Indoor Air Quality
Below are a few typical questions asked about indoor air quality. If your question isn't answered here please write to us at chic@cmhc-schl.gc.ca and we'll respond promptly.
- How can I tell if there is an indoor air quality problem in my home?
- I think there is a problem — what can I do?
- How do I find a professional to come and inspect my home?
- I would like to have someone test the air in my house for mold
- Is it safe for me to clean the mold myself?
- Is bleach recommended for cleaning?
- My basement is chronically damp. Is there something I can do?
- Will a portable air purifier help with a mold problem?
- Would a HEPA furnace filter help with a mold problem?
- Is a HEPA vacuum cleaner useful for molds?
- Is an HRV suggested to solve a mold problem?
- I have noticed mold in my apartment. What can I do?
1. How can I tell if there is an indoor air quality problem in my home?
One way is by comparing how you feel inside your house and away from your house. Note how you feel when you are away on holiday or stayed at someone else's place for a period of time. Did the symptoms improve when you left your house? What happened when you came back? Some people can tell by being away from the house for even a day. However, the symptoms may be so severe that they do not change with location.
Observe if guests or visiting family experience unusual symptoms while staying with you.
People with allergies react to contaminants faster than those without allergies.
You can also observe all areas of your house. Look for evidence of dampness or staining or presence of unusual odours.
top of page
2. I think there is a problem — what can I do?
It is important that the problem be identified. You can audit your home using the checklists in The Clean Air Guide. You may be able to pinpoint the location or source of the problem in the house. You can determine if the problem is present all the time, only at certain times or only at certain times of the year. Observe whether the symptoms become aggravated by any particular activities.
Once you have zeroed in on a problem, look up the suggested solution and determine if it is appropriate. You can do simple, inexpensive measures. However, consider getting professional advice before implementing corrective measures that are involved or costly. You could end up spending more money doing renovations that will not solve the problem.
top of page
3. How do I find a professional to come and inspect my home?
The brochure, "Breathe Cleaner Air in Your Home", explains Indoor Air Quality investigations and what you should expect to receive from an investigator. There are private consultants who have completed the CMHC Residential IAQ Investigator Training Program who provide consulting services to the public. Call 1-800-668-2642 for the name of a trained investigator in your area.
top of page
4. I would like to have someone test the air in my house for mold.
Testing the air in your house will not give you the information you need to solve a problem. An inspection by a trained investigator will provide you with more useful information, such as whether there is a mold problem or not, the causes or sources of moisture and how to correct them. An air sample, on the other hand may tell you the kinds of molds that may be present in the air. To find out where the molds are coming from, samples from different parts of the house would need to be taken. The results will not tell you the action needed to correct the problem.
top of page
5. Is it safe for me to clean the mold myself?
It depends on how much mold you are dealing with. A small area of mold occupies approximately 1 square meter. You can clean this yourself. Please refer to About Your House "Fighting Mold: The Homeowner's Guide" and Clean up Procedures for Mold in Houses. You may need a contractor trained in cleaning mold to deal with more extensive areas.
top of page
6. Is bleach recommended for cleaning?
In the past, bleach was recommended for cleaning mold. CMHC, Health Canada and other health agencies are no longer recommending bleach for cleaning. The most compelling reason is that cancer-causing substances can be formed by the reaction of bleach with organic materials. The fumes are also irritating to the lungs and mucus membranes. Furthermore, cleaning mold does not mean having to kill mold. A detergent solution followed by rinsing effectively removes the mold. To prevent mold from coming back, keep the area dry.
top of page
7. My basement is chronically damp. Is there something I can do?
The first step is to clear the basement of stored materials that are no longer needed. Clothing, cardboard boxes, paper, books, pieces of wood, etc. absorb moisture and become places for mold to grow. Discard as much materials as possible to make it easier to clean the basement. The second step is to determine why the basement is very damp. Is there a leak or is water seeping in through the walls or floor? The latter would require steps to stop the water from coming in and may involve major work. Some simple things you can do include making sure downspouts have extensions and soil around the foundation slopes away from the house. If these do not make any difference than you need someone to advise you whether work around the foundation is needed.
Moisture could also come from interior sources and these have to be identified and corrected. Common sources are using a humidifier, a hidden plumbing leak, line-drying clothes or venting a clothes dryer into the house.
Control humidity in the basement by using a dehumidifier. If buying one, choose one with a high capacity that can operate at a low temperature and is rated to be energy efficient. Operate the dehumidifier from spring to fall. A dehumidifier would serve as an interim measure, but bear in mind that it may not be sufficient to stop mold from growing until exterior sources are corrected.
top of page
8. Will a portable air purifier help with a mold problem?
The most effective solution for a mold problem is to identify the causes and eliminate them. An air purifier can reduce airborne mold spores, but would only be effective if the rate these are removed is faster than the rate they are produced. Very little benefit may be obtained if the area being cleaned is too large for the unit to handle or there is a moldy carpet or there is a strong hidden mold source in the house.
top of page
9. Would a HEPA furnace filter help with a mold problem?
A HEPA (High Efficiency Particulate Air) filter is unlikely to make much difference. In the first place, a one-inch medium efficiency pleated paper filter has adequate filtering capability for the majority of homes. It can replace typical throwaway furnace filters with no required modifications to the ducting. A HEPA filter can more effectively trap finer particles than a medium efficiency filter, but it is more than what is needed in most homes where pets, carpets and other sources of particulates may still be present. To install a HEPA filter, the cold air plenum would need to be modified to accommodate the thickness of the HEPA filter. Because of the increased resistance to air flow, the blower would also have to be upgraded. Lastly, A HEPA filter cannot be replaced as frequently as the pleated paper filters because of the higher cost. It can end up accumulating a lot more dirt than a less efficient filter before it gets replaced.
top of page
10. Is a HEPA vacuum cleaner useful for molds?
A HEPA vacuum cleaner is a useful investment. It captures fine particles that a typical vacuum cleaner would blow back into the air. Better-built HEPA vacuums have tighter housing that prevents these fine particles from leaking out. An alternative to HEPA vacuum cleaners is a central vacuum cleaner that exhausts to the outside.
If you have a mold problem in your house and you cannot get the problem fixed immediately for one reason or another, vacuuming frequently with a HEPA vacuum cleaner is recommended as an interim measure. Mold spores are in settled dust. Your exposure to mold is lowered by reducing the amount of dust.
top of page
11. Is an HRV suggested to solve a mold problem?
An HRV cannot correct an existing mold problem. The mold has to be cleaned up and the cause has to be corrected. An HRV would then enhance the quality of the air. Installing an HRV by itself without prior cleaning and correcting the cause would have a similar effect as airing the place by means of an open window.
Operating an HRV controls moisture in the home during the cold months and supplies fresh air into the house. During the warm months, a dehumidifier should be used to reduce humidity levels in the basement.
top of page
12. I have noticed mold in my apartment. What can I do?
Report the mold to your landlord or property manager. After you have notified your landlord, you can clean small areas of mold yourself. Wear a respirator and gloves. Let the landlord know if the mold comes back after cleaning. The underlying problem has to be identified and corrected.
top of page
Edit Elements...