An interim report released by the U.S. Centres for Disease Control and Prevention (CDC) has found high levels of formaldehyde in the indoor air of trailers (caravans) and mobile homes supplied as emergency housing to people displaced by Hurricanes Katrina and Rita in December 2007 and January 2008. Processed wood products used in the construction of fittings in the trailers/homes were found to be responsible for the observed formaldehyde levels.

Formaldehyde is a volatile chemical which can irritate the eyes, nose, throat and respiratory system. It is also a recognized carcinogen (i.e. a cancer-causing agent). In this study, measured levels ranged from 3 to 590 ppb, with an average of 77ppb, which is significantly higher than both the typical U.S. background levels of 10 – 30 ppb in indoor air and the level of 0.05 ppm (i.e. 50 ppb) recommended as safe for sleeping areas by Building Biologists. As this study was conducted during the cooler months, the recorded levels are likely to underestimate occupant formaldehyde exposure during warmer weather, as the rate of formaldehyde release from pressed wood products increases with increasing temperature.

The researchers recommend that people living in these temporary homes spend as much time as possible outdoors, open windows as often as possible to let in fresh air, and try to maintain the inside temperature at the lowest possible level.

References

Centres for Disease Control and Prevention   2008   Interim Findings on Formaldehyde Levels in FEMA-Supplied Travel Trailers, Park Models and Mobile Homes   Online, available at : http://www.cdc.gov/nceh/ehhe/trailerstudy

Baubiologie Maes    2003   Standard of Building Biology Methods of Testing (SBM-2003)   Online, available at : http://www.baubiologie.de/dwonloads/nglish/sbm2003_engl_new.pdf