Indoor Air Quality

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Indoor air quality is very important. On average, people in industrialized nations spend about 90% of their time indoors, and most of that is in their homes. The unfortunate thing is that modern homes can contain substances that are potentially hazardous to our health. These range from normal dust, to major irritants, such as the chemical vapor off-gassing from the newer synthetic building materials being used today.

Indoor air quality is often referred to as the sleeping giant of the building industry. It can be 10 times worse than outdoor air on smoggy days in big cities. Of all the chemicals that EPA regulates, only two are more prevalent outdoors than inside our homes and schools. This is a quiet epidemic brewing right under our noses. As the complexity of houses, especially with the dawn of synthetic products, increase, so do the risks to human health, not only for the chemically sensitive and the allergy sufferers but for all of our children.

Problem Sources

Contaminants can enter our bodies in three main ways: ingestion, touch, and inhalation. The pollutants of main concern when assessing a homes’ IAQ, are the airborne contaminants, which usually affect humans through inhalation.

These contaminants are either biological or chemical. The biological ones can originate either in the home or outside. Molds, dust mites, pollen, animal dander, and bacteria are all considered biological contaminants, with molds being the trickiest of the bunch. Molds produce both particulates (spores and residual matter) and gases (volatile compounds characterized as musty odors). High moisture content inside homes supports the growth and presence of mold. The spores are already there. All spores need to grow into colonies is the addition of water, typically in warm, dry places.

The other forms of contaminants are chemicals, which include both gases and particulates. Though the sources are numerous for chemical contaminants, there are several main chemicals, some obvious and some not, that pose a risk.

Combustion by-products, including carbon monoxide, from furnaces, boilers and water heaters can also be a major source of problems. Sealed combustion units alleviate the potential of back drafting these gasses into the living space.

Radon is potentially responsible for as many cases of lung cancer as cigarettes. Preventative rough-in for future radon mitigation is a simple and cost-effective procedure in new construction.

The single most significant source of potential health hazards is from attached garages. Car exhaust contains many known carcinogens and can migrate into the living space through doors and when doors are opened to the garage. These gasses can also migrate though poorly sealed walls and ceilings. An exhaust fan reduces the potential for exhaust to reach the house.

Occupant activity (like smoking a cigarette), combustion of gases from burning fossil fuels (operating a water heater), gases released from building materials (emissions as paint cures), and gases from cleaning products (chlorine from bleach) are some sources, though there are many, many more.

Major Contaminants

Formaldehyde often finds its way into a home in the form of an adhesive, urea-formaldehyde, in pressed wood products such as particleboard, cabinetry, and trim. Formaldehyde, a possible carcinogen (cancer causing agent), is a strong- smelling gas which can irritate the eyes, nose, and throat; cause nausea and fatigue; aggravate allergies; and induce attacks in people with asthma. Over time, some people develop heightened sensitivities to formaldehyde.

Radon can cause lung cancer with prolonged exposure. It is a radioactive gas, typically enters a home by seeping up from the underlying earth and rock. Although there are no immediate health effects, long-term exposure to radon is a factor in approximately 2,000 to 20,000 lung cancer deaths each year (It is important to note that because smokers are more susceptible to cancer as a result of radon exposure, 75 percent of these deaths are the result of the combination of smoking and radon exposure). Because of its fatal consequences, the Environmental Protection Agency and the Surgeon General recommend that all homes test their radon levels below the third floor. In the U.S., the average indoor radon level is 1.3 picocuries per liter (pCi/L), while average outdoor levels are only 0.4 pCi/L. The EPA suggests that action be taken to increase ventilation if tests result in a radon level above 4 pCi/L.

Volatile Organic Compounds (VOCs) are both naturally occurring and synthetic, and are characterized by the fact that they release vapors at room temperature. In a home, VOCs are found especially in wood paneling, particleboard, carpets, paints, glues, finishes, and solvents. VOCs can cause a wide variety of symptoms from headaches, eye irritation, and chronic coughing to memory loss, fatigue, and depression.

Adverse Effects

Many chemicals and VOC’s (Volatile Organic Compounds) found as contaminants in homes are known to cause adverse effects on human health. Though molds can cause allergic reactions, they can also cause chronic illness in humans. The increased susceptibility to disease, aggravation of existing ailments, and the sensitization to the same or other environmental agents is of vast importance.

When assessing whether you are being plagued with indoor air contaminants, you should first try to make sense of the situation. At face value, does there appear to be an air quality issue. Common questions like, “Do you feel better outside than inside your home?”, will help you assess if you need to take further steps.

Due to the seriousness of IAQ issues, and the increased diagnosis of “sick building syndrome,” which is linked to poor IAQ, lawsuits have ensued. Even though “sick buildings” are typically more of a concern in commercial buildings, this problem will increasingly become an issue for residential builders.

Indoor Air Quality and Productivity

Recent studies reveal the link between productivity of workers and IAQ. According to the U.S. Environmental Protection Agency, the medical and lost-productivity costs of workers breathing poor air amounts to tens of billions of dollars each year in the United States alone. Improving energy efficiency leads to better working conditions, resulting in significantly increased worker productivity. In the same vein as lighting quality and temperature comfort, IAQ clearly affects worker conditions. OSHA estimates the total annual cost of poor IAQ to U.S. employers at $15 billion due to worker inefficiency and sick leave. In its 1994 rule, OSHA calculated a three percent loss of productivity from IAQ. Green designs resulting in productivity gains of one percent can provide savings to a company greater than the savings from reduced energy consumption.

Case Study

I got a call from a homeowner who was at his wit’s end. He recounted that for several months his kids had been constantly sick with headaches, fever, coughs, and other flu-like symptoms. The doctors didn’t seem to be able to help the kids and they were missing a lot of school. During the same period, his wife had two or three migraine headaches a week. She was losing a lot of sleep. All of them were exasperated. He asked me if these conditions could possibly be from something in his home. I asked him many questions about their home and lifestyle and if they had done any remodeling. Nothing seemed relevant to their situation. Finally, he told me he had gotten a bonus at work and had bought built-in shelves and desks for his kids and their master bedroom. He hadn’t mentioned it because he couldn’t see how that made any difference. I asked him to go to the rooms and pull out a shelf and describe to me what he saw. It turned out to be particleboard with a melamine veneer. I suggested that he try an experiment. Take everything off the shelves and remove them for the weekend since all the shelf edges were not sealed and I suspected they were off-gassing formaldehyde. I asked him to call me a week later to report if there was any difference. He called and said that the kids’ symptoms had decreased and he was encouraged. The next weekend he removed all of the built-in cabinetry. He called me two weeks later and said all of their symptoms were gone. The kids felt great and his wife hadn’t had a headache since he took the shelves out.

How Bad is My Home?

First, you should try to assess your location. Do I live in an area with prevailing winds from a large urban area? Is there likely to be radon in my neighborhood? Are my kids often sicker than others? Questions like those geared to your neighboring outside environment will be quite important when grasping the whole picture.

It is also essential to look at the house history. Was the house recently renovated? If so, there is a possibility that some of the building materials may be off gassing and a cause of discomfort or pain? Has there been a flood or leaky pipes in the house in the past? Has mold ever been remediated there?

Regardless, you should begin a thorough assessment of your house. Start in the basement, and go up in a logical manner, room by room, trying to list all potential contaminants (biological and chemical), and their sources.

You will later be able to correlate the sources and symptoms with an appropriate corrective action. It is a good idea to get help with your house audit, as sometimes our senses are less acute after having been in the same place for awhile.


For over a decade product manufacturers in the building industry have been introducing products that reduce formaldehyde, volatile organic compounds and other potentially harmful chemicals. Today there is a wide range of products available that replace existing paints, adhesives, flooring and other finishes that are much healthier for children inside homes.

Fresh air is also critical to optimal health. Most homes in cold climates are sealed up so tightly that the air is heated and recirculated constantly with only the air that leaks through the envelope providing fresh air. Intentional mechanical ventilation provides control over ventilation rates and helps prevent mold. Heat recovery ventilation is a good insurance policy against build-up of indoor air problems without paying an energy penalty for direct fresh air ventilation. It exhausts stale indoor air while providing fresh air with only a small energy cost. Many of these units help to pressurize the house slightly reducing infiltration and resisting radon and car exhaust intrusion.

Green buildings reduce IAQ problems by providing good ventilation to allow fresh air to flow through the house, installing an exhaust system for radon gas, avoiding wood products which contain formaldehyde and sealing those which do, using low or no VOC interior paint, solvent-free finishes, and solvent-free construction adhesives.

Action Plan

With all the news in hand, you can next create a personal action plan. What are the sources of the problem, where are they, and what can I do to correct them? Prioritize the corrective measures needed, estimate their cost, and assess their feasibility with timeframes to completion. Doing this will definitely help you see the potential costs associated with fixing a sick house. The unfortunate fact is that renovation and repairs to fix the contaminant ailments can be pricey. The good news is that there are now test kits to assess chemicals and mold in your home.

If you decide to address these issues, seek recommendations from friends, review internet list-serve group sources, and keep in mind not to forget, old fashioned research.

  • Read other important information about indoor air quality:

    Common Ailments associated with Indoor Air Quality (IAQ)

    • Allergic Rhinitis
    • Anemia
    • Asthma
    • Asbestosis
    • Cancer
    • Cardiovascular stress
    • Coughing
    • Digestive problems
    • Dizziness
    • Dry, chapped, irritated skin
    • Emphysema
    • Eye, nose and throat irritation
    • Fatigue
    • Headaches
    • Impaired lung function/ shortness of breathe
    • Impaired vision
    • Impaired coordination
    • Influenza
    • Learning impairment
    • Liver and kidney damage
    • Loss of bone calcium
    • Nervous System depression
    • Nose bleeds
    • Pneumonia
    • Rashes
    • Respiratory distress
    • Respiratory infection
    • Sinus congestion

    Read more on Indoor Air Pollutants: Where To Find Them and What To Do.