Smoking, burning items, ventilation, microorganisms and certain pollutants affect indoor air quality.

Most people spend the majority of their time indoors. The quality of the indoor air we breathe can affect our health.

The best way to improve indoor air quality is to reduce or remove sources of pollutants and provide good ventilation. See HealthLink BC's indoor air quality resource for more information.

Factors that affect indoor air quality include:

  • Gases like carbon monoxide and radon.
  • Particulate matter from cigarette smoke and burning items.
  • Microorganisms. Examples include mould, bacteria and dust mites.
  • Temperature and humidity.

See Health Canada’s webpage for more information.

Indoor air quality at work

WorkSafeBC is responsible for the safety of all employees within the province of B.C.

Indoor air quality at home


Radon is a colourless, odourless, tasteless gas that comes from soil and rocks. Radon soil levels vary across Canada. You can view this radon map to see the levels in B.C. Radon can build up in your home to hazardous levels. Radon is the second leading cause of lung cancer globally.

You can take action to mitigate radon exposure in your home. Radon levels vary house-to-house, even between next door neighbours. The only way to know the radon level in your home is to test it.

Since people spend as much as 75% of our time at home, it’s a good idea to test your home for radon. Testing should be done in the winter when windows are closed and the best tests are long-term tests that take as least three months. A testing kit is easy to use and costs about $40. For home owners interested in testing their houses, kits are available from the BC Lung Association website or call 1-800-665-LUNG (5864). Radon testing kits can be purchased at hardware stores.

If elevated radon levels are found, basic measures can be taken to address the problem, such as installing a venting system to direct the radon gas to the outdoors where the gas can be diluted to safe levels.

Resources for Radon


Moulds are fungi naturally found both indoors and outdoors. Warm and moist conditions promote mould growth. Mould is often not dangerous; however, it can cause allergic reactions and illness in people with pre-existing conditions or weak immune systems. Some studies have found increases in common symptoms such as coughing, wheezing and headaches in people who live in homes with dampness and visible mould.

See HealthLink BC’s page on preventing mould.

Related resources


Asbestos is a mineral used for its insulating properties. It is in certain vinyl floor tiles, soundproofing ceiling tiles, roof shingles, insulation, drywall and other materials. If inhaled, asbestos can cause cancer and other illnesses. You can be exposed to asbestos when a building is being renovated or demolished. You can also be exposed during car maintenance. Asbestos can cause cancer and other diseases. Always hire a professional to test for it if you are renovating or repairing a building.

Related resources

Carbon Monoxide

Carbon monoxide (CO) is a colourless, odourless, tasteless gas that comes from burning fuel. It can cause illness and death. Risk is greatest during winter as heating appliances like furnaces are used more. These can release carbon monoxide if not properly maintained. Poor ventilation around gas-powered cooking devices or cars can also increase risk.

People with health problems, such as heart and lung disease, are at greater risk for harm. Infants, children, pregnant people and older adults are also at greater risk.

  • Have your furnace and fireplace cleaned and checked before each heating season.
  • Only use fuel-burning space heaters in well-ventilated areas. Electrical space heaters pose no danger of CO poisoning, unlike those that burn fuels, such as kerosene.
  • Do not start or leave cars, trucks or other vehicles running in an enclosed area, such as a garage, even with the outside door open.
  • Do not use portable heaters or lanterns while sleeping in enclosed areas, such as tents, campers and other vehicles. This is even more important at high altitudes, where the risk of CO poisoning is increased.
  • When using a gas-powered generator for electricity, be sure to keep it a safe distance away from the home.
  • Install CO detectors in your home to warn you if CO levels begin to rise.
  • Ensure heating vents are kept clear of snow.
  • If your home loses power due to a storm, do not use fuel-burning appliances indoors to warm your home; go to a warming centre instead.

Seek medical attention right away if you think you or a member of your family has CO poisoning.

Signs and symptoms of CO poisoning may include:

  • Dull headache
  • Weakness
  • Dizziness
  • Nausea or vomiting
  • Shortness of breath
  • Confusion
  • Blurred vision
  • Loss of consciousness

CO poisoning can be particularly dangerous for people who are sleeping or intoxicated.

Related resources

Poor indoor air quality from combustion

When we burn any fuel, such as wood, natural gas, propane, kerosene, charcoal or tobacco, it can make pollutants and particles that are harmful to our health.

We do not always think of the pollutants that are created when we cook or heat our homes, but wood stoves and gas appliances can create indoor air pollution. Natural gas and propane can also release carbon monoxide and other harmful chemicals into the air which can harm people and pets.

The best ways to improve air quality are to control sources and have proper ventilation.

To control sources:

  • Follow the manufacturers’ instructions for all combustion appliances.
  • Regularly service and clean appliances and vents such as chimneys.
  • Use only fuels recommended for each appliance.
  • Make sure that wood stoves are installed and maintained correctly. Doors should be tight fitting to prevent leakage.
  • Use only aged or dried wood, not pressure treated or painted wood that may form more toxic compounds when burned.
  • Inspect furnace and flues, and repair cracks and damaged parts. Open the flue when using your fireplace. Do not let a fire within a wood heater smolder, especially just before opening the firebox.
  • Change your furnace and air conditioning filters every couple of months if using them often. Consider using a more effective furnace filter.
  • Never allow smoking in or near the home.
  • When you are cooking, cook on the back burners where possible.

Improve ventilation

  • Use a stove hood and fan that vents outside when cooking with gas stoves and ranges.
  • When you need to replace a space heater, buy a vented heater.
  • Make sure enough fresh air gets into your home from the outdoors, especially when using combustion appliances.
  • Make sure fresh air intake vents are not blocked or covered.
  • Do not have air intake vents coming into your home from your garage. Never idle a vehicle in an attached garage.

More information is available from

Actions you can take to improve your air quality at home

  • Get your home tested for radon (radon is low in most areas of the Fraser Health region, but some areas have higher levels).
  • Get a carbon monoxide alarm.
  • Use a hood fan when cooking and a fan when showering.
  • Do not leave cars idling in your garage.
  • Improve ventilation. You can do so by leaving indoor doors open, opening windows and keeping vents clear.
  • Repair water leaks right away.
  • See this Health Canada webpage for more information.
  • See the York Region Clean air at home guide.