Formaldehyde and VOC emissions at different manufacturing stages of wood-based panels

Formaldehyde and VOC emissions from wood-based panels are recognized as one of the major causes of poor indoor air quality. These emissions may be strongly influenced by the raw materials and manufacturing techniques of the panels. However, there is very little published information regarding this issue. In this study we determine and compare formaldehyde and VOC emissions, including their species and content, at different manufacturing stages of wood-based panels such as urea-formaldehyde resin, wood chip, wood fiber after resin application, medium density fiberboard, and phenol-formaldehyde resin. We found that: (1) in total, 34 individual VOCs were identified, but none of them were in all the specimens, indicating considerable VOC species changes during the manufacturing process; (2) the formaldehyde in wood-based panels came primarily from urea-formaldehyde resin, and there existed a linear relationship between the formaldehyde content in resins and formaldehyde specific emission rate from wood-base panels; (3) VOCs in wood-based panels mainly came from the wood chips; (4) the drying and hot-pressing techniques were helpful in reducing the formaldehyde and VOC emissions from wood-based panels. Some suggestions are presented for the control of formaldehyde and VOC emissions from wood-based panels during the manufacturing process.