Indoor Air Quality

Indoor Air Quality

Should everyone be concerned with the quality of the indoor environment?
Yes. Construction practices used today to reduce energy consumption and moisture damage to buildings have reduced natural air leakage. Without ventilation, normal activities such as laundry, cooking and showers can cause excessive moisture generation resulting in high humidity, occupant discomfort, bacterial or fungus growth and lingering odours.

What then are the total adverse effects of poor IAQ?
Both the health and welfare of the occupants will suffer. The structure of the building may also be damaged.   Some household members may have headaches, or irritations of the nose, throat, lungs, eyes or skin.

What are some of the major pollutants?

• Aldehydes
• Carbon dioxide
• Carbon monoxide
• Combustion by-products
• Dirt particles
• Excessive levels of radon gas
• Excessive moisture
• Pollen
• Tobacco smoke

In what way will poor IAQ adversely affect the structure of a house?
Both visible and hidden damage to the structure may be caused by prolonged build-up of moisture levels in the walls and attic.

How does this happen?
Interior damage to the structure is caused by moisture migration due to air and vapour pressure differentials between the inside and the outside of the structure.

What are some methods of improving and controlling air quality?

• Removing the source of the problem
• Ventilation
• Air cleaning (filtration)
• Air conditioning
• Dehumidification
• Humidification
• Local exhaust fans

What equipment is used?

• Ventilators
• Air conditioners
• Dehumidifiers
• Electronic/media air cleaners
• Humidifiers

 What is ventilation?
It’s a device that exhausts contaminated indoor air from a building or delivers a fixed quantity of outdoor air into a building.

Is there an industry position in Canada regarding IAQ and ventilation?
The Heating, Refrigeration and Air Conditioning Institute of Canada (HRAI) recognizes ventilation as a primary solution to acceptable indoor air quality.

What considerations are important in ventilation?
There are three: amount, balance and distribution.

How do I know what is a proper amount of ventilation?
Minimum ventilation quantities [cubic feet/minute (cfm) or Litre’s/second (L/s) are specified in the National Building Code. Also, the Canadian Standard Association (CSA) National Standard CSA F-326-M1989 (Residential Mechanical Ventilation Requirements) establishes current ventilation rates consistent with current construction practices.

How is balanced ventilation achieved?
Have an equal amount of supply (intake) and exhaust air.