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Volatile Organic Compounds (VOCs) Assessments

Jason Yost • Jan 19, 2023

Volatile Organic Compounds (VOCs) Assessments

I was hired by the FBI to work in two of their offices. These offices had received several occupant complaints of Building Related Symptoms (BRS). (BRS are symptoms that one experiences only while inside a given environment.) Both buildings had been newly constructed within three years of my assessment; both buildings’ construction crews performed normal moisture monitoring and met the Army Corp of Engineers’ specifications for construction design and integrity; and, both buildings were experiencing the same complaints: headaches, nausea, and eye irritation. And regardless of where the occupant was inside the building the symptoms were the same. 

4-PCH and IAQ

During my assessment several things were discovered, including: (1) the Heating, Ventilation and Air Conditioning (HVAC) system didn’t include an outdoor dilution system (commonly referred to as an Energy Recovery Ventilator or ERV), and (2) the glued-down, rubber-backed carpet tiles were coming loose from the concrete foundation. Upon further investigation, elevated moisture content was measured in the rubber backing and concrete subfloor below the loose carpet tiles. Water was seeping upward, through the pores in the concrete slab, into the flooring adhesive and rubber backing. To quickly summarize: Sampling determined an airborne agent, namely 4-Phenylcyclohexene (4-PCH), was slightly elevated in the indoor atmosphere. This was the environmental stressor causing so much irritation and illness. 

Agents, like 4-PCH, are generally referred to as Volatile Organic Compounds (or VOCs). VOCs refer to a board classification of thousands of organic gases found indoors and outdoors. According to the EPA’s Total Exposure Assessment Methodology (TEAM), studies have found that levels of about a dozen common organic pollutants may be 2 – 5 times higher inside homes than outside, regardless of whether the homes were in rural or highly industrial areas. This is due to several factors, including but not limited to (1) the differences in how the closed indoor environments are artificially ventilated as compared to the varying means and ways the outdoor environment is ventilated and (2) the concentration of building materials indoors that emit VOCs. 

carpet and IAQ

Sources of VOCs may include paints, varnishes, pressed wood products, floor coverings (e.g., carpet) and their adhesives, cosmetics, air fresheners, cleaning products, electronics, dry-cleaned clothing and furnishings, Environmental Tobacco Smoke (ETS), cooking, microorganisms, and many other sources. And the off-gassing rate of each of these products may be increased with the introduction of heat (e.g., from sunlight), moisture (e.g., from water seeping in through the foundation), or ozone or hydroxyl generating air devices. 

Over the past 20 years the EPA has authored a series of “Toxic Organic Compound” sampling methods of the ambient air. These methods are more commonly referred to as the “TO methods”. The early methods of analysis were cumbersome, but times have changed with the TO-15 method. TO-15 uses more sophisticated canister technology, capable of detecting parts per trillion of certain VOCs. The GC/MS instrument also makes it possible to look at “unknown compounds” and make tentative identifications. It is this versatility that makes TO-15 one of the most powerful tools that an investigator can use for any initial evaluation.

VOC testing

But you’re asking, how can this help me? Good question.


TO-15 can be used for most Indoor Air Quality (IAQ) investigations. You can use it for odor identification, general investigations, and clearance testing after remediation. TO-15 can also be used in mold investigations by identifying the microbial Volatile Organic Compounds (mVOCs); this is especially important where odors are present, but no elevations of mold spores are found in initial air sampling. Certain mVOcs, like 3-methyl-1-butanol, 2-hexanone and 2-heptone have been used as fungal growth indicators.


I have found TO-15 sampling useful in measuring (1) the degree of hydrocarbon contamination in a building adjacent to a service station; (2) find out what was causing an acrid odor on the side of a complainant’s home that receives the early morning sun; (3) measure workplace exposures to various compounds in a pesticide plant; (4) to evaluate the IAQ in a structure occupied by a chemically sensitized occupant; (5) in a facility adjacent to a waste-water treatment plant to measure infiltration of unwanted VOCs; and, (6) to gather information on fixed gases like carbon monoxide and carbon dioxide.


If you’re dealing with a known, suspect, or potential IAQ problem, contact us to learn more about how Gulf Coast Center for Indoor Air Quality Services can serve you with your IAQ assessment needs.

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