People spend approximately 90% of their time indoors at
homes, public buildings and offices where concentrations of many pollutants,
including volatile organic compounds (VOCs), are frequently higher than the outdoor
urban air. Adverse health effects can result from the buildup of several VOCs
in the indoor air, including formaldehyde, benzene, toluene and xylene.
Building materials and furnishings are sine sources of VOC emissions.
Development of commercially viable building and furnishing materials with
reduced emissions would allow for implementing more stringent codes that enable
improvement of the indoor air quality.
Reconstituted (engineered) wood products have emerged in recent
decades as popular building and furnishing materials. They are composed of
wooden elements of various size and shape, bonded by a synthetic resin.
Examples of reconstituted wood products are particleboard, medium density
fiberboard (MDF) and hardwood plywood (made commonly with urea-formaldehyde
resins), and oriented strandboard and softwood plywood (made with
phenol-formaldehyde resins). Reconstituted wood products constitute the
majority of indoor surfaces (building products, cabinets and furniture). They
can emit a variety of VOCs into the indoor air environment; examples include
formaldehyde, acetone, hexanal, propanol, butanone, benzene and benzadehyde.
Synthetic resins are the primary sources of any formaldehyde emission from
reconstituted wood products.
Some adverse effects of reconstituted wood products on the indoor air quality have created a need for development of low-emission reconstituted wood products, and for development of building codes that encourage their broad adoption. This need can be addressed in a fundamental way through development of lower-emission binders that meet relevant performance, cost and sustainability requirements. Development of refined inorganic polymer binders and compatible processing techniques could be a viable approach to addressing the need for reconstituted wood products that are friendlier to the indoor air quality.
