Formaldehyde In The Indoor Environment
What formaldehyde is
Sources of formaldehyde
Measuring for formaldehyde
Formaldehyde: A human carcinogen
Other health problems associated with formaldehyde
Decreasing exposure to formaldehyde
What NOT to do
What Formaldehyde Is
Formaldehyde is a colorless gas with a strong odor at room temperature. Formaldehyde is a type of volaticle organic compound (VOC) that is a common indoor air pollutant. Formaldehyde is an important chemical used widely to manufacture building materials and numerous household products. It is also a by-product of combustion and certain other natural processes.
Formaldehyde, by itself or in combination with other chemicals, serves a number of purposes in manufactured products. For example, it is used as a preservative, as an embalming fluid, as a component of glues and adhesives, and as a preservative in some paints and coating products. Formaldehyde is also used to add permanent-press qualities to clothing and draperies.
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 subflooring and shelving and in cabinetry and furniture); hardwood plywood paneling (used for decorative wallcovering and used in cabinets and furniture); and medium density fiberboard (used for drawer fronts, cabinets, and furniture tops).
Sources of Formaldehyde Formaldehyde is a very common chemical and can be found in the following items:
In addition to being found in these products, it is also a by-product from burning wood, kerosene, or natural gas, and from automobiles. The rate at which products such as these release formaldehyde can change. Formaldehyde emissions are greater when products are new and decrease as these products age. Some products like furniture and cabinetry with pressed wood may emit low levels of formaldehyde for long periods. Higher indoor temperatures or high humidity can also increase the release of formaldehyde.
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, because 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. Average concentrations in older homes without UFFI are generally well below 0.1 ppm. Though formaldehyde is not used in the making of carpets, it has been used in the adhesive to hold down carpeting as well an adhesive or bonding agent for many other materials found in homes, schools, and offices such as upholstery, particleboard and plywood paneling.
Measuring for Formaldehyde
Formaldehyde is usually present in concentrations less than 0.03 ppm both outdoors and indoors. However, in homes with many new pressed wood products, levels can be greater than 0.3 ppm. This could be a problem since formaldehyde is a probable carcinogen and there are no known safe levels of exposure to carcinogens. Because of this, the National Institute of Occupational Safety and Health (NIOSH) recommends that 0.1ppm not be exceeded for more than 15 minutes during a 10-hour day. Also to prevent possible health effects over a working lifetime, NIOSH has recommended that workers not be exposed to more than 0.016 ppm averaged over a 10-hour workday. The legal limit for workplaces covered by Occupational Safety Health Administration (OSHA) is 0.75 ppm averaged over an 8-hour work shift. In addition, 2 ppm should not be exceeded during any 15-minute work period. The World Health Organization recommends that exposure should not exceed 0.05 ppm. The odor of formaldehyde is generally first sensed at 1 ppm but some individuals can smell it at 0.05ppm.
Though do-it-yourself formaldehyde measuring devices are available, they just provide a "ballpark" estimate. In addition, there is usually no single sample taken at one particular time that can give a reliable indication of the overall exposure. Because there are many factors that can affect the level of formaldehyde on a given day in an office or residence, it is recommended that a professional (such as an industrial hygienist) conduct the testing.
The International Agency for Research on Cancer, a World Health Organization panel of 26 scientists from 10 countries, has concluded that formaldehyde is a human carcinogen. Previously, the WHO has classified formaldehyde as a probable human carcinogen. After reviewing the latest epidemiologic studies, the panel determined that there is now sufficient evidence that formaldehyde causes nasopharyngeal cancer in humans, a rare cancer found in developed countries that impacts the back of the mouth and nose. The panel also found limited evidence for cancer of the nasal cavity and paranasal sinuses and “strong but not sufficient evidence" for leukemia.
These findings are significant because the US Environmental Protection Agency has adopted a more less stringent assessment than the WHO. The evidence reviewed by both the EPA and WHO included results from recent studies by the National Cancer Institute, the National Institute of Occupational Safety and Health (OSHA) and a study from England showing that exposure to formaldehyde might also cause leukemia in humans. The WHO panel noted that the scientific evidence has not yet determined how formaldehyde would cause cancer and called for more research. The EPA concluded that the studies were contradictory and not thoroughly reviewed.
Check back here for further updates. The section below reviews other health problems associated with formaldehyde.
Other Health Problems Associated With Formaldehyde
Health problems caused by formaldehyde can either be acute which occur immediately or within a few days of exposure or they can be chronic which are long-term health effects that might not show up for many years. Exposure to formaldehyde can result in:
Eye, nose, and throat irritation; possible eye damage
Coughing; Chest tightness; wheezing, and asthma
Skin rash and/or hives
Nausea and/or vomiting
Cancer (has been shown to cause cancer of the nasal passages in animals)
Exposure to large amounts of formaldehyde may cause pulmonary edema (fluid build-up in the lungs) as well as damage the liver, kidneys, and the central nervous system.
Sensitivity among different people varies widely. Some people may become more sensitive to formaldehyde after an initial exposure. It is estimated that 10 percent to 20 percent of the US population have hyperreactive airways, which may make them more susceptible to irritant effects of formaldehyde. Children and adults have developed allergic reactions, including hives, from exposure to formaldehyde. Other persons have developed allergic reactions (such as allergic skin disease and hives) because of either direct skin contact with solutions of formaldehyde or by wearing permanent-press clothing containing formaldehyde.
Decreasing Exposure to Formaldehyde
In 1985, Department of Housing and Urban Development (HUD) passed a standard requiring that pressed wood products used in manufactured housing (such as prefabricated and mobile homes) contribute less than 0.4 ppm of formaldehyde to the air. 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.
There are no HUD standards for medium-density fiberboard (MDF). This type of 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.
In addition to the HUD standard, voluntary efforts by product manufacturers to reduce the use of formaldehyde-based resins have greatly reduced formaldehyde emissions. Since the early 1980s, manufacturers have reduced formaldehyde emissions from pressed wood products by 80 percent to 90 percent.
There continue to be things that you can do to reduce you exposure to formaldehyde exposures:
The best strategy to reduce exposure to formaldehyde is to avoid the use of products that contain it. Use alternate products such as lumber, metal, or solid wood furniture.
Choose and purchase materials that emit minimal levels of formaldehyde in the air. These products may be recognized by contacting the GREENGUARD Product Guide. This guide lists products that meet current requirements of the State of Washington, EPA, and OSHA for formaldehyde. Interior products such as textiles, flooring, furniture, chairs, insulation, wallcoverings, paints and other products are listed.
Make sure combustion sources are properly adjusted.
Some hair salons have measurable levels of formaldehyde. This is due to some state regulations that require formaldehyde tablets (which slowly release as formaldehyde gas) be kept in drawers containing hair supplies as a disinfectant. If you are sensitive to formaldehyde, ask your hair stylist about formaldehyde before making an appointment.
Ask about the formaldehyde content of pressed wood products, including building materials, cabinetry, and furniture before you purchase them. 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.
If you do buy products made of pressed wood, look for low-emitting plywood or particleboard stamped to certify that it meets HUD emission standards. The HUD stamp may look like this:
Another way to recognize a low-emitting formaldehyde product is also to look for products that are labeled or stamped to be in conformance with American National Standards Institute (ANSI) criteria. Particleboard should be in conformance with ANSI A208.1-1993. For particleboard flooring, look for ANSI grades "PBU," "D2," or "D3" actually stamped on the panel. MDF should be in conformance with ANSI A208.2-1994, and hardwood plywood with ANSI/HPVA HP-1-1994.
Buy furniture or cabinets that contain a high percentage of laminated or coated panel surface and edges. Unlaminated or uncoated (raw) panels of pressed wood products will generally emit more formaldehyde than those that are laminated or coated.
Avoid using foamed-in-place insulation containing formaldehyde, especially urea-formaldehyde foam insulation.
Coat exposed board products with a finish like polyurethane varnish, oil-based alkyd resin paint, or thick vinyl film. Some research has indicated that coating pressed wood products (including all surfaces and edges) may reduce formaldehyde emissions. To be effective, any such coating must cover all surfaces and edges, be applied in multiple or thick layers, and it should remain intact. Carefully follow the manufacturer's instructions while applying these coatings and apply in a well-ventilated area. Give the freshly painted item several weeks to air out.
Use exterior grade plywood instead of interior grade plywood, because it is formulated differently and emits the gas at lower rates. Adhesives in wood products contain either urea-formaldehyde, or UF, resins, commonly found in particleboard for subflooring, hardwood plywood paneling and medium-density fiberboard, or they contain phenol-formaldehyde, or PF, resins, found in soft plywood and other products meant for exterior use. The PF resin woods generally emit lower levels of formaldehyde, according to the Environmental Protection Agency. The HUD stamp will NOT appear on products made from phenol-formaldehyde resins even though they DO meet the HUD limits.
Where new formaldehyde-containing products have been installed, ventilation can be temporarily increased and high relative humidity should be avoided. Air-conditioning and dehumidification may help to reduce formaldehyde emissions. (Drain and clean dehumidifier collection trays often so that microorganisms do not grow in them.)
Remove products that release formaldehyde into the indoor air. When other materials in the area (such as carpets, gypsum boards, etc.) have absorbed formaldehyde, these products may also start releasing it into the air.
Wash permanent-press clothing before wearing it
Avoid smoking indoors
What NOT to Do
One method NOT recommended by the Consumer Product Safety Commission to reduce formaldehyde is a chemical treatment with strong ammonia (28 percent to 29 percent ammonia in water), which results in a temporary decrease in formaldehyde levels. Ammonia in this strength is extremely dangerous to handle and may damage the brass fittings of a natural gas system, adding a fire and explosion danger.
State of California Air Resources Board. Indoor Air Quality Guideline for Formaldehyde in the Home,August 2004(916)323-5043. http://www.arb.ca.gov/research/indoor/formaldGL08-04.pdf
US Consumer Product Safety Commission. An Update on Formaldehyde - 1997 Revision. CPSC Document #725 (reprinted by the US EPA). Washington, DC.
International Agency for Research on Cancer. IARC Monograph Programme on the Evaluation of Carcinogenic Risks to Humans. Lyon, France. Website: http://monographs.iarc.fr.