The relative humidity may strongly affect indoor air concentrations of VOC pollutants

Volatile organic compounds (VOCs) may be emitted from a building into the indoor air leading to a compromised indoor air quality (IAQ). We studied the influence of relative humidity (RH) on VOCs concentrations in a room of a building that had been subjected to water damage. Air samplings at RH 21–22 % revealed only small amounts of 2-ethylhexanol (3 μg/m 3 ) and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB, 8 μg/m 3 ) whereas samplings performed at RH 58–75 % gave 3-fold higher concentrations of 2-ethylhexanol and 1.5-fold higher concentrations of TXIB. In a second series of experiments we found that increasing the RH from 40 to 85 % resulted ín dramatic increase in the release of n-butanol and trichloroanisole from a sill that had previously been impregnated with chlorophenols, taken from a building with IAQ complaints. This study illustrates the importance of monitoring RH when sampling indoor air for VOCs to achieve reliable results. Peer-review under the responsibility of the organizing committee of the ICMB23.