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 2020, SO_X emissions decreased by 78% from 3 009 kilotonnes (kt) to 651 kt
• In 2020, 3 sources accounted for 93% (607 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 2020

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 2 in the Data sources and methods for a complete list of the air pollutant emissions sources included under each category. New interactive figures provide a dynamic and customizable format to explore the emissions.
Source: Environment and Climate Change Canada (2022) Air Pollutant Emissions Inventory.

In 2020, the oil and gas industry accounted for approximately 38% of total national SO_X emissions (245 kt). Ore and mineral industries and electric utilities followed with 30% (193 kt) and 26% (168 kt) of national emissions. For the ore and mineral industries, 44% (85 kt) of its SO_X emissions came from the non-ferrous refining and smelting industry. 

The largest reduction in emissions between 1990 and 2020 was from ore and mineral industries with a reduction in emissions of 1 288 kt. The largest driver of the reduction from the source was from the non-ferrous refining and smelting industry with a reduction of 1 180 kt over the period.

This significant decrease in SO_X emissions from 1990 to 2020 (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)
• better emission control technologies within the oil and gas sector and the closure of a petroleum refining facility in Newfoundland and Labrador
• implementation of regulations on low-sulphur fuels^{Footnote 3Footnote 4}  

More recently, between 2019 and 2020, SO_X emissions have declined mainly due to decreases in emissions from electric utilities of 37 kt (18%) and the oil and gas industry of 26 kt (10%).

Sulphur oxide emissions by province and territory

Key results

• In 2020, Alberta and Ontario accounted for 45% (295 kt) of national SO_X emissions
• Between 1990 and 2020
  • the largest reduction were observed in Ontario and Manitoba. Emissions in these provinces decreased by 1 010 kt (90%) and 507 kt (99%)
  • Saskatchewan was the only province that experienced an increase in SO_X (3%, or 3 kt)

Sulphur oxide emissions by province and territory, Canada, 1990, 2005 and 2020

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 (2022) Air Pollutant Emissions Inventory.

Alberta had the highest SO_X emissions level in 2020, accounting for 28% (183 kt) of total national emissions. Emissions in the province mainly came from the oil and gas industry and electric utilities, combined accounting for 95% (174 kt) of the emissions. Between 2005 to 2020, the province experienced a 60% decline in emissions (278 kt) with the oil and gas industry, notably reductions from natural gas and crude oil production, responsible for a large part of the reductions.

Ontario was the second-highest emitter of SO_X in 2020, accounting for 17% (113 kt) of total national emissions. Emissions from ore and mineral industries was the largest contributor to SO_X emissions in the province in 2020. The sharp reduction (90%) in SO_X emissions in Ontario between 1990 and 2020 was mainly due to emission reductions from ore and mineral industries (notably the non-ferrous refining and smelting industry) and electric utilities. The majority of the reductions (388 kt or 77%) occurred between 2005 and 2020.

Saskatchewan ranked third, with 16% (106 kt) of total national emissions; electric utilities and the oil and gas industry were the most important sources of emissions in the province. 

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.

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.

In 2020, 2 593 facilities across Canada reported SO_X emissions representing 89% of total national emissions. Of these facilities:

• 2 191 facilities reported emissions under 25 tonnes (t)
• 379 facilities reported emissions between 25 to 6 000 t
• 23 facilities reported emissions above 6 000 t located in Alberta (6), Ontario (4), Quebec (4), Saskatchewan (4), Nova Scotia (3), Newfoundland and Labrador (1) and British Columbia (1) 

Sulphur oxide emissions by reporting facilities, Canada, 2020

Source: Environment and Climate Change Canada (2022) 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 2020, NO_X emissions were 1 447 kilotonnes (kt). This is 36% lower than in 1990
• Transportation (road, rail, air and marine) was the largest source of NO_X representing 35% (508 kt) of total emissions in 2020

Total nitrogen oxide emissions by source, Canada, 1990 to 2020

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 2 in the Data sources and methods for a complete list of the air pollutant emissions sources included under each category. New interactive figures provide a dynamic and customizable format to explore the emissions.
Source: Environment and Climate Change Canada (2022) Air Pollutant Emissions Inventory.

While transportation (road, rail, air and marine) was the largest single contributor of NO_X, it was also the sector that experienced the largest reduction between 1990 and 2020. Emissions of NO_X from this sector decreased by 393 kt (44%) during that period. 

The oil and gas industry emitted the next largest proportions of NO_X emissions in 2020, representing 31% (449 kt) of total national emissions. This sector also experienced the largest increase 30% (103 kt) in emissions between 1990 and 2020, partly offsetting reductions from other sectors.

The decline in NO_X emissions between 1990 and 2020 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 2019 and 2020, NO_X emissions have declined mainly due to decreases in emissions from transportation (road, rail, air and marine) sources of 82 kt (14 %), notably from light-duty gasoline vehicles and trucks, and the oil and gas industry of 33 kt (7%) mostly from reductions in natural gas and crude oil production.

Nitrogen oxide emissions by province and territory

Key results

• In 2020, among provinces and territories, Alberta emitted the most NO_X. The province accounted for 39% (568 kt) of national emissions
• Between 1990 and 2020,
  • the largest reduction was observed in Ontario. Emissions decreased by 62% (373 kt) in the province
  • NO_X emissions increased in Nunavut and Northwest Territories by 25% (4 kt) 

Nitrogen oxide emissions by province and territory, Canada, 1990, 2005 and 2020

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 (2022) Air Pollutant Emissions Inventory.

The oil and gas industry is an important source of NO_X emissions in Alberta, accounting for 62% (352 kt) of the province's NO_X emissions in 2020. The increasing contribution of this sector to the province's emissions between 1990 and 2020 was more than offset by emission reductions from the transport and electric utilities sectors.

Ontario and British Columbia both contributed the second and third largest proportion of NO_X emissions in 2020, accounting for 16% (229 kt) and 14% (209 kt) of total national emissions, with transportation (road, rail, air and marine) being the most important source in both provinces followed by off-road vehicles and mobile equipment in Ontario and the oil and gas industry in British Columbia. However, Ontario experienced the largest decrease in emissions (373 kt) between 1990 and 2020 in large part due to emission reductions from transportation (road, rail, air and marine), electric utilities and off-road vehicles and mobile equipment. The majority of total NO_X emission reductions occurred between 2005 and 2020 (309 kt).

Quebec ranked fourth, with 11% (155 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 (138 kt) between 2005 and 2020 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.

In 2020, 3 496 facilities across Canada reported NO_X emissions representing 36% of total national emissions. Of these facilities:

• 2 024 facilities reported emissions under 50 tonnes (t)
• 1 366 facilities reported emissions between 50 to 800 t
• 106 facilities reported emissions above 800 t located in Alberta (42), Ontario (19), Quebec (9), British Columbia (8), Newfoundland and Labrador (8), Saskatchewan (7), Nova Scotia (5), New Brunswick (4) and Nunavut and Northwest territories (4)

Nitrogen oxide emissions by reporting facilities, Canada, 2020

Source:  Environment and Climate Change Canada (2022) National Pollutant Release Inventory.

Navigate data using the interactive map

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 5} 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 2020, VOC emissions in Canada were 1 462 kilotonnes (kt). This is a 1 407 kt (49%) decrease from 1990 levels
• Since 2000, the oil and gas industry has been the highest contributor to VOC emissions. In 2020, the sector accounted for 36% (534 kt) of total emissions

Total volatile organic compound emissions by source, Canada, 1990 to 2020

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, agriculture (livestock, crop production and fertilizer) and other miscellaneous sources. Consult Table 2 in the Data sources and methods for a complete list of the air pollutant emissions sources included under each category. New interactive figures provide a dynamic and customizable format to explore the emissions.
Source: Environment and Climate Change Canada (2022) Air Pollutant Emissions Inventory.

Paints and solvents, and transportation (road, rail, air and marine) were also important sources of VOC emissions in 2020 contributing 18% (261 kt) and 9% (132 kt) of total emissions.

The largest emissions reduction between 1990 and 2020 was from off-road vehicles and mobile equipment, with emissions reductions of 694 kt (85%).

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 improved emission controls
• lower levels of VOCs in products such as paints, solvents and cleaners

Compared to the previous year, VOC emissions decreased by 179 kt (11%) in 2020. The largest reduction was from the oil and gas industry 83 kt (13%), notably from reductions in crude oil production. 

Volatile organic compound emissions by province and territory

Key results

• Alberta emitted the highest proportion of VOCs in 2020. The province represented 31% (457 kt) of national emissions
• Between 1990 and 2020,
  • Ontario experienced the largest reduction in VOC emissions. Emissions in the province decreased by 64% (545 kt)
  • Saskatchewan was the only province that experienced an increase in VOC emissions of 14% (26 kt)

Volatile organic compound emissions by province and territory, Canada, 1990, 2005 and 2020

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 (2022) Air Pollutant Emissions Inventory.

Alberta was the highest emitting province of VOCs in 2020 (457 kt), with the oil and gas industry as the main source, contributing 72% (327 kt) of the province's emissions.

Ontario was the second-highest emitter of VOCs, accounting for 21% (308 kt) of total national emissions in 2020. 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 545 kt (64%) between 1990 and 2020, mainly as a result of emission reductions from off-road vehicles and mobile equipment and transportation (road, rail, air and marine). More than half of the reductions in Ontario (51%) occurred between 2005 to 2020.

Saskatchewan was the third largest emitter, with 15% (213 kt) of total national emissions in 2020, where the oil and gas industry accounted for 74% of the emissions in that province.

Most provinces and territories experienced significant reductions in emissions between 1990 and 2020 with the exception of Saskatchewan, where emissions increased 14% over the period. The oil and gas industry is responsible for the increase in emissions in Saskatchewan.  

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.

In 2020, 4 127 facilities across Canada reported VOC emissions representing 17% of total national emissions. Of these facilities:

• 2 325 facilities reported emissions under 15 tonnes (t)
• 1 711 facilities reported emissions between 15 to 400 t
• 91 facilities reported emissions above 400 t located in Alberta (35), Ontario (21), Saskatchewan (10), British Columbia (6), Manitoba (6), Quebec (6), Newfoundland and Labrador (3), New Brunswick (3) and Nova Scotia (1)

Volatile organic compound emissions by reporting facilities, Canada, 2020

Source:  Environment and Climate Change Canada (2022) National Pollutant Release Inventory.

Navigate data using the interactive map

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 2020, NH₃ emissions were 487 kilotonnes (kt). This is 24% higher than in 1990
• Agriculture (livestock, crop production and fertilizer) was the main source of NH₃ emissions in 2020. Emissions from this source accounted for more than 94% (457 kt) of total national emissions

Total ammonia emissions by source, Canada, 1990 to 2020

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 2 in the Data sources and methods for a complete list of the air pollutant emissions sources included under each category. New interactive figures provide a dynamic and customizable format to explore the emissions.
Source: Environment and Climate Change Canada (2022) Air Pollutant Emissions Inventory.

Between 1990 and 2020, agriculture (livestock, crop production and fertilizer) experienced the largest increase (28% or 101 kt) in NH₃ emissions. It also remained the key source of NH₃ emissions throughout that period. Emissions from other sources (12 kt), manufacturing (12 kt) and transportation (road, rail, air and marine) (6 kt) combined represented 6% of national emissions in 2020.

The growth in NH₃ emissions from agriculture (livestock, crop production and fertilizer) between 1990 and 2020 is mainly due to the increased use of synthetic nitrogen fertilizers. 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.

Ammonia emissions by province and territory

Key results

• In 2020, Alberta and Saskatchewan accounted for almost half (235 kt) of national NH₃ emissions
• Between 1990 and 2020,
  • Ontario experienced the largest emissions reduction of 19 kt (17%)
  • The largest increase in NH₃ emissions was in Saskatchewan with emissions more than doubling (a 53 kt increase)

Ammonia emissions by province and territory, Canada, 1990, 2005 and 2020

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 (2022) Air Pollutant Emissions Inventory.

In 2020, Alberta emitted the most NH₃ of all the provinces and territories, accounting for 27% (133 kt) of total national emissions. Saskatchewan contributed the second-largest proportion of NH₃, representing 21% (102 kt).

Ontario and Quebec followed with 19% and 13% (92 kt and 64 kt) of total national emissions, respectively. For both provinces, livestock farms and the application of fertilizers were the most important sources of NH₃ emissions.

Virtually all of the increase in emissions between 1990 and 2020 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.

In 2020, 253 facilities across Canada reported NH₃ emissions representing 13% of total national emissions. Of these facilities:

• 158 facilities reported emissions under 25 tonnes (t)
• 87 facilities reported emissions between 25 to 400 t
• 8 facilities reported emissions above 400 t located in Alberta (5), British Columbia (1), Manitoba (1) and Saskatchewan (1)

Ammonia emissions by reporting facilities, Canada, 2020

Source: Environment and Climate Change Canada (2022) National Pollutant Release Inventory.

Navigate data using the interactive map

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 2020,
  • CO emissions in Canada were 4 655 kilotonnes (kt), a decrease of 59% from 1990 levels
  • Transportation (road, rail, air and marine) was the largest source of CO emissions in Canada representing 35% (1 637 kt) of total emissions

 Total carbon monoxide emissions by source, Canada, 1990 to 2020

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, ore and mineral industries, manufacturing and other miscellaneous sources. Consult Table 2 in the Data sources and methods for a complete list of the air pollutant emissions sources included under each category. New interactive figures provide a dynamic and customizable format to explore the emissions.
Source: Environment and Climate Change Canada (2022) Air Pollutant Emissions Inventory.

In 2020, transportation, off-road vehicles and mobile equipment were the 2 most important sources of CO. These sources combined represented 62% (2 880 kt) of national emissions.

The largest reduction in emissions between 1990 and 2020 occurred in transportation (road, rail, air and marine) with an emission decrease of 3 857 kt (70%).

The decline in CO emissions between 1990 and 2020 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).

More recently, between 2019 and 2020, CO emissions have declined mainly due to decreases in emissions from transportation (road, rail, air and marine) sources of 234 kt (13 %), notably from the use of light-duty gasoline vehicles and trucks.

Carbon monoxide emissions by province and territory

Key results

• In 2020, Quebec and Ontario accounted for 50% (2 324 kt) of national CO emissions
• Between 1990 and 2020,
  • all provinces and territories experienced significant reductions in emissions
  • the largest reductions occurred in Ontario (2 141 kt or 65%), British Columbia (1 695 kt or 72%) and Quebec (1 059 kt or 47%)

Carbon monoxide emissions by province and territory, Canada, 1990, 2005 and 2020

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 (2022) Air Pollutant Emissions Inventory.

In 2020, Quebec emitted the most CO of all the provinces and territories, representing 26% (1 196 kt) of the total national emissions. Ore and mineral industries, specifically the aluminum industry representing 93% (344 kt) of the sector’s emissions, was the most important source of CO emissions for Quebec.

The province of Ontario ranked second, with 24% (1 128 kt) of total national emissions in 2020, with 79% of those emissions from 2 sources, namely transportation (road, rail, air and marine) and off-road vehicles and mobile equipment.

Alberta, the third largest CO emitter, accounted for 19% (890 kt) of total national emissions. The oil and gas industry accounted for 43% of the province's CO emissions.

The sharp decrease in emissions between 1990 and 2020 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 1990 to 2005 notably for British Columbia with emissions decreasing by 1 156 kt (49%) and for Ontario with emissions decreasing by 1 187 kt (36%).

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.

In 2020, 3 304 facilities across Canada reported CO emissions representing 18% of total national emissions. Of these facilities:  

• 1 488 facilities reported emissions under 25 tonnes (t)
• 1 731 facilities reported emissions between 25 to 1 000 t
• 85 facilities reported emissions above 1 000 t located in Alberta (29), Quebec (15), British Columbia (15), Ontario (14), New Brunswick (6), Newfoundland and Labrador (3) and Saskatchewan (3)

Carbon monoxide emissions by reporting facilities, Canada, 2020

Source:  Environment and Climate Change Canada (2022) National Pollutant Release Inventory.

Navigate data using the interactive map

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 6}  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 2020, PM_2.5 emissions were 1 432 kilotonnes (kt). This is 15% 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 62% (884 kt) of total national emissions in 2020.
  • These emissions increased by 67% (354 kt) between 1990 and 2020. Dust from construction operations and unpaved roads accounted for the majority of the increase.

Total fine particulate matter emissions by source, Canada, 1990 to 2020

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 2 in the Data sources and methods for a complete list of the air pollutant emissions sources included under each category. New interactive figures provide a dynamic and customizable format to explore the emissions.
Source: Environment and Climate Change Canada (2022) Air Pollutant Emissions Inventory.

In 2020, 86% of PM_2.5 emissions came from open source emissions, such as dust and fires, and agriculture (livestock^{Footnote 7} , crop production and fertilizer). In general, these 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.

The remaining 14% of PM_2.5 emissions in 2020 came from home firewood burning (80 kt or 6%) and other sources, including:

• ore and mineral industries, representing 2% (34 kt) of the emissions
• transportation (road, rail, air and marine), representing 1% (17 kt)
• manufacturing and miscellaneous sources, such as emissions from commercial cooking, each representing about 1% (16 kt) of emissions
• off-road vehicles and mobile equipment, representing 1% (14 kt)
• the oil and gas industry, representing less than 1% (12 kt)
• other emissions (less than 1%) coming from building heating and energy generation, electric utilities, incineration and wastes, and the use of paints and solvents

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

The decreases in PM_2.5 emissions between 1990 and 2020 are mainly attributable to emission reductions from agriculture (livestock, crop production and fertilizer), manufacturing and home firewood burning. These reductions outweigh the increase in emissions from dust and fires (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 in homes that control emissions and burn more efficiently were the main drivers leading to the reductions. Since 2010, however, emissions from dust and fires have gradually increased, as a result of an increase from road dust and dust from construction operations, with a slight drop in 2020, offsetting reductions from the other sources. The emission reduction in 2020 is driven predominantly by decreased use of unpaved roads.

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-immediate and local benefits.

Key results

• Emissions of black carbon were 29 kt in 2020, a decrease of 22% from 2013
• In 2020, 3 sectors accounted for 83% of national black carbon emissions:
  • off-road vehicles and mobile equipment
  • transportation (road, rail, air and marine)
  • home firewood burning

Total black carbon emissions by source, Canada, 2013 to 2020

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 2 in the Data sources and methods for more details.  New interactive figures provide a dynamic and customizable format to explore the emissions.
Source: Environment and Climate Change Canada (2022) Canada's Black Carbon Emissions Inventory.

In 2020, off-road vehicles and mobile equipment (for example, lawn and garden equipment, recreational vehicles, excavators, graders) and transportation (road, rail, air and marine) accounted for the largest proportions of total national emissions, both representing 30% (9 kt) of emissions. Home firewood burning was also a large contributor, representing about 23% (7 kt) of total national emissions. The remaining 17% of emissions came from the oil and gas industry, building heating and energy generation and other sources (such as ore and mineral industries).

For both transportation and off-road vehicles and mobile equipment, the use of diesel engines was the main source of black carbon emissions.

Black carbon emissions by province and territory

Key results

• In 2020, 3 provinces, Alberta, Ontario and Quebec, accounted for 62% (18 kt) of total national black carbon emissions
• Between 2013 and 2020,
  • all provinces and territories, with the exception of Prince Edward Island, experienced reductions in black carbon emissions between 4% to 56%
  • Ontario and Quebec experienced the largest reductions in emissions of 2.1 kt and 1.6 kt, respectively. For both provinces, the reductions were mainly attributable to lower emissions from off-road vehicles and mobile equipment

Black carbon emissions by province and territory, Canada, 2013 and 2020

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 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 2020, the oil and gas industry was a major contributor to total national emissions of sulphur oxides (SO_X) (38%),  volatile organic compounds (VOCs) (36%), nitrogen oxides (NO_X) (31%) and carbon monoxide (CO) (11%)
• The oil and gas industry is also a source of emissions of fine particulate matter (PM_2.5) and ammonia (NH₃). However, in 2020, it made up less than 1% of the total emissions of these pollutants

Contribution of the oil and gas industry to total air pollutant emissions by activity type, Canada, 2020

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 2020. In the oil and gas industry, upstream activities include exploration, drilling, production and field processing and downstream activities include refining, storage and distribution.
Source: Environment and Climate Change Canada (2022) Air Pollutant Emissions Inventory.

In 2020, the oil and gas industry was the sector contributing the most to total national emissions of SO_X and VOCs. It was also the second-largest contributor to emissions of NO_X, and the fourth-largest contributor to emissions of CO.

Most of emissions from the oil and gas industry came from upstream activities compared to downstream activities. In 2020, 97% of CO, 96% of VOC and NO_X and 86% 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 54% and 12% , respectively, between 1990 and 2020
• CO and NO_X increased by 49% and 30% over that period

Changes in emissions of key air pollutants from the oil and gas industry, Canada, 1990 to 2020

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 2020.
Source: Environment and Climate Change Canada (2022) Air Pollutant Emissions Inventory.

The increases in CO and NO_X emissions between 1990 and 2020 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. 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 2020, transportation, off-road vehicles and mobile equipment accounted for more than half (62%) of total national emissions of carbon monoxide (CO), 47% of nitrogen oxides (NO_X) and 17% of total emissions of volatile organic compounds (VOCs)
• While also a source of emissions for fine particulate matter (PM_2.5), sulphur oxides (SO_X) and ammonia (NH₃), the sectors represented less than 3% of total national emissions of these other pollutants

Contribution of transportation, off-road vehicles and mobile equipment to total air pollutant emissions by transportation mode, Canada, 2020

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 (2022) 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 29% (414 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 2020, emissions from passenger cars, motorcycles and light trucks amounted to 1 146 kt of CO, 94 kt of NO_X and 95 kt of VOCs. These emissions represented 25%, 6% and 7% of all emissions of these pollutants respectively.

Other sources (mainly composed of off-road vehicles and equipment)^{Footnote 8}  are also a significant source of pollution. Their combined emissions make up 27%, 12% and 8% 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 2020, total emissions of NO_X, CO and VOCs from transportation, off-road vehicles and mobile equipment decreased by 47%, 64% and 79%, 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 2020

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 2020.
Source: Environment and Climate Change Canada (2022) 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 2020. 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 (92%), large trucks and buses (44%) and marine transportation (19%). From 2000 to 2020, new regulations contributed to a decrease in emissions from light trucks (69%), large trucks and buses (51%) and emissions from marine travel by 10%. Emissions from air, marine and rail travel represented 11% of national emissions of NO_X in 2020.

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 2020, electric utilities were the source of 26% 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, 2020

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 2020. 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 (2022) Air Pollutant Emissions Inventory.

In 2020, 96% of SO_X and 66% 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 wind, 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:

• 59% of electricity comes from hydro
• 15% comes from nuclear power plants
• 7% comes from non-hydro renewable sources, such as wind, solar, tidal power and biomass^{Footnote 9} 

Changes in emissions from electric utilities

Key results

• Emissions of SO_X and NO_X from electric utilities declined by 73% and 61%, respectively, between 1990 and 2020
• Most of that decline occurred from 2005 onward

Changes in emissions of key air pollutants from electric utilities, Canada, 1990 to 2020

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 2020. 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 (2022) Air Pollutant Emissions Inventory.

The majority of the decline in SO_X and NO_X emissions between 1990 and 2020 occurred from 2005 onwards. Between 2005 and 2020, 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 10}  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 13}  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, 2022, and cover the period from 1990 to 2020. 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 to submit annual inventories of its black carbon emissions to the United Nations Economic Commission for Europe beginning in 2015. 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, 2022.

Black carbon is considered a short-lived climate pollutant, meaning it 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 14}  Black carbon absorbs more solar radiation 460 to 1 500 times than CO₂.^{Footnote 15}  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 impact near-term warming, which is particularly important in the Polar Regions, such as the Arctic.^{Footnote 16}  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 2020 are current as of March 2, 2022.

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 level 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 17}  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 18}

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 (PDF;4.14 MB) 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 the exception of 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 19}  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 2020. For the regional indicators (provincial/territorial), emissions are presented for 1990 and 2020. Facility level emissions information are available from 2011 to 2020.

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 2 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.