VOCs, or Volatile Organic Compounds, are compounds that contain carbon atoms and evaporate easily at room temperature. Too small to see and virtually ubiquitous indoors and outdoors, they can be inhaled during normal breathing.
“Volatile” means that the compound vaporizes. “Organic” in this context means “containing carbon molecules”. Although “organic” also generally suggests “naturally occurring,” many VOCs are man-made.
Some VOCs, such as the odors emitted by many decorative flowers, are pleasant when inhaled. However, not all VOCs have an associated odor, which means people can’t always tell they’re breathing them in. This is a problem because, while many VOCs are harmless, many are dangerous.
Examples of Common VOCs
The following list includes examples of some of the most common VOCs and some household products where you might find them. This list is by no means exhaustive.
- Acetone (nail polish remover and furniture wax)
- Formaldehyde (pressed wood products, insulation and synthetic fabrics)
- Chloroform (as a byproduct of water chlorination)
- Benzene (paint, glue, gasoline and cigarette smoke)
- Butanal (released by stoves, candles and cigarettes)
- Dichlorobenzene (air fresheners and moth balls)
- Ethanol (glass cleaners and detergents)
- Terpenes (wood-based panels)
- Ethylene glycol (paint and solvents)
- Xylene (gasoline, adhesives, lacquers)
Microbial volatile organic compounds
Microbial volatile organic compounds (mVOCs) are particularly small. They include mold as well as other fungi and certain bacteria.
Certain mVOCs are often blamed for causing ‘sick house syndrome’ and ‘sick building syndrome’. Health professionals sometimes use these terms when referring to people with a mixture of adverse reactions to the structures in which they live or work. Moisture as well as naturally occurring mVOCs like mold and human-made VOCs in building materials can all play a role in sick house/building syndrome.
Although not technically an mVOC, radioactive radon gas is often classified in public records as mVOCs because it is invisible when inhaled and can dangerously contaminate homes and other structures. Produced by the breakdown of uranium in soil, rock and water under a building, radon is the leading cause of lung cancer in non-smokers, according to the Environmental Protection Agency (EPA).
Sources of human-made VOCs
Thousands of everyday man-made products contain VOCs which turn into gases at room temperature.
Since some VOCs are accidentally produced during combustion or industrial processes, there are an unknown number. Instead of creating ever-longer lists of VOCs, the EPA, American Lung Association, and various researchers have identified some of the most common human sources of dangerous VOCs.
In homes, offices, places of business, healthcare facilities and factories, common sources of VOCs can include:
- Natural gas in stoves and fuels used to heat homes
- Cleaning solvents, disinfectants and deodorants
- glues and many arts and crafts materials like permanent markers,
- Paints, strippers, varnishes and lacquers
- Mastics, sealants and adhesives
- Printers and copiers
- Carpets and upholstery
- Fire extinguishers
- PVC pipes
- Pressed wood products commonly found in low cost mobile home furniture, flooring, walls and cabinetry
- Personal care products, cosmetics and nail polish removers
- Dry cleaned clothes
- Industrial processes
- Fumigants used to control pests and insects,
Hospitals and healthcare facilities are often high in VOCs due to their heavy reliance on cleaning solutions and disinfectants and due to the plastics used in buildings.
Common outside sources include:
- Exhaust gas
- Propane and butane in outdoor torches, gas grills and heaters
- Industrial emissions
- Smoke from fireplaces and wood-burning stoves
- Emissions from oil and gas fields
- Agricultural fumigants.
Outside in sunlight, some VOCs bind to larger airborne molecules and contribute significantly to particulate air pollution and ground-level ozone (smog).
The EPA regulates VOCs that help create smog. However, it does not regulate outdoor VOCs which do not contribute to smog. This means it does not regulate VOCs which are primarily found indoors.
Volatile Organic Compounds in Groundwater
According to the United States Geological Survey (USGS), when man-made liquids in surface waters like lakes, rivers, and streams contain VOCs, the VOCs tend to evaporate into the air. However, if VOCs find their way into groundwater due to a leak in an underground storage tank, for example, or due to improper disposal, they can enter aquifers. Some VOCs cling to the ground of the aquifer. Bacteria disintegrate some of them. Even so, a significant amount can end up in the drinking water supply.
VOCs from chlorinated water and methyl tert-butyl ether (MtBE) are often found in well water. MtBE is a liquid that has been added to gasoline. Its use was discontinued when scientists realized it sickened the liver and kidneys and caused cancer in laboratory animals. Although no longer on the market, MtBE is particularly persistent in groundwater and water supplies.
Most water from public water supplies is regularly tested for VOCs. Water that is in private wells can be tested in certified labs for VOC concentrations.
How to Avoid Indoor VOCs
VOCs are difficult to avoid indoors. Often they are in building materials and furniture. They are also numerous in everyday household products.
The EPA and the Centers for Disease Control and Prevention (CDC) recommend avoiding overexposure to VOCs. Together, their ideas for how to proceed include:
- Open windows if possible and weather permitting.
- Use products containing VOCs only in well-ventilated areas.
- Follow label precautions and even exceed recommendations when possible.
- Shop for paints, paint sealants, glues, varnishes, lacquers, and more. in small quantities and do not store leftovers in open containers.
- Safely dispose of leftover VOC products if you are not likely to use them. (Many municipalities coordinate special toxic waste collection days.)
- To minimize the off-gassing of formaldehyde, apply a sealer to the pressed wood. (Be careful, though, not to use a high-VOC sealant.) The EPA also recommends using an air conditioner and dehumidifier on hot days to slow the rate of off-gassing.
- Use insect and pest control systems that do not rely on fumigation.
- Keep materials containing VOCs out of reach of children and pets.
- Do not mix products containing VOCs unless the labels tell you to.
- Prohibit smoking tobacco at home.
- Don’t accept dry-cleaned clothes that have a strong odor. A dry cleaner can keep clothes until the VOCs have degassed. It may also be a good idea to hang dry-cleaned clothes outside for a while before wearing them.
- Use cosmetics and nail polish remover without acetone.
- When cooking, use a range hood with an exhaust fan.
Unfortunately, the EPA warns that terms like “green,” “eco,” and “eco-friendly” on product labels aren’t always reliable indicators of VOC levels. Ditto, unfortunately, for “low VOC” and “zero VOC”.
In the United States, no national organization other than the Food and Drug Administration (FDA) regulates the labeling of VOCs, and the FDA only regulates food, drug, and personal care product labels. Some international programs regulate VOC labeling, but they do not always use standardized standards.
Although HEPA filters work well at capturing small airborne solid particles like dust, pollen, mold, and bacteria, they cannot capture gases. To remove VOCs from indoor air, the EPA recommends the use of portable air purifiers that rely on activated carbon filters. According to the agency, they can remove 95-99% of VOCs from the air.
Beware of VOCs in Personal Care Products
Cosmetics, perfumes and nail polish removers are common sources of many VOCs. True, not all of them are harmful. Some, however, are. For example, while acetone is a natural chemical that humans make in their bodies, in high doses in personal care products it has known effects on the eyes, skin, respiratory system, and nervous system. center of humans. Acetone is found in many nail polish removers and lotion-based cosmetics.
The FDA does not have the authority to approve ingredients in cosmetics, perfumes, and nail polish removers. This means that it does not test them for safety before allowing them in a product. Instead, the agency regulates the ingredients. It does this largely by insisting that all ingredients be clearly listed on product labels.
Even so, the FDA may have difficulty ensuring that products carry useful information on their labels. For example, it cannot require manufacturers to disclose trade secrets. For this reason, the labels are sometimes less clear. For example, rather than naming a specific chemical additive that creates a fragrance and is proprietary to a manufacturer, a product label may simply use the generic term “fragrance”.