Researching on indoor air pollution recently, I discovered this study from 2005 on the "half-life" of formaldehyde in homes, based on the age of the house and the types of materials used. It makes for thought-provoking reading. Here's the abstract and a link:
"Decay is the decrease in formaldehyde concentrations in homes or the decrease in emissions from formaldehyde containing products over time. The decrease in formaldehyde concentrations over time (decay) in home studies is typically determined by associating formaldehyde concentrations by home age. The average half life in such studies is highly variable, varying from about 1 year to more than 20 years, depending on the nature of the home population under study and other factors.
studies generally show that formaldehyde concentrations are higher in new homes than older homes of the same type. These types of studies have limitations as a means of assessing product emission decay profiles. The introduction of additional sources of formaldehyde as the homes age tends to cloud interpretations that seek to relate concentration change over time with emission decay of the original formaldehyde containing products in the home. Laboratory studies provide a better understanding of decay from specific products. A shorter half life, from less than a month to a little over a year, is demonstrated in laboratory experiments. Limited laboratory information indicates a 1 to 2 year half life for multiple tested UF-bonded wood products, which is longer than the half life of a UF-bonded product tested singly.
Decay profiles from laboratory studies, however, are not necessarily reflective of home exposures. Controlled studies in unoccupied homes, while limited, suggest a reduction of 25 to 40% in formaldehyde concentration during the first 4 to 8 weeks, and a half life of 18 to 24 months."
Download the Full PDF HERE