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Air pollution

Air pollution is chemicals, particles and other materials in the air in amounts that could damage the environment or harm the health or comfort of humans, animals, and plants. 

  • How you’re exposed to air pollution

    Outdoor air pollution
    The air outside can be polluted in many ways. Major sources of outdoor air pollution include:

    • transportation (mainly from gasoline and diesel engines)   
    • power generation (such as smoke from coal-burning power plants)
    • emissions from industrial plants
    • emissions from agricultural processes (such as from animals and soil management)
    • emissions from residential heating and cooking
    • natural events such as forest fires

    Most types of outdoor air pollution are a mixture of many harmful substances, including particulate matter (small particles in the air), sulphur oxides, carbon monoxide, nitrogen oxides, volatile organic compounds (VOCs), benzene and polycyclic aromatic hydrocarbons (PAHs). Ground-level ozone, another harmful substance, is formed from a combination of pollutants.

    Air pollution in your community can be affected by:

    • some types of local businesses
    • local traffic patterns (vehicle type and traffic density)
    • whether you live in an urban or rural location
    • geography (for example, valleys versus plains)
    • weather patterns (for example, wind direction)

    Indoor air pollution
    Air inside your home can also be polluted. Major sources of indoor air pollution include:

    • second-hand smoke
    • radon
    • indoor burning of coal or wood
    • chemicals from household products (such as paint or cleaning products)
    • biological pollutants that come from living organisms (such as mould or dust mites)
  • Air pollution and cancer

    Air pollution makes existing lung disease and heart problems worse. It has also been linked to certain cancers.

    The International Agency for Research on Cancer (IARC) classifies types of air pollutants based on their link with cancer. For example, gasoline engine exhaust is classified as a possible cancer-causing substance. Radon, diesel engine exhaust and outdoor air pollution are known to cause cancer and are classified as known carcinogens. IARC has also classified individual components of air pollution as known carcinogens. These components include particulate matter, some volatile organic compounds (such as benzene) and certain PAHs (such as benzo[a]purene). Find out more about how cancer-causing substances are classified.

    We know that smoking is the main cause of lung cancer in Canada. There is now strong evidence that outdoor air pollution also causes lung cancer. The risk for lung cancer increases with more exposure to air pollution and particulate matter. Researchers have also found that radon gas in indoor air can lead to lung cancer.

    A recent review of evidence found a link between outdoor air pollution and an increased risk of bladder cancer.

    More research is needed to study the link between cancer and other components of air pollution, such as nitrogen oxides and sulphur oxides.

  • Tips to reduce your exposure
    Outdoor air pollution

    You can reduce your exposure to air pollution. Check daily air quality levels and air pollution forecasts in your area. This information is usually provided with your weather forecast as the Air Quality Health Index. Follow the advice given with the forecast. Try to plan strenuous outdoor activities at times when the air quality is best, especially if you’re sensitive to air pollution. Try to avoid exercising near areas where traffic is heavy.

    You can also lower your own contribution to air pollution. You can do this by using public transportation, cycling and walking instead of driving. If you have to drive, avoid idling your vehicle. You can also reduce the amount of heating and cooling that your home needs by making sure it is properly insulated.

    Indoor air pollution

    You can reduce indoor air pollution by getting rid of the source of the pollutant and lowering indoor emissions. Most importantly, don't allow smoking indoors or in vehicles.

    Test your home for radon. Take steps to reduce radon levels in your home, if necessary. Hire a certified radon professional to make sure the radon levels in your home are effectively reduced. Make sure that fuel-burning appliances are properly installed and ventilated, working properly, well maintained and inspected regularly.

    Ensure adequate ventilation. Ventilation increases the amount of outdoor air that comes inside. It removes stale indoor air and reduces indoor air pollutants.

    Switch from a coal- or wood-burning heat source to an electric, natural gas or oil heat source. If you cook or heat with coal or wood, minimize your risk by using efficient stoves and fireplaces with effective chimneys. Rather than high-temperature frying, use lower-temperature cooking methods (such as steaming, boiling, poaching, stewing, casseroling or braising).

    Consider using an air cleaner, which removes particles from the air. Unfortunately, most air cleaners are not very good at removing gases. That’s why controlling the source of indoor air pollution and having good ventilation are much better options for improving indoor air quality.

    Do not idle your vehicle or run other fuel-burning engines in a closed garage or workshop.

  • Suggested links for more information

    General information about outdoor air pollution
    Learn more about sources of outdoor air pollution, potential health effects, and how you can protect yourself and take steps to protect the air around you.

    Health Canada – Outdoor air
    The Canadian Lung Association – Outdoor air quality
    Health Canada – Road traffic and air pollution
    Health Canada – Smog and your health
    Environment Canada – Particulate matter
    CAREX Canada – Carcinogen profile: diesel engine exhaust
    CAREX Canada – Carcinogen profile: polycyclic aromatic hydrocarbons (PAHs)
    CAREX Canada – Carcinogen profile: particulate air pollution

    General information about indoor air pollution
    Learn more about sources of indoor air pollution, potential health effects, and how you can protect yourself.

    The Canadian Lung Association – Indoor air quality
    Health Canada – Indoor air pollutants

    Tracking air quality
    Use these tools to inform and protect yourself when air quality in your environment is polluted.

    Environment Canada – Air quality health index
    Environment Canada – National Pollutant Release Inventory (NPRI)
    Canadian Institute for Environmental Law and Policy – A citizen’s guide to the National Pollutant Release Inventory (PDF)

    Taking action against air pollution
    Find out what measures individuals, industry, government and other bodies are taking to combat air pollution and how you can get involved.

    Environment Canada – Take Action for the Environment – Air
    Environment Canada – Reducing emissions from diesel-fuelled buses
    Canadian Public Health Association – Resource development to raise awareness about the health effects of air pollution



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