The Energy Crisis of the late seventies prompted householders to seal their homes more efficiently to prevent heat loss. However, according to the Canada Mortgage and Housing Corporation (CMHC), houses can contain a number of pollutants that can damage our health. These pollutants can release chemicals that create a more polluted environment than the outdoor air in a large metropolitan city. Since most of us, especially those who live in colder climates, spend most of our time inside, indoor pollution can pose a more serious risk to our health than outdoor pollution.

Indoor pollutants can be broken down into two types: biological and chemical substances. Biological pollutants include molds, mildew, dust mites found in mattresses and pillows, pollen, animal dander (dried saliva and skin particles) and bacteria. These pollutants result from high humidity levels, damp, dirty, rotting house structures or furnishings, wall-to-wall carpeting, water accumulation from leaks or humidifiers, plants, insects, and household pets. These contaminants can cause allergies, pneumonitis, asthma and other respiratory illness.

Chemical pollutants include combustion gases, radon, lead, pesticides, asbestos and other compounds that can be released from paint, turpentine, cleaning agents, and other household products. These contaminants can increase the risk of cancer, lung disease, allergies, kidney and liver disease, and damage to the nervous system.

These substances enter your body mainly through the air we breathe and trigger symptoms such as irritated eyes, headaches, dizziness, fatigue, asthma, respiratory infections, nausea, impaired vision and coordination, skin rashes and other more serious symptoms.

Sometimes certain smells can indicate a problem with a contaminant. Old musty or dusty smells can be a sign of a biological contaminant. Even if no smell is detected, condensation on walls and windows or moldy discolorations in the kitchen or bathroom can be a sign of a biological contaminant, while the detection of radon or carbon monoxide can indicate a chemical contaminant.

Generally, a new house has a higher level of toxins than an old house. This is because new building products release more chemical pollutants into the air. For example, new houses can be up to 15 times more polluted with Volatile Organic Compounds (VOC's) than houses built a few years ago.

However, if you have an old house, it can also pose serious health risks from various chemical pollutants. Combustion gases such as carbon monoxide come from leaking or back-drafting chimneys, fireplaces, unvented gas stoves and heaters, automobile exhaust and cigarette smoke. Radon, a radioactive gas is produced by the breakdown of uranium in the soil or rock underneath the house. This gas can enter the house through foundation leaks. Lead is found in lead-based paint, as well as lead-contaminated soil, dust, or water. Asbestos comes from old, deteriorating insulation or fireproofing in older homes. Formaldehyde is found in paints, glues, carpets, vinyl wall or floor coverings, wood products, toiletries, and various household products. Other sources of chemical pollutants include pesticides, termicides and fungicides.

Keeping all of this in mind, you can take basic strategies to reduce indoor pollution in your home. First, you must identify the source of pollution then try to eliminate it. Separate the source of pollution from the rest of the house by sealing in the source with safer building materials. Ensure that the area is well ventilated to bring in fresh clean air in the polluted area. An adequate ventilation system provides one air change about every three hours. Incoming and return air should be filtered and the air should be evenly distributed in the home. The system should maintain moderate temperature and humidity levels to minimize the emissions of toxins and the growth of molds.

If you are shopping for a home, here are some ideas on how to ensure that you are buying a healthy home. Choose a house located away from industrial pollution, heavy traffic, and power lines. Ensure that the finishing on floors has a low-toxicity level. Examples include hardwood, linoleum or ceramic tile. Wall drywall and ceiling finishes should be painted with non-toxic paint. Your home should contain low VOC, formaldehyde-free furniture and furnishings. Examples include natural, non-dyed, non-allergenic fabrics, hardwood furniture with low-tox finishes. Household and personal care products should be unscented and non-toxic. You should not use aerosol air fresheners, deodorizers, mothballs or perfumes, especially if you are asthmatic. Make sure that your home has adequate lighting to prevent mold growth. Avoid house polluting activities such as smoking. Don't leave your car idling in the garage for a long time, especially if it's attached to your house.

We may not be able to control all of the factors in our environment, but we can control the pollution in our homes. The home is our sanctuary — our place to retreat. Our home is where we raise our children, eat, sleep and spend a considerable amount of time. Therefore, we should ensure that our home promotes our health because your health begins at home!