Emission patterns and emission rates of MVOC and the possibility for predicting hidden mold damage?

Laboratory trials were performed in order to search for the variety of the production of microbial volatile organic compounds (MVOC), which could be used as indicators for hidden mold damage. Concerning MVOC production the experiments showed a dependency on the mold genus/species, the different strains used and the building materials used as substrate. It could be proved that the production of certain MVOC is not consistent at all times. On the whole low emission rates in terms of microg/h/m2 of the MVOC were found. Extrapolating the emissions rates from the laboratory trails to an indoor air situation results in concentrations below the analytical detection limit in most cases. According to these results only heavy or very large fungal contaminations might be detected by this method in indoor air. The studies were performed at the Institute of Hygiene and Environmental Medicine, Charite, Germany.

Microorganisms like bacteria and molds produce a huge variety of substances, and a part of them are released into the environment. Some compounds like, e.g. alcohols or ketones are volatile, therefore found in the air and called MVOC. Those compounds were considered helpful to track especially hidden mold damage. The study presented here showed, that the emission pattern varies from genus to genus and sometimes even from fungal strain to fungal strain. The results concerning the emission rates from different infested building materials proved, that the concentrations produced are much too low to be detected in indoor air, especially considering the dilution because of ventilation. Therefore, we conclude that MVOC should not be used as predictors for mold damage in indoor environments.