What are VOCs?
Volatile organic compounds (VOCs) are emitted as gases from certain solids or liquids. VOCs include a variety of chemicals, some of which may have short- and long-term adverse health effects.
Concentrations of many VOCs are consistently higher indoors (up to ten times higher) than outdoors. VOCs are emitted by a wide array of products numbering in the thousands. Examples include: paints and lacquers, paint strippers, cleaning supplies and pesticides.
They are released by building materials such as carpet, linoleum, composite wood products, insulation and furnishings to name a few. Office equipment such as printers, copiers, fax machines, adhesives, permanent markers, and photographic solutions. may also emit VOCs.
Organic chemicals are widely used as ingredients in household products. Paints, varnishes, and wax all contain organic solvents, as do many cleaning, disinfecting, cosmetic, degreasing, and hobby products. Fuels are made up of organic chemicals. All of these products can release organic compounds while you are using them, and, to some degree, when they are stored.
VOCs are chemicals that have high vapor pressures and fairly low boiling points and that tend to vaporize from the liquid or solid state under normal atmospheric conditions. Vapor pressure relates to the equilibrium of a substance between its solid or liquid state and its gas state, that is, the rate at which a liquid evaporates or a solid sublimates. If the vapor pressure is high, then the substance will move to the gas phase more quickly. Substances with high vapor pressure at room temperature are said to be volatile. VOCs also often have low boiling points (often below room temperature) that contribute to their vaporization. Examples of some common VOCs are formaldehyde, benzene, toluene, limonene, and hexane.
Microbial Volatile Organic Compounds (mVOCs)
Some compounds produced by molds and mildew are volatile and are released directly into the air. These are known as microbial volatile organic compounds (mVOCs). Because these compounds often have strong and/or unpleasant odors, they can be the source of odors associated with molds.
As mold “consumes” it’s food, the chemical reactions of enzymes, substrates and mold growth produce carbon dioxide, water, and volatile organic compounds (VOC’s). Because these items are a result of actions essential to the growth of the organism, they are classified as primary metabolites.
For mold, many types of VOC’s are produced and typically include aldehydes, alcohols, keytones, and hydrocarbons. They have complex structures and names like “2-methyl-1-propanol”.
When you smell a “musty-moldy” odor, it’s generally the VOC’s you are noticing. VOC’s are often considered irritants to mucus membranes, however, are also capable of both short-term and long-term adverse health effects. If you do smell these odors, it’s a sure sign the mold is consuming and growing and you need to take action.
Frequently found MVOCs include geosmin, hexanone, and octanols. Some of these MVOCs have been found to be irritants to humans and contribute to sick building syndrome, also known as building-related symptoms. Microbial VOCs can be easily measured in the air at very low levels, and their presence is an indication of mold contamination. Since mold is frequently found inside walls and other inaccessible areas, Microbial VOC measurements are used as a way of confirming and locating mold contamination.
Health Effect of VOCs
Volatile organic compounds can even be found in small amounts in the air we breathe out of our lungs. Normal human breath can contain a mixture of several hundred VOCs. Some researchers have even found a combination of 22 VOCs that may even help detect lung cancer since those with lung cancer exhale more VOCs than those without lung cancer. However, this is NOT a way to accurately diagnose lung cancer at this time.1
Each VOC chemical has its own toxicity and potential for causing different health effects. The possible risk of health effects from inhaling any chemical depends on how much is in the air, how long and how often a person breathes it in. Scientists look at short-term (acute) exposures as hours to days or long-term (chronic) exposures as years to even lifetime.
Common symptoms of exposure to VOCs include:
Short-Term (Acute) to high levels of VOCs
• Eye, nose and throat irritation
• Headaches
• Nausea / Vomiting
• Dizziness
• Worsening of asthma symptoms
Long-Term (Chronic) to high levels of VOCs Increased risk of:
• cancer
• Liver damage
• Kidney damage
• Central Nervous System damage
How Are VOC’s Sampled?
The best way to sample the widest range of compounds with the greatest of ease is TO-15, a sophisticated canister technology capable of seeing parts per trillion of certain volatile organic compounds. 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 used for investigation and for any initial evaluation.
The TO-15 analysis as written by the EPA refers to a specific 63 compound list of regulated compounds. The list was developed to support the Clean Air Act. Safety Environmental Testing will also perform a non-target compound library search. This will provide a listing of up to 10-20 extra compounds that are not targets. These compounds are referred to tentatively identified compounds (TICs).
Removing VOCs from the Air
Using an activated carbon (a carbon or charcoal that is very porous and has a large surface area) filter is the most reliable way to remove VOCs from the air. VOCs attach to and accumulate on the activated carbon in the process known as adsorption. These filters become exhausted or “spent” and must be frequently replaced. Otherwise, the adsorbed VOCs may desorb, or leave the surface of the activated carbon and return to the air.