Indoor Air Quality FAQs

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 - Collection

VOC (Volatile Organic Compound) testing using our A2 TDT (thermal desorption tubes) is collected for 2 hours for typical indoor environments. Maximum recommended sampling time is 4 hours. Contact us for project-specific recommendations outside this type of testing. 

Formaldehyde testing using our A14-type TDT (thermal desorption tubes) is 20 to 30 minutes. Maximum recommended sampling time is 45 minutes.

For general testing, place the sampling equipment in a central location approximately 3-5 feet above the floor. Keep the building conditions in
normal operating mode.
For problem specific testing, place the sampling equipment in the center of the problem area and isolate the area by closing doors as much as
possible. Increase the temperature above normal to maximize the VOCs in the air.

The pump flow rate is 0.2 L/min or 200 ml/min.

•Close outside doors and windows - preferably for one entire day before sampling.
•Leave all interior doors (including closets) open to allow the air to flow freely.
•Refrain from frying or cooking with oils the day before and during the test toprevent artificially high VOC results. Also, please do not cook at all during the test.
•Do not clean or dust during the test or within 12 hours of beginning the test.For homes greater than 2,000 square feet or with several levels, you may want to consider performing more than one test in order to collect air samples representative of the entire home. Some possible sampling locations in larger homes are: the center area of each floor; one side of the house on one floor and the other side of the house on another floor; two sides of a single-story home; or any room(s) in the house where the occupants spend the most time, like a family room, basement, bedroom, etc.

•To the extent possible, keep the area closed and operating in a normal manner.
•Do not clean or dust during the test or within 12 hours of beginning the test.

Some industrial locations may have high concentrations, especially in production or manufacturing areas. If high concentrations are suspected or unusual sampling conditions exist, contact Prism to discuss sampling modifications (e.g., decrease in sample collection time).
•Do not clean or dust during the test or within 12 hours of beginning the test.

 - General

We recommend that you return your pump to Prism annually for recertification and calibration.

Each analysis has its own turn around time (TAT), either 2, 5, or 10 business days. Refer to your Price List (Bulletin 905), Air Survey Matrix (Bulletin 933), or contact us for the analysis specific TAT.

The hold time following sample collection for a thermal desorption tube (TDT) is 30 days. As the TDT sits it will pick up small amounts of VOCs from the surrounding air which eventually may cause slightly higher results. This process is continuous so although the TDT will adsorb VOCs in the first 30 days the amount is expected to be minimal.

 - Shipping

To purchase additional thermal desorption tubes (TDT), contact us by phone or email.

2625 Denison Drive Mt. Pleasant, MI 48858

Availability of expedited service is dependent on sample load and instrument availability. Contact the lab (989.772.5088)
to ensure expedited service is available before submitting samples.

Service Price Multiplier

Same Day or Weekend  3 X
1 Business Day  2 X
2 Business Day  1.5 X
3 Business Day  1.25 X
4 Business Day to Std TAT  1.10 X


Rush shipping is available. Contact us (989-772-5088) for specific estimates.



Organic compounds (those containing carbon) that are readily volatile, or evaporated, at "room" temperature. Some organizations define this by the boiling point range of the compounds, approximately 50 to 250 degrees C.

VOCs are in everyone's air from the building, activities, and contents. The combination of all VOCs, i.e., total VOC, and the specific composition
of the VOCs can affect air quality. Higher levels of VOCs typically lead to a variety of health issues. Certain chemical compounds can cause severe reactions or unpleasant odors, even at low concentrations.

VOCs can cause a range of symptoms, especially for more sensitive groups like children, pregnant women, elderly. They can also exacerbate existing conditions such as asthma. VOCs can also affect the ability to concentrate and have other less noticeable effects.

Possible Symptoms:

  • Respiratory discomfort including wheezing, burning sensation in throat, scratchy throat, shortness of breath
  • Skin reactions including rash, burning sensation
  • Eye irritation
  • Organ and tissue damage (minor to cancer)

Since everyone reacts to VOCs differently, it can be difficult to set guidelines.

Workplaces have limits to protect worker health.

Temperature, humidity, air flow/ventilation, chemical reactions with other compounds.

Mold VOCs

MVOCs are Volatile Organic Compounds (VOCs) that molds produce during their digestive process. They are primary metabolites and are therefore an indication of active mold growth.

Spores are the primary means of reproduction by molds. They are released at certain points in the mold life cycle or in response to a threat. Spores are spread by air currents and can settle and be carried on materials, people, and animals. Spores can remain viable for a long time until they can find a suitable environment to grow to form new colonies. *Note that Prism's Mold analyses do not include mold spore or mycotoxin determination.

Mycotoxins are chemicals that are produced during certain parts of the mold life cycle and can evoke a toxic response (e.g., severe allergic reactions and respiratory irritation and exacerbation of asthma symptoms or other respiratory ailments) in humans and animals. Mycotoxins have low volatility, meaning they have relatively low concentrations in air, so contact or ingestion rather than inhalation is often the main route of exposure for these chemicals. *Note that Prism's Mold analyses do not include mold spore or mycotoxin determination.

MVOCs are not different from other VOCs except that the source is from actively growing mold. MVOCs are subject to the same factors that affect other VOCs, primarily temperature and humidity.

TMVOC stands for Total Mold VOC and it is the sum of the 21 VOCs that are used to indicate active mold growth.

Since MVOCs do not indicate the genus/species, the individual MVOCs are most useful when sampling in a large building where molds in different areas may provide a different MVOC fingerprint, indicating that they are different even though the specific genus species cannot be identified or in situations where long term monitoring is occurring and changes in the individual MVOC proportions may indicate changes in the mold population or growing conditions.

Low temperature and/or humidity may slow down mold growth and reduce the concentrations of MVOCs. High ventilation rates or air filtering may dilute the MVOCs.


*Accreditation Pending

Formaldehyde is a colorless, strong-smelling gas. It is produced naturally by humans, plants (especially woods), and animals. Many man made materials also contain formaldehyde, including engineered wood products (e.g., particle board, plywood, OSB, MDF, flooring, etc.), some preservatives, personal care and cleaning products, cosmetics, permanent press fabrics, glues, air fresheners, paints and coatings. Formaldehyde is also a byproduct of combustion, which includes some vehicle exhaust, fuel-burning appliances (gas stoves, kerosene space heaters, etc.), fireplaces, wildfires, structural fires, tobacco smoke, and trash fires.

Formaldehyde is a known human carcinogen (cancer-causing agent), it can also cause nasal and eye irritation, increased risk of asthma and allergies, and neurological effects. At concentrations over 500 ppb it can also cause eczema and changes in lung function. Animal studies also showed decreased body weight, gastrointestinal ulcers, and liver and kidney damage at high doses.

Group 1 Carcinogen (see IARC reference below).

Formaldehyde cannot be reliably measured in blood, urine, or body tissues following exposure. Formaldehyde is produced in the body and would be present as a normal constituent in body tissues.

Since formaldehyde has several natural sources (photo chemical oxidation, especially of terpenes; combustion; plants, primarily wood, and animals; decomposition of plant and animal material), outdoor levels typically range from a few ppb in rural areas to ~20 ppb in more urban areas.

Indoor air usually has more formaldehyde than outdoor air, ranging from ~20 ppb to several hundred ppb depending on the situation. Concentrations are typically higher in the summer because of the higher temperature and humidity.

Tobacco Smoke

Tobacco smoke is a mixture of thousands of chemicals produced from the burning of tobacco products. These products include finely cut pieces of the tobacco plant as well as a number of additives that serve as flavorings and preservatives.

No, marijuana produces different VOCs than tobacco.

This test is not designed to cover e-cigarettes, but nicotine will be present in emissions from e-cigarettes, so this test may not be applicable to e-cigarettes other than in the immediate vicinity of vaping (vaping is the term used to describe the vaporization process used with e-cigarettes, it is equivalent to smoking when using a tobacco product).

There is no safe level for tobacco smoke. The U.S. Environmental Protection Agency, the U.S. National Toxicology Program, the U.S. Surgeon General, and the International Agency for Research on Cancer have all classified tobacco smoke as a known human carcinogen (a cancer causing agent).

Tobacco smoke can spread from neighboring spaces. A number of factors influence how much tobacco smoke travels from adjacent spaces and determines whether the tobacco smoke is detected with this test. These factors include:

i. amount, duration, and location of smoking

ii. how long the smoking has been occurring (e.g., weeks, months, years)

iii. type of material and construction of the wall/floor/ceiling

iv. building envelope (i.e., how tight is the building)

v. air exchange rates

vi. temperature and humidity

vii. amount of porous materials (e.g., carpet, draperies, furniture, etc.)

viii. location of the sample collection equipment

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About Prism

Yes, Prism is accredited by the American Industrial Hygiene Association (AIHA) in Industrial Hygiene for thermal desorption GC-MS (TD GC-MS).