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://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.
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.
