MARIETTA, GA.—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. Because it is so common, there is a tendency not to give the impact of formaldehyde exposure a second thought.
Every so often, however, the results of a new study, such as the Sierra Club’s recent investigation of the trailers used by the Federal Energy Management Assn. (FEMA) to house tens of thousands of Gulf Coast residents left homeless after Hurricane Katrina, serve as an important reminder of how prevalent formaldehyde is in the indoor environment and that the levels measured constitute a potential health threat. The following provides some basic facts about formaldehyde.
What is Formaldehyde?
Formaldehyde is a simple and common aldehyde, known as HCHO. It is a colorless gas at room temperature, but it can have a pungent odor.
What are the Potential Health Effects of Formaldehyde Exposure?
When formaldehyde is present in the air at levels exceeding 0.1 ppm, some people may experience watery eyes; burning sensations of the eyes, nose, and throat; coughing; wheezing; nausea; and skin irritation. Some people are very sensitive to formaldehyde, while others have no reaction to the same level of exposure. Other health effects include coughing, fatigue and severe allergic reactions. High concentrations also may trigger asthma attacks.
Although the short-term health effects of formaldehyde exposure are well known, less is known about its potential long-term effects. Because of the concern that formaldehyde may cause cancer, the U.S. Environmental Protection Agency has classified formaldehyde as a probable human carcinogen under conditions of unusually high or prolonged exposure. The International Agency for Research on Cancer (IARC), however, upgraded its initial classification of formaldehyde as a probable human carcinogen to a known human carcinogen in 2004.
The California Air Resources Board supported the IARC findings by classifying formaldehyde as a “toxic air contaminant” after state experts concluded that based on current research, there is “no safe exposure threshold [for formaldehyde] … to preclude cancer.”
What are the Sources of Formaldehyde in Indoor Environments?
Primary sources include pressed wood products such as particleboard, plywood, and medium density fiberboard; finished furniture, shelving, and cabinetry made with composite boards and certain coatings; decorative fabrics and textiles; and paper products. It may be used as a biocide in certain paints and coatings, adhesives, and personal care items.
What are Considered Normal Levels?
Based on hundreds of measurements collected in residences, office buildings and schools, formaldehyde is ubiquitous in indoor environments, with typical concentrations ranging from 0.01 ppm to 0.03 ppm in office buildings and 0.05 ppm to 0.08 ppm in homes; an average level of 0.03 ppm has been found in schools. New or recently renovated or refurbished environments may have higher levels.
Are There Recommended IAQ Guidelines?
Available clinical and epidemiological data indicate that individual responses to formaldehyde may vary substantially. Irritation may occur at levels of 0.08 ppm or less, and odor detection has been measured as low as 0.03 ppm. The World Health Organization recommends keeping exposures below 0.10 ppm. The State of California recommends that levels be kept below 0.027 ppm.
The Occupational Safety and Health Administration’s Hazard Communication Standard includes an important labeling provision addressing formaldehyde emissions from products; hazard warning labels are required on any manufactured product that may emit 0.10 ppm or greater, regardless of its formaldehyde content.
In order to receive certification as a low-emitting product from the Greenguard Environmental Institute, products must emit 0.05 ppm or lower. Products meeting Greenguard’s Children and Schools Standard for sensitive populations must meet 0.014 ppm, based on intended use.
How can Formaldehyde Levels be Measured in Indoor Environments?
Excellent measurement techniques are available for determining formaldehyde levels in indoor environments. Air samples can be collected on specially treated solid cartridges and analyzed by liquid chromatography. Levels as low as 2 ppb can be measured. Air Quality Sciences, Marietta, Ga., offers passive monitors that can collect formaldehyde over a five- to seven-day period. These monitors are easy to use and are excellent for determining human exposure in indoor environments.
Because formaldehyde levels are influenced by temperature, humidity and ventilation and can fluctuate during a day, passive monitors account for these variations and provide a more accurate measurement of long-term exposure. These passive monitors detect levels as low as 10 ppb and results can be obtained shortly after being returned to the laboratory.