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Canada’s Air Pollutant Emissions Inventory Report 2025: annex 2

In-House Estimation Methodologies

The in-house emissions estimation methodologies and emission models used in Canada’s Air Pollutant Emissions Inventory (APEI) are generally based on those developed by the United States Environmental Protection Agency (U.S. EPA) and adapted to use Canadian data, thereby accounting for differences in climate, fuels, technologies and practices. Therefore, methods used are generally consistent with those used in the United States, or otherwise, those recommended in the EMEP/EEA Air Pollutant Emission Inventory Guidebook (EEA, 2023).

Table A2–1 summarizes the in-house estimation methodologies for the entire time series, organised by the relevant sectors and subsectors. It also provides a general description of the inventory methodology approaches and the pollutants covered by each of those. Sectors and subsectors whose emissions are developed using only facility-reported data are not included in this table. More information on the origin of emissions (in-house estimates, facility-reported data or a combination of both) for each source is available in Chapter 3, Table 3–1.  

For complete descriptions of the APEI methodologies, including the references to activity data and emission factors used, please refer to Canada’s Air Pollutant Emissions Inventory Methodology Document on the Government of Canada Open Data PortalFootnote 1 .

Table A2–1: Summary of Air Pollutant Emissions Inventory In-House Estimation Methodologies

Ore and Mineral Industries
Sectors Subsectors Description of Methodology PM2.5 SOx Nox VOCs CO NH3 Pb Cd Hg D/F  PAHs HCB PM10 TPM
Asphalt Paving Industry No Total use of asphalt by province and territory is multiplied by pollutant—specific emission factors. Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes
Cement and Concrete Industry Concrete Batching and Products National domestic consumption of Portland cement is multiplied by the ratio of concrete produced to Portland cement used, distribution percentage by province/territory, and emission factors for each pollutant. Yes No No No No No Yes Yes No No No No Yes Yes
Foundries Ferrous Foundries Total production from grey iron or steel foundries by province and territory are multiplied by pollutant—specific emission factors, which are based on the type of foundry. Yes Yes Yes Yes Yes No No No No No No No Yes Yes
Mining and Rock Quarrying Rock, Sand and Gravel Total quantity of rock, sand and gravel produced by province and territory is multiplied by pollutant—specific emission factors to estimate PM emissions. Yes No No No No No No No No No No No Yes Yes
Mining and Rock Quarrying Silica Production Total quantity of silica produced by province and territory is multiplied by pollutant—specific emission factors to estimate PM emissions. Yes No No No No No No No No No No No Yes Yes
Oil and Gas Industry
Sectors Subsectors Description of Methodology PM2.5 SOx NOx VOCs CO NH3 Pb Cd Hg D/F  PAHs HCB PM10 TPM
Downstream Oil and Gas Industry Refined Petroleum Products Bulk Storage and Distribution Emissions are calculated using gross sales of gasoline for on-road motor vehicles multiplied by sector-specific emission factors. No No No Yes No No No No No No No No No No
Downstream Oil and Gas Industry Natural Gas Distribution Emission estimates are generated using data from comprehensive inventories and extrapolated from 2012 onwards based on gas distribution pipeline length. Yes Yes Yes Yes Yes Yes No No No No No No Yes Yes
Upstream Oil and Gas Industry Upstream Oil and Gas Industry subsectors, except Natural Gas Transmission and StorageFootnote2

Emission estimates are generated using data from comprehensive inventories and extrapolated from 2012 onwards using various provincial-level activity data.

Operator reported activity data and province-specific gas compositions are used to directly estimate emissions from reported venting and flaring in Alberta (2010-) and Saskatchewan, and from surface casing vent flows in Alberta and British Columbia.

 Yes Yes Yes Yes Yes Yes No No No No No No Yes Yes
Upstream Oil and Gas Industry Natural Gas Transmission and Storage Emission estimates are generated using data from comprehensive inventories and extrapolated from 2012 onwards. CO transmission emissions are extrapolated based on pipeline length, while natural gas storage emissions are extrapolated based on annual volumes of gas injected and withdrawn. Yes Yes Yes Yes Yes Yes No No No No No No Yes Yes
Manufacturing
Sectors Subsectors Description of Methodology PM2.5 SOx NOx VOCs CO NH3 Pb Cd Hg D/F  PAHs HCB PM10 TPM
Bakeries No Wheat flour consumption per capita data are multiplied by population data, the fraction of flour use in yeast-leavened baked goods, the ratio of product to flour, and an emission factor. No No No Yes No No No No No No No No No No
Construction Fuel Combustion No Sector-specific fuel consumption data taken from the Report on Energy Supply and Demand (RESD) are multiplied by fuel and sector-specific emission factors. Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes
Grain Industry Grain Industry PM emissions by province and territory are estimated using grain production statistics from the Canadian Grains Commission and country-specific emission factors for primary, process, transfer and terminal elevator grain handling practices. Yes No No No No No No No No No No No Yes Yes
Wood Products Sawmills and Panel Board Mills PM emissions by province and territory are calculated using a combination of NPRI facility-reported data and several production and capacity indicators. Emissions of all other pollutants are calculated using production rate estimates, hog fuel combustion data, and other fuel use data. Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes
Transportation and Mobile Equipment
Sectors Subsectors Description of Methodology PM2.5 SOx NOx VOCs CO NH3 Pb Cd Hg D/F  PAHs HCB PM10 TPM
Air Transportation Air Transportation (landing and takeoffs [LTO]) Aircraft-specific activity (LTO) by province and territory is multiplied by pollutant-specific emission factors. Yes Yes Yes Yes Yes Yes Yes No No No Yes No Yes Yes
Domestic Marine Navigation, Fishing and Military No Vessel-specific activity (movements) is multiplied by pollutant-specific emission factors. Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes No Yes Yes
On-Road Transportation No Vehicle-specific activity is multiplied by pollutant-specific emission factors in the Motor Vehicle Emission Simulator (MOVES) model. Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes
Off-Road Vehicles and Equipment No Application-specific activity is multiplied by pollutant-specific emission factors. For Pb, emission factors are derived from data collected under the Gasoline Regulations (SOR/90-247). For all other pollutants, emission factors are sourced from the U.S. EPA. Yes Yes Yes Yes Yes Yes Yes No No No No No Yes Yes
Rail Transportation No Railway activity (fuel consumption) is multiplied by pollutant-specific emission factors. Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes
Agriculture
Sectors Subsectors Description of Methodology PM2.5 SOx NOx VOCs CO NH3 Pb Cd Hg D/F  PAHs HCB PM10 TPM
Agricultural Fuel Combustion No Sector-specific fuel consumption data taken from the RESD are multiplied by fuel and sector-specific emission factors. Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes
Animal Production No Animal population data are estimated using semi-annual surveys and corrected to the Census of Agriculture (COA), and country specific NH3 and PM emissions from livestock operations and manure management are used. Yes No No Yes No Yes No No No No No No Yes Yes
Crop Production Inorganic Fertilizer Application Fertilizer shipment data are used with country specific NH3 emission factors.    Yes No No No No Yes No No No No No No Yes Yes
Crop Production Sewage Sludge Application Biosolids production data from ChemInfo Services (2017) are multiplied by the default emission factor for inorganic N sources. No No No No No Yes No No No No No No No No
Crop Production Harvesting Harvesting operation data are multiplied by the PM emission factors  from the California Air Resources Board (CARB, 2003) and Pattey and Qiu (2012). Yes No No No No No No No No No No No Yes Yes
Crop Production Tillage Practices Activity data for tillage operations in croplands from the COA  are used with PM emission factors derived from the U.S. EPA (1985). Yes No No No No No No No No No No No Yes Yes
Crop Production Wind Erosion Crop area cultivation data from the COA are used with country specific PM emission factors. Yes No No No No No No No No No No No Yes Yes
Commercial/Residential/Institutional Sources
Sectors Subsectors Description of Methodology PM2.5 SOx NOx VOCs CO NH3 Pb Cd Hg D/F  PAHs HCB PM10 TPM
Commercial and Institutional Fuel Combustion and Residential Fuel Combustion No Sector-specific fuel consumption data taken from the RESD are multiplied by fuel and sector-specific emission factors. Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes
Commercial Cooking No Pollutant-specific emission factors for each type of food and each type of commercial cooking equipment are multiplied by consumption rate and restaurant counts to estimate emissions. Yes No No Yes Yes No No No No No YesFootnote 3 No Yes Yes
Home Firewood Burning No Emissions from home firewood burning are calculated using consumption information taken from the Households and the Environment Survey and equipment-specific emission factors. Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No Yes Yes
Humans No Annual population data by province and territory are multiplied by an NH3 emission factor. A mass balance of Hg from dental amalgams is completed to estimate Hg emissions. No No No No No Yes No No Yes No No No No No
Marine Cargo Handling No Port-specific material handling quantities are multiplied by emission factors that account for wind speeds and the moisture contents of the materials. Yes No No No No No No No No No No No Yes Yes
Service Stations No Activity data associated with the refuelling of underground fuel tanks, on-road vehicles, and off-road vehicles and equipment are multiplied by emission rates sourced by the U.S. EPA. No No No Yes No No No No No No No No No No
Waste
Sectors Subsectors Description of Methodology PM2.5 SOx NOx VOCs CO NH3 Pb Cd Hg D/F  PAHs HCB PM10 TPM
Crematoriums Human Cremation Pet Cremation Emissions are calculated using the annual number of cremations for humans and pets combined with pollutant-specific emission factors. For human cremation, mercury from dental amalgams is included which is covered by the Mercury in Products model. Yes Yes Yes Yes Yes No Yes Yes Yes Yes Yes Yes Yes Yes
Waste Incineration Hazardous Waste, Medical Waste, Municipal Waste, Sewage Sludge, Other Time-series gaps in facility-reported emissions (NPRI) are filled using interpolation or are estimated from reported quantities incinerated and technology-specific emission factors from the U.S. EPA AP-42 and EMEP/EAA. Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
Waste Incineration Residential Waste Burning The quantity of residential waste burned in outdoor barrels or open pits is combined with the pollutant-specific emission factors to estimate emissions. Yes Yes Yes Yes Yes Yes No No Yes Yes Yes Yes Yes Yes
Waste Treatment and Disposal Landfills Air pollutants are estimated using the AP-42 methods (U.S. EPA, 1998), based on the modelled landfill gas generated and reported landfill gas recovered (ECCC, 2025). Yes Yes Yes Yes Yes No No No Yes Yes No No Yes Yes
Waste Treatment and Disposal Biological Treatment of Waste - Composting Municipal and commercial facility-level activity data are compiled from industry surveys, annual reports or facility-based websites. Emission factors are derived from the CARB methodology. Yes Yes Yes Yes Yes Yes No No No No No No Yes Yes
Paints and Solvents
Sectors Subsectors Description of Methodology PM2.5 SOx NOx VOCs CO NH3 Pb Cd Hg D/F  PAHs HCB PM10 TPM
Dry Cleaning, General Solvent Use, Printing and Surface Coatings No Emissions are estimated using statistical activity data on the production, distribution, end-use patterns and disposal of VOC-containing products. More detailed data on solvent quantities and practices are collected from a subset of solvent and formulated product users, producers and distributors in Canada. Emission factors are based on the portion of controlled release of the VOC in use. No No No Yes No No No No No No No No No No
Dust
Sectors Subsectors Description of Methodology PM2.5 SOx NOx VOCs CO NH3 Pb Cd Hg D/F  PAHs HCB PM10 TPM
Coal Transportation No Dust raised from open rail cars, trucks and barges are estimated based on methods from Cope at Bhattacharyya 2001, which factor trip distance, precipitation and dust controls. Yes No No No No No No No No No No No Yes Yes
Construction Operations No Dust emissions are estimated based on the surface area of soil disturbance and duration of construction projects. The geographic region, type of construction (residential, industrial-commercial-institutional, engineering) and soil characteristics are considered. Yes No No No No No No No No No No No Yes Yes
Mine Tailings No Wind-born dust from exposed mine tailings, are estimated based on exposed surface area (Fuentes et al. 2020), regional wind speed, precipitation and snow cover. Yes No No No No No No No No No No No Yes Yes
Paved and Unpaved Roads No

Dust emissions are estimated using AP-42 methods (U.S. EPA, 2011), paired with an in-house traffic distribution model.

Note: Improvements to the in-house traffic distribution model are anticipated to result in significant downward revisions to unpaved road dust emission estimates by approximately 70% for the 2026 APEI. If you have any questions on this planned improvement, please contact us at apei-iepa@ec.gc.ca or 1-877-877-8375.

 Yes No No No No No No No No No No No Yes Yes
Fires
Sectors Subsectors Description of Methodology PM2.5 SOx NOx VOCs CO NH3 Pb Cd Hg  D/F PAHs HCB PM10 TPM
Prescribed Burning No The total number of hectares burned from controlled fires in each province/territory per year is multiplied by a conversion factor to convert the area burned into the mass of forest debris burned which determine the release of pollutants. Yes Yes Yes Yes Yes Yes No No No Yes Yes No Yes Yes
Structural Fires No The number of structure fires (including vehicle and building fires) in each province and territory is multiplied by a loading factor to convert the number of fires into tonnes of structure burned and pollutant-specific emission factors are used. Yes No Yes Yes Yes Yes No No No No No No Yes Yes
Mercury in Products No Emissions are estimated based on a model that includes partitioning factors for the various streams through the life cycle of mercury-containing products, from manufacture through final disposal. No No No No No No No No Yes No No No No No

References

[CARB] California Air Resources Board. 2003. Emission inventory procedural manual – Volume III: Methods for assessing area source emissions.

Cheminfo Services Inc. 2017. Study of the typical management and disposal practices of wastewater treatment sludge in Canada and impacts on municipal solid waste landfills. Internal report. Gatineau (QC): Pollutant Inventories and Reporting Division, Environment and Climate Change Canada.

Cope, D., Bhattacharyya, K. 2001. A Study of Fugitive Coal Dust Emissions in Canada. Report prepared for The Canadian Council of Ministers of the Environment. November 2001.

[ECCC] Environment and Climate Change Canada. 2025. National Inventory Report 1990–2023: Greenhouse Gas Sources and Sinks in Canada.

[EEA] European Environment Agency. 2023. EMEP/EEA air pollutant emission inventory guidebook 2023. Technical guidance to prepare national emission inventories. Report No. 06/2023. Luxembourg: Publications Office of the European Union.

Fuentes M, Millard K, Laurin E. 2020. Big geospatial data analysis for Canada’s Air Pollutant Emissions Inventory (APEI): using google earth engine to estimate particulate matter from exposed mine disturbance areas. GIScience & Remote Sensing, 57(2): 245–257.

Pattey E, Qiu G. 2012. Trends in primary particulate matter emissions from Canadian Agriculture. Journal of the Air & Waste Management Association, 6297): 737-747.

[U.S. EPA] United States Environmental Protection Agency, 1985. Compilation of Air Pollutant Emission Factors, Vol. I: Stationary Point and Area Sources, AP-42. 4th Edition. GPO No. 055-000-00251-7.Research Triangle Park (NC): Office of Air Quality Planning and Standards.

[U.S. EPA] United States Environmental Protection Agency. 1998. Compilation of Air Pollutant Emission Factors, Volume I: Stationary Point and Area Sources, Chapter 02 Section 04. Final, 5th Edition. Research Triangle Park (NC): Office of Air Quality Planning and Standards.

[U.S. EPA] United States Environmental Protection Agency. 2011. Compilation of Air Pollutant Emission Factors, AP-42, Fifth Edition, Volume I: Stationary Point and Area Sources, Section 13.2.1, Paved Roads. Research Triangle Park (NC): Office of Air Quality Planning and Standards.

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2025-05-22