Mold may be present with or without a musty, mold-like odor. If conditions are dry, the odor may be go away. The mold will still be there. This is one of the reasons mold-sniffing dogs have not replaced humans and the traditional testing methods for mold. A dog can not smell mold all of the time. The mold might be too dry, not producing the types of mVOCs the dog is trained to detect, or the odor might not be from mold.
The term Microbial Volitive Organic Compounds (mVOCS) is used to categorize chemical compounds that off-gas readily at room temperature. Microbial VOCs (mVOCs) are a sub-category of VOCs thought to be associated with mold growth.
In a study done, air sampling for mVOCs was performed in 40 dwellings with visible mold damage and 44 dwellings where mold was not present. The results showed no significant association between the MVOCs sampled in the absence or presence of mold. Only a few compounds indicated a statistically significant, but weak association with the mold status. The concentration of MVOCs was mainly influenced by other factors.
Two of the compounds often used as main indicators for mold damage [2-Methylfuran and 3-methylfuran ], had a high correlation with smoking and correlated with air exchange rates. This study concluded, “The assumption that mold infestations might be detected by microbial VOC emissions must be considered with great reservation.” (Reference: April, 2008 issue of Indoor Air, “Microbial volatile organic compounds in the air of moldy and mold-free indoor environments”.)
I stopped testing for mVOCs a short time after experiments using air testing for odors to test for mold .There were projects on which I could see visible mold or smell an odor from the damp, musty conditions present. Yet, the mVOC tests failed to detect any of the so called marker compounds thought to be associated with mold growth.
Similarly, when I tested homes with visible mold, as a reference and buddy check to see if the test was valid, I didn’t always detect compounds claimed to be associated with mold growth. From my testing, I observed two other things.
First, microbial VOCs can be from types of microbes other than mold. Bacteria for example, also produce a plethora of different types of VOCS, as well as alcohols and other compounds associated with musty odors. When you smell musty odors, bacteria have a big influence on what you are smelling.
Second, it turns out a lot of common household objects off-gas VOCs in the category of compounds classified as mVOCs. It could be something in your house off-gassing, not mold. At the same time, there could be mold in your house, hidden in the walls somewhere, mold that is not smelly.
The best thing to do is not to test for by mold by testing for odors. It’s OK to use your nose. Don’t use laboratory testing for mVOCS. Stick to the traditional tests for mold.
When you smell something musty, and mold-like, it does not matter whether there is mold or not – the problem, the source, should be identified, investigated, and remediated. I use my nose in mold inspections all the time. I’m focused on finding the source. If the cause of the odor is something got wet or is wet or damp, that’s all that matters. Fix it. Stop the source of moisture. Remediate the odor. This may require doing the same things done for mold remediation, even if mold is not present.
