1. Partition coefficient of formaldehyde (a water-soluble compound) in calcium silicate did not change when humidity increased from 25%RH to 50%RH, but it increased by 56%
when humidity increased from50%RH to 80%RH.
The increase of partition coefficient of formaldehyde was likely because
formaldehyde molecule is absorbed into the significantly more adsorbed water under the 80%RH condition.
Partition coefficient of toluene (a water non-soluble compound) decreased slightly with increasing humidity condition from 25%RH to 80%RH.
It was possibly because the competition of water vapor molecule for available adsorption site with toluene molecule.