Improve indoor air quality in your home

Poor indoor air quality can affect your health. The most effective way to improve your indoor air is to identify activities that can contribute to poor indoor air quality and remove or reduce the sources of indoor air pollutants.

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Sources of indoor air pollution and how to reduce exposure


Cigarette smoke emits a wide range of chemicals, such as:

To improve your indoor air quality, make your home smoke-free by banning all use of tobacco products indoors.

Attached garage

Idling your car, starting your gas-powered lawnmower or snowblower, operating a generator or using a barbecue inside your garage can produce pollutants that can infiltrate into the home, including:

These pollutants can enter the home when the garage door is open or closed. Avoid idling your car, gas-powered lawnmower or snowblower in your garage.

Fuel-burning equipment and improperly sealed fuel containers can emit volatile organic compounds through off-gassing. Store equipment and containers in a shed or other location not attached to the house.

If you have a door between your house and an attached garage, keep the door closed and make sure it is well sealed.


Whether you cook on an electric or gas stove, cooking can generate indoor air pollutants. Cooking methods like frying emit more particles than others, boiling can also increase humidity levels, gas stoves also produce gases and ultrafine particles. Using your range hood, could decrease the amount of pollutants like:

Cooking on the back burner and using the range hood, preferably on the high setting, will help lower humidity and reduce particles and gases by more than 80% when compared to slower speeds. For your fans to be effective, make sure:

  • nothing is placed in front of outside vents
  • to check the fans to make sure there is enough air movement
  • they fully extend over the stove burners

For more information: Cooking factsheet

Mould, dampness and water leaks

  • Areas where stagnant water builds up or damp places like showers and basements are ideal environments for biological pollutants like bacteria, mould, and fungi.
  • High humidity, leaks, water infiltration and flooding can cause mould to grow indoors.
  • To prevent mould, fix any moisture problems immediately and control humidity levels in your home. Relative humidity should be maintained at 30-50%
  • If you already have mould, small amounts can be cleaned up right away using soap and water. If you have a large amount of mould, you may need to consider hiring a professional.
  • In case of a flood, immediate action is important. Your house and furnishings are less likely to grow mould if they are dried within 48 hours. For more information, see Flood cleanup.

Mould infographic
Relative humidity indoors
Cleaning and preventing mould


Appliances like gas and wood fireplaces, gas or wood stoves, gas or oil furnaces and gas water heaters can emit:

Make sure fuel-burning appliances are installed, maintained and working according to manufacturers' instructions. Ensure you have at least one working certified carbon monoxide alarm in your home adjacent to sleeping areas.

Have a qualified professional inspect them yearly, including chimneys and flues.

Renovations and home improvement

Building materials can release gases and other contaminants into the air such as:

These materials include:

  • glues
  • flooring
  • solvents
  • insulation
  • wood products
  • paints and varnishes

When conducting renovations and working with building materials, follow the manufacturer's instructions for installation and use.

  • When renovating, open the windows.
  • Make sure there is enough ventilation during major projects like:
    • painting
    • cleaning
    • varnishing
    • home improvement

Household items and furniture

Household items can release gases such as volatile organic compounds (VOCs) , including formaldehyde, into the air in your home. Some items can also produce particles. Items that can release gases or particles include:

  • carpets
  • cleaning products
  • candles and incense
  • furniture and cabinets
  • personal care products

Carpets, fabric, foam chair cushions, pillows and mattresses can also attract dust mites. These mites produce allergens.

Increasing ventilation in your home can reduce the indoor levels of pollutants produced by household items and furniture. Consider selecting low-emission cleaning products, and limit the use of candles and incense.


Different hobbies can release gases and particles. Hobbies that can contribute to indoor air pollution include:

  • carving
  • woodworking
  • arts and crafts

Make sure that you work in a well-ventilated area when participating in hobbies that produce air pollutants.

House cleaning and laundry

Cleaning and laundry activities can produce particles and can increase the amount of moisture in the air. Methods to help reduce the impact of cleaning and laundry activities on indoor air include:

  • clean floors with a damp mop or cloth
  • vacuum often:
    • install a central vacuum that is vented outdoors, or is equipped with a high-efficiency particle air (HEPA) filter that traps small particles
    • if using a portable vacuum, it should be equipped with a HEPA filter
  • use a mattress and pillow protector, vacuum mattresses and wash sheets once a week in hot water to protect from dust mites
  • hang laundry outdoors to dry when possible
  • make sure your dryer vents to the outside and is not blocked
  • clean the lint tray every time you use the dryer and check for lint build-up on the outside vent

Regular cleaning can help improve indoor air quality.

Ventilation as a way to improve indoor air quality

Ventilation describes the movement of air into or out of homes and proper ventilation is a key component of good indoor air quality. Ventilation can help improve indoor air quality by removing pollutants from the home and by bringing in fresh air from outside. This is especially important when renovating or when using chemical products in the home.

Benefits of good ventilation

Improving ventilation in your home

Ventilation and the indoor environment

Ventilation helps protect against the spread of COVID-19

Air cleaning and filtering

Filtering the air can reduce some indoor air pollutants. But air cleaning is rarely effective on its own, and should be used alongside:

  • improving ventilation
  • reducing contaminants at the source

Portable air cleaners (also known as air purifiers), particularly high-efficiency particle air (HEPA) filters and electrostatic precipitators, can reduce levels of some air contaminants. HEPA filters collect particle pollutants with a fine filter. But electrostatic precipitators collect pollutants with electrostatic energy, which causes pollutants to stick to the filter.

Some air cleaners with electrostatic precipitators may also produce low levels of ozone, which can irritate the lungs. Ozone generators are sometimes marketed as air cleaners, but they are not recommended in homes.

Air cleaners can be effective in removing particles but most do not remove gases.

Choosing a portable air purifier

Testing air quality in your home

How to keep your home safe from these common indoor air pollutants.


Test your home for radon. Radon is a radioactive gas that comes from the breakdown of uranium in soil and rock. It can’t be seen, tasted or smelled.

Radon can accumulate to high levels and become a risk to your health in enclosed spaces, like your home.

Radon: About, health effects and testing your home

Carbon monoxide

Install carbon monoxide detectors. Every home should have smoke and carbon monoxide detectors on each floor, beside each sleeping area

Carbon monoxide is a gas that can’t be seen, tasted or smelled. It can only be detected with a certified carbon monoxide detector.

Other pollutants

Other pollutants, such as mould and chemicals, are difficult to measure correctly and the results are hard to interpret. Testing for these pollutants will not always tell you whether there’s a risk for your health or how to fix the issue.

The best ways to improve your indoor air quality are to address sources of indoor air pollution and improve your home’s ventilation.

Awareness resources

Search our list of air quality awareness resources to learn more about indoor air pollutants and how to improve indoor air quality.

Related links

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