An Introduction to Indoor Air Quality (IAQ)
Basic Information on Pollutants and Sources of Indoor Air Pollution
- Biological Pollutants
- Carbon Monoxide (CO)
- Formaldehyde/Pressed Wood Products
- Lead (Pb)
- Nitrogen Dioxide (NO2)
- Radon (Rn)
- Respirable Particles
- Secondhand Smoke/ Environmental Tobacco Smoke
- Stoves, Heaters, Fireplaces, and Chimneys
- Volatile Organic Compounds (VOCs)
Formaldehyde is an important chemical used widely by industry to manufacture building materials and numerous household products. It is also a by-product of combustion and certain other natural processes. Thus, it may be present in substantial concentrations both indoors and outdoors.
Sources of formaldehyde in the home include building materials, smoking, household products, and the use of un-vented, fuel-burning appliances, like gas stoves or kerosene space heaters. Formaldehyde, by itself or in combination with other chemicals, serves a number of purposes in manufactured products. For example, it is used to add permanent-press qualities to clothing and draperies, as a component of glues and adhesives, and as a preservative in some paints and coating products.
TSCA Assistance Line
For further information on formaldehyde and consumer products, call the EPA Toxic Substance Control Act (TSCA) Assistance Line (202) 554-1404.
In homes, the most significant sources of formaldehyde are likely to be pressed wood products made using adhesives that contain urea-formaldehyde (UF) resins. Pressed wood products made for indoor use include: particleboard (used as sub-flooring and shelving and in cabinetry and furniture); hardwood plywood paneling (used for decorative wall covering and used in cabinets and furniture); and medium density fiberboard (used for drawer fronts, cabinets, and furniture tops). Medium density fiberboard contains a higher resin-to-wood ratio than any other UF pressed wood product and is generally recognized as being the highest formaldehyde-emitting pressed wood product.
Other pressed wood products, such as softwood plywood and flake or oriented strand board, are produced for exterior construction use and contain the dark, or red/black-colored phenol-formaldehyde (PF) resin. Although formaldehyde is present in both types of resins, pressed woods that contain PF resin generally emit formaldehyde at considerably lower rates than those containing UF resin.
- Sources of Formaldehyde
- Health Effects
- Levels in Homes
- Steps to Reduce Exposure
- Additional Resources
- Proposed Rulemaking: Formaldehyde Emissions from Pressed Wood Products
Since 1985, the Department of Housing and Urban Development (HUD) has permitted only the use of plywood and particleboard that conform to specified formaldehyde emission limits in the construction of prefabricated and mobile homes. In the past, some of these homes had elevated levels of formaldehyde because of the large amount of high-emitting pressed wood products used in their construction and because of their relatively small interior space.
The rate at which products like pressed wood or textiles release formaldehyde can change. Formaldehyde emissions will generally decrease as products age. When the products are new, high indoor temperatures or humidity can cause increased release of formaldehyde from these products.
During the 1970s, many homeowners had urea-formaldehyde foam insulation (UFFI) installed in the wall cavities of their homes as an energy conservation measure. However, many of these homes were found to have relatively high indoor concentrations of formaldehyde soon after the UFFI installation. Few homes are now being insulated with this product. Studies show that formaldehyde emissions from UFFI decline with time; therefore, homes in which UFFI was installed many years ago are unlikely to have high levels of formaldehyde now.
Sources of Formaldehyde
Pressed wood products (hardwood plywood wall paneling, particleboard, fiberboard) and furniture made with these pressed wood products. Urea-formaldehyde foam insulation (UFFI). Combustion sources and environmental tobacco smoke. Durable press drapes, other textiles, and glues.
Formaldehyde, a colorless, pungent-smelling gas, can cause watery eyes, burning sensations in the eyes and throat, nausea, and difficulty in breathing in some humans exposed at elevated levels (above 0.1 parts per million). High concentrations may trigger attacks in people with asthma. There is evidence that some people can develop a sensitivity to formaldehyde. It has also been shown to cause cancer in animals and may cause cancer in humans. Health effects include eye, nose, and throat irritation; wheezing and coughing; fatigue; skin rash; severe allergic reactions. May cause cancer. May also cause other effects listed under "organic gases."
- EPA's Integrated Risk Information System profile on Formaldehyde: www.epa.gov/iris/subst/0419.htm
Levels in Homes
Average concentrations in older homes without UFFI are generally well below 0.1 (ppm). In homes with significant amounts of new pressed wood products, levels can be greater than 0.3 ppm.
Steps to Reduce Exposure
- Use "exterior-grade" pressed wood products (lower-emitting because they contain phenol resins, not urea resins).
- Use air conditioning and dehumidifiers to maintain moderate temperature and reduce humidity levels.
- Increase ventilation, particularly after bringing new sources of formaldehyde into the home.
Ask about the formaldehyde content of pressed wood products, including building materials, cabinetry, and furniture before you purchase them.
If you experience adverse reactions to formaldehyde, you may want to avoid the use of pressed wood products and other formaldehyde-emitting goods. Even if you do not experience such reactions, you may wish to reduce your exposure as much as possible by purchasing exterior-grade products, which emit less formaldehyde.
- For further information on formaldehyde and consumer products, call the EPA Toxic Substance Control Act (TSCA) assistance line (202) 554-1404
Some studies suggest that coating pressed wood products with polyurethane may reduce formaldehyde emissions for some period of time. To be effective, any such coating must cover all surfaces and edges and remain intact. Increase the ventilation and carefully follow the manufacturer instructions while applying these coatings. (If you are sensitive to formaldehyde, check the label contents before purchasing coating products to avoid buying products that contain formaldehyde, as they will emit the chemical for a short time after application.)
Maintain moderate temperature and humidity levels and provide adequate ventilation.
The rate at which formaldehyde is released is accelerated by heat and may also depend somewhat on the humidity level. Therefore, the use of dehumidifiers and air conditioning to control humidity and to maintain a moderate temperature can help reduce formaldehyde emissions. (Drain and clean dehumidifier collection trays frequently so that they do not become a breeding ground for microorganisms.) Increasing the rate of ventilation in your home will also help in reducing formaldehyde levels.
Proposed Rulemaking: Formaldehyde Emissions from Pressed Wood Products
On July 7, 2010, President Obama signed the Formaldehyde Standards for Composite Wood Products Act (PDF, 9 pp., 135 K, about PDF) into law. This legislation, which adds a Title VI to TSCA, establishes limits for formaldehyde emissions from composite wood products: hardwood plywood, medium-density fiberboard, and particleboard. The national emission standards in the Act mirror standards previously established by the California Air Resources Board for products sold, offered for sale, supplied, used or manufactured for sale in California. Congress directs EPA to promulgate final regulations implementing the Act by January 1, 2013. Learn more at www.epa.gov/opptintr/chemtest/formaldehyde/ .
An Update on Formaldehyde: 1997 Revision (CPSC document #725)
This booklet to tell you about formaldehyde found in the indoor air. This booklet tells you where you may come in contact with formaldehyde, how it may affect your health, and how you might reduce your exposure to formaldehyde. Visit the CPSC website at www.cpsc.gov.
ToxFAQs™ for Formaldehyde (Formaldehido) (June 1999) U.S. Dept. of Health and Human Services, Agency for Toxic Substances and Disease Registry (ATSDR) www.atsdr.cdc.gov/tfacts111.html
Safety and Health Topics: Formaldehyde U.S. Dept. of Labor, Occupational Safety and Health Administration (OSHA) www.osha.gov/SLTC/formaldehyde/
American Lung Association www.lungusa.org Search "formaldehyde" for resources