Credit: Courtesy the Fraunhofer Institute
Diagram of a formaldehyde molecule in pressed-wood products.
Formaldehyde is a colorless, strong-smelling gas used in many household products and building materials—particularly pressed-wood products such as particle board and plywood. Although formaldehyde is a naturally occuring substance produced in small amounts by many living organisms, it has been shown that in large amounts, it can cause both short-term and long-term health effects in humans, including cancer.
LEED and other environmental guidelines give points for limiting the use of formaldehyde (in particular, the addition of urea-formaldehyde). Some manufacturers have also limited the formaldehyde content of wood products. Armstrong, for example, has offered cabinets made of formaldehyde-free plywood since 2005. But the majority (by one estimate, over 85 percent) of pressed-wood products are still made with formaldehyde-based adhesives, prompting the advocacy of increased regulations by organizations such as the California Air Resources Board (CARB).
Scientists at the Fraunhofer Institute for Wood Research in Braunschweig, Germany have been developing a strategy for reducing formaldehyde emissions in wood products. Noting that particular aluminosilicate minerals called modified zeolites are good at absorbing these emissions, the scientists believe that the use of these materials will reduce the off-gassing typically experienced with pressed-wood products.
"Zeolites are already used as a filling material in particleboards, but it’s an entirely new idea to use them for adsorbing pollutants in wood materials," states Katrin Bokelmann, project manager at the Fraunhofer Institute for Silicate Research.
Early experiments with zeolites in spruce roundwood-based particle board have resulted in a drop in emissions of 40 percent. According to Jan Gunschera, project manager at the Fraunhofer Institute for Wood Research, "The air in living spaces should be measurably improved. Our tests indicate that this technology can even reduce indoor air pollutant levels.”
From a human health standpoint, this report is good news for the burgeoning world of wood-based building materials. The approach is clearly treating a symptom, though, rather than a cause. The best strategy would be for manufacturers to severely restrict or eliminate the use of urea-formaldehyde, a classified carcinogen, in building materials altogether. Thus, wood-product companies should view modified zeolite technology as a short-term breakthrough rather than a long-term solution to improve the human health effects of building materials.