Air Quality in the Home

By Kim Kennett

Updated in June 2015 by the Manitoba Association of Home Economists

Clean air in our home, and hence, good air quality, is important to everyday health. A number of household air pollutants are responsible for various allergic and health-related problems of individuals, whether these problems are associated within the home, at school or in the office building in which we work. Exposure and prolonged exposure to contaminants can also have a number of indirect health effects, including increased susceptibility to diseases and heightened sensitization.

In Manitoba, we are monitoring Air Quality through The Air Quality Health Index (AQHI). Refer to the Government of Manitoba info sheet here.

How does the AQHI work?

The AQHI is measured on a colour-coded scale from 1 to 10+ (shown below). The higher the number, the greater the health risk associated with local air quality. The AQHI numeric ratings (from 1 to 10+) are also grouped into risk categories (low, moderate, high, very high) that are designed to help you easily and quickly identify your level of risk.

Each risk category is associated with specific health advice for those at risk (children, seniors, people with heart or lung conditions and diabetics) and the general population.

Health Risk Air Quality Health Index Health Messages
    At Risk Population General Population
Low 1 – 3 Enjoy your usual outdoor activities. Ideal air quality for outdoor activities.
Moderate 4 – 6 Consider reducing or rescheduling strenuous activities outdoors if you are experiencing symptoms. No need to modify your usual outdoor activities unless you experience symptoms such as coughing and throat irritation.
High 7 – 10 Reduce or reschedule strenuous activities outdoors. Children and the elderly should also take it easy. Consider reducing or rescheduling strenuous activities outdoors if you experience symptoms such as coughing and throat irritation.
Very High Above
Avoid strenuous activities outdoors. Children and the elderly should also avoid outdoor physical exertion. Reduce or reschedule strenuous activities outdoors, especially if you experience symptoms such as coughing and throat irritation.

Indoor air quality may be affected by chemical and biological contaminants. Biological contaminants originate within the home or from the outdoors. These include mould, dust mites, pollen, animal dander and bacteria. Chemical contaminants include both gases and particulates (particles). Gases may be released:

  • By occupant activity (such as smoking)
  • By burning of fossil fuels
  • From building materials, furniture, fabrics, floor coverings, carpets and paints
  • From cleaning products, bleach, pesticides and personal care products
  • Through cooking and hobbies
  • From soil and rocks (such as radon)

Chemical particulates include dust and soil, combustion processes, cigarette smoke, as well as building materials and furnishings such as concrete, lead paint, insulation, carpets and draperies.

Ask yourself the following questions to determine is you have an indoor air quality problem:

  • Do you notice an odour as you enter the house?
  • Do you feel better outdoors or in other people’s homes than in your home?
  • Do you ever feel sick in your home? Do you associate specific symptoms with particular odours? Are these symptoms worse in certain areas of the house? At a particular time of day or year?

The source of chemical contaminants may be off-gassing from new homes or renovations, such as new building materials and new furnishings. The use of pesticides can also result in air quality problems. Biological contaminants tend to be a problem of older homes: stale or earthy smells, damp or musty basements or crawl spaces, or basement flooding.

Your home’s air quality will also be affected by where you live, including:

  • The geographical area – urban (air pollution), rural (exposure to agricultural chemicals), prevailing winds
  • The district – proximity to industrial and landfill sites, dust from busy roads, pollen from plants and trees, gas stations, dry cleaners, railway lines and airports, high voltage lines
  • The immediate neighbourhood – wood smoke from wood-burning fireplaces, exhaust from cars, pollen from trees and shrubs, odours from swamps and ponds, pesticide usage
  • The house history – activities/hobbies/home businesses which affect air quality, use of pesticides, presence of pets, age of home, new/old building materials, fire/flood, smoke, moisture and drainage problems

The Clean Air Guide: How to Identify and Correct Indoor Air Problems in Your Homefrom the Canada Mortgage and Housing Company, assists homeowners with evaluating air quality and rectifying problems. To order your copy of this guide, refer to the CMHC website.

Mould and Mildew

Mould and mildew in the home are caused by excess moisture. Symptoms of moisture problems include musty odours, green or black stains on walls or ceilings, carpet stains and mildew on furniture. Condensation on windows or walls, peeling paint or curling floor tiles and rotting window sills are also indications that you have excess moisture in your home.

For more information on coping with mould and mildew in your home, please refer to the article on this website, “Dealing with Mould,” by Millie Reynolds.


Lead may be a concern in older homes in which building and finishing materials contained lead. Until the conclusion of World War II, lead was used as a pigment in many paints and up until the 1990s as a sealant or to speed up drying time. It wasn’t until 1992 that Canadian paint manufacturers stopped using lead in the production of paint. Lead-based paint shouldn’t be a problem unless it is peeling or flaking which produces lead-laden dust. Thus, renovating an older home can expose the occupants to lead through sanding/scraping/removal of materials.

Lead paint may be covered by lead-free paint and damaged areas carefully repaired, or walls can be covered with more durable coverings, such as wallpaper. Another alternative is to replace painted doors, windows, baseboards, moldings and other trims, or have professionals remove the paint.

Lead may also be in the home as a result of dust and soil containing lead. Homes located in areas where industry has used lead or where older structures such as bridges or water towers are deteriorating, may be at higher risk. In cases where lead is in the soil, it is important to keep the home as dust free as possible.

Another source of lead exposure can be old water pipes and soldering from older plumbing systems, installed prior to 1950. If you are unsure about lead in your drinking water, water can be tested. This is especially important for rural residents. Some treatment devices can remove lead, but consistently high levels of lead may mean that plumbing systems need to be replaced.

Radon Gas

Radon gas is a colourless, odourless and tasteless radioactive gas and is a product of the breakdown of uranium in the soil. Radon can cause health concerns if it enters an enclosed space, such as a home. Canadians who live in areas where uranium has been mined or processed have experienced problems with radon gas. Homes may be tested for radon gas levels.

Air quality in the home in which you live translates to quality of life. Your living environment is key to a healthy home.


The Clean Air Guide: How to Identify and Correct Indoor Air Problems in Your Home, CMHC, 1993.

Lead in Your Home, CMHC, 1984.

Moisture and Air: Problems and Remedies, Householder’s Guide, CMHC.

Radon: A Guide for Canadian Homeowners, CMHC, 1997.

Government of Manitoba:

Updated October 2020