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Sources of Indoor Air Pollution - Formaldehyde
For further information on formaldehyde and consumer
products, call the EPA Toxic Substance Control Act (TSCA) Assistance Line (202) 554-1404. |
Introduction
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.
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 strandboard, 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.
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.
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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 - http://www.epa.gov/iris/subst/0419.htm
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.
- 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.
Reducing Exposure to Formaldehyde in Homes
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.
Additional Resources
An Update on
Formaldehyde: 1997 Revision (CPSC document #725). U.S.
Consumer Product Safety Commission
The U.S. Consumer Safety Commission has
produced 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. The PDF version of this document is available here (formaldehyde_cpsc.pdf
(38 KB file)).
Indoor Air Quality
Guideline - Formaldehyde in the Home
State of California Air
Resource Board, #1, September 1991.
National Cancer Institute Fact Sheet "Formaldehyde and Cancer: Questions
and Answers" -
http://cis.nci.nih.gov/fact/3_8.htm
Occupational Safety and Health Administration's fact sheet on Formaldehyde
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www.osha.gov/SLTC/formaldehyde/
The National Safety Council's Environmental Health Center
fact sheet on Formaldehyde
American Lung
Association
1740 Broadway
New York, NY 10019-4374
(local ALA offices also have information)
The Formaldehyde Institute, Inc.
1330 Connecticut Ave., N.W.
Washington, DC 20036
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