Indoor air quality

Cassette Air Conditioner on ceiling in modern light office with green ficus plant leaves.

Canadians spend an average of 90% of their time indoors at home, work and in recreational environments, so our indoor environment plays an important role on our health.

Indoor air quality impacts

The quality of the air we breathe indoors can affect the health of building occupants.  Whether at home, work or other indoor spaces, being aware and understanding the factors that can affect indoor air quality can in turn reduce your risk of experiencing adverse health effects.

Indoor air quality can be impacted by:

  • Moisture build-up, dampness, and/or water leaks
  • Inadequate ventilation
  • Poorly maintained heating and ventilation systems
  • Building materials and furnishings such as newly installed cupboards, flooring and carpets
  • Household cleaning and maintenance products
  • Vehicle emissions from attached garages
  • Hobbies or activities such as metal or wood working
  • Outdoor sources such as pesticides and/or outdoor air pollution
  • Wood burning fireplaces

Inadequate ventilation can increase the indoor air pollutants by not bringing in sufficient outdoor air to dilute emissions.  Additionally, elevated temperature and humidity levels can lead to higher concentrations of air pollutants.


Emissions impacting indoor air quality can depend on the quantity, concentration, and the level of risk associated with the emissions.  Some sources like smoking or cleaning, can release air pollutants intermittently whereas other sources such as building materials and furnishings can release air pollutants more continuously.  Insufficient fresh air circulation from outdoors can leave indoor air remaining stagnant, resulting in increased pollutants levels. 

Ventilation methods such as natural ventilation (i.e. air moving through opened windows and doors), and mechanical ventilation systems can greatly support and improve air exchange.  There are different types of mechanical ventilation such as bathroom fans, kitchen exhaust hoods and HVAC (heating, ventilation and air conditioning) systems within a building to allow ventilation and adequate air change rates.  For more information on indoor air pollutants and improving indoor air quality in your home, please visit Health Canada’s –Air quality and health page.

More information

More information and infographics on sources of indoor air pollution in the home from Health Canada – Improve Indoor Air Quality in Your Home

Information on indoor air quality in the workplace can be found from Canadian Centre for Occupation Health and Safety. Contact WorkSafe BC for air quality issues/complaints related to places of employment.

Learn more on choosing a portable air purifier from Health Canada


Mould refers to a diverse group of fungi that can be found both indoors and outdoors.  Moisture and warm temperature can promote the growth of mould indoors.  Mould can be found in poorly ventilated areas such as bathrooms, areas with water leaks, behind drywall with moisture build-up, and on windows with condensation.  Controlling the sources of moisture and ensuring adequate ventilation is key in preventing mould growth.  It can become a problem for individuals who are sensitive to mould as inhalation or direct contact with mould spores can trigger allergic reactions.  Those with compromised immune systems or underlying respiratory conditions may experience more severe reactions.

By implementing appropriate measures, mould prevention or management can be applied to promote healthy indoor environments.  There are many practical strategies such as effective moisture control, proper ventilation and regular maintenance in mould prevention.

Click on the links below to learn more on the step-by-step guidance when you encounter mould growth in your indoor space and when to seek professional assistance and how to prevent mould recurrence.

Health Canada – Guide to addressing moisture and mould indoors

Canada Mortgage and Housing Corporation – Mould in Housing

Related articles

Outdoor air quality

Air quality monitoring projects