Air quality testing can help you to identify pollutants in your home air.

Your Guide to Indoor Air Quality Testing

Do you know what’s in your air? 

We mean do you really know what is lurking, unseen, in the air that you breathe deeply every day and every night? 

Until recently, there was very little information available to the public on the topic of air quality. We knew about the heavy hitter pollutants like carbon monoxide, secondhand smoke, and formaldehyde, but the more obscure, silent-killer pollutants were largely unknown. 

The tide is turning, friends. 

Air quality testing is on the radar and home air quality tests are increasing in popularity. This means that you, from the comforts of your own home, can effectively determine the quality of your home air like a more relatable Bill Nye the Science Guy. 

You can view this blog as a personal guide to indoor air quality testing. We will answer the following questions:

  • What is air quality testing?
  • How does air quality testing work?
  • What are the most common indoor air pollutants?
  • What should you test for in your home?

What is Air Quality Testing?

Air quality refers to the levels of pollutants present in the surrounding air; air quality with low contaminant levels is referred to as “good” air quality while air quality with moderate or high levels of contaminants is referred to as “bad” air quality. 

Air quality testing identifies and measures contaminants in the indoor air. Air quality testing can help you determine whether there are unhealthy levels of a particular contaminant in your home air. 

How Does Air Quality Testing Work?

Most air quality tests collect air samples, surface samples, or bulk samples to test for common indoor air pollutants. 

In an air sample test, indoor air is measured against outdoor air to determine the differences in pollution. Surface samples require the use of a swab, tape, or a petri-type dish to collect a specific sample from the questionable surface. Lastly, bulk samples collect a large volume of material to test for a particular contaminant. 

An air quality monitor is an electronic device that routinely collects air quality data measured against baseline levels. This device is always “on” and constantly monitors changes in contaminant levels. 

The Most Common Indoor Air Pollutants

According to the Environmental Protection Agency (EPA), there are 13 indoor pollutants that may interfere with air quality in private homes and buildings. In this particular article, we will focus on the 7 most prominent pollutants specific to homes and private residences, which include:

  • Biological pollutants
  • Carbon monoxide
  • Formaldehyde
  • Indoor particulate matter
  • Pesticides
  • Secondhand smoke
  • Volatile organic compounds. 

Biological Pollutants

Biological pollutants most commonly trigger allergy and asthma symptoms and fit the mold for what we normally envision when we hear the phrase “air pollution.” Biological pollutants include: pet dander, insect parts, bacteria, viruses, pollen, mold, pest droppings, and more. 

You can keep biological pollution at bay by regulating home humidity levels. Optimal home humidity levels for maximum comfort and air quality is between 40% and 60%; you can achieve this humidity range by regularly using a humidifier in the most occupied areas of your home.

Carbon Monoxide

Carbon monoxide is an invisible, odorless gas that can go completely unnoticed without proper detection. Carbon monoxide is extremely toxic and potentially lethal in high concentrations. As of 2018, 38 states require private dwellings to install carbon monoxide detectors. 

Common sources of carbon monoxide in the home are:

  • Gas or space heaters without proper ventilation
  • Backdraft from appliances
  • Gas stoves
  • Car exhaust from attached garages
  • Tobacco smoke


Similar to carbon monoxide, formaldehyde is a toxic, colorless gas. Fortunately, formaldehyde has a strong odor, and can be identified rather quickly. There are many sources of formaldehyde gas, which include both home appliances and home products. 

Formaldehyde is a compound found in:

  • The resins found in certain wood products including the most common hardwood plywood
  • Certain building materials 
  • Insulation
  • Glue
  • Paint, coating, lacquers, finishes
  • Certain paper products
  • Certain beauty and consumer products (as a preservative)
  • Many fertilizers

Indoor Particulate Matter

Stove Top

Indoor particulate matter (PM) refers to either solid or liquid particles that remain suspended in the air. PM that is larger than 10 micrometers in diameter is considered troublesome because it can be inhaled through the nose or mouth and cause damage to internal organs.  

The most common sources of indoor particulate matter are:

  • Stoves
  • Heaters
  • The fireplace or chimney
  • Tobacco smoke


A pesticide is a chemical used both indoors and outdoors to kill insects, vermin, bacteria, fungi, and other “pests.” Pesticide fumes can contaminate air from the use of insecticides (ant spray, cockroach spray), termiticides, rodenticides, fungicides, and disinfectants. 

Secondhand Smoke

Smoking popularity has decreased from 20% of American adults in 2005 to 14% of American adults in 2019. While this statistic is promising, there is still a significant number of Americans who smoke cigarettes. 

Secondhand smoke is the combination of smoke emitted from cigarettes, cigars, or pipes in tandem with the smoke exhaled by the smoker. Secondhand smoke contains over 7,000 substances and is considered a Group A carcinogen. 

Volatile Organic Compounds

Person Spraying Aerosol Paint on Wall

Volatile organic compounds (VOCs) are gases that escape from various solid or liquid products. VOCs can be found both indoors and outdoors; in fact, studies conducted by the EPA's Total Exposure Assessment Methodology or TEAM revealed that organic compounds are 2 to 5 times more likely to be found in the home than outdoors. 

The most common sources of VOCs are:

  • Paint products
  • Wood preservatives
  • Aerosol sprays
  • Disinfectants
  • Air fresheners
  • Car products (fuel, oil, etc.)
  • Dry-cleaned clothing

What Should You Test for in Your Home?

With so many potential contaminants in your home air, where exactly do you start?

Fortunately, you do not have to test for every single potential indoor air contaminant to effectively analyze your home air quality. The best strategy to implement when selecting an air quality test for your home is deductive reasoning. 

For example, if you and your family experience allergy-like symptoms in your home (including congestion, runny nose, itchy skin, etc.), you may want to test the levels of biological pollutants. Or, if you have an older home and suspect that certain rooms lack adequate ventilation, you can test for indoor particulate matter and formaldehyde. 

You can purchase home air quality tests and air quality monitors on Amazon or your local home improvement store. If you would prefer to leave the analysis to a professional, you can hire an air quality testing company to assess your home.