The alpha-pinene was the major chemical components that were released when
softwoods were dried (Danielsson and Rasmuson 2002). By comparing alpha-pinene
concentration collected during microwave drying and air dying (room temperature), the VOC
emissions during microwave drying was quantified. Table 3 shows that the alpha-pinene
concentrations collected during microwave drying were slightly higher than one collected
during air drying. This may be caused by the lower final MC for the case of microwave
drying. This finding was also approved by extractive method (Du et al. 2005). Since VOC
emission came mainly from extractives, the changing of extractives in wood furnishes could
be used to estimate VOC emission.