concentration threshold
Ammonia 1A 10 tonnes MPO MPO by weight of ≥ 1%
Benzo(a)pyrene 2 50 kg total PAHs NA
Benzo(b)fluoranthene 2 50 kg total PAHs NA
Benzo(k)fluoranthene 2 50 kg total PAHs NA
Cadmium 1B 5 kg MPO MPO by weight of ≥ 0.1%
Carbon monoxide 4 20 tonnes air release NA
Dioxins and furans 3 Activity-based NA
Hexachlorobenzene 3 Activity-based NA
Indeno(1,2,3-c,d)pyrene 2 50 kg total PAHs NA
Lead 1B 50 kg MPO MPO by weight of ≥ 0.1%
Mercury 1B 5 kg MPO NA
Nitrogen oxides 4 20 tonnes air release NA
PM10 - particulate matter ≤ 10 microns 4 0.5 tonnes air release NA
PM2.5 - particulate matter ≤ 2.5 microns 4 0.3 tonnes air release NA
Sulphur dioxide 4 20 tonnes air release NA
Total particulate matter 4 20 tonnes air release NA
Volatile organic compounds 4 10 tonnes air release NA

In 2020, approximately 6,000 facilities reported releases to air of one or more APEI pollutants to the NPRI.

Using the 2020 NPRI database, with data available as of November 12, 2021, facility information and air emissions data for pollutants listed in Table 3–2 were extracted for each province and territory. The quality control process described in section 3.6 was applied to the NPRI data to identify outliers or missing substance reports.

For facilities reporting to the NPRI for the first time, the North American Industry Classification System (NAICS) codes (Statistics Canada, 2017), reported by the facilities, are used to assign preliminary APEI sector and subsector classifications. Additional research and verifications are then performed to confirm or correct the classification. The assigned classification is used for subsequent reporting years, as long as the facility does not change operations.

NPRI reporting facilities may not report all three PM size fractions.: TPM, PM10, PM2.5 . For cases where only one or two of the three PM size fractions are reported to the NPRI, a distribution procedure is applied to estimate a complete set of PM emissions for facilities. The procedure is based on sector-specific PM distribution profiles developed using 2006–2016 facility-reported PM emissions data  for most sectors, 2002–2017 facility-reported emissions data or detailed studies for other sectors. Where ratios were calculated using facility-reported data the ratio for each facility is calculated and then averaged by sector. The resulting distributions are presented in Table 3–3.

The PM distribution procedure described in equations 3–1, 3–2 and 3–3 is applied on a case-by-case basis to fill data gaps.

Equation 3–1: PM10 distribution ratio

Note:
Refer to Annex 4.4 for more information on international marine navigation and air transportation reporting emissions.

PM10 ratio = PM10 emissions / TPM emissions

Where

PM10 ratio = Ratio of the sector’s PM10 emissions to TPM emissions

PM10 emissions = PM10 emissions for the sector

TPM emissions = Total particulate matter emissions for the sector

Equation 3–2:  PM2.5 distribution ratio

PM2.5 ratio = PM2.5 emissions / TPM emissions

Where

PM2.5 ratio = Ratio of the sector’s PM2.5 emissions to its TPM emissions

PM2.5 emissions = PM2.5 emissions for the sector

TPM emissions = Total particulate matter emissions for the sector

Equation 3–3:  PM2.5/PM10 distribution ratio

PM2.5 / PM10 ratio = PM2.5 emissions / PM10 emissions

Where

PM2.5/PM10 ratio = Ratio of the sector’s PM2.5 emissions to its PM10 emissions

PM2.5 emissions = PM2.5 emissions for the sector

PM10 emissions = PM10 emissions for the sector

The TPM, PM10 and PM2.5 emissions calculated using the distribution procedure are added to the list of facility-reported data and flagged as an ECCC estimate within the compiled APEI final database.

Table 3–3 Particulate Matter distribution ratios

Note:
–  Indicates that PM10 and PM2.5 ratios are not used for these estimates

Ore and Mineral Industries
Sector Subsector PM10 ratio PM2.5 ratio PM2.5/PM10 ratio
Aluminium industry Alumina (Bauxite Refining) 0.399 0.309 0.798
Aluminium industry Primary Aluminium Smelting and Refining 0.686 0.559 0.798
Aluminium industry Secondary Aluminium Production (Includes Recycling) 0.951 0.937 0.926
Asphalt Paving industry 0.385 0.177 0.513
Cement and Concrete Industry Cement Manufacturing 0.623 0.31 0.474
Cement and Concrete Industry Concrete Batching and Products 0.497 0.23 0.465
Cement and Concrete Industry Gypsum Product Manufacturing 0.715 0.508 0.643
Cement and Concrete Industry Lime Manufacturing 0.576 0.309 0.512
Foundries Die Casting 0.711 0.51 0.81
Foundries Ferrous Foundries 0.711 0.51 0.723
Foundries Non-ferrous Foundries 0.927 0.49 0.719
Iron and Steel Industry Primary (Blast Furnace and DRI) 0.598 0.403 0.65
Iron and Steel Industry Secondary (Electric Arc Furnaces) 0.616 0.474 0.802
Iron and Steel Industry Steel Recycling 0.711 0.51 0.287
Iron and Steel Industry Other (Iron and Steel Industry)
Iron Ore Industry Pelletizing 0.48 0.212 0.41
Mineral Products Industry Brick Products 0.757 0.23 0.323
Mineral Products Industry Clay Products 0.802 0.094 0.484
Mineral Products Industry Other (Mineral Products Industry) 0.762 0.545 0.665
Mining and Rock Quarrying Coal Mining Industry 0.368 0.064 0.147
Mining and Rock Quarrying Iron Ore Mining 0.513 0.191 0.432
Mining and Rock Quarrying Limestone 0.460 0.165 0.397
Mining and Rock Quarrying Metal Mining 0.532 0.283 0.509
Mining and Rock Quarrying Potash 0.599 0.316 0.503
Mining and Rock Quarrying Rock, Sand and Gravel 0.46 0.165 0.397
Mining and Rock Quarrying Silica Production
Mining and Rock Quarrying Other (Mining and Rock Quarrying) 0.465 0.197 0.398
Non-Ferrous Refining and Smelting Industry Primary Ni, Cu, Zn, Pb 0.649 0.375 0.606
Non-Ferrous Refining and Smelting Industry Secondary Pb, Cu 0.574 0.396 0.748
Non-Ferrous Refining and Smelting Industry Other (Non-Ferrous Refining and Smelting Industry) 0.494 0.444 0.859
Oil and Gas Industry
Sector Subsector PM10 ratio PM2.5 ratio PM2.5/PM10 ratio
Downstream Oil and Gas Industry Petroleum Refining
Downstream Oil and Gas Industry Refined Petroleum Products Bulk Storage and Distribution 0.100 0.100 0.750
Downstream Oil and Gas Industry Refined Petroleum Product Pipelines 1.000 1.000 1.000
Downstream Oil and Gas Industry Natural Gas Distributiona 1.000 1.000 1.000
Downstream Oil and Gas Industry Other (Downstream Oil and Gas Industry) 0.743 0.641 0.628
Upstream Oil and Gas Industry Accidents and Equipment Failures
Upstream Oil and Gas Industry Disposal and Waste Treatment
Upstream Oil and Gas Industry Heavy Crude Oil Cold Productiona
Upstream Oil and Gas Industry Light Medium Crude Oil Productiona 1.000 1.000 1.000
Upstream Oil and Gas Industry Natural Gas Production and Processinga 1.000 1.000 1.000
Upstream Oil and Gas Industry Natural Gas Transmission and Storagea 1.000 1.000 1.000
Upstream Oil and Gas Industry Oil Sands In-Situ Extractiona 1.000 1.000 1.000
Upstream Oil and Gas Industry Oil Sands Mining and Extractionb 0.658 0.447 0.680
Upstream Oil and Gas Industry Bitumen and Heavy Oil Upgradingb 0.677 0.428 0.631
Upstream Oil and Gas Industry Petroleum Liquids Storagea 1.000 0.831 0.831
Upstream Oil and Gas Industry Petroleum Liquids Transportation
Upstream Oil and Gas Industry Well Drilling/Servicing/Testing
Electric Power Generation (Utilities)
Sector Subsector PM10 ratio PM2.5 ratio PM2.5/PM10 ratio
Coal 0.578 0.293 0.484
Diesel 0.967 0.962 0.943
Natural Gas 0.909 0.663 0.902
Waste Materials 0.734 0.54 0.76
Other (Electric Power Generation) 0.735 0.608 0.924
Manufacturing
Sector Subsector PM10 ratio PM2.5 ratio PM2.5/PM10 ratio
Abrasives Manufacturing 0.415 0.231 0.669
Bakeries 0.861 0.744 0.760
Biofuel Production
Chemicals Industry Chemical Manufacturing 0.737 0.595 0.754
Chemicals Industry Cleaning Compound Manufacturing 1.000 1.000 1.000
Chemicals Industry Fertilizer Production 0.575 0.235 0.52
Chemicals Industry Paint and Varnish Manufacturing 0.919 0.564 0.701
Chemicals Industry Petrochemical Industry 0.894 0.424 0.587
Chemicals Industry Plastics and Synthetic Resins Fabrication 0.791 0.566 0.744
Chemicals Industry Other (Chemical Industry) 0.485 0.465 0.886
Electronics 0.958 0.833 0.834
Food Preparation 0.651 0.409 0.634
Glass Manufacturing 0.836 0.755 0.919
Grain Industries Grain Processing
Grain Industries Warehousing and Storage
Metal Fabrication 0.747 0.590 0.771
Plastics Manufacturing 0.731 0.474 0.817
Pulp and Paper Industry Converted Paper Product Manufacturing 0.805 0.640 0.773
Pulp and Paper Industry Pulp and Paper Product Manufacturing 0.737 0.560 0.757
Textiles 1.000 1.000 0.759
Vehicle Manufacture (Engines, Parts, Assembly, Painting) 0.694 0.427 0.748
Wood products Panel Board Mills 0.596 0.361 0.589
Wood products Sawmills 0.423 0.197 0.451
Wood products Other (Wood Products) 0.688 0.549 0.732
Asbestos Industryc 0.373 0.141 0.428
Rubber Manufacturingc 0.638 0.402 0.602
Ship & Boat Building & Repairingc 0.510 0.076 0.151
Drinking Waterc 1.000 1.000 0.968
Asphalt Shingle and Coating Material Manufacturingc 0.851 0.701 0.801
Other (Manufacturing) 0.645 0.359 0.503
Transportation and Mobile Equipment
Sector Subsector PM10 ratio PM2.5 ratio PM2.5/PM10 ratio
Air Transportation
Domestic Marine Navigation, Fishing and Military
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 Ttrucks
Light-Duty LPG/NG Vehicles
Motorcycles
Off-road Diesel Vehicles and Equipment
Off-road Gasoline/LPG/CNG Vehicles and Equipment
Rail Transportation
Tire Wear and Brake Lining
Agriculture
Sector Subsector PM10 ratio PM2.5 ratio PM2.5/PM10 ratio
Agricultural Fuel Combustion 0.646 0.503 0.749
Animal Production
Crop Production Harvesting
Crop Production Inorganic Fertilizer Application
Crop Production Sewage Sludge Application
Crop Production Tillage Practices
Crop Production Wind Erosion
Commercial / Residential / Institutional
Sector Subsector PM10 ratio PM2.5 ratio PM2.5/PM10 ratio
Commercial and Institutional Fuel Combustion 0.761 0.581 0.599
Commercial Cooking
Construction Fuel Combustion
Home Firewood Burning
Human
Marine Cargo Handling 0.396 0.147 0.365
Residential Fuel Combustion
Service Stations
Other (Commercial / Residential / Institutional)
Incineration and Waste
Sector Subsector PM10 ratio PM2.5 ratio PM2.5/PM10 ratio
Crematoriums 1.000 1.000 1.000
Waste Incineration Municipal Incineration 0.737 0.680 0.913
Waste Incineration Residential Waste Burning
Waste Incineration Sewage Sludge Incineration
Waste Incineration Other (Waste Incineration) 0.718 0.359 0.479
Waste Treatment and Disposal Biological Treatment of Waste 1.000 1.000 1.000
Waste Treatment and Disposal Landfills 0.778 0.603 0.743
Waste Treatment and Disposal Municipal Wastewater Treatment 1.000 1.000 0.968
Waste Treatment and Disposal Specialized Waste Treatment and Remediation 0.818 0.790 0.953
Waste Treatment and Disposal Waste Sorting and Transfer 0.800 0.200 0.250
Paints and Solvents
Sector Subsector PM10 ratio PM2.5 ratio PM2.5/PM10 ratio
Dry Cleaning 1.000 1.000 1.000
General Solvent Used Varies Varies Varies
Printingd Varies Varies Varies
Surface Coatings 1.000 1.000 1.000
Dust
Sector Subsector PM10 ratio PM2.5 ratio PM2.5/PM10 ratio
Coal Transportation
Construction Operations 0.800 0.200 0.250
Mine Tailings
Paved Roads
Unpaved Roadse 0.265 0.027 0.100
Fires
Sector Subsector PM10 ratio PM2.5 ratio PM2.5/PM10 ratio
Prescribed Burning
Structural Fires

Notes:
Based on the most recent facility-reported data from NPRI.
a. Adapted from Clearstone Engineering Ltd (2014).
b. Adapted from Clearstone Engineering Ltd (2017). Emissions from Bitumen and Heavy Oil Upgrading and Oil Sands Mining and Extraction are combined together and reported as Oil Sands Mining, Extraction and Upgrading in this report.
c. Emissions from these subsectors (Asbestos Industry; Rubber Manufacturing; Ship & Boat Building & Repairing; and Asphalt Shingle and Coating Material Manufacturing) are reported under Other (Manufacturing).
d. Values for PM ratios for these categories vary by subsector: Printing and General Solvent Use—values range from 0.786 to 1.0.
e. Ratios derived from particulate matter ratios provided in the NPRI Toolbox guidance document entitled Guidance on Estimating Road Dust Emissions from Industrial Unpaved Surfaces.

3.3 In-house emission estimates

The reporting of substances by facilities to the NPRI remains the primary source of industrial air pollution data in Canada. Sectors with significant sources of facility-reported data (e.g., petroleum refineries, smelters) are well represented by emissions data from the NPRI.

The completeness of the APEI is assessed by the level of inclusion of all known, quantifiable sources of pollutant emissions in the provincial, territorial and national totals that are attributed to anthropogenic activities. Where NPRI facility-reported data do not provide for complete sector coverage, additional estimates are developed in-house by ECCC. An overall estimation of completeness in this case is related to the availability and reliability of the activity data and methodologies used for the in-house estimates.

The development of complementary in-house estimates is not required in sectors where NPRI facility data provide complete coverage of air pollutant emissions (e.g., pulp and paper). To produce a complete inventory of emissions, complementary in-house estimates are necessary for subsectors that have limited coverage in the NPRI because many facilities do not meet the reporting thresholds (e.g.,  Natural Gas Production and Processing, Light/Medium Crude Oil Production, Sawmills, Ferrous Foundries, etc. ).

Other sources of air pollutants, such as Residential Fuel Combustion, Transportation or Fires, are not subject to reporting to the NPRI, and coverage is assured solely through the calculation of in-house emission estimates for these sources.

Although all major sources of air pollutant emissions are included in the APEI, a number of sources are not  , such as the burning of agricultural wastes and demolition activities in the construction industry.

In-house estimates are calculated using information such as production data and activity data, using various estimation methodologies, emission models and emission factors.Footnote 1 Depending on the source, there are three methodological tiers that represent varying levels of complexity: Tier 1 is the simplest; Tier 2, the intermediate; and Tier 3, the most demanding in terms of complexity and data requirements. Tier 2 and 3 methods are referred to as higher tier methods and are considered more accurate. Tier 1 methods typically apply a simple linear relation between activity data and emission factors. The default Tier 1 emission factors are chosen such that they represent typical process conditions, and they tend to be technology independent. UNECE provides Tier 1 methods for all sources and substances that countries that have ratified the protocols of the Convention on Long-range Transboundary Air Pollution are required to report. Tier 2 methods use the same or simil ar activity data as Tier 1 methods, but apply country-specific emission factors, which need to be developed using country-specific information. Tier 3 methods go beyond the previous two methods and may include using facility-level data, specific information on the types of technologies being used at facilities, pollution abatement equipment, and/or sophisticated models. It is a good practice to use higher tier methods for categories that are large contributors to   total emissions. 

Calculations of in-house estimates are based on the latest data available at the time of inventory development. When possible, the data are updated each year. These emission estimates are calculated at the provincial, territorial and national level. Table 3–1 illustrates the complete list of sectors and subsectors of the APEI for which emissions are based on in-house estimates and provides the activity data year on which the 2020 in-house estimate is based.

Detailed information on in-house estimation methodologies is presented in Annex 2.

3.4 Reconciliation

In several sectors, such as the Upstream Oil and Gas Industry, estimation of total emissions involves combining estimates provided by facilities with estimates developed in-house by ECCC. To prevent double counting of emissions and to confirm that the APEI includes all emissions, a comparison and reconciliation of emission estimates from various sources is performed for each pollutant, industry sector and geographical region, as appropriate.

3.4.1 General procedures

The approach for reconciling facility-reported data and in-house estimates for a specific pollutant is as follows:

Equation 3–4

If, InHouseEstimateTotal ≥ FacilityReportedDataTotal

Then, InHouseEstimateREC = InHouseEstimateTotal - FacilityReportedDataTotal

Equation 3–5

If, InHouseEstimateTotal ≤ FacilityReportedDataTotal

Then, InHouseEstimateREC = 0

Some points to consider:

There are sectors where the typical reconciliation approach is not used. Sections 3.4.2, 3.4.3 and 3.4.4 provide information on reconciliation approaches that are unique in nature. 

3.4.2 Wood Products

Particulate matter emissions (TPM, PM10 and PM2.5) from the Sawmills and Panel Board Mills subsectors (Wood Products sector) were not reconciled using the procedure described in section 3.4.1. Rather, NPRI facility-reported data from these subsectors were used to characterize the entire industry. The facility-reported data, together with a number of production indicators, were used to estimate the PM emissions from facilities that are not required to report to the NPRI. The sum of the resulting emission estimates represents the total emissions for these subsectors. All other pollutants were reconciled at the subsector and provincial level according to the standard procedure and equations outlined in section 3.4.1.

3.4.3 Dry Cleaning, General Solvent Use, Printing and Surface Coatings

The in-house estimates in the Dry Cleaning, General Solvent Use, Printing, and Surface Coatings sectors (Paints and Solvents source category) include a total of 92 different kinds of solvents and applications. The challenge is to reconcile the in-house estimates with facility-reported data, which include a variety of sources (solvent use as well as processes, fuel combustion, road dust, etc.) grouped under the same NAICS. Given the comlexity of the solvent sectors, reconciliation of in-house estimates with facility-reported data from the NPRI requires that the following steps be performed by a specially designed database application (Cheminfo Services, 2019):

  1. allocation of the solvent use in-house estimates to the 4-digit NAICS level from the NPRI
  2. allocation of the NPRI VOC inventory totals at the 4-digit NAICS level to “Process” and “Solvent” type emissions
  3. subtraction of the “Solvent” type NPRI emissions from the solvent in-house emissions estimates

If subtraction of the facility-reported data from the in-house estimates for a certain solvent use yields a small negative value, the emission estimate for that in-house estimate is set to zero. 

3.4.4 Mercury in products

Mercury (Hg) can be released to air throughout the life cycle of mercury-containing products, including during manufacture, distribution, use, disposal, transportation and final disposition, as well as through waste streams. Releases can also result from breakage and processing. Reconciliation of Hg air emissions from mercury in products with NPRI involves a review and characterization of the source of the Hg air emissions included in the facility-reported estimate. This is to ensure that the Hg emissions estimated through the life-cycle approach are not duplicated in the facility-reported data. In situations where overlap exists, either the area source emissions from mercury in products are removed from reporting in the APEI or a proportion method is applied. The proportion method only changes the mercury in product emissions, while the point-source emissions  remain unchanged (Equation 3–6 and Equation 3–7):

Equation 3–6

Equation 3-7

Final Emissions for Mercury in Products = Sum of Mercury in Product Emissions × Proportion

This is done at the provincial and territorial level by year.

3.5 Compilation and reporting

The time interval between the receipt of emissions data from industries and submission of the emissions and report to UNECE is relatively short. Tools used to compile emissions, populate the UNECE Nomenclature for Reporting (NFR) tables   , perform quality control tests and generate the different tables and figures for this report are automated as much as possible to allow quick compilation, ensure efficient corrections and reduce the possibility of errors. 

3.6 Data quality control

Quality control for the inventory takes place at each step of the process, in three main phases. In phase 1, quality control is performed on the most recently submitted NPRI facility-reported data, prior to inclusion of the data in the estimates. Phase 2 of the quality control occurs on the in-house estimates at a subsector level, while phase 3 is performed on the final database of reconciled and compiled emissions, including NFR tables. See Figure 3-2 for a visual representation of the different quality control check points.

Figure 3–2: Quality control check points

Figure 3–2 section-3.6.1 section-3.6.2 section-3.6.2.a section-3.6.1.a section-3.6.2.b section-3.6.1.b section-3.6.2.c section-3.6.1.c section-3.6.3.a section-3.6.3 section-3.6.3.b section-3.6.3.c section-3.6.3.d section-3.5

Long description for Figure 3–2

Figure 3–2 is a flow chart displaying an overview of the quality control process of the Canada’s annual Air Pollutant Emissions Inventory and checkpoints at various stages of the process. The chart is based on the process of emissions estimation described earlier in Figure 3–1. In this figure, there are two big boxes side by side at the top that represent first two phases of the quality control process. The big box on the left describes Phase 1 quality control on facility-reported emissions data and associated check points. The big box on the right describes quality control check points during the Phase 2 In-House Emission estimation. The two quality control phases are performed independently.

Within the big box on the top left, at the background there are several small boxes and circles with arrows describing the Facility-Reported Emissions process from Figure 3–1 supplemented by two highlighted grey boxes representing specific quality control check points at different steps. The first quality control check is done for the 17 pollutants after their Extraction from the National Pollutant Release Inventory (NRPI) database. The grey box shows a high-level data quality control that is described in section 3.6.1.a. The second grey box representing Sectoral Data Quality Control stands right after the inventory step of Facility Data provision to the Air Pollutant Inventory database. Description of the quality control is provided in section section 3.6.1.b. The Sectoral Data Quality Control box is also connected to the last quality control box in Phase 1, right below, named “Contacting facilities with potential issues” described in section 3.6.1.c.

In the big box on the top right-hand side of this figure, the first Phase 2 grey quality control box is Data Quality Control on Activity Data. The process of the quality control at this step is described in section section 3.6.2.a. It comes right after Activity Data and Emissions Factors step of the inventory process. From there, at the background, one arrow splits off to the left, to Calculation of In-House Estimates, which is supplemented with the second quality control grey box Data quality control on estimates described in section 3.6.2.c. Another arrow splits off to the right and leads to Emissions Models. Here, the third grey box of Data quality control on emissions model outputs covers the box of Emissions Models inventory step at the background. This quality check is described in section section 3.6.2.b.

Both, the big top left box and the big top right box at the background then merge into the Reconciliation step, when the quality control (QC) Phase 3 starts: Quality control on Compiled Air Pollutant Emissions Inventory which is described in section 3.6.3. The Data Quality Control is performed before data enters the Air Pollutant Inventory Database and is described in detail in section 3.6.3.a. From there, four arrows at the background split off to reporting steps and are overlapped with grey quality control box, which represents the MS Power BI analysis on the compiled emissions explained in the section 3.6.3.b. Beneath the first three boxes from left to right representing the air pollutant inventory database products, the grey quality control boxes show the specific Data Quality Control checks that are done on the end products before reporting. These checks are described in section 3.6.3.c. The separate Data quality control check on cross reference is performed for the data used to report to the United Nations Economic Commission for Europe (UNECE) represented by the box under the most right UNECE Submission reporting step. This quality control check is described in section 3.6.3.d.

3.6.1 Phase 1: facility-reported emissions data

The quality control process involves a system of documented activities and procedures performed to identify data outliers, inconsistencies, missing data, inaccuracies and errors. This phase is divided into two parts.

First, high level completeness tests are completed on NPRI data before sharing facility data with sectoral experts. This step involves comparison with the previous year’s dataset and identifiying any significant changes. High level checks on the number of facilities reporting, number of records included in the database, number of new facilities and total emissions by pollutants by year are performed to ensure sufficient completeness before proceeding to more detailed analysis and quality control (Refer to 3.6.1.a in Figure 3-2).

Once the initial checks are satisfied, the facility-reported dataset is prepared and shared with sectoral experts for more specific and in depth quality control. The quality control process is adapted where necessary such that category-specific or sector-specific quality control procedures are applied, as appropriate. (Refer to 3.6.1.b in Figure 3-2) A key part of the quality control process is identifying missing NPRI facility reporters and assessing new reporters to ensure that the correct data are captured and allocated to the appropriate sectors and subsectors.

Identifying outliers (i.e., reports that significantly depart from comparable NPRI facility-reported data) is critically important to ensuring the usability of the NPRI facility-reported data.

Potential outliers are defined as any NPRI facility report that:

In addition to identifying missing NPRI facilities and outliers, the quality control review includes analysis of:

Finally, quality control checks are also performed on facility information. These checks include facility identification numbers and geographical information (i.e., city, province and territory, address and latitude andlongitude).

Once the review of the facility data is complete, facilities are contacted to resolve identified issues with significant impacts. Identification, facility follow-up and resolution of such issues are conducted at the earliest stage of the quality control review. Where unresolved issues persist, any updates to the data will be reflected in the next inventory edition. (Refer to 3.6.1.c in Figure 3-2)

3.6.2 Phase 2: in-house emission estimates

The objective of Phase 2 of the quality control process is to identify and verify inconsistencies in the APEI at the subsector level. A series of verification and quality control checks are undertaken on the in-house emission estimates to ensure quality, accuracy and consistency. The following are verified:

Activity data (refer to 3.6.2.a in Figure 3-2) and emission estimates are reviewed by multiple sector experts to identify outliers, similar to the review of facility reported data. Potential outliers are defined as sector level activity data and emissions that:

Emissions estimates (refer to 3.6.2.b in Figure 3-2) are further compared against other metrics for the sectors, such as: heating degree days, electricity generation, population, or gross domestic product. These comparisons are used to confirm general trends identified. Additional information is gathered from industry associations or news releases related to temporary shut-downs, plant closures, and re-tooling of facilities which is used to confirm trends.

Best-available emission factors are chosen by sector experts to reflect Canadian conditions for the various sectors. For example, emission factors for residential firewood burning are currently taken from the US EPA as their technology is also used in Canada. 

Prior to implementation, in-house models are rigorously tested to ensure activity data and emission factors are correctly applied, unit conversions are consistent throughout and resulting emissions estimates are in the appropriate sector (refer to 3.6.2.c in Figure 3-2).

3.6.3 Phase 3: Compiled Air Pollutant Emission Inventory

Phase 3 includes all tests performed immediately prior to compiling the estimates as well as the analysis of the results and different products once they have been compiled in a final database. Before integrating the emissions estimates from all sources, automated quality control tests are done on each individual part. The tests performed include checking for duplicates, ensuring that all sources are considered and all mandatory fields are filled according to the standards, and verifying units. The purpose of the tests is to ensure the quality of the compiled data. (Refer to 3.6.3.a in Figure 3-2)

Once all estimates have been compiled, trend analysis graphics and recalculations graphics are produced to analyze the consistency of the estimates. Data visualization tools, such as Microsoft Power BI, are also used to perform trend and recalculation analysis and to identify any abnormal gaps. Data are analyzed at different levels. They are analyzed by pollutant, by source, sector or sub-sectors. Gaps can be identified either from their impact on the overall contribution to the national trend or from their impact on the category itself. Trends are also analyzed by province and territory. Any significant changes from year to year and any recalculated emissions are identified and explained. (Refer to 3.6.3.b in Figure 3-2)

Quality control is also performed on all other APEI products, including the data tables presented in this report as well as data published online (Refer to 3.6.3.c in Figure 3-2). At this stage, the quality control tests mainly consist of verifying that totals (for different layers of disaggregation, different years and different pollutants) match the compiled estimates. The various end products are also compared against each others as an additional quality control step.

As a last step, quality control tests are made on the  NFR  tables (Refer to 3.6.3.d in Figure 3-2). Some tests are automated and are run on the compiled tables that will be submitted to the United Nations Economic Comissions for Europe. They include verifying totals for each pollutant and each year and comparing those values with what is reported in this report. A completeness test is also run to make sure every cell has a value, either a numerical value or a notation key. Other quality control checks are also made by sectoral experts and are, in some cases, cross referenced with the sector-level estimates. For more information on the NFR  tables, refer to Annex 4.

3.7 Recalculations

Emission recalculation is an essential practice in the maintenance of an up-to-date air pollutant emissions inventory. The APEI is continuously updated with improved estimation methodologies, statistics and more recent and appropriate emission factors. As new information and data become available, previous estimates are updated and recalculated from the base year (1990) to ensure a consistent and comparable trend in emissions. Recalculations of previously reported emission estimates are common for both in-house estimates and facility-reported emissions data. More information on recalculations is provided in Annex 3.

References, Chapter 3, Air pollutant emissions inventory development

Cheminfo Services. 2016. Compilation of volatile organic compound (VOC) emissions from the use of solvents in Canada: Inventory update. VOC emission trends compilation: 2005 to 2017, Final report. Unpublished report. Markham (ON): Cheminfo. Prepared for Environment and Climate Change Canada.

[EC] Environment Canada. 2014. Technical report on Canada’s upstream oil and gas industry. Vols. 1–4. Calgary (AB): Prepared by Clearstone Engineering Ltd.

[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. Vols 1–3. Calgary (AB): Prepared by Clearstone Engineering Ltd.

Statistics Canada. 2017. North American Industry Classification System (NAICS) Canada 2017 Version 3.0, Ottawa (ON): Statistics Canada.

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