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Formaldehyde is classified as a human carcinogen (cancer-causing substance) by the International Agency for Research on Cancer, and as a probable human carcinogen by the U.S. Environmental Protection Agency(EPA). According to an article in the American Journal of Public Health from November of 1982, formaldehyde in sidestream cigarette smoke is evident in concentrations of up to three orders of magnitude above occupational limits, which readily accounts for eye and nasal irritation. "Low-tar" cigarettes appear at least as irritating as other cigarettes. More than half the irritant is associated with the particulate phase of the smoke, permitting deposition throughout the entire respiratory tract and raising the issue of whether formaldehyde in smoke is associated with bronchial cancer(1).

What is formaldehyde?
Formaldehyde is a colorless, flammable, strong-smelling gas. It is an important industrial chemical used to manufacture building materials and to produce many household products. It is used in pressed wood products such as:

• particleboard
• plywood
• fiberboard
• glues and adhesives
• permanent press fabrics
• paper product coatings
• some insulation materials

In addition, formaldehyde is commonly used as an

• industrial fungicide
• germicide
• disinfectant
• and as a preservative in mortuaries and medical laboratories.

How are people exposed to formaldehyde?
According to a 1997 report by the U.S. Consumer Product Safety Commission, formaldehyde is normally present in both indoor and outdoor air at low levels, usually less than 0.03 parts of formaldehyde per million parts of air(ppm). The outdoor air in rural areas has lower concentrations while urban areas have higher concentrations. Residences or offices that contain products that release formaldehyde to the air can have formaldehyde levels of greater than 0.03 ppm. Products that may add formaldehyde to the air include particleboard used as flooring underlayment, shelving, furniture and cabinets; MDF in cabinets and furniture; hardwood plywood wall panels, and urea-formaldehyde foam used as insulation. As formaldehyde levels increase, illness or discomfort is more likely to occur and may be more serious. Formaldehyde can also be released by:

• burning wood
• burning kerosene
• burning natural gas
• burning cigarettes
• automobile emissions
• natural processes

What affects formaldehyde levels?
Formaldehyde levels in the indoor air depend mainly on what is releasing the formaldehyde (the source), the temperature, the humidity, and the air exchange rate (the amount of outdoor air entering or leaving the indoor area). Increasing the flow of outdoor air to the inside decreases the formaldehyde levels. Decreasing this flow of outdoor air by sealing the residence or office increases the formaldehyde level in the in door air.

As the temperature rises, more formaldehyde is emitted from the product. The reverse is also true; less formaldehyde is emitted at lower temperature. Humidity also affects the release of formaldehyde from the product. As humidity rises more formaldehyde is released.

The formaldehyde levels in a residence change with the season and from day-to-day and day-to-night. Levels may be high on a hot and humid day and low on a cool, dry day. Understanding these factors is important when you consider measuring the levels of formaldehyde.

Some sources - such as pressed wood products containing urea-formaldehyde glues, urea-formaldehyde foam insulation, durable press fabrics, and draperies - release more formaldehyde when new. As they age, the formaldehyde release decreases.

What are the short-term health effects of formaldehyde exposure?
When formaldehyde is present in the air at levels exceeding 0.1 ppm, some individuals may experience health effects such as:

• watery eyes
• burning sensations of the eyes, nose, and throat
• coughing
• wheezing
• nausea
• skin irritation

Some people are very sensitive to formaldehyde, while others have no reaction to the same level of exposure.

Can Formaldehyde Cause Cancer?