Formaldehyde and Out-Gassing
| 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. |
Steps to Reduce
Exposure
- Use "exterior-grade" pressed wood products
(lower-emitting because they contain phenol resins, not urea
resins).
- Use dehumidifiers
and air conditioning to maintain moderate
temperature and reduce humidity levels.
- Increase ventilation, particularly after bringing new sources
of formaldehyde into the home.
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| 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.
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.
Health Effects
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
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 dehumidifiers and air conditioning to maintain moderate
temperature and reduce humidity levels.
- Increase ventilation, particularly after bringing new sources
of formaldehyde into the home.
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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.
Steps to Reduce
Exposure
- Use "exterior-grade" pressed wood products
(lower-emitting because they contain phenol resins, not urea
resins).
- Use dehumidifiers
and air conditioning to maintain moderate
temperature and reduce humidity levels.
- Increase ventilation, particularly after bringing new sources
of formaldehyde into the home.
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