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What is Indoor Air Quality?

Indoor air quality (IAQ) has received a lot of attention over the last several years. The increased interest in this topic is likely due to the link between indoor air quality and your health. Additionally, the number of hours that we spend inside has significantly increased over the years. With an increase in modern technology and the conveniences that are attributed to the increase in technology, there is a correlation to the increase of time spent inside.

How much time do you spend outside each day? A recent study found that Americans, on average, spend almost 90% of their time indoors! There are several illnesses that have been linked to poor indoor air quality. Since we are spending so much time indoors these days, the air you breathe inside is more important than ever to your health!

Importance of IAQ

Due to the amount of time we spend indoors, it is important to look at the quality of the air you breathe. According to the EPA, indoor air can be two to five times more polluted than outside air. This poor air quality can lead to serious issues with your health.

OSHA recommends that the air temperature and humidity be at a “comfortable level” and for there to be an “adequate supply of fresh outdoor air.” Humidity is an important consideration, because excess humidity over time may result in a moisture and mold problem. Mold is a known contaminant that creates health issues in some individuals.

Picture of ATMOX Family in Living Space

Although OSHA’s recommendations seem rather subjective, three key issues are connected to building related sickness: moisture, lack of ventilation, and cleanliness. 

Additionally, off-gassing from furniture, carpets, flooring, and other structural components can contain VOCs which can have an adverse effect on your health. The use of cleaning products, pesticides and even some office machines negatively affect your air quality. 

Health Effects

There is a broad range of negative health effects that can occur from exposure to poor indoor air quality. Of course, the reaction one may have also depends on the type of exposure and length of exposure. You can have an immediate reaction to the poor air conditions, or the effects may not show up until years later. 

Negative health effects may include but are not limited to the following:

  • Asthma or breathing difficulties
  • Eye irritation
  • Nose and throat irritation
  • Headaches
  • Dizziness
  • Fatigue
  • Respiratory disease
  • Heart disease
  • Cancer

With short term exposure, leaving the affected area generally relieves symptoms. However, if your home has poor indoor air quality, you will want to improve the air you are breathing. 

Crawl Space Affect on IAQ

The crawl space in your home is often dirty, dark, and dank. Therefore, these spaces are an ideal breeding ground for moisture problems. Your crawl space is an extension of your home and affects the air within your living space

You may wonder, how does the crawl space relate to your indoor air quality? The air within your crawl space rises and infiltrates your living space through small openings and gaps. This is due to the stack effect. The air rises from the crawl space and acts as a transport for heat, moisture and even odors into your living space. Therefore, you are breathing air from your crawl space, so the quality of air in your crawl space is important.

How to Improve Your Air Quality

The three key components affecting indoor air quality are moisture levels, condition of the crawl space, and ventilation of your crawl space.  Addressing the air quality of your crawl space should not be overlooked as an important factor in the air quality of your living space. The fact is you can’t have true indoor air quality without exchanging the air with outside air.

Improving the conditions of your crawl space

In order to address the air quality in the crawl space, you need to start with addressing moisture or water issues that may exist. Moisture negatively affects your space and therefore your air. Therefore, inspect your crawl space for potential water intrusion or signs of moisture. Begin with an inspection of the perimeter of your home for potential water intrusion issues. A thorough inspection of the exterior of your home should begin with:

  • Overflowing gutters
  • Direction of downspouts
  • Grading around the house
  • Gaps and cracks in the foundation
  • Vent Wells

Additionally, you will need to inspect the interior of your crawl space for signs of water and moisture related issues. Inspect the interior of your crawl space for the following:

  • Signs of water intrusion such as efflorescence
  • Mold
  • Standing water
  • Plumbing leaks
  • Condition of insulation
  • Signs of pests

Water intrusion and crawl space moisture are two separate issues to address.


Fresh outside air exchanges stagnant indoor air as well as reduces moisture. Inadequate or too little ventilation will allow inside air pollutants to build. According to the EPA, even high temperatures and humidity levels can increase the buildup of some pollutants. Without proper ventilation, the air can settle into your crawl space creating issues for your home and your indoor air quality.

Traditional crawl spaces have open vents around the perimeter of the crawl space with no mechanical assistance to exchange and circulate air. With passive air ventilation, there is likely not enough air flow to easily pass over all areas of the space. This is especially true in odd-shaped or segmented crawl spaces.

ATMOX Picture of Man Opening Window for Fresh Air

Mechanical ventilation addresses all areas of the crawl space and ensures there is balanced airflow. This type of ventilation uses fans to assist airflow across and around the crawl space. Healthy air can only be achieved by exchanging the air within the crawl space.


Inside a crawl space, a dehumidifier is one of your moisture control tools. A dehumidifier works effectively to decrease moisture and filter air when running. The dehumidifier’s internal fan pulls air into the unit. The air passes through a filter removing potentially harmful particles. The filtered air is condensed to remove excess moisture. The dry filtered air is then expelled back into the crawl space. Therefore, the dehumidifier is actually improving your indoor air quality through its filtration and drying process.


Ventilation is stressed over and over again as a common denominator for improving air quality. Using outside air will decrease the concentrations of indoor pollutants. With a reduction in moisture and an exchange of crawl space air, you will improve the air you and your family breathe!

Post Author: ATMOX TOM