Air pollution: drivers and impacts

Air pollutionFootnote 1 can affect Canadians' health, the environment, buildings, structures and the economy. Air pollution problems such as smogFootnote 2 and acid rain result from the presence of, and interactions among, various air pollutants released to the atmosphere through natural processes and human activities.

Natural sources of air pollution include forest fires, volcanoes and emissions of volatile organic compounds (VOCs) from vegetation. Human sources of air pollution include activities that rely on carbon-based fuels (for example, transportation, off-road vehicles and mobile equipment, electric utilities), industrial processes such as oil and gas production, as well as certain products, such as paints and solvents.

Key drivers of air pollution

Outdoor air pollutant concentrations can be influenced by many factors. These include the quantity of air pollutants released by sources, the distance from the sources, and meteorological conditions such as air temperature, the stability of the air, wind speed and direction. Some air pollutants can be carried by the wind and affect the air quality in locations which are hundreds to thousands of kilometres away from the sources.

The growth in Canada's population and economy increases the demand for the production and delivery of goods and services, transportation and housing. Most of the energy used to meet this demand still comes from fossil fuels, which impacts the quality of the air we breathe. Economic growth includes a growing demand for Canadian exports (especially from the oil and gas industry) that also results in releases of air pollutants.

Despite this growth in demand, the quantity of emissions of many air pollutants has generally decreased in Canada in the past two decades. These reductions were achieved through various means, including the implementation of regulations, non-regulatory instruments, and technological improvements for transportation vehicles and industrial processes. The adoption of more environmentally sustainable practices by consumers and industry, such as using public transit and carpooling, and optimizing production processes to reduce energy use, have also contributed to the decrease.

Consult the Air pollutant emissions indicators for more information on the key sources contributing to air emissions by pollutant.

Key impacts of air pollution

Human health impacts

  • Globally, exposure to air pollution is a major cause of illness and even death. As a result of exposure, an estimated 4.2 million premature deaths occur every year from outdoor air pollution.Footnote 3 In Canada, air pollution is linked to an estimated 15 300 premature deaths every year.Footnote 4 
  • Exposure to nitrogen oxides (NOX) and sulphur oxides (SOX) can irritate the lungs, reduce lung function and increase susceptibility to allergens in people with asthma. Both NOX and SOX are also precursors of fine particulate matter (PM2.5), and contribute to the formation of smog and acid rain.
  • Fine particulate matter and ground-level ozone (O3) are the main components of smog and they have been associated with eye, nose and throat irritations, shortness of breath, exacerbation of respiratory conditions and allergies, chronic obstructive pulmonary disease and asthma, increased risk of cardiovascular disease and premature death.Footnote 5 The young, the elderly, those with acute illnesses and those living near cities are at greater risk.
  • Carbon monoxide (CO) is a product of incomplete combustion of hydrocarbon-based fuels. It can have a significant impact on human health by entering the blood stream through the lungs inhibiting the blood's capacity to carry oxygen to organs and tissues. CO is particularly harmful to persons with heart disease and individuals with respiratory conditions. It can also affect healthy individuals, impairing exercise capacity, visual perception, manual dexterity, learning functions, and ability to perform complex tasks.Footnote 6
  • Ammonia (NH3) is a colourless gas mostly generated from livestock waste management and fertilizer production. It is poisonous if inhaled in great quantities and is irritating to the eyes, nose, and throat in lesser amounts.Footnote 7

Environmental impacts

  • Ground-level ozone (O3) can reduce the growth and productivity of some crops, injure flowers and shrubs and may contribute to forest decline in some parts of Canada.Footnote 8 Ecosystem changes can also occur, as plant species that are more resistant to O3 can become more dominant than those that are less resistant.Footnote 9 
  • Various particulate matter constituents taken up by plants from the soil can reduce plant growth and productivity by interfering with photosynthesis and can cause physical damage to plant surfaces via abrasion.Footnote 7 
  • Nitrogen oxides (NOX) and SOX can cause or accelerate the corrosion and soiling of materials and are major contributors to acid rain. Acid rain affects soils and water bodies, and stresses both vegetation and animals. The interactions between acid rain, ultraviolet (UV) radiation and climate change can magnify the impacts of acid rain.Footnote 10 
  • Emissions of mercury and other hazardous pollutants work in synergy with sulphur dioxide (SO2) and NOX to worsen the harmful effects of acid deposition on fish and wildlife. Increasing acidity of water bodies increases the rate of conversion of mercury into its more toxic form methyl mercury (MeHg) that can build up in fish and shellfish and ingested by humans and wildlife.Footnote 5 
  • Ammonia (NH3) can contribute to the nitrification and eutrophication of aquatic systems  leading to the premature aging of water bodies from excessive plant growth. As the plant material decays, it can reduce the amount of oxygen available for fish and other aquatic animals and degrade the quality of the water. 

Economic impacts

  • The health effects of PM2.5 and O3 can impose economic costs from lost productivity, increased need for medical care, decreased quality of life and increase the risk of premature death. The total economic valuation of the health impacts attributable to air pollution in Canada is $120 billion dollars per year.Footnote 4 
  • Increased O3 levels also reduce the growth of crops, plants and trees, leading to economic losses in agriculture and forestry. This costs Canadian farmers millions of dollars in lost production each year.Footnote 11 
  • Smog can accelerate the discolouration, fading and tarnishing of materials (for example, rubbers, textiles, surface coatings), increasing the rate at which they need to be replaced or cleaned.Footnote 9

Ways to tackle air pollution

To help reduce overall air pollution levels:

  • When possible, instead of taking a car, use public transportation, walk or ride a bicycle when and where it is safe to do so
  • Look for alternatives to fossil fuel-powered machines and vehicles such as hybrid or zero-emission vehicles. Choose to use a push-type lawnmower instead of one that runs on gasoline
  • Consider fuel efficiency when buying a vehicle. Keep all vehicles well maintained to ensure they operate efficiently
  • Reduce energy use by making your home more energy efficient. Keep gas-, oil- and wood-burning stoves, heaters and appliances in good condition or replace them with newer cleaner burning models. Turn off the lights when leaving a room and unplug electronics when not in use
  • Buy products that are low in, or free from, volatile organic compounds or other contaminants
  • Plant trees and a variety of vegetation to increase the urban forest canopy, biodiversity, provide shade and improve air quality
  • Rethink consumer behaviours by differentiating your needs and your wants; refuse, reduce, reuse, repair and finally recycle the goods you consume

To reduce your exposure to air pollution and its potential health effects:

  • Check the Air Quality Health Index forecast for your community and adapt your schedule accordingly
  • Avoid or reduce strenuous outdoor activities when smog levels are high. Consider indoor activities instead
  • Avoid or reduce exercising near areas of heavy traffic, especially during rush hour
  • Take special precautions if there is smoke from a wildfire affecting your community
  • Keep your medication with you if you suffer from heart or respiratory problems
  • Talk to your family doctor or a health care professional if you have concerns about your health or the health of a family member

The Federal Sustainable Development Strategy is the Government of Canada's primary vehicle for sustainable development planning and reporting. It sets out the Government's sustainable development priorities, establishes goals and targets, and identifies actions to achieve them. The 2019 to 2022 Strategy, Canada's fourth, outlines the actions toward sustainability that the Government will take in collaboration with partners within Canada and internationally, including actions related to tackling air pollution.

The Government of Canada is taking action to help reduce the overall levels of air pollution. Releasing pollutants into the atmosphere is subject to a number of regulations developed and implemented under the authority of the Canadian Environmental Protection Act, 1999. The regulations aim to limit the amount of pollutants that are released into the air each year.

The Government of Canada has put in place regulations to phase out coal-fired electricity, adopted the most stringent national standards in the world for air pollutant emissions from new cars and light trucks, and put a price on carbon pollution that is creating incentives for industry to invest in cleaner technologies.

In 2016, as part of the federal government's contribution to the implementation of the Air Quality Management System, the Government of Canada introduced the Multi-sector Air Pollutants Regulations, which establish Canada's first ever mandatory national air pollutant emissions standards for major industrial facilities. The federal government also published a suite of non-regulatory instruments to reduce air pollutants from a number of industrial sectors and equipment types. The Government of Canada continues to work with provinces, territories and stakeholders to set more stringent Canadian Ambient Air Quality Standards (CAAQS, the standards) to drive air quality improvements across the country. More stringent standards for PM2.5 and O3 were established in 2013, with an effective year of 2015 and 2020. A new standard for ozone with an effective year of 2025 was established in 2019. Standards for sulphur dioxide (SO2) and nitrogen dioxide (NO2) were established in 2017 for 2020 and 2025. The PM2.5 standard is currently under review. The regulations and standards will contribute to reducing emissions of air pollutants and further protect human health and the environment for Canadians.

To learn more about the expected impact of regulations developed by the Government of Canada, consult the Regulatory Impact Analysis StatementFootnote 12 that accompanies each regulation. The statements outline the reasoning behind the development of a particular regulation, its objectives, and its expected costs and benefits. They also include details about consultations that were conducted and about how the government intends to track the performance of the regulation.

Related indicators

The Air health trends indicator provides an overview of the public health impacts attributable to outdoor air pollution in Canada.

The Air quality indicators track ambient concentrations of PM2.5, O3, SO2, NO2, and VOCs at the national and regional level and at local monitoring stations.

The International comparison of urban air quality indicators present and compare the air quality in selected Canadian urban areas with a population greater than one million to the air quality in selected international urban areas having comparable data.

The Air pollutant emissions indicators track emissions from human activities of 6 key air pollutants: SOX, NOX, VOCs, NH3, CO and PM2.5. Black carbon, which is a component of PM2.5, is also reported. For each air pollutant, data are provided at the national, provincial/territorial and facility level and by major source.

The International comparison: air pollutant emissions in selected countries indicators compares Canada's emissions of 5 key air pollutants with those of top member countries of the Organisation for Economic Co-operation and Development.

The Human exposure to harmful substances indicators track the concentrations of 4 substances (mercury, lead, cadmium and bisphenol A) in the Canadian population.Footnote 13

The Emissions of harmful substances to air indicators track human-related emissions to air of 3 toxic substances, namely mercury, lead and cadmium and their compounds. For each substance, data are provided at the national, regional (provincial and territorial) and facility level and by source. Global emissions to air are also provided for mercury.

The Population exposure to outdoor air pollutants indicator tracks the proportion of the Canadian population living in areas where outdoor concentrations of air pollutants are less than or equal to the 2020 Canadian Air Ambient Quality Standards.

Other information

Related regulations

Regulations specific to air pollutants under the Canadian Environmental Protection Act, 1999 (the act) include, but are not limited to, the following:

All regulations administered under the act are available in the registry.

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