Canada’s Air Pollutant Emissions Inventory Report 2022: annex 2.3

A2.3 Estimation methodologies for Manufacturing by sector/subsector

For years prior to 2010, there are several source categories for which in-house estimates were developed to use in combination with facility-reported data and historical data from provinces, such as Chemical Manufacturing (1990–2000) and Pulp and Paper Product Manufacturing (1990–2006). Improvement of these estimates is under consideration for future inventories.

Bakeries

Description

Bakeries release volatile organic compounds (VOC) during the leavening process of industrial baking. Emissions from products leavened by baking powder (used mainly for pastries) are negligible, but VOCs are released when yeast is used for leavening. Yeast is used nearly exclusively in the production of bread and bread-like pastries.

General inventory method

Pollutant(s) estimated:
VOCs

Total quantity of wheat flour available per person is multiplied by population, the fraction of flour use in yeast-leavened baked goods, the ratio of product to flour, and an emission factor for VOCs emitted per t of product.

Activity data

Bread production values are estimated using:

• national wheat flour available: Statistics Canada (2021)
• population data for provinces and territories: Statistics Canada (n.d.)
• fraction of flour use in yeast-leavened baked goods and ratio of product to flour ratio: Cheminfo Services (2005)

Emission factors (EF)

Cheminfo Services (2005)

EF_VOC = 2.36 kg per tonne of baked goods produced

Grain Industry

Description

Grain Industry covers emissions from grain elevators. Grain elevators are divided into four groups in the Air Pollutant Emissions Inventory (APEI):

Primary elevators receive grain by truck from producers for either storage or forwarding. These elevators sometimes clean or dry grain before it is transported to terminal or process elevators (U.S. EPA, 1985).

Process elevators are grain processing plants or mills. While elevator unloading, conveying and storing operations are performed at these locations, direct manufacturing or processing of grain for use in other products are also carried out (U.S. EPA, 1985).

Terminal elevators dry, clean, blend and store grain for shipment.

Transfer elevators generally perform the same function as terminal elevators.

General inventory method

Pollutant(s) estimated:
TPM, PM₁₀, PM_2.5

Total grain production by province and territory is multiplied by process-specific emission factors for primary elevators, process elevators, transfer elevators and terminal elevators. Calculated emissions are reconciled with facility-reported data emissions reported through the National Pollutant Release Inventory (NPRI).

Activity data

The Canadian Grain Commission (CGC) provides year-to-date deliveries and shipment data for grains for Western provinces (AB, BC, MB and SK) at weekly periods where the majority of grain crops are grown. These data include primary, process, transfer and terminal elevators. The reports follow an “August to July” crop production cycle, so three representative weekly reports are selected to estimate the grain throughput for a calendar year; weeks 21-22 (W22), week 52 (W52) from the previous year (PY) and weeks 21-22 (W22) from current year (CY). PY-W52 represents grain throughput from August and July and PY-W22 represents throughputs from August to December of the previous year (CGC, 2017). The current calendar year’s estimate of grain throughput is calculated as:

Grain throughputs = (PY-W52) – (PY-W22) + (CY-W22)

Estimation of grain distribution among provinces: The CGC does not report primary delivery data from Eastern provinces (NS, NB, PE). Consequently, grains that are delivered to primary elevators outside of Western provinces are assumed to be consistent with the grain deliveries in Ontario ON.

The division of grains between Western Canada and Eastern Canada is performed based on the total Canadian grain (Statistics Canada, 2017). However, the sum of each grain type shows the annual receipts in Western Canada as one value (there is no breakdown by province), and therefore, two assumptions are made in order to estimate provincial grain receipts. First, it is assumed that all grains received by ON primary elevators are transferred to process elevators in ON (including inter-provincial transfers). Second, the portion of receipts shared by each province is calculated based on the provincial proportions from the 1995 Criteria Air Contaminants (CAC) inventory. This inventory also provides the provincial distribution for transfer elevators. All grains from process elevators in ON are subsequently transported to terminal elevators, while transfer elevators in Ontario receive and ship grains from Western provinces.

Unlike process elevators, terminal elevators are only located at four ports in three provinces: BC (Vancouver, Prince Rupert), ON (Thunder Bay), MB (Churchill). With receipts and shipment data for each port from CGC statistics, terminal elevator throughputs are computed by averaging the received and shipped grains of the three ports ON (Thunder Bay), BC (Vancouver, Prince Rupert) and MB (Churchill).

Emission factors (EF)

Emissions for each process are calculated by multiplying the total activity level (grain throughputs in thousand metric tonnes) by the emission factor, control efficiency and handling ratio. The handling ratio represents the actual amount of grains treated in a process. Handling process emissions are regulated by the “control efficiency” factor. It is assumed that no loss occurs between processes, so the activity level is identical for all processes in each elevator. Accordingly, the total Canadian TPM, PM₁₀ and PM_2.5 annual emissions is the sum of emissions from all processes involved in the four elevators. The emission factors and parameters are listed in following section.

Emission = Activity level × (1 – Control Efficiency) × Emission factor × Handling ratio

All emission factors and parameters are identical in all provinces (Pinchin Environmental Ltd, 2007).

Note:
NA = Not applicable (not included in calculation for these processes)

Reconciliation: The emissions calculated at the provincial scale are considered as area source (AS) estimates. Point source (PS) values are those directly reported by the grain-handling facilities to the National Pollutant Release Inventory and they serve as the most reliable estimate of emission values. Thus, the AS and PS estimates are subjected to a reconciliation procedure before submission to the inventory. When cumulative AS values for a province were found to be lower than the cumulative PS value for the same province, the AS value was replaced by the PS value. The precedence of PS values over AS is determined based on their reliability.

Warehousing and Storage: These are PM emissions categorized for facilities that store the grains. The PS emissions are summed by province for the reporting facilities.

Sawmills, Panel Board Mills and Other (Wood Products) (under Wood Products)

Description

Sawmills cover emissions from facilities that typically produce hardwood and softwood lumber from logs. The process of converting wet logs into dry lumber includes debarking, sawing, drying and planing steps, which all release air emissions.

Panel Poard Mills include emissions from several types of mills, all producing hardwood and softwood-based materials. These include:

• veneer and plywood mills
• waferboard mills, consisting primarily of oriented strand board (OSB) mills
• particle board and medium-density fiberboard (MDF) mills

Other Wood Products encompass emissions from furniture and cabinet manufacturers, wood treating plants, wood pellet mills and masonite manufacturers.

The combustion of various fuels for energy production or waste disposal, notably wood residues, natural gas, liquefied petroleum gas (LPG) and fuel oil is a common practice at wood products facilities. Significant amounts of air pollutant emissions result from combustion in this sector.

General inventory method

Pollutant(s) estimated:
TPM, PM₁₀, PM_2.5, SO_x, NO_x, VOCs, CO, NH₃, Pb, Cd, Hg, dioxins/furans, B[a]p, B[b]f, B[k]f, I(cd)p

Sawmills and panel board mills

• TPM, PM₁₀ and PM_2.5: Estimation methodology makes use of the NPRI facility-reported data in addition to a number of production and capacity indicators to estimate the PM levels of facilities not reporting to the NPRI (Natural Resources Canada, Forest Products Association of Canada and the Composite Panel Association, corporate website information, annual reports, Resource Information Systems Inc. publications, Madison publications and occasional discussion with industry representatives);
• All other pollutants: Production rate estimates, hog fuel combustion data, and other fuel use data are used to estimate emissions of the remaining pollutants (Meil et al., 2009; U.S. EPA, 2014).

The in-house estimates for sawmills and panel board mills were carried forward in 2016 based on 2015 mill capacities. Capacity data were available for 2017. The 2018 capacity data were updated based on 2019 data. Capacity data were available for 2019 and 2020.

Other wood products

All pollutants: In-house estimates are not calculated for this subsector. For the whole time series, emissions are from facility data reported to provinces/territories and NPRI facility-reported data.

Activity data

NPRI 2020 data and data sources for facilities not reporting to the NPRI, including:

• Natural Resources Canada: Status of Energy Use in the Canadian Wood Products Sector (Meil et al. 2009)
• The State of Canada’s Forests Annual Report 2020 (NRCan, Canadian Forest Service, 2021)
• Forest Products Association of Canada annual reports (proprietary reports)
• Environment and Climate Change Canada’s Forestry Products Group
• RISI North American Wood Panels and Engineered Wood Products Capacity Report (RISI 2020)
• Madison’s 2017 Online Lumber Directory (Madison 2017)
• Verbal communications with industry representatives (unpublished)

Emission factors (EF)

Sawmills: U.S. EPA (2012)

Plywood manufacturing, particle board, oriented strand board: U.S. EPA (1995)

Fuel combustion: Meil et al. (2009) and U.S. EPA (1992, 1995, 2014)

References, Annex 2.3, Estimation methodologies for Manufacturing by sector/subsector

Cheminfo Services. 2005. Survey of small and medium commercial baking establishments to estimate average VOC emission factors. Unpublished report. Markham (ON): Cheminfo. Prepared for Environment Canada.

[CGC] Canadian Grain Commission. 2017. Grain statistics weekly 2017–2018 (database).

Madison. 2017. Madison’s 2017 online lumber directory.

Meil J, Bushi L, Garrahan P, Aston R, Gingras A, Elustondo D. 2009. Status of energy use in the Canadian wood products sector. Report No. M144-214/2009. Ottawa (ON): Natural Resources Canada.

[NRCan] Natural Resources Canada, Canadian Forest Service Publications. 2020. The state of Canada’s forests. Annual report 2019. Catalog ID. 40084. Ottawa (ON): Natural Resources Canada.

Pinchin Environmental Ltd. 2007. CAC emissions from the Canadian grain handling industry – 1985-2007. Unpublished report. Mississauga (ON): Health Canada.

[RISI] Resource Information Systems Inc. 2019. North American wood panels and engineered wood products capacity report.

Statistics Canada. No date. Table 17-10-0005-01 (formerly: CANSIM 051-0001) Population estimates on July 1st, by age group and sex (database) [last updated 2021 Sept 29; accessed 2020 Dec 8].

Statistics Canada. 2017. Table 32-10-0351-01 (formerly CANSIM 001-0001) Producer deliveries of major grains (database).

Statistics Canada. 2021. Table 32-10-0054-01 (formerly CANSIM 002-0011) Food available in Canada: Wheat flour (database).

[U.S. EPA] United States Environmental Protection Agency. 1985. Compilation of air pollutant emissions factors, 5th Edition [accessed 2014 Aug 27]. Research Triangle (NC): Office of Air Quality Planning and Standards.

[U.S. EPA] United States Environmental Protection Agency. 1992. Compilation of air pollutant emissions factors, Volume I: Stationary point and area sources, 4th Edition. Research Triangle Park (NC): Office of Air Quality Planning and Standards.

[U.S. EPA] United States Environmental Protection Agency. 1995. Compilation of air pollutant emission factors, Volume I: Stationary point and area sources, 5th Edition [updates for 2002]. Research Triangle Park (NC): Office of Air Quality Planning and Standards.

[U.S. EPA] United States Environmental Protection Agency. 2012. EPA memorandum - EPA Region 10 HAP and VOC emission factors for lumber drying [PDF].

[U.S. EPA] United States Environmental Protection Agency. 2014. WebFIRE (database). Durham (NC): Technology Transfer Network Clearinghouse for Inventories & Emissions Factors.