Canada’s Air Pollutant Emissions Inventory Report 2023: executive summary
Complete report: Canada’s Air Pollutant Emissions Inventory Report 2023 (PDF version)
Canada’s Air Pollutant Emissions Inventory (APEI) is a comprehensive inventory of anthropogenic emissions of 17 air pollutants at the national, provincial and territorial levels. This inventory serves many purposes: it fulfills Canada’s international reporting obligations under the 1979 Convention on Long-range Transboundary Air Pollution (CLRTAP) and the associated protocols ratified by Canada for the reduction of emissions of sulphur (expressed as sulphur dioxides or SO2), nitrogen oxides (NOx), fine particulate matter (PM2.5), cadmium (Cd), lead (Pb), mercury (Hg), volatile organic compounds (VOCs), dioxins and furans, and other persistent organic pollutants (POPs). The APEI also reports emissions of additional air pollutants including ammonia (NH3)Footnote 1 , carbon monoxide (CO), coarse particulate matter (PM10) and total particulate matter (TPM). In addition, the APEI supports monitoring and reporting obligations under the Canada-U.S. Air Quality Agreement and the development of air quality management strategies, policies and regulations, provides data for air quality forecasting, and informs Canadians about pollutants that affect their health and the environment.
The APEI is compiled from many different data sources. Emission data reported by individual facilities to Environment and Climate Change Canada's (ECCC) National Pollutant Release Inventory (NPRI) are supplemented with well-documented, science-based estimation tools and methodologies to quantify total emissions. Together, these data sources provide a comprehensive coverage of air pollutant emissions across Canada.
Recent observed changes in Canada's air pollution emissions (2019 to 2021)
The most recent years for which data are available for this report, 2020 and 2021, were marked by the COVID-19 pandemic. This coincides with observed emission decreases between the years 2019 and 2020 for almost all pollutants with the exception of NH3. Between 2020 and 2021, most of the pollutant emissions increased, but remained below their 2019 pre-pandemic levels, except for NH3 and hexachlorobenzene (HCB) that exceeded their 2019 emission levels in 2021. In contrast to these increases, SOx, Pb and polycyclic aromatic hydrocarbons (PAHs) emissions continued to decrease between 2020-2021, while VOC emissions remained stable. The categories that were major contributors to emission changes between 2019 and 2020 are similar to those observed between 2019 and 2021 occurring in numerous source categories, most notably:Footnote 2
- Transportation and Mobile Equipment showed decreases of NOx (-58 kt or -9.5%), VOCs (-36 kt or -14%) and CO (-311 kt or -10%).
- These reductions are mostly due to a decrease in the vehicle kilometres traveled (VKT) in the light-duty gasoline vehicles and trucks categories between 2019 and 2020.
- Between 2020 and 2021, the VKT increased but was still below pre-pandemic levels, leading to slight increases in NOx (9.2 kt or 1.7%) and CO (71 kt or 2.6%).
- A similar change is noted from the Unpaved Road Dust source, also linked to the VKT, with an emission decrease of PM2.5 (59 kt or 14%) between 2019 and 2020 followed by an increase (16 kt or 4.5%) between 2020 and 2021.
- The Oil and Gas Industry contributed to the decrease in SOx (-5.3 kt or -2.0%) and VOCs emissions (-91 kt or -15%).
- The overall decreases in SOx can be explained in part by reductions in total crude oil and natural gas production in 2020, along with decreases in the Petroleum Refining subsector that are mainly due to the closure of the Come-By-Chance refinery in Newfoundland and Labrador.
- Between 2020 and 2021, there was an increase in SOx emissions (19 kt or 8.0%) due to overall increases in crude bitumen and natural gas production in 2021, as well as increased flaring at natural gas processing facilities.
- The VOC reductions result from decreases in venting and fugitive equipment leaks at oil and natural gas production and processing facilities.
- Coal electric power generation saw emission decreases of SOx (-39 kt or -20%) and Hg (-103 kg or -18%) attributed to a decrease in coal consumption, mostly notable between 2019 and 2020.
- Decreases in Ore and Mineral Industries emissions of Pb (-26 t or -26%), Cd (-1.9 t or -41%) and HCB (-1.7 kg or -36%) are in part due to the permanent closure of a non-ferrous metal smelter in December 2019.
- Between 2020 and 2021, Pb emissions from the Non-Ferrous Refining and Smelting Industry decreased significantly (-20 t or -21%) due in part to a facility shutdown but mainly due to normal operational variations at another facility.
- Emissions from Cd increased by (0.36 t or 15%) between 2020 and 2021 mostly due to a return to pre-pandemic production levels in the Non-Ferrous Refining and Smelting Industry.
- Similarly, the return to pre-pandemic production levels in the Iron and Steel and Iron Ore Pelletization sectors contributed to the HCB emission increase (0.18 kg or 6.4%) between 2020 and 2021.
Canada’s air pollution emission trends (1990 to 2021)
This edition of the Air Pollutant Emissions Inventory Report summarizes the most recent estimates of air pollutant emissions for 1990 to 2021, as of February 2023. The inventory indicates that emissions of 14 of the 17 reported air pollutants are decreasing compared to historical levels, and a few key sources of pollutants account for a significant portion of the downward trends. In particular:
- Non-Ferrous Refining and Smelting is a major contributor to emissions of Hg, Cd, SOx, and Pb; emissions of these pollutants from this source have decreased by 99%, 97%, 95% and 93%, respectively, over this time period, in part owing to closure of outdated smelters and implementation of pollution prevention measures.
- Home Firewood Burning is a major contributor to emissions of PM2.5, VOCs, CO and PAHs; emissions of these pollutants from this source have decreased by 46%, 42%, 37% and 32%, respectively, over this time period, owing to a 32% reduction in wood consumption and the adoption of more efficient wood combustion equipment.
- Coal-fired electric power generation is a major contributor to emissions of HCB, Hg and SOx; emissions of these pollutants from this source have decreased by 98%, 76% and 69%, respectively, over this time period, as emissions control equipment was adopted on some older units, and more recently, as coal-fired power plants have closed down and have been replaced by lower-emission sources such as natural gas power plants.
- Light-Duty Gasoline Trucks and Vehicles are major contributors to emissions of NOx and PAHs; emissions of these pollutants from these sources have decreased by 89% and 82%, respectively, over this time period.
- The decrease in emissions is despite a 58% increase in the total VKT of these vehicles, and is primarily due to improved fuel economy and implemented regulations that have effectively lowered NOx and hydrocarbon emissions from engines.
- Transportation associated with the combustion of gasolineFootnote 3 is a major contributor to emissions of CO and VOCs; emissions of these pollutants from this source have decreased by 72% and 68%, respectively, over this time period.
- The decrease in emissions is despite a 21% increase in the total fuel consumption of on-road light-duty gasoline trucks and vehicles and a 40% increase in the total fuel consumption of off-road gasoline engines, and is primarily due to implemented regulations that have effectively lowered CO and hydrocarbon emissions from engines.
- Waste Incineration is a major contributor to emissions of dioxins and furans and HCB; emissions of these pollutants from this source have decreased by 70% and 36%, respectively, over this time period, in part owing to improvements in incineration technologies.
Despite significant decreases in emissions of most pollutants, since 2005, emissions of particulate matter have risen by 38% (TPM), 33% (PM10) and 18% (PM2.5). These increases are largely from dust emissions associated with transportation on unpaved roads as well as construction operations. Another exception to the general downward trends is the steady increase in emissions of NH3, which in 2021 were 25% above 1990 levels, and 1% above 2005 levels. The upward trend in NH3 emissions is primarily driven by the use of inorganic nitrogen fertilizer.
Irrespective of the downward trends observed in Canadian emissions, air quality issues may still arise when emissions sources are spatially concentrated. While the APEI provides valuable information on emissions within Canada, it does not distinguish localized sources of emissions within the provincial and territorial level aggregations.
Canada’s air pollution emissions relative to international commitments
Canada reports on atmospheric emissions of air pollutants to the United Nations Economic Commission for Europe (UNECE) through the European Monitoring and Evaluation Programme (EMEP) Centre on Emission Inventories and Projections (CEIP) pursuant to the 1979 CLRTAP and its associated protocols. This edition of the Air Pollutant Emissions Inventory Report indicates that:
- Emissions of SOx were 0.6 million tonnes in 2021, which are 56% below the 2010 emission ceiling under the 1999 Gothenburg Protocol and 69% below 2005 levels; therefore, Canada has met its commitment to reduce emissions of SOx by 55% from 2005 levels by 2020 and beyond, as per the amended Gothenburg Protocol.
- Emissions of NOx were 1.3 million tonnes in 2021, which are 41% below the 2010 emission ceiling under the 1999 Gothenburg Protocol and 42% below 2005 levels; therefore, Canada has met its commitment to reduce emissions of NOx by 35% from 2005 levels by 2020 and beyond, as per the amended Gothenburg Protocol.
- Emissions of non-methane VOCs (NMVOCs) were 1.4 million tonnes in 2020, which are 33% below the 2010 emission ceiling under the 1999 Gothenburg Protocol and 39% below 2005 levels; therefore, Canada has met its commitment to reduce emissions of NMVOC by 20% from 2005 levels by 2020 and beyond, as per the amended Gothenburg Protocol.
- Emissions of fine particulate matter (particulate matter less than or equal to 2.5 microns in diameter [PM2.5]) were 1.5 million tonnes in 2021.
- Emissions of PM2.5 decreased from most sources with the notable exceptions of dust sources (not from combustion) such as construction operations and roads; Canada’s emission reduction commitment for PM2.5 excludes these two sources along with crop production.
- In line with Canada’s commitment, PM2.5 emissions in 2021 were 30% lower compared to 2005 levels; therefore, Canada has met its commitment to reduce emissions of PM2.5 by 25% from 2005 levels by 2020 and beyond, as per the amended Gothenburg Protocol.
- Emissions of Cd, Pb, and Hg in 2021 were 89%, 81% and 81% below the ceilings established under the 1998 Aarhus Protocol on Heavy Metals.
- Emissions of all POPs in 2021 were below the ceilings established under the 1998 Aarhus Protocol on Persistent Organic Pollutants, including the four species of PAHs (81% below), HCB (69% below), and dioxins and furans (63% below).
Canada’s air emissions regulations and non-regulatory measures
Downward trends in emissions of air pollutants reflect the ongoing implementation of a wide range of regulatory and non-regulatory instruments that aim to reduce or eliminate pollutants in order to improve and maintain air quality in Canada. Regulations related to the 17 APEI pollutants are under the Canadian Environmental Protection Act, 1999 (CEPA 1999).
A number of greenhouse gas regulations are also expected to achieve significant co-benefit reductions in air pollutants, for example the Regulations Respecting Reduction in the Release of Methane and Certain Volatile Organic Compounds (Upstream Oil and Gas Sector).
Non-regulatory instruments include guidelines, as well as codes of practice, performance agreements, and/or pollution prevention planning notices for various sectors. More information on Canada’s air emissions Regulations and non-regulatory measures, including a list of Regulations related to APEI pollutants, can be found in Chapter 1.3.
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