Formaldehyde is a naturally occurring substance in the environment and is made of carbon, hydrogen and oxygen. According to the World Health Organization, natural processes in the upper atmosphere may contribute up to 90 percent of the total formaldehyde in the environment (WHO, International Programme on Chemical Safety, Concise International Chemical Assessment Document: Formaldehyde). Since formaldehyde is a by-product of combustion, cars and trucks emit formaldehyde, as does burning wood (EPA Office of Air Quality, National-Scale Air Toxics Assessment, SAB Review Draft, Table 4-8, 2001). Formaldehyde does not accumulate in the environment because it is broken down within a few hours by sunlight or by bacteria present in soil or water. Neither does formaldehyde accumulate in the body, as humans metabolize formaldehyde quickly (ATSDR; Lu et al, 2010).
In The Home and Outdoors
One of the most important uses of formaldehyde is in adhesives, which are employed in the production of wood composite products that are extensively used in furniture, kitchen cabinets, counters and flooring. While small quantities of formaldehyde gas can be emitted from various wood composite products, very little formaldehyde is present in a form that can be released. These low-level emissions diminish over time. The U.S. Department of Housing and Urban Development (HUD) has standards that limit formaldehyde emissions from wood products, and industry has set its own voluntary standards that are even more restrictive. In 2010, Congress enacted legislation mandating a national emissions standard for composite wood products. More information about formaldehyde's use in composite wood products can be found in the graphic, "Formaldehyde: Contributing to a Sustainable Future for Wood Products."
According to the U.S. Consumer Product Safety Commission (CPSC) in a 1997 paper, formaldehyde is normally present at low levels in both outdoor and indoor air.
There are emissions of formaldehyde from some industrial facilities, but the EPA has established limits and requires facilities to report the amount of formaldehyde used. EPA also regulates the amount of formaldehyde emitted in automobile exhaust.