FREQUENTLY ASKED QUESTIONS
Indoor Air Quality and Lab Testing
- What are some indications of poor indoor air quality?
- My house is comfortable and I don't have any health problems. Should I test my indoor air?
- How do I know if I have allergies?
- The dust keeps coming back after I dust! What is dust and where does it come from?
- Why is controlling moisture intrusion important for indoor air quality?
- Why are basements considered a potential source of indoor air quality problems?
Air Duct Cleaning
Mold
Crawlspaces
What are some indications of poor indoor air quality?
If the house seems stuffy or stale, this is an indication of inadequate ventilation. Not enough fresh air from the outside is being brought in. An indoor air quality screen of temperature, relative humidity, carbon monoxide, and carbon dioxide would provide the information you need to assess your IAQ condition. Indoor carbon dioxide concentrations should be around 800 ppm to 1,000 ppm. Concentrations greater than 1,000 ppm are an indication of not enough fresh air.
My house is comfortable and I don't have any health problems. Should I test my indoor air?
Probably not. If you are not experiencing any health problems or allergy related symptoms, then having an indoor air quality screening may not be necessary.
How do I know if I have allergies?
That's a good question! The best way is to ask your physician! Also let common sense prevail. If you sneeze frequently, your eyes run, and you break out with a rash every time you pet or hold a cat, then you are probably allergic to cats. The same with dogs. It's more difficult to tell with pollen and mold, however, because when we experience the symptoms, we can't see the offending culprit (mold or pollen) like we do with a cat or dog, and so we often don't associate the symptoms with anything. If you are not experiencing any symptoms until you crawl into bed and your bed is old, you may have dust mites in the bed, and you may be allergic to them. There are plenty of books at the local library and bookstore from which you can learn a lot about allergies; and of course, don't forget to ask your doctor. One book in particular is Allergies and Asthma for Dummies, written by William E. Berger, M.D. This is an excellent book packed with lots of information in an easily digestible format. Another good book about indoor air quality is Help, My House is Killing Me. This is written by a home inspector and can be found at your local library or bookstore.
Will cleaning my air ducts help my allergies?
Depending on the source of the offending allergens, some families can benefit tremendously from having their air ducts cleaned. If the air ducts are a source of mold or allergens, removing the dust and allergens will help. Other families may notice no significant difference. If family members are experiencing allergy problems, check with your physician first to rule out other problems. If poor indoor air quality is responsible, then having the air ducts professionally inspected and cleaned may help significantly. Click here to see the results of a study demonstrating a significant decrease in airborne mold after air duct cleaning.
Are there any other benefits of duct cleaning?
Absolutely! It's incredible the amount of dust that can collect in the air ducts! If your ducts have never been cleaned, more than likely they have accumulated a considerable amount of dust over the years. When the dust from the air ducts, the blower motor, and the heater and air conditioning coils is removed, your HVAC system will run more efficiently, helping to offset increasing energy costs.
The dust keeps coming back after I dust! What is dust and where does it come from?
First off, remember that house dust is not necessarily an indication of poor housekeeping! Household dust is a normal breakdown product of fibers and other materials found throughout your indoor environment. House dust can consist of plant pollen, fungal spores, dust mite allergens, animal dander, insect fragments, and fibers from pillows, curtains, carpet, clothes, linen, and particles from wood, paper, hair, skin flakes, tobacco ash, salt, sugar, other commonly used spices and minerals. The average six-room home in the U.S. collects 40 pounds of dust each year! Lots of it can end up in your air ducts!
House dust may be the most prevalent of all allergy triggers in your life. Recent studies show that the major inhalant allergens found in house dust can be the most important risk factors in triggering asthma attacks.
Why is controlling moisture intrusion important for indoor air quality?
Mold needs three things to grow: a food source, air, and moisture. If you limit just one of them, it will not grow. Moisture is the one thing you can control. Mold can grow on almost anything: concrete walls, gypsum board, wallpaper, wood products and many other things. Air is usually plentiful. If moisture is present, then you probably have mold growing nearby. Mold does not always show itself, as it may be growing in the wall cavity. We look for signs of moisture first, and if we find it, then we look for signs of mold.
Humidity levels greater than 50% can be a sign of trouble. These levels can contribute to the growth of mold and dust mites! Keeping your humidity level below 50% ensures you'll be comfortable and the molds and dust mites will be kept at bay.
Why are basements considered a potential source of indoor air quality problems?
Concrete blocks and foundations often settle with time. Cracks in the concrete walls make it easy for water to intrude into the basement. If the basement is unfinished, you can readily see the water intrusion, and although we don't like it, we are at least aware of the problem and can deal with it. If the basement is finished, one is often not aware of the problem until it is too late. The sheetrock and other building materials can serve as a wick for moisture, facilitating the growth of mold.
Carpeted basements can also be problematic. The carpeting adsorbs moisture, often becoming damp to the touch. Mold frequently can be growing in the carpet or underneath in the padding material. Whenever the carpet is disturbed or vacuumed, mold spores will be released.
Moisture can also collect on the backside of walls, invisible to the naked eye. Whenever the walls are disturbed, spores can gain entry to the air through a crack or gap in the wall.
Leaks and floods are especially problematic, resulting in wet walls, sheetrock, carpet and insulation. These materials can remain damp for weeks after the standing water has gone, providing ideal conditions for mold growth. Severe mold contamination can be lurking unobserved behind the walls and under the carpet.
How can moisture problems in the crawl space influence my indoor air quality?
It can have a dramatic impact in a couple of ways. First, if you have a moisture problem in the crawl space, it can lead to elevated humidity levels in the interior of the home. The high humidity in the crawl space will equilibrate with the rest of the home, so there will be a continuing movement of moisture from the crawl space into the interior of the home, causing areas of elevated humidity and moisture. Wall interiors and plywood underlayment can become damp, providing good conditions for mold growth on the walls, flooring, and beneath the carpet. Secondly, if you have a mold problem in the crawl space, the microbial volatile fatty acids (MVFAs) produced can diffuse into the interior of the home as well. The diffusion is slow but with time you may detect a musty odor that is originating from the crawl space and is entering by diffusion through the floor. And third, if you have a mold problem and mold spores are being produced, they can enter the home through holes in the floor or through leaks in your duct work. Cracks in the floor and around pipes and venting can allow moldy air to circulate to upper levels, causing problems.
Why does there seem to be an increase in mold related problems with newer homes?
There is an increase in mold problems with newer homes for two main reasons. First, manufactured wood products are increasingly being used in place of plywood or lumber. Manufactured wood products include wafer board, oriented strand board (OSB), particleboard (chipboard), and hardboard (fiberboard). These manufactured wood products are used for wall and roof sheathing, wall paneling, sub flooring, and joists. These manufactured or reconstituted woods are bonded together using a formaldehyde based glue. When damp they can become an excellent food source for mold. Secondly, energy costs have resulted in the construction of well-insulated highly energy-efficient homes, often having vapor barriers installed, but are poorly ventilated. This can create moisture problems that, if not corrected, will allow mold to grow. To prevent the mold growth, humidity levels should be below 50% and if water leakage occurs, it should be fixed immediately and the building material(s) dried out.
My bathroom gets really damp. Should I be concerned about high humidity?
Bathrooms are usually one of the smallest rooms in a home, yet the most intensely used. Because water is always present, the potential for mold problems is high. If the room is carpeted, the potential is even greater and it makes it even more difficult to detect the problem. The cold toilet tank is often below the dew point. The moisture from the air condenses on the toilet tank, running onto the carpet, creating ideal conditions for mold to begin growing.
Showers increase the probability of problems developing, especially if the shower panels or tile become damaged and water gains entry behind the walls. The mold contamination can be severe, yet you may not see visible signs of mold. When the wall is disturbed, spores can be released and make their way into the air. Always ensure the shower wall is intact and if damage or breaks occur, it should be repaired immediately to prevent water from gaining access to the insulation and other building materials.