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Mold: Just One Component Impacting Indoor Air Quality

Research indicates that we spend as much as 90% of our time indoors. Given the amount of time we spend indoors, indoor air quality is essential for our health and well being. The EPA has stated that within recent years, research has indicated that the air we breathe indoors is more polluted than the outdoor air of even the largest industrialized cities. Other studies have shown indoor air quality can affect worker productivity in offices by as much as 50%.

Mold is just one of many factors that impact that air we breathe. As mold inspectors and remediators, our expertise is mold. But we should all be aware of other factors that influence indoor air quality besides mold. Sometimes a mold inspection will actually reveal that other indoor pollutants are in fact the cause of the problem and not mold.

In addition to mold, some other sources of indoor pollutants can include:

  1. Carbon Monoxide

  2. Asbestos

  3. Radon

  4. Lead

  5. Chimneys, fireplaces, stoves

  6. Cigarette and tobacco smoke

  7. Pets

  8. Construction materials

  9. Beauty care products

According to the EPA, immediate effects of indoor air pollutants can include irritation of the eyes, nose, throat, as well as headaches, dizziness and fatigue. Symptoms of other diseases such as asthma may also show up soon after exposure to indoor air pollutants. Long term effects of exposure to indoor air pollutants can be in the form of respiratory diseases, heart diseases and cancer. These long term effects may not even show up until years after the exposure to the indoor air pollutant. Check with the EPA to find specific health effects for a particular indoor air pollutant.

While we know as a whole that indoor air pollutants can cause harmful effects, there is still uncertainty about the amount of indoor air pollutants one must be exposed to or the time one must be exposed to indoor air pollutants to produce a specific health effect. Each person reacts differently to exposure to indoor air pollutants. By the way, this can also be said for mold. We know mold can produce harmful effects but everyone reacts differently to mold and there are currently no standards that indicate how much mold one must be exposed to or how long one must be exposed to mold to produce a certain health effect.

It is also important to note that not all mold companies are trained in the detection and removal of these other indoor pollutants such as asbestos. In most cases, you will need to hire another company that specializes in removing these other indoor pollutants. Also, a typical mold inspection will not include testing for these other indoor pollutants. Other means of detection by the homeowner – such as purchasing a test kit for determining radon levels – will be necessary to determine levels of these other indoor pollutants, unless the mold inspection company offers these other services and is trained in these fields as well.

I suspect my home is contaminated with higher than acceptable indoor air pollutants. What should I do?

Per EPA guidelines, there are three basic strategies to improving air quality:

  1. Source removal

  2. Ventilation improvements

  3. Air Cleaners

The best method is to remove the source. It is beyond the scope of this article to go into the details of removal of each and every indoor pollutant. Suffice it say for our purposes, whether its mold, asbestos, lead, etc., proper removal of the source that is causing the high levels of indoor air pollutants is the best course of action.

Ventilation improvements are discussed below in its own section to conclude this article.

As for air cleaners, there are a wide range of models on the market ranging from cheap small units that can be placed on a table to expensive systems that are installed throughout the entire house. Three factors influence the effectiveness of the air cleaner:

  1. The filter being used

  2. The amount of air drawn into the air filtration device

  3. The type of indoor air pollutant present

Not all filters are created equal. Some filters are much more effective at collecting pollutants from the air than others (In the mold remediation industry, one should only use air purifiers with HEPA filters as part of mold remediation protocol).

And not all air cleaners draw in the same amount of air – it varies from one air filtration device to another.

The type of indoor air pollutant is also important in assessing the effectiveness of an air cleaner. Air filtration devices and cleaners are not recommended to clean certain types of indoor air pollutants such as radon, per the EPA.


As mentioned above, ventilation is a key variable in regulating indoor air pollutant levels. Proper ventilation is crucial for having high quality indoor air. For a given volume of air that enters a room, an equal amount of air must leave the room. As an example, when you open your window in your bedroom and fresh air enters, an equal amount of air will also exit your bedroom to the outside.

Air exchange is fundamental because it helps dilute indoor air pollutants. If you ever had a cooking mishap in the kitchen and set off the smoke alarm (and as amateur cooks, we can relate), you know how important is to open windows immediately to let fresh air in, which will dilute the emissions from the heat source and allow the polluted smoke air to exit the home.

This is an obvious example demonstrating the effects of indoor air pollutants (in this case, smoke) and ventilation in controlling these indoor air pollutants. But in many cases, the indoor air pollutant is far less obvious. You could be building up indoor air pollution slowly and not even realize it.

With modern day construction, ventilation and air exchange are often unintentionally sacrificed for the sake of energy conversation. Unless these homes are designed with mechanical forms of ventilation to let outdoor air into the home, the level of indoor pollutants may be higher in these homes. Older homes on the contrary are often very leaky and can let in much more air indoors from the outside. (We are not advocating one way or the other for tight or leaky homes. We are just trying to juxtapose one vs. the other for the purposes of discussing ventilation.)

When you open your window to let fresh air in, this is a form of natural ventilation. But there are two other forms of ventilation: mechanical ventilation (e.g. bathroom and kitchen exhaust fans) and infiltration (e.g. air flowing into openings, joints, cracks, through walls, windows, etc.). By the way, it is crucial that bathroom and exhaust fans vent outside and not terminate in the attic or moisture problems could follow and cause potential attic mold growth. When there is little natural, mechanical or infiltration ventilation, and the rate at which outdoor air is replacing indoor air is low, indoor air pollutant levels can rise.

In addition, letting outdoor in also is important in controlling moisture, which is important for many reasons, not the least of which is that high levels of moisture can lead to mold growth. Also, regular household cleaning and maintenance is essential in reducing dander, dust mites, pollens that adversely impact indoor air quality in and of themselves but which can also be a source of food for mold growth if moisture is present.

As the above article illustrates, there are other factors that affect indoor air quality in your home besides mold. Keep these factors in mind the next time you want to assess the quality of air in your indoor environment.

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