Air pollutant emissions

Note: The percentages have been rounded off and their sum may not add up to 100.

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Sulphur oxide emissions by source

Emissions of sulphur oxides (SO_X)  in the atmosphere can have adverse effects on human health and the environment. The SO_X emissions released by human activities consist mostly of sulphur dioxides (SO₂). Sulphur dioxide can affect respiratory systems of humans and animals and cause damage to vegetation, buildings and materials. It also contributes to the formation of fine particulate matter (PM_2.5) and acid rain.

Key results

• Between 1990 and 2022, SO_X emissions decreased by 78% from 3 012 kilotonnes (kt) to 652 kt
• In 2022, 3 sources accounted for 93% (604 kt) of the total SO_X emissions: the oil and gas industry, electric utilities and ore and mineral industries

Total sulphur oxide emissions by source, Canada, 1990 to 2022

How this indicator was calculated

Note: The indicator reports air pollutant emissions from human activities only. It does not include emissions from natural sources such as forest fires and from vegetation. The category "other sources" includes emissions from transportation (road, rail, air and marine), off-road vehicles and mobile equipment, home firewood burning, incineration and waste, agriculture (livestock, crop production and fertilizer), dust and fires, paints and solvents, building heating and energy generation, manufacturing, and other miscellaneous sources. Consult Table 1 in the Data sources and methods for a complete list of the air pollutant emissions sources included under each category. Interactive figures provide a dynamic and customizable format to explore the emissions.
Source: Environment and Climate Change Canada (2024) Air Pollutant Emissions Inventory.

In 2022, the oil and gas industry accounted for approximately 42% of total national SO_X emissions (275 kt). Electric utilities and ore and mineral industries followed with 24% (154 kt) and 27% (175 kt) of national emissions. For the ore and mineral industries, 41% (73 kt) of its SO_X emissions came from the non-ferrous refining and smelting industry.

The largest reduction in emissions between 1990 and 2022 was from ore and mineral industries with a reduction in emissions of approximately 1 308 kt. The largest driver of the reduction from the source was from the non-ferrous refining and smelting industry with a reduction of 1 193 kt over the period.

This significant decrease in SO_X emissions from 1990 to 2022 (78%) is due in large part to government actions to fight acid rain and related federal-provincial and United States agreements ^{Footnote 1 Footnote 2}  on capping SO_X emissions by 1994. Further reductions were also realized through:

• technological upgrades, new air pollution controls for non-ferrous metal smelters and the closure of 4 major smelters in Manitoba, Ontario, Quebec and New Brunswick
• lower emissions from fossil-fuel-fired (for example, coal-fired) power-generating utilities as a result of better technologies and plant closures (for example, the phase-out of coal electricity generation in Ontario)
• implementation of regulations on low-sulphur fuels^{Footnote 3Footnote 4}  

More recently, between 2021 and 2022, SO_X emissions have declined due to decreases in emissions from the electric utilities industry of 15 kt (9%). In contrast, an increase in SO_X emissions was observed for ore and mineral industries (13 kt, 8%), the oil and gas industry (12 kt, 5%) and other sources (0.1 kt, <1%).

Sulphur oxide emissions by province and territory

Key results

• In 2022, Alberta and Saskatchewan accounted for 45% (293 kt) of national SO_X emissions
• Between 1990 and 2022
  • the largest reduction were observed in Ontario and Manitoba. Emissions in these provinces decreased by 1 006 kt (89%) and 507 kt (99.6%), respectively
  • Saskatchewan was the only province that experienced an increase in SO_X (20%, or 20 kt)

Sulphur oxide emissions by province and territory, Canada, 1990, 2005 and 2022

How this indicator was calculated

Note: The indicator reports air pollutant emissions from human activities only. It does not include emissions from natural sources such as forest fires and from vegetation.
Source: Environment and Climate Change Canada (2024) Air Pollutant Emissions Inventory.

Alberta had the highest SO_X emissions level in 2022, accounting for 26% (170 kt) of total national emissions. Emissions in the province mainly came from the oil and gas industry and electric utilities, combined accounting for 94% (161 kt) of the emissions. Between 2005 to 2022, the province experienced a 63% decline in emissions (289 kt) with the oil and gas industry, notably reductions from natural gas processing and oil sands mining extraction and processing, accounting for a large part of the reductions since 2005.

Saskatchewan was the second-highest emitter of SO_X in 2022, accounting for 19% (123 kt) of total national emissions. Emissions from electric utilities, specifically coal electric power generation, was the largest contributor to SO_X emissions in the province.  

Ontario ranked third, with 18% (119 kt) of total national emissions of SO_X; the ore and mineral industries sector was the most important source of emissions in the province in 2022.

Sulphur oxide emissions by facilities

The National Pollutant Release Inventory provides detailed information on air pollutant emissions from industrial and commercial facilities that meet its reporting criteria.^{Footnote 5}

The Canadian Environmental Sustainability Indicators provide access to this information through an interactive map. The map allows you to explore SO_X emissions from individual facilities.

Key results

• In 2022, 2 391 facilities across Canada reported SO_X emissions representing 88% of total national emissions. Of these facilities:
  • 1 967 facilities reported emissions under 25 tonnes (t)
  • 406 facilities reported emissions between 25 to 6 000 t
  • 18 facilities reported emissions of 6 000 t or more located in Ontario (5), Alberta (4), Quebec (3), Saskatchewan (3) and Nova Scotia (3)

Sulphur oxide emissions by reporting facilities, Canada, 2022

Source: Environment and Climate Change Canada (2024) National Pollutant Release Inventory.

Navigate data using the interactive map

Nitrogen oxide emissions by source

Nitrogen oxides (NO_X) include emissions of nitric oxide (NO) and nitrogen dioxide (NO₂). Nitrogen dioxide can have adverse effects on human health and the environment. Nitrogen oxides contribute to acid rain, which can lead to the acidification of aquatic and terrestrial ecosystems. It also contributes to the eutrophication of lakes and to the formation of ground-level ozone (O₃) and fine particulate matter (PM_2.5).

Key results

• In 2022, NO_X emissions were 1 303 kilotonnes (kt); this is 42% lower than in 1990
• The oil and gas industry was the largest source of NO_X representing 34% (443 kt) of total emissions in 2022

Total nitrogen oxide emissions by source, Canada, 1990 to 2022

How this indicator was calculated

Note: The indicator reports air pollutant emissions from human activities only. It does not include emissions from natural sources such as forest fires and from vegetation. The category "other sources" includes emissions from ore and mineral industries, manufacturing, building heating and energy generation, home firewood burning, incineration and waste, agriculture (livestock, crop production and fertilizer), dust and fires, paints and solvents, and other miscellaneous sources. Consult Table 1 in the Data sources and methods for a complete list of the air pollutant emissions sources included under each category. Interactive figures provide a dynamic and customizable format to explore the emissions.
Source: Environment and Climate Change Canada (2024) Air Pollutant Emissions Inventory.

The oil and gas industry was the largest contributor of NO_X emissions between 1990 and 2022. Emissions of NO_X from this sector increased by 100 kt (29%) during that period. 

The transportation (road, rail, air, and marine) sector emitted the next largest proportion of NO_X emissions in 2022, representing 28% (370 kt) of total national emissions. This sector also experienced the largest decrease in emissions (534 kt or 59%) between 1990 and 2022.

The decline in NO_X emissions between 1990 and 2022 is mostly attributable to 2 factors:

• the reduction in emissions from transportation after 2000, given the progressive introduction of cleaner technology and fuels for vehicles
• lower emissions from fossil-fuel-fired (for example, coal-fired) power-generating utilities as a result of better emission control technologies and certain plant closures (for example, the closure of coal power plants in Ontario)

More recently, between 2021 and 2022, NO_X emissions from transportation (road, rail, air and marine) sources have increased by 7 kt (2%), notably from domestic marine navigation. Likewise, the oil and gas industry saw NOx emissions increase by 5 kt (1%) between 2021 and 2022.

Nitrogen oxide emissions by province and territory

Key results

• In 2022, among provinces and territories, Alberta emitted the most NO_X. The province accounted for 40% (520 kt) of national emissions
• Between 1990 and 2022,
  • the largest reduction was observed in Ontario. Emissions decreased by 413 kt (69%) in the province
  • NO_X emissions increased in Newfoundland and Labrador by 4 kt (7%) and in Northwest Territories and Nunavut by 4 kt (26%)^{Footnote 6}  

Nitrogen oxide emissions by province and territory, Canada, 1990, 2005 and 2022

How this indicator was calculated

Note: The indicator reports air pollutant emissions from human activities only. It does not include emissions from natural sources such as forest fires and from vegetation.
Source: Environment and Climate Change Canada (2024) Air Pollutant Emissions Inventory.

The oil and gas industry is an important source of NO_X emissions in Alberta, accounting for 66% (345 kt) of the province's NO_X emissions in 2022. The increasing contribution of this sector to the province's emissions between 1990 and 2022 was more than offset by emission reductions from the transport and electric utilities sectors.

British Columbia and Ontario contributed the second and third largest proportions of NO_X emissions in 2022, with British Columbia accounting for 15% (190 kt) and Ontario accounting for 14% (184 kt) of total national emissions, with transportation (road, rail, air and marine) being the most important source in both provinces followed by the oil and gas industry in British Columbia and off-road vehicles and mobile equipment in Ontario. However, Ontario experienced the largest decrease in emissions (413 kt) between 1990 and 2022 in large part due to emission reductions from transportation (road, rail, air and marine), electric utilities, manufacturing, ore and mineral industries and off-road vehicles and mobile equipment. In Ontario, the majority of total NO_X emission reductions occurred between 2005 and 2022 (357 kt).

Quebec ranked fourth, with 9% (123 kt) of total national emissions. Transportation (road, rail, air and marine) was the most important source of NO_X in this province. Quebec also experienced a large decrease in emissions (167 kt) between 2005 and 2022 mainly due to emission reductions from transportation (road, rail, air and marine).

Nitrogen oxide emissions by facilities

The National Pollutant Release Inventory provides detailed information on air pollutant emissions from industrial and commercial facilities that meet its reporting criteria.

The Canadian Environmental Sustainability Indicators provide access to this information through an interactive map. The map allows you to explore NO_X emissions from individual facilities.

Key results

• In 2022, 3 646 facilities across Canada reported NO_X emissions representing 39% of total national emissions. Of these facilities: 
  • 2 211 facilities reported emissions under 50 tonnes (t)
  • 1 313 facilities reported emissions between 50 to 800 t
  • 122 facilities reported emissions of 800 t or more located in Alberta (53), Ontario (19), Quebec (12), British Columbia (11), Saskatchewan (7), Newfoundland and Labrador (6), Nova Scotia (5), New Brunswick (4), Northwest Territories and Nunavut (2), Nunavut (2) and Manitoba (1)

Nitrogen oxide emissions by reporting facilities, Canada, 2022

Source:  Environment and Climate Change Canada (2024) National Pollutant Release Inventory.

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Volatile organic compound emissions by source

Volatile organic compounds (VOCs) are carbon-containing gases and vapours released into the atmosphere by natural sources and human activities.^{Footnote 7}  There are hundreds of VOCs that are emitted and that affect the health of Canadians and the environment. VOCs are primary precursors to the formation of ground-level ozone and particulate matter which are the main pollutants contributing to the formation of smog.

Key results

• In 2022, VOC emissions in Canada were 1 407 kilotonnes (kt); this is a 38% (880 kt) decrease from 1990 levels
• Since 1990, the oil and gas industry has been the highest contributor to VOC emissions. In 2022, the sector accounted for 37% (526 kt) of total emissions

Total volatile organic compound emissions by source, Canada, 1990 to 2022

How this indicator was calculated

Note: The indicator reports air pollutant emissions from human activities only. It does not include emissions from natural sources such as forest fires and from vegetation. The category "other sources" includes emissions from incineration and waste, ore and mineral industries, dust and fires, building heating and energy generation, electric utilities and other miscellaneous sources. Consult Table 1 in the Data sources and methods for a complete list of the air pollutant emissions sources included under each category. Interactive figures provide a dynamic and customizable format to explore the emissions.
Source: Environment and Climate Change Canada (2024) Air Pollutant Emissions Inventory.

Apart from the oil and gas industry, paints and solvents, and off-road vehicles and mobile equipment were also important sources of VOC emissions in 2022 contributing 19% (271 kt) and 9% (131 kt) of total emissions, respectively.

The largest emissions reduction between 1990 and 2022 was from transportation (road, rail, air and marine), with emissions reductions of 281 kt (81%). 

The long-term decrease in VOC emissions is mainly attributable to 3 factors:

• the progressive introduction of cleaner technologies and fuels resulting in emission reductions from transportation, off-road vehicles and mobile equipment
• emission reductions from most industrial and non-industrial sources from facility closures, decrease in production and improved emission controls
• lower levels of VOCs in products such as paints, solvents and cleaners

Compared to the previous year, VOC emissions increased by less than 2 kt (0.13%) in 2022. The largest increase was from the oil and gas industry 11 kt (2%), light medium crude oil production. 

Volatile organic compound emissions by province and territory

Key results

• Alberta emitted the highest proportion of VOCs in 2022; the province represented 34% (472 kt) of national emissions
• Between 1990 and 2022,
  • Ontario experienced the largest reduction in VOC emissions; emissions in the province decreased by 330 kt (54%)
  • Saskatchewan was the only province that experienced an increase in VOC emissions, with 19 kt (11%), the oil and gas industry being responsible for the increase in emissions

Volatile organic compound emissions by province and territory, Canada, 1990, 2005 and 2022

How this indicator was calculated

Note: The indicator reports air pollutant emissions from human activities only. It does not include emissions from natural sources such as forest fires and from vegetation.
Source: Environment and Climate Change Canada (2024) Air Pollutant Emissions Inventory.

Alberta was the highest emitting province of VOCs in 2022 (472 kt), with the oil and gas industry as the main source, contributing 72% (340 kt) of the province's emissions.

Ontario was the second-highest emitter of VOCs, accounting for 20% (284 kt) of total national emissions in 2022. The main emission sources are paints and solvents, off-road vehicles and mobile equipment, and manufacturing. Ontario also experienced the largest reduction in emissions, with 330 kt (54%) between 1990 and 2022, mainly as a result of emission reductions from manufacturing and transportation (road, rail, air and marine). The majority of the reductions in Ontario occurred between 2005 and 2022 (295 kt).

Quebec was the third largest emitter, with 15% (205 kt) of total national emissions in 2022, where paints and solvents and home firewood burning collectively accounted for 52% of the emissions in that province.

Volatile organic compound emissions by facilities

The National Pollutant Release Inventory provides detailed information on air pollutant emissions from industrial and commercial facilities that meet its reporting criteria.

The Canadian Environmental Sustainability Indicators provide access to this information through an interactive map. The map allows you to explore VOC emissions from individual facilities.

Key results

• In 2022, 4 427 facilities across Canada reported VOC emissions representing 17% of total national emissions. Of these facilities:
  • 2 722 facilities reported emissions under 15 tonnes (t)
  • 1 626 facilities reported emissions between 15 to 400 t
  • 79 facilities reported emissions of 400 t or more located in Alberta (31), Ontario (19), Saskatchewan (7), Quebec (7), British Columbia (6), Manitoba (3), New Brunswick (3), Newfoundland and Labrador (2) and Nova Scotia (1)

Volatile organic compound emissions by reporting facilities, Canada, 2022

Source:  Environment and Climate Change Canada (2024) National Pollutant Release Inventory.

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Ammonia emissions by source

Ammonia (NH₃) is a colourless gas with a noticeable odour at high concentrations. It can be poisonous if inhaled in great quantities and is irritating to the eyes, nose, and throat. It can also contribute to the nitrification and eutrophication of aquatic systems. In the air, the gas combines with sulphates and nitrates to form secondary fine particulate matter (PM_2.5).

Key results

• In 2022, NH₃ emissions were 482 kilotonnes (kt). This is 22% higher than in 1990
• Agriculture (livestock, crop production and fertilizer) was the main source of NH₃ emissions in 2022. Emissions from this source accounted for more than 94% (451 kt) of total national emissions

Total ammonia emissions by source, Canada, 1990 to 2022

How this indicator was calculated

Note: The indicator reports air pollutant emissions from human activities only. It does not include emissions from natural sources such as forest fires and from vegetation. The category "other sources" includes emissions from incineration and waste, the oil and gas industry, home firewood burning, ore and mineral industries, electric utilities, building heating and energy generation, off-road vehicles and mobile equipment, dust and fires, paints and solvents, and other miscellaneous sources. Consult Table 1 in the Data sources and methods for a complete list of the air pollutant emissions sources included under each category. Interactive figures provide a dynamic and customizable format to explore the emissions.
Source: Environment and Climate Change Canada (2024) Air Pollutant Emissions Inventory.

Between 1990 and 2022, agriculture (livestock, crop production and fertilizer) experienced the largest increase (95 kt or 27%) in NH₃ emissions. It also remained the key source of NH₃ emissions throughout that period. Emissions from manufacturing (10 kt), other sources (7 kt), incineration and waste (7 kt) and transportation (road, rail, air and marine) (6 kt) combined represented 6% of national emissions in 2022.

The growth in NH₃ emissions from agriculture (livestock, crop production and fertilizer) between 1990 and 2022 is mainly due to the increased use of synthetic nitrogen fertilizers in crop production. Up to 2005, larger livestock populations also added to the growth. However, from 2006 to 2011, livestock populations decreased and NH₃ emissions from that source have since declined slowly. More recently, emissions from crop production have been steadily increasing since 2006.^{Footnote 8}

Ammonia emissions by province and territory

Key results

• In 2022, Alberta and Saskatchewan accounted for almost half (238 kt) of national NH₃ emissions
• Between 1990 and 2022,
  • Ontario experienced the largest emissions reduction with 20 kt (18%)
  • The largest increase in NH₃ emissions was in Saskatchewan with emissions more than doubling (a 51 kt increase)

Ammonia emissions by province and territory, Canada, 1990, 2005 and 2022

How this indicator was calculated

Note: The indicator reports air pollutant emissions from human activities only. It does not include emissions from natural sources such as forest fires and from vegetation.
Source: Environment and Climate Change Canada (2024) Air Pollutant Emissions Inventory.

In 2022, Alberta emitted the most NH₃ of all the provinces and territories, accounting for 29% (138 kt) of total national emissions. Saskatchewan contributed the second-largest proportion of NH₃, representing 21% (99 kt).

Ontario followed with 19% (91 kt) of total national emissions. Livestock farms and the application of fertilizers were the most important sources of NH₃ emissions.

Virtually almost all of the increase in emissions between 1990 and 2022 took place in Saskatchewan, Alberta and Manitoba.

Ammonia emissions by facilities

The National Pollutant Release Inventory provides detailed information on air pollutant emissions from industrial and commercial facilities that meet its reporting criteria.

The Canadian Environmental Sustainability Indicators provide access to this information through an interactive map. The map allows you to explore NH₃ emissions from individual facilities.

Key results

• In 2022, 299 facilities across Canada reported NH₃ emissions representing 4% of total national emissions. Of these facilities:
  • 196 facilities reported emissions under 25 tonnes (t)
  • 95 facilities reported emissions between 25 to 400 t
  • 8 facilities reported emissions of 400 t or more located in Alberta (5), British Columbia (1), Manitoba (1) and Saskatchewan (1)

Ammonia emissions by reporting facilities, Canada, 2022

Source: Environment and Climate Change Canada (2024) National Pollutant Release Inventory.

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Carbon monoxide emissions by source

Carbon monoxide (CO) is a colourless, odourless, tasteless and poisonous gas. Once inhaled into the bloodstream, it can inhibit the blood's capacity to carry oxygen to organs and tissues, affecting human health.

Key results

• In 2022,
  • CO emissions in Canada were 4 499 kilotonnes (kt), a decrease of 65% from 1990 levels
  • Off-road vehicles and mobile equipment was the largest source of CO emissions in Canada, representing 37% (1 681 kt) of total emissions

 Total carbon monoxide emissions by source, Canada, 1990 to 2022

How this indicator was calculated

Note: The indicator reports air pollutant emissions from human activities only. It does not include emissions from natural sources such as forest fires and from vegetation. The category "other sources" includes emissions from dust and fires, electric utilities, building heating and energy generation, incineration and waste, agriculture (livestock, crop production and fertilizer), paints and solvents, manufacturing and other miscellaneous sources. Consult Table 1 in the Data sources and methods for a complete list of the air pollutant emissions sources included under each category. Interactive figures provide a dynamic and customizable format to explore the emissions.
Source: Environment and Climate Change Canada (2024) Air Pollutant Emissions Inventory.

In 2022, transportation, off-road vehicles and mobile equipment were the 2 most important sources of CO. These sources combined represented 59% (2 656 kt) of national emissions.

The largest reduction in emissions between 1990 and 2022 occurred in transportation (road, rail, air and marine) with an emission decrease of 5 125kt (84%).

The decline in CO emissions between 1990 and 2022 is mainly due to increasingly stringent engine and vehicle regulations and the progressive introduction of cleaner and more efficient technology in vehicles (for example, catalytic converters).

Carbon monoxide emissions by province and territory

Key results

• In 2022, Quebec and Alberta accounted for 49% (2 186 kt) of national CO emissions
• Between 1990 and 2022,
  • all provinces and territories experienced reductions in emissions
  • the largest reductions occurred in Ontario (2 625 kt or 73%), British Columbia (1 782 kt or 77%) and Quebec (1 326 kt or 54%)

Carbon monoxide emissions by province and territory, Canada, 1990, 2005 and 2022

How this indicator was calculated

Note: The indicator reports air pollutant emissions from human activities only. It does not include emissions from natural sources such as forest fires and from vegetation.
Source: Environment and Climate Change Canada (2024) Air Pollutant Emissions Inventory.

In 2022, Quebec emitted the most CO of all the provinces and territories, representing 25% (1 144 kt) of the total national emissions. Ore and mineral industries, specifically the aluminum industry representing 92% (358 kt) of the source's emissions, was the most important source of CO emissions for Quebec.

The province of Alberta ranked second, with 23% (1 042 kt) of total national emissions in 2022, with 74% of those emissions from 2 sources, namely off-road vehicles and mobile equipment and the oil and gas industry.

Ontario, the third largest CO emitter, accounted for 21% (950 kt) of total national emissions. The off-road vehicles and mobile equipment sector accounted for 41% of the province's CO emissions.

The sharp decrease in emissions between 1990 and 2022 in all provinces and territories is mainly attributable to emission reductions from transportation (road, rail, air and marine). Some of the largest reductions occurred between 2005 and 2022 notably for Ontario with emissions decreasing by 1 498 kt (61%).

Carbon monoxide emissions by facilities

The National Pollutant Release Inventory provides detailed information on air pollutant emissions from industrial and commercial facilities that meet its reporting criteria.

The Canadian Environmental Sustainability Indicators provide access to this information through an interactive map. The map allows you to explore CO emissions from individual facilities.

Key results

• In 2022, 3 490 facilities across Canada reported CO emissions representing 18% of total national emissions. Of these facilities:  
  • 1 698 facilities reported emissions under 25 tonnes (t)
  • 1 701 facilities reported emissions between 25 to 1 000 t
  • 91 facilities reported emissions of 1 000 t or more located in Alberta (31), Quebec (19), Ontario (19), British Columbia (10), New Brunswick (5), Saskatchewan (5) and Newfoundland and Labrador (2)

Carbon monoxide emissions by reporting facilities, Canada, 2022

Source:  Environment and Climate Change Canada (2024) National Pollutant Release Inventory.

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Fine particulate matter emissions by source

Particulate matter (PM) is directly emitted into the air in solid or liquid form. It is also formed in the air from precursor substances such as sulphur oxides, nitrogen oxides, volatile organic compounds and ammonia.^{Footnote 9}  Fine particulate matter (PM_2.5) refers to particulate matter with a size of less than 2.5 micrometres (also called microns). It is one of the major components of smog. When inhaled deeply into the lungs, even small amounts of PM_2.5 can cause serious health problems. It can also damage vegetation and structures, contribute to haze and reduce visibility.

Key results

• In 2022, PM_2.5 emissions were 1 299 kilotonnes (kt); this is 22% lower than in 1990
• Emissions from dust and fires (for example, road dust, dust from construction operations and prescribed burning) accounted for the majority of PM_2.5 emissions, reaching 58% (755 kt) of total national emissions in 2022
  • These emissions increased by 43% (225 kt) between 1990 and 2022. Dust from construction operations, specifically non-residential construction, and unpaved roads accounted for the majority of the increase

Total fine particulate matter emissions by source, Canada, 1990 to 2022

How this indicator was calculated

Note: The indicator reports air pollutant emissions from human activities only. It does not include emissions from natural sources such as forest fires and from vegetation. The category "other sources" includes emissions from ore and mineral industries, transportation (road, rail, air and marine), manufacturing, off-road vehicles and mobile equipment, the oil and gas industry, building heating and energy generation, electric utilities, incineration and wastes, paints and solvents, and other miscellaneous sources. Consult Table 1 in the Data sources and methods for a complete list of the air pollutant emissions sources included under each category. Interactive figures provide a dynamic and customizable format to explore the emissions.
Source: Environment and Climate Change Canada (2024) Air Pollutant Emissions Inventory.

In 2022, 85% of PM_2.5 emissions came from open source emissions, such as dust and prescribed fires, and agriculture (livestock^{Footnote 10} , crop production and fertilizer). PM_2.5 emissions does not include emissions from natural sources such as wildfires and vegetation. In general, these open source emissions are spread over large geographical areas, are highly dependent on weather conditions (for example, wind and rain) and are located outside of urban areas.  As such, exposure of PM_2.5 to most people in Canada is not driven by emissions from open sources, but rather from PM_2.5 that forms when pollutants react in the atmosphere. 

The remaining 15% of PM_2.5 emissions in 2022 came from home firewood burning (80 kt or 6%) and other sources, including:

• ore and mineral industries, representing 3% (34 kt) of the emissions
• manufacturing and miscellaneous sources, such as emissions from commercial cooking, each representing about 1% (15 kt and 16 kt) of emissions
• off-road vehicles and mobile equipment, representing about 1% (15 kt)
• the oil and gas industry, representing about 1% (14 kt)
• transportation (road, rail, air and marine), representing less than 1% (9 kt)
• other emissions (less than 1%; 8 kt) coming from building heating and energy generation, electric utilities, incineration and waste, and the use of paints and solvents

Many of the sources above, despite representing a small proportion of national emissions, can have a disproportionate health impact on the population because they are generally concentrated in populated areas.

The decreases in PM_2.5 emissions between 1990 and 2022 are mainly attributable to emission reductions from agriculture (crop production) (322 kt or 48%), manufacturing (99 kt or 87%) and home firewood burning (60 kt or 43%). These reductions outweigh the increase in emissions from dust and prescribed fires (225 kt or 43%), specifically road dust and dust from construction operations, over the period. The adoption of conservation practices in crop production and the use of new fireplace inserts, furnaces and stoves that burn more efficiently to control home firewood burning emissions were the main drivers leading to the reductions.

Fine particulate matter emissions by province and territory

Key results

• In 2022, Saskatchewan emitted the most PM_2.5. The province represented 27% (353 kt) of total national emissions
• Between 1990 and 2022, all provinces decreased their emissions
  • The largest decrease was observed in Saskatchewan with 160 kt (31%)
  • PM_2.5 emissions increased by 0.1 kt (5%) in Yukon and 1 kt (25%) in Northwest Territories and Nunavut

Fine particulate matter emissions by province and territory, Canada, 1990 and 2022

How this indicator was calculated

Note: The indicator reports air pollutant emissions from human activities only. It does not include emissions from natural sources such as forest fires and from vegetation.
Source: Environment and Climate Change Canada (2024) Air Pollutant Emissions Inventory.

In 2022, Saskatchewan was the highest emitting province of PM_2.5 emissions, accounting for 27% (353 kt) of total national emissions. Agriculture (specifically wind erosion) and dust and fires (specifically dust from unpaved roads) were the largest sources of PM_2.5 emissions in the province.

Alberta ranked second in 2022, with 25% (320 kt) of total national PM_2.5 emissions. Dust and fires (specifically dust from unpaved roads) were the largest sources, with agriculture (livestock, crop production and fertilizer) being the second-largest source of PM_2.5, specifically from wind erosion, tillage practices and harvesting.

Ontario ranked third, with 17% (215 kt), and Quebec ranked fourth with 11% (148 kt). For these 2 provinces, dust and prescribed fires were the largest source of emissions.

The exclusion of emissions from dust and prescribed fires and agriculture (livestock, crop production and fertilizer) provides a different breakdown of PM_2.5 emissions in each province and territory. With these emissions removed, Quebec becomes the largest emitting province of PM_2.5 in 2022, representing 30% (57 kt) of total emissions (191 kt). Ontario ranks second with 24% (45 kt) of emissions. Alberta and British Columbia rank third and fourth, representing 14% and 13% (27 kt and 26 kt, respectively) of emissions. Between 1990 and 2022, with dust, prescribed fires and agriculture excluded, all of the provinces and territories experienced emissions reductions between 74% (British Columbia, with a 74 kt emission reduction) and 40% (Prince Edward Island, with a 0.8 kt emission reduction).

Fine particulate matter emissions by facilities

The National Pollutant Release Inventory provides detailed information on air pollutant emissions from industrial and commercial facilities that meet its reporting criteria.

The Canadian Environmental Sustainability Indicators provide access to this information through an interactive map. The map allows you to explore PM_2.5 emissions from individual facilities.

Key results

• In 2022, 4 621 facilities across Canada reported PM_2.5 emissions representing 4% of total national emissions. Of these facilities: 
  • 2 512 facilities reported emissions under 1 tonne (t)
  • 2 016 facilities reported emissions between 1 to 100 t
  • 93 facilities reported emissions of 100 t or more located in Quebec (21), British Columbia (18), Alberta (17), Ontario (16), Saskatchewan (11), Newfoundland and Labrador (4), New Brunswick (2), Northwest Territories (1), Nunavut (1), Nova Scotia (1) and Manitoba (1)

Fine particulate matter by reporting facilities, Canada, 2022

Source: Environment and Climate Change Canada (2024) National Pollutant Release Inventory.

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Black carbon emissions by source

Black carbon is a component of PM_2.5 and is generated by the incomplete combustion of fossil fuels and biomass. It is a short-lived climate pollutant, and is linked to both climate warming and adverse human health effects. Reductions in black carbon emissions have near-term climate and local benefits, such as improving air quality, slowing climate warming, reducing snow and ice melts, increasing crop yields and reducing negative impacts to ecosystem health and human health.

Key results

• Emissions of black carbon were 25.7 kt in 2022, a decrease of 31% from 2013 
• In 2022, 3 sectors accounted for 78% of national black carbon emissions:
  • off-road vehicles and mobile equipment
  • home firewood burning
  • transportation (road, rail, air and marine) 

Total black carbon emissions by source, Canada, 2013 to 2022

How this indicator was calculated

Note: The indicator reports air pollutant emissions from human activities only. It does not include emissions from natural sources such as forest fires. The chart includes emissions from the most significant sources of black carbon. "Other sources" includes emissions from ore and mineral industries, manufacturing, electric utilities and agriculture. Consult Table 1 in the Data sources and methods for more details. Interactive figures provide a dynamic and customizable format to explore the emissions.
Source: Environment and Climate Change Canada (2024) Canada's Black Carbon Emissions Inventory.

In 2022, off-road vehicles and mobile equipment (for example, lawn and garden equipment, recreational vehicles, excavators, graders) accounted for the largest proportion of total national emissions, representing 33% (8 kt) of emissions. Home firewood burning and transportation (road, rail, air and marine) were also large contributors, representing 27% (7 kt) and 19% (5 kt) of total national emissions. The remaining 21% of emissions came from the oil and gas industry, building heating and energy generation and other sources (such as ore and mineral industries).

Black carbon emissions by province and territory

Key results

• In 2022, 3 provinces, Alberta, Quebec and Ontario, accounted for 61% (16 kt) of total national black carbon emissions
• Between 2013 and 2022,
  • all provinces and territories experienced reductions in black carbon emissions between 2% to 66%
  • Alberta, Ontario and Quebec experienced the largest reductions in emissions with decreases of 2.2 kt, 2.2 kt and 2.6 kt, respectively. For these 3 provinces, the reductions were mainly attributable to lower emissions from transportation (road, rail, air and marine) and off-road vehicles and mobile equipment

Black carbon emissions by province and territory, Canada, 2013 and 2022

Air pollutant emissions from the oil and gas industry

The oil and gas sector is an important contributor to air pollutant emissions. Most emissions from the oil and gas sector come from upstream (i.e., exploration, drilling, production and field processing) activities and to a lesser extent from downstream (i.e., refining, storage and distribution) activities. Air pollutants are responsible for the formation of fine particulate matter (PM_2.5), ozone (O₃), smog and acid rain. They also adversely affect human health, the environment, and the economy. 

Key results

• In 2022, the oil and gas industry was a major contributor to total national emissions of sulphur oxides (SO_X) (42%),  volatile organic compounds (VOCs) (37%), nitrogen oxides (NO_X) (34%) and carbon monoxide (CO) (12%)
• The oil and gas industry is also a source of emissions of fine particulate matter (PM_2.5) and ammonia (NH₃). However, in 2022, it made up only 1% of the respective total emissions of these pollutants

Contribution of the oil and gas industry to total air pollutant emissions by activity type, Canada, 2022

How this indicator was calculated

Note:  In the oil and gas industry, upstream activities include exploration, drilling, production and field processing and downstream activities include refining, storage and distribution. Fine particulate matter and ammonia are not shown in the chart due to their low share (≤ 1%) of total emissions in 2022.
Source: Environment and Climate Change Canada (2024) Air Pollutant Emissions Inventory.

In 2022, the oil and gas industry was the sector contributing the most to total national emissions of SO_X, VOCs and NO_X. It was also the third-largest contributor to emissions of CO.

Most emissions from the oil and gas industry came from upstream activities compared to downstream activities. In 2022, 98% of NH₃, 96% of VOC, NO_{X and} CO, 90% of PM_2.5 and 82% of SO_X emissions from the oil and gas sector were from upstream activities.

Changes in emissions from the oil and gas industry

Key results

• Emissions of SO_X and VOC emissions decreased 49% and 12% , respectively, between 1990 and 2022
• CO and NO_X increased by 56% and 29% over that period

Changes in emissions of key air pollutants from the oil and gas industry, Canada, 1990 to 2022

How this indicator was calculated

Note: Fine particulate matter and ammonia are not shown in the chart due to their low share (≤ 1%) of total emissions in 2022.
Source: Environment and Climate Change Canada (2024) Air Pollutant Emissions Inventory.

The increases in CO and NO_X emissions between 1990 and 2022 were due to growth in oil and gas production (the upstream sector of the industry), as emissions from the downstream sector declined due to facility closures during that period.^{Footnote 11}  This increase is in part explained by the fact that crude oil production more than doubled in Canada since 1990. The growth was mostly driven by a rapid increase in oil sands production. During the same period, production of natural gas from unconventional sources, such as those requiring the use of multi-stage fracturing techniques, also increased significantly.

The decrease in SO_X emissions was mostly the result of a decrease in emissions from oil sands mining, extraction and upgrading, and natural gas production and processing, attributed to better emission control technologies.

For VOCs, the recent decline was partly due to reductions in crude oil production and petroleum refining, storage and distribution. In addition in 2020, federal and provincial regulations to reduce fugitive emissions from the sector came into effect contributing further to the decline.

Air pollutant emissions from transportation, off-road vehicles and mobile equipment

Transportation, off-road vehicles and mobile equipment are among the largest sources of air pollutants in Canada. Burning fossil fuels to power vehicles and engines causes emissions of many air pollutants. Air pollutants are responsible for the formation of fine particulate matter, ozone, smog and acid rain. They also adversely affect human health, the environment and the economy.

Key results

• In 2022, transportation, off-road vehicles and mobile equipment accounted for more than half (59%) of total national emissions of carbon monoxide (CO), 42% of nitrogen oxides (NO_X) and 14% of total emissions of volatile organic compounds (VOCs)
• While also a source of emissions for fine particulate matter (PM_2.5), ammonia (NH3) and sulphur oxides (SO_X), the sectors represented less than 2% of total national emissions, respectively

Contribution of transportation, off-road vehicles and mobile equipment to total air pollutant emissions by transportation mode, Canada, 2022

How this indicator was calculated

Note: "Passenger cars and motorcycles" include cars powered by motor gasoline, diesel, liquefied petroleum gas and compressed natural gas engines as well as all types of motorcycles. "Passenger light trucks" include light-duty trucks powered by motor gasoline, diesel, liquefied petroleum gas and compressed natural gas engines. "Large trucks and buses" include heavy-duty trucks powered by motor gasoline, diesel, liquefied petroleum gas and compressed natural gas engines.
Source: Environment and Climate Change Canada (2024) Air Pollutant Emissions Inventory.

The contribution of each transportation mode to emissions of different air pollutants is in large part explained by the mix of fuels used in these modes.

Large trucks and buses, and rail and marine travel rely predominantly on diesel fuel. Aviation relies on turbo aviation fuel. These transportation modes are the largest sources of NO_X transportation-related emissions accounting for 26% (337 kilotonnes [kt]) of total NO_X emissions.

Passenger cars and light trucks mostly use gasoline and are an important source of pollutants, especially in urban centres. In 2022, emissions from passenger cars, motorcycles and light trucks amounted to 804 kt of CO, 33 kt of NO_X and 46 kt of VOCs. These emissions represented 18%, 3% and 3% of all emissions of these pollutants respectively.

Other sources (mainly composed of off-road vehicles and equipment)^{Footnote 12}  are also a significant source of pollution. Their combined emissions make up 37%, 13% and 9% of the total emissions of CO, NO_X and VOCs, respectively. Emissions mostly come from household use of gasoline- or diesel-powered recreational and lawn and garden equipment and from the operation of agricultural, construction and mining equipment.

Changes in emissions from transportation, off-road vehicles and mobile equipment

Key results

• Between 1990 and 2022, total emissions of NO_X, VOCs and CO from transportation, off-road vehicles and mobile equipment decreased by 57%, 69% and 72%, respectively
• Since 2000, all 3 pollutants demonstrated the same downward trend in their emissions level

Changes in emissions of key air pollutants from transportation, off-road vehicles and mobile equipment, Canada, 1990 to 2022

How this indicator was calculated

Note: Fine particulate matter, sulphur oxides and ammonia are not shown in the chart due to their low share (≤ 5%) of total emissions in 2022.
Source: Environment and Climate Change Canada (2024) Air Pollutant Emissions Inventory.

Pollutant emissions have decreased despite economic and population growth as well as growth in transport activities for the period between 1990 and 2022. This decrease is mainly attributable to the adoption of new regulations that lead to the gradual introduction of emission control technologies and clean fuel for vehicles.

Between 1990 and 2000, NO_X emissions increased by 23%. It includes the increase in emissions from light trucks (116%), large trucks and buses (20%) and marine transportation (19%). From 2000 to 2022, new regulations contributed to a decrease in emissions from light trucks (91%), large trucks and buses (72%) and emissions from marine travel by 79%. Emissions from air, marine and rail travel represented 16% of national emissions of NO_X in 2022.

Transportation emissions are influenced by a variety of factors. These include population and economic growth, volume of passenger and freight travel, vehicle type, emission control technologies, fuel efficiency and fuel type.

Air pollutant emissions from the electric utilities

Electricity generation produces a large share of total national sulphur oxides (SO_X) and nitrogen oxides (NO_X). SO_X and NO_X are mostly emitted from power plants burning fossil fuels such as coal and, to a lesser extent, natural gas and diesel. These air pollutants are responsible for the formation of fine particulate matter, ozone, smog and acid rain. They also adversely affect human health, the environment, and the economy.

Key results

• In 2022, electric utilities were the source of 24% and 7% of total national emissions of sulphur oxides (SO_X) and nitrogen oxides (NO_X), respectively
• Most of the air pollutant emissions from electric utilities come from burning coal
• Electric utilities are also a source of carbon monoxide (CO), volatile organic compounds (VOCs), fine particulate matter (PM_2.5) and ammonia (NH₃) emissions. However, they account for less than 1% of the total national emissions of these pollutants

Contribution of electric utilities to total air pollutant emissions by fuel source, Canada, 2022

How this indicator was calculated

Note: Carbon monoxide, fine particulate matter, volatile organic compounds and ammonia are not shown in the chart due to their low share (≤ 1%) of total emissions in 2022. The indicator excludes emissions from industries that generate electricity and heat as a supporting activity rather than as their primary purpose. "Other sources" include fuel sources such as waste material and other uncategorized sources of electricity generation.
Source: Environment and Climate Change Canada (2024) Air Pollutant Emissions Inventory.

In 2022, 93% of SO_X and 64% of NO_X emissions from electric utilities came from burning coal.

While generating electricity by burning fossil fuels causes air pollutant emissions, the use of non-fossil energy sources, such as hydro, nuclear and other renewable sources to generate electricity does not emit air pollutants. A large share of the electricity generated in Canada comes from sources that do not emit air pollutants:

• 60% of electricity comes from hydro
• 15% comes from nuclear power plants
• 8% comes from non-hydro renewable sources, such as wind, solar, tidal power and biomass^{Footnote 13} 

Changes in emissions from electric utilities

Key results

• Emissions of SO_X and NO_X from electric utilities declined by 75% and 65%, respectively, between 1990 and 2022
• Most of that decline occurred from 2005 onward

Changes in emissions of key air pollutants from electric utilities, Canada, 1990 to 2022

How this indicator was calculated

Note: Carbon monoxide, fine particulate matter, volatile organic compounds and ammonia are not shown in the chart due to their low share (≤ 1%) of total emissions in 2022. Excludes emissions from industries that generate electricity and heat as a supporting activity rather than as their primary purpose.
Source: Environment and Climate Change Canada (2024) Air Pollutant Emissions Inventory.

The majority of the decline in SO_X and NO_X emissions between 1990 and 2022 occurred from 2005 onwards. The majority of the decline in SO_X and NO_X emissions between 1990 and 2022 occurred from 2005 onwards. Between 2005 and 2022, the share of electricity that came from burning fossil fuels fell from 22% to 19%. This decrease was mostly the result of a drop in electricity generation from coal power plants.^{Footnote 14}  The emissions reductions since 2005 are mainly due to:

• the change in the mix of energy sources used to generate electricity
• the introduction of regulations
• domestic and international agreements
• better removal technologies
• plant closures

The Air Pollutant Emissions Inventory and the Black Carbon Emissions Inventory provide data and estimates on releases of air pollutants from human activities. These pollutants contribute to smog, acid rain, reduced air quality and climate change. Improvements to data and the analysis of trends are made periodically as new emission estimation methodologies are adopted and additional information is made available. Historical emissions are updated on the basis of these improvements.

Air Pollutant Emissions Inventory

The Air Pollutant Emissions Inventory fulfills many of Canada's international pollution levels reporting obligations. Specifically, under the 1979 Convention on Long-range Transboundary Air Pollution, Canada is committed to submitting an annual inventory of emissions of key air pollutants to the United Nations Economic Commission for Europe. The inventory is a comprehensive assessment of 17 air pollutants^{Footnote 18} , combining emissions reported by facilities to the National Pollutant Release Inventory, with emissions estimated by Environment and Climate Change Canada. Estimates are developed using the latest estimation methods and are based on published statistics or other sources of information such as surveys and reports. The Air Pollutant Emission Inventory provides a comprehensive overview of pollutant emissions across Canada.

The national and provincial/territorial inventory data are current as of March 15, 2024, and cover the period from 1990 to 2022. Emissions data are compiled into a database for reporting approximately one year after data collection, validation and calculation have been completed. After this process is the interpretation of results and public reporting of the inventory. The Air pollutant emissions indicators are reported following the public release of the inventory data.

Black carbon emissions inventory

As a member of the Arctic Council, Canada committed under the Framework for Action on Enhanced Black Carbon and Methane Emissions Reductions (2015) to submit annual inventories of its black carbon emissions to the United Nations Economic Commission for Europe and to share these with the Arctic Council Secretariat. Canada already voluntarily reports black carbon emissions to the United Nations Economic Commission for Europe as a Party to the Gothenburg Protocol, which was amended in 2012 to include black carbon as a component of fine particulate matter. The Black Carbon Emissions Inventory is compiled using PM_2.5 emissions data from combustion-related sources from the Air Pollutant Emissions Inventory. Black carbon estimates are published separately from the Air Pollutant Emissions Inventory. The data are current as of March 15, 2024.

Black carbon is considered a short-lived climate pollutant, meaning it contributes to warming but has a relatively short lifespan in the atmosphere (from a few days to a few weeks) compared to carbon dioxide (CO₂) (which can persist in the atmosphere for thousands of years) and other longer-lived greenhouse gases (GHGs). Although their life spans are short, short-lived climate pollutants are potent global warmers contributing to warming of the Earth's surface.^{Footnote 19}  When black carbon deposits on snow and ice, it darkens the surface, accelerating heating and melting, creating a warming impact that is particularly strong in the Arctic and other snow covered areas (including glaciers).^{Footnote 20}  Short-lived climate pollutants, including black carbon, are important pollutants to consider when addressing climate change because they can respond relatively quickly to efforts to control their releases and thus taking action to reduce their emissions can have nearly immediate impacts to slow near-term warming. The Intergovernmental Panel on Climate Change (IPCC) special report on Global Warming states that reductions in short-lived climate pollutants are required to limit warming to a maximum of 1.5^oC, and Canada's Changing Climate Report flags short-lived climate pollutants as an important part of climate policy discussions.

National Pollutant Release Inventory

The National Pollutant Release Inventory is a database of pollutant releases (to air, water and land), disposals and transfers for recycling from industrial, commercial and institutional facilities. The data from these facilities is provided by the operators of the facilities as mandated by the Canadian Environmental Protection Act (the Act). Under the Act, owners or operators of facilities that manufacture, process or otherwise use or release one or more of the substances tracked by the inventory, and meet substance-specific reporting thresholds and other requirements, must report their pollutant releases, disposals and transfers annually to the department. The inventory data from 1993 to 2022 are current as of November 23, 2023.

Compilation of air pollutant emissions

The Air Pollutant Emissions Inventory is developed using 2 types of information:

• facility-reported data, consisting of emissions from relatively large industrial, commercial and institutional facilities
• in-house estimates, including diffuse sources and other sources that are too numerous to be accounted for individually, such as road and non-road vehicles, agricultural activities, construction and solvent use

The Air Pollutant Emissions Inventory is developed using many sources of information, procedures and emission estimation models. Emissions data reported by individual facilities to the department's National Pollutant Release Inventory 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 compilation framework has been developed that makes use of the best available data, while ensuring that there is no double-counting or omissions. Additional information on the inventory compilation process is provided in Chapter 3 of the Air Pollutant Emissions Inventory Report.

Facility-reported emissions data

Facility-reported emissions data generally refers to any stationary sources that emit pollutants through stacks or other equipment at specific locations. The major source of facility-reported data is the National Pollutant Release Inventory.

Facility-reported data from the National Pollutant Release Inventory are used in the Air Pollutant Emissions Inventory without modifications, except when data quality issues are detected and not addressed during the quality control exercise. The National Pollutant Release Inventory reporting requirements and thresholds vary by pollutant and, in some cases, by industry. Details on these reporting requirements and thresholds are available on the National Pollutant Release Inventory website.

A distinction has been made between reporting facilities and non-reporting facilities. Reporting facilities meet the threshold required to report to the National Pollutant Release Inventory; while non-reporting facilities do not meet these thresholds due to their size or emission levels, and therefore are not required to report to the inventory. Some facilities may be required to report emissions on only certain pollutants. Therefore, emissions from the non-reporting facilities or of non-reported pollutants must be estimated in‑house to ensure complete coverage.

In-house emission estimates

In-house emission estimates are calculated with information such as production data and activity data, using various estimation methodologies and emission models. These emission estimates are at the national, provincial and territorial levels, rather than at any specific geographic locations. These include emissions from non-industrial, residential, commercial, transportation, and other sources, such as open burning, agricultural activities and construction operations. The Air Pollutant Emissions Inventory uses in-house estimates for the following emission sources:

• any residential, governmental, institutional, or commercial operation that does not report to the National Pollutant Release Inventory
• on-site solid waste disposal facilities
• motor vehicles, aircraft, vessels or other transportation equipment or devices
• other sources, such as open burning, agricultural activities and construction operations

In general, in-house emission estimates are calculated from activity data and emission factors.^{Footnote 21}  Activity data usually comprise statistical production or process data at the provincial, territorial or national level. This information is typically provided by provincial/territorial agencies, federal government departments, industry associations, etc. For each source category, activity data are combined with emission factors to produce provincial/territorial-level emission estimates.

The in-house emission estimate methodologies and emission models used in Canada are often based on those developed by the United States Environmental Protection Agency (U.S. EPA) and are adapted to reflect the Canadian climate, fuels, technologies and practices. Methods used in Canada's Air Pollutant Emissions Inventory are therefore generally consistent with those used in the United States or those recommended in the emission inventory guidebook.^{Footnote 22}

The Air Pollutant Emissions Inventory reports air pollutant emissions from mobile sources such as on-road vehicles, off-road vehicles and engines. For the current edition of the Air Pollutant Emissions Inventory, an emissions estimation model developed by the U.S. EPA (MOVES) was used. The emissions for off-road vehicles and engines (such as graders, heavy trucks, outboard motors and lawnmowers) were estimated using the U.S. EPA's NONROAD emission estimation model (see "off-road vehicles and equipment" in Table A2-4 of Annex 2 of the Air Pollutant Emissions Inventory Report). The parameters in both models were modified to take into account variations in the Canadian vehicle fleet, emission control technologies, types of fuels, vehicle standards, and types of equipment engines and their application in various industries. The emission estimates for civil and international aviation, railways and navigation are estimated using detailed vehicle movement statistics coupled with fuel consumption, engine information, and emission rates by vehicle types.

Calculation of black carbon emissions

Emissions of black carbon are calculated by applying factors to estimate the fraction of black carbon in PM_2.5 emissions from combustion-related sources, with some exceptions, for example, the mobile sources, where models are used. The factors primarily come from the United States Environmental Protection Agency's SPECIATE database. SPECIATE is a repository of particulate matter speciation profiles^{Footnote 23}  of air pollution sources. Annex 2 of Canada's Black Carbon Emissions Inventory lists all the ratios used for each source.

Recalculations

Emission recalculation is an essential practice in the maintenance of an up-to-date air pollutant emissions inventory. The Air Pollutant Emissions Inventory 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 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 emission data. More information on recalculations is provided in Annex 3 of the Air Pollutant Emissions Inventory Report.

Emissions reconciliation

In several sectors, estimation of total emissions involves combining estimates provided by facilities with estimates developed in-house by the department. To prevent double counting of emissions and to confirm that the Air Pollutant Emissions Inventory 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. More information on the reconciliation process is provided in section 3.4 of the Air Pollutant Emissions Inventory Report.

Temporal coverage

Historical data are provided at the national level for the period from 1990 to 2022. For the regional indicators (provincial/territorial), emissions are presented for 1990 and 2022. Facility level emissions information are available from 2011 to 2022.

Air pollutant emissions by source classification

For the purpose of reporting the indicators, calculated emissions data from the Air Pollutant Emissions Inventory and Black Carbon Emissions Inventory are grouped into the following 13 sources:

1. agriculture (livestock, crop production and fertilizer)
2. building heating and energy generation
3. dust and fires
4. electric utilities
5. home firewood burning
6. incineration and waste
7. manufacturing
8. miscellaneous
9. off-road vehicles and mobile equipment
10. oil and gas industry
11. ore and mineral industries
12. paints and solvents
13. transportation (road, rail, air and marine)

Table 1 shows the allocation of air pollutant emission sources reported in the indicators compared with the sources and sectors reported by the Air Pollutant Emissions Inventory.