Dissertations in Forestry and Natural Sciences

Taneli Väisänen: Effects of Thermally Extracted Wood Distillates on
the Characteristics of Wood-Plastic Composites
Table 4. The VOCs studied in studies II, III and IV.
VOCs
Studies
Formaldehyde (m/z 31.018 CH3O + )
Methanol (m/z 33.034 CH5O + )
Acetaldehyde (m/z 45.034 C2H5O + )
Acetic acid (m/z 61.029 C2H5O2 + )
Cyclohexene (m/z 83.0706 C6H11 + )
Furan (m/z 69.034 C4H5O + )
Benzene (m/z 79.0548 C6H7 + )
Furfural (m/z 97.1000 C5H5O2 + )
Guaiacol (m/z 125.1233 C7H9O2 + )
Monoterpenes (m/z 137.1330 C10H17 + and 81.0704 C6H9 + )
II
III
II and IV
II
II, III, and IV
II
III and IV
II, III, and IV
II, III, and IV
II, III, and IV
The VOC emission values calculated by the software were
expressed as parts per billion (ppb). In studies III and IV, these
emission values were converted into emission rates (µg/m 2 h)
according to the following equation:
E voc = 0.0409 C vocF voc M voc
A sample
, (6.1)
where Cvoc is the concentration of the VOC (ppb), Fvoc is the flow
rate (m 3 /h), and Mvoc is the molar mass of the individual VOC
molecule (g/mol). The unitless constant 0.0409 was obtained
from the conversion of units using the ideal gas law at 1 atm
pressure and 25 °C, and Asample is the area of the WPC sample. In
study II, the emission rates were calculated with respect to the
mass of the samples; the emission rates were expressed as
µg/kgh, therefore.
The emission rates were further converted into real room air
concentrations (µg/m 3 ) using product loading factor (Lp), which
is equal to the sample surface area divided by the chamber
volume. By applying this conversion, it was possible to compare
the VOC emissions of the material with the odor thresholds of
VOCs, and thus one could estimate whether a certain VOC
could be smelled. The real room air concentration is expressed
as follows:
C real room = E vocL p
n
, (6.2)
84 Dissertations in Forestry and Natural Sciences No 222