Canada's Air

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Canada's Air

Canadians enjoy a good level of outdoor air quality. Emissions of air pollutants that cause smog and acid rain have decreased significantly during the past decades. These reductions have contributed to the reduction of the air pollutants that Canadians breathe every day – pollutants that can contribute to health issues such as asthma and cardiovascular diseases.

While significant progress has been made to reduce air pollution, poor air quality remains a serious issue in some areas of Canada. Canadians living in heavily populated and industrialized areas of the country may be exposed to potentially harmful levels of outdoor air pollutants, at concentrations that exceeded established standards. Air pollutants such as fine particulate matter and ground-level ozone, the major components of smog, can adversely affect the health of Canadians, especially small children, the elderly, and those with heart and lung conditions, even at low concentrations.

This website provides information on the Air Quality Management System, air quality across Canada, air pollution and its effects, and actions to improve the air that we breathe.

Air Quality
Management System

 
  • In order to better protect human health and the environment, in 2012 ministers of the environment, with the exception of Québec, agreed to implement a new Air Quality Management System (AQMS) to guide work on air emissions across Canada.
  • AQMS is a comprehensive and collaborative approach by federal, provincial and territorial governments to reduce the emissions and ambient concentrations of various pollutants of concern.
  • AQMS provides a framework for collaborative action across Canada to further protect human health and the environment from harmful air pollutants through continuous improvement of air quality.
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Hover or click on the graphic for more information.

Although Quebec supports the general objectives of the AQMS, it will not implement the system since it includes federal industrial emission requirements that duplicate Quebec’s regulation. However, Quebec is collaborating with jurisdictions on developing other elements of the system, notably air zones and airsheds.
Mechanisms

Air Pollutants

The air pollutants included in this report are:

Click on the terms below to learn the difference between pollutant emissions and ambient concentrations.

Particulate Matter (PM)

Particulate matter (PM), a major component of smog, consists of airborne particles in solid or liquid form. PM may be classified as primary or secondary, depending on the process that led to its formation. Primary PM is emitted directly into the atmosphere from a source, such as a smokestack or exhaust pipe, or from wind-blown soils or vehicle traffic on a dirt road. Secondary PM is formed in the atmosphere through a series of chemical and physical reactions involving gases such as sulphur oxides (SOx) and nitrogen oxides (NOx). PM exists in various sizes and the particles of most concern for human health are those with a diameter of less than 2.5 micrometres (PM2.5).

Ground-Level Ozone (O3)

Ground-level ozone (O3), is a colourless, odourless and highly irritating gas that forms close to the Earth’s surface. O3 is a major component of smog. In contrast to “primary” pollutants which are emitted directly into the atmosphere from a source, O3 is considered a “secondary” pollutant because it is formed through complex chemical reactions between nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the presence of sunlight. While O3 at ground-level is a significant environmental and health concern, approximately 10 to 40 kilometres above the Earth's surface, there is a beneficial layer of stratospheric ozone which shields the earth from harmful ultraviolet radiation. Ozone is also a short-lived climate pollutant and also contributes to climate change.

Nitrogen Dioxide (NO2)

Nitrogen dioxide (NO2) belongs to the oxides of nitrogen group of compounds (NOx) that are formed primarily through the burning of fossil fuels. While transportation sources represent over half of all emissions, energy production and industrial processes also emit significant amounts of NOx, mainly as Nitric Oxide (NO) and Nitrogen Dioxide (NO2). NO2 at higher concentrations has a strong, harsh odour and can typically be seen over large cities as a brownish haze. Once formed, NO2 can combine with water molecules in the air to form compounds like nitric acid and nitrous acid. Ultimately, these compounds fall to earth through precipitation (such as rain, snow and fog) where they contribute to the acidification and eutrophication of ecosystems.

Sulphur Dioxide (SO2)

Sulphur dioxide (SO2) is a colourless gas that smells like burnt matches. It belongs to a group of sulphur-containing gases called sulphur oxides (SOx). SO2 is emitted when fossil fuels or raw materials containing sulphur are burned or used in an industrial process like metal ore smelting or electric power generation. It can also be produced in large quantities during extraction and processing of fossil fuels. SO2 contributes to the formation of PM2.5 and smog, and when combined with water molecules in the air, it can form compounds like sulfuric acid, which eventually falls to earth as acid rain, snow and fog.

Volatile Organic Compounds (VOCs)

Volatile organic compounds (VOCs) are organic chemicals that easily turn to vapour under normal atmospheric conditions. When VOCs are exposed to sunlight, complex chemical reactions occur with NOx that lead to the production of O3 and fine particulate matter (PM2.5), two key components of smog. Smog is known to have adverse effects on human health and the environment. VOCs cover a wide range of chemicals including fumes from oil-based paint, household cleaning products, solvents and gasoline, as well as from some natural sources. Across Canada, the main human-related sources are related to the extraction of oil and gas, the use of paints and solvents, transportation, and home firewood burning.

Canada-wide Air Pollutant Emissions Trends Over Time

 

Overall, air pollutant emissions have decreased since 1990. Governments, businesses and individual Canadians have all contributed to these achievements. This chart shows the percentage change in emissions from 1990 levels of four key air pollutants.

 

 

Source: Environment and Climate Change Canada, 2017. Air Pollutant Emissions Indicators.

 

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Effects on Human Health and the Environment

 

According to the World Health Organization (WHO) air pollution represents the biggest environmental risk to human health and can severely affect the environment.  Even at low levels, air pollution has been clearly linked to increased heart and breathing problems, increased hospitalization and emergency room visits and premature death. Health Canada estimates there are 14,000 to 15,000 deaths in Canada each year due to air pollution from human activity.

 

Improved air quality reduces heart attacks and hospital visits, avoids hundreds of thousands of child asthma attacks, and prevents millions of lost school and work days in Canada alone.  Cleaner air can also reduce damage to crops, forests, surface waters, and infrastructure such as buildings and bridges, and can help address climate change impacts since some air pollutants are also greenhouse gases or contribute to the formation of greenhouse gases.

Health Effects - Exposure to ozone (O3) can cause respiratory symptoms such as throat irritation, coughing, shortness of breath, and reduced lung function. Ozone exposure can also aggravate existing conditions like asthma or other chronic lung diseases. Sensitive populations such as children, and people suffering from respiratory or cardiovascular conditions are at higher risk, especially during summer months when ozone levels increase.

Environmental Effects - Ozone is absorbed directly by plants through pores in their leaves. Once inside the plant, O3 can damage leaves, reduce photosynthesis, impair reproduction and decrease agricultural crop yields. This can reduce the variety of plants in an ecosystem. While mostly known for its adverse effects on health and the environment, ozone is also a greenhouse gas that contributes to climate change.

Health Effects - Exposures to fine particulate matter (PM2.5) can negatively impact the heart and lungs, and can lead to health issues like asthma attacks, chronic bronchitis, and heart attacks. Exposure to PM2.5 is also linked to increased emergency room visits and hospitalization due to respiratory and cardiovascular problems, as well as increased risk of premature mortality. Children and those with pre-existing cardiovascular and respiratory disease have greater sensitivity to effects.

Environmental Effects - Impacts on the environment can vary depending on the chemical make-up but, mostly, PM can cause changes to soil and water chemistry. This can adversely impact organisms and vegetation. PM2.5 can stain and damage stone and other materials, including culturally important objects such as statues and monuments. PM2.5 also contributes to reduced visibility, which affects cities, airports, and wilderness areas, and can negatively impact tourism and the economy.

Health Effects - Exposure to SO2 can have negative impacts on respiratory health, including reduced lung function, increased respiratory symptoms, and airway inflammation. Persons with asthma, about 9% of the Canadian population, are especially vulnerable, along with sensitive populations such as children and those with pre-existing respiratory disease. Effects can also include increased emergency room visits and hospitalizations for respiratory causes.

Environmental Effects - SO2 can affect ecosystems both directly and indirectly, and contributes to the formation of PM2.5. Direct effects occur when plants absorb the SO2 through their leaves. Indirect effects occur when sulphur-containing compounds, like the sulfuric acid in acid rain, are deposited onto soil and water. Once absorbed by the plant, SO2 can interfere with photosynthesis and energy metabolism, and can cause decreased plant growth and yield. SO2 can damage materials and structures including objects of cultural importance like statues and monuments.

Health Effects - Short-term exposure to NO2 can elicit a range of adverse respiratory effects including decreased lung function, increased respiratory symptoms, and airway inflammation, and cause aggravation of respiratory diseases, particularly asthma and chronic obstructive pulmonary disease. Long-term exposure to NO2 may contribute to allergic responses, asthma development and may increase susceptibility to respiratory infections. Inhalation of NO2 has also been linked to effects on the cardiovascular system, and some reproductive effects.

Environmental Effects - NO2 can affect ecosystems both directly and indirectly and contributes to the formation of ozone. Direct effects occur when plants absorb the NO2 through their leaves, which can lead to lesions and dead tissue, and to altered plant growth and yield. Indirect effects occur when NO2 (and other NOx) reacts with water and oxygen to form acid rain, or when an overabundance of nitrogen adversely affects an ecosystem.

Health Effects - Adverse health effects from exposure to VOCs depends upon the nature of the chemical, the level of exposure, and the length of exposure. Many substances included in this grouping have little effect on health. For those that do, the effects can vary greatly, from irritation (eye, nose and throat), headaches, nausea, dizziness, and the worsening of asthma symptoms, to more severe effects like damage to the liver, kidneys, and central nervous system. Some VOCs, like benzene, are carcinogens, and long-term exposure to them can increase the risk of developing cancer.

Environmental Effects - VOCs contributes to the formation of PM 2.5  and O3, which are the main ingredients of smog. Smog reduces visibility in many areas, including cities, airports and wilderness areas and can negatively impact tourism and the economy. PM 2.5 and O3 can adversely affect vegetation by damaging leaves, reducing photosynthesis, impairing reproduction and growth, and decreasing crop yields.

CAAQS

 

CCME developed Canadian Ambient Air Quality Standards (CAAQS) for PM2.5, O3, SO2 and NO2. All CAAQS consist of three interrelated elements:

  • an averaging time period
  • a numerical value
  • the statistical form of the numerical standard.

 

Pollutant Averaging Time Numerical Value Statistical Form
2015 2020 2025
Fine Particulate Matter (PM2.5) 24-hour

28

μg/m3

27

μg/m3

  The 3-year average of the annual 98th percentile of the daily 24-hour average concentrations
Annual

10.0

μg/m3

8.8

μg/m3

  The 3-year average of the annual average of all 1-hour concentrations
Ozone (O3) 8-hour

63

ppb

62

ppb

  The 3-year average of the annual 4th highest daily 8-hour average concentrations
Sulphur Dioxide (SO2) 1-hour -

70

ppb

65

ppb

The 3-year average of the annual 99th percentile of the SO2 daily maximum 1-hour average concentrations
Annual -

5.0

ppb

4.0

ppb

The average over a single calendar year of all 1-hour average SO2 concentrations
Nitrogen Dioxide (NO2) 1-hour -

60

ppb

42

ppb

The 3-year average of the annual 98th percentile of the daily maximum 1-hour average concentrations
Annual -

17.0

ppb

12.0

ppb

The average over a single calendar year of all 1-hour average concentrations

Air Zones and Airsheds

 

Air zones and airsheds are used to manage air quality at the local and regional levels respectively.

The smaller geographic areas within provinces and territories are air zones. The larger areas outlined by the black lines are airsheds.

Tip

Mouse over the map to highlight the air zone names.

Click on an air zone to open that region’s website (in a new tab).

Click and scroll on the map to zoom in or out.

Click and drag on the map to move it around

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CAAQS Management Levels

 

CAAQS are supported by four colour-coded Management Levels. Each management level is determined by the amount of a pollutant within an air zone and provides recommended air quality management actions. If the amount of a pollutant within an air zone increases, the management actions become more stringent. This helps ensure that CAAQS are not treated as pollute-up-to levels and actions will be taken to keep clean areas clean.

 

When determining the CAAQS management levels, provinces and territories can consider the influence of human activities originating outside of the province or territory and of exceptional events such as forest fires.

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Scroll the table to the right to see other pollutants 

Air quality management levels

Management Levels for the Ozone CAAQS (parts per billion) Management Levels for the Annual Fine Particulate Matter CAAQS (micrograms per cubic metre) Management Levels for the 24-hour Fine Particulate Matter CAAQS (micrograms per cubic metre) Management Levels for the 1-hour Sulphur Dioxide CAAQS (parts per billion) Management Levels for the Annual Sulphur Dioxide CAAQS (parts per billion) Management Levels for the 1-hour Nitrogen Dioxide CAAQS (parts per billion) Management Levels for the Annual Nitrogen Dioxide CAAQS (parts per billion)
2015 2020 2015 2020 2015 2020 2020 2025 2020 2025 2020 2025 2020 2025
Red
>63 >62 >10.0 >8.8 >28 >27 >70 >65 >5.0 >4.0 >60 >42 >17.0 >12.0
Orange
>56 and ≤63 >56 and ≤62 >6.4 and ≤10.0 >6.4 and ≤8.8 >19 and ≤28 >19 and ≤27 >50 and ≤70 >50 and ≤65 >3.0 and ≤5.0 >3.0 and ≤4.0 >31 and ≤60 >31 and ≤42 >7.0 and ≤17 >7.0 and ≤12
Yellow
>50 and ≤56 >4.0 and ≤6.4 >10 and ≤19 >30 and ≤50 >2.0 and ≤3.0 >20 and ≤31 >2.0 and ≤7.0
Green
≤50 ≤4.0 ≤10 ≤30 ≤2.0 ≤20 ≤2.0

CAAQS Achievement

 

This map shows CAAQS achievement across Canada (use drop-down menu to select the pollutant).

  • Blue areas = air zones that achieved the 2015 CAAQS.
  • Red areas = air zones that exceeded the 2015 CAAQS.
  • White areas = insufficient data to determine achievement.

Achievement of the CAAQS means that the measured air pollutant concentration in an air zone does not exceed the CAAQS numerical value.

Tip

Select the pollutant of interest from the drop down menu. Mouse over the map to highlight the air zone names. Click on an air zone to open that region’s website (in a new tab). Scroll on the map to zoom in or out. Click and drag on the map to move it around.

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Improving our air quality benefits Canadians

Between 2000 and 2011, added across all Canadians there were 11 million fewer days with breathing problems and 5.7 million fewer days on which someone restricted their activity (i.e. stayed indoors, didn’t go to work) due to health problems made worse by air pollution.

Click here for more information.

Sources of Pollutant Emissions in 2015

 

Emissions of air pollutants come from human activities and natural causes. This chart presents emissions from human-activities only. Percentages are measured against a Canada-wide total which excludes open sources (like road dust) and natural sources (like forest fires).

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Ambient Trends by Pollutant

 

The ambient air we breathe contains air pollutants at various concentrations. This graph shows Canada-wide average concentrations by pollutant and year.

There is a strong relationship between ambient concentrations and the pollutant emissions shown on the next page.

 

Source: National Air Pollution Surveillance (NAPS) program data products, 2017

Tip

Use the drop down menu to select a pollutant. Mouse-over the graph to see the CAAQS value (red line) and the year-by-year ambient concentrations.

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Emission Trends by Source

 

This chart shows pollutant emissions from key sectors for each pollutant (use the drop down menu to select a pollutant).

 

 

 

Source: Environment and Climate Change Canada, 2017. Air Pollutant Emission Inventory 

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Pollutant Emissions by Province and Territory

 

Emissions vary by source and by province and territory. Overall emissions are decreasing across Canada.

 

The emission trends were compiled by Environment and Climate Change Canada and may differ from those compiled by provinces and territories.

 

 

Source: Environment and Climate Change Canada, 2017. Air Pollutant Emission Inventory, 

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Acid Rain

 

Acid deposition, commonly referred to as acid rain, continues to damage Canadian ecosystems. Acidification of lakes and streams makes the water unsuitable to support some fish and other plants and animals. Acid deposition damages forest soils by stripping the soil nutrients and increasing the release of toxic chemicals such as aluminium, as well as directly damaging some sensitive tree species.

In October 1998 all energy and environment ministers signed The Canada-Wide Acid Rain Strategy for Post-2000. The Strategy is a framework to address the problem of acid deposition. Additional resources can be found here.

Regular reporting on SO2 and NO2 emissions and forecasts and progress in implementing The Strategy is required. Similar information can be found in the biennial Canada – United States Air Quality Agreement progress report.

The animated map on the right shows wet nitrate deposition in Canada and the United States from 1982 to 2012. Wet nitrate deposition is measured in kilograms of nitrate per hectare per year (kg NO3- ha-1 yr-1). The dots in western and northern Canada show the deposition levels measured at individual monitoring stations. There are an insufficient number of stations in this region of Canada to produce contours like those shown in eastern Canada and the USA.

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Improving our air quality benefits Canadians

 

Canadians have already benefited from actions to improve air quality. Between 2000 and 2011, fine particulate matter, a main pollutant in smog, declined in many parts of Canada, particularly in Ontario and Quebec. The improved air quality in 2011 is estimated by Health Canada1 to have prevented:

  • 4,100 deaths,

  • 2200 hospital visits,

  • 770,000 asthma events.

There were also 11 million fewer instances where Canadians experienced breathing symptoms and 5.7 million fewer occasions where someone restricted their activity by, for example, not attending work or school due to health problems made worse by air pollution.

A number of actions contributed to the reduction of fine particulate matter and other air pollutants in Canada such as improved emission standards for vehicle engines and fuels, and better controls of air pollutant emissions from industrial sources such as power plants.

 

Stieb, David M. et al. Estimated public health impacts of changes in concentrations of fine particle air pollution in Canada, 2000 to 2011. Can J Public Health ,[S.I.], v. 106, n. 6, p., e362-e368, jun. 2015. ISSN 1920-7476

Air Quality Actions

 

Canadians can take action in their everyday lives to improve air quality. These actions can range from selecting your means of transportation; to actions at home or at the office; to modifying your purchasing habits. Click on the icons below for practical suggestions. You can find more tips and information if you search the web for local programs and environmental organizations in your part of Canada.

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Click on a graphic for more information.

Air Quality Actions

 

Canadians can take action in their everyday lives to improve air quality. These actions can range from selecting your means of transportation; to actions at home or at the office; to modifying your purchasing habits. Click on the icons below for practical suggestions. You can find more tips and information if you search the web for local programs and environmental organizations in your part of Canada.

Tip

Scroll right to see how you can improve the air quality, and click on a graphic for more information.