Removing Musty Smell

Mold remediation may be the only answer for eliminating musty odors

by Thad Godish, Ph.D

My aunt's home has a very strong musty/mold odor.  It is so bad it clings to visitors' clothing and hair.  If you cook in the house, even the food takes on the house's odor even after a very short time (bread even absorbs it and food in the refrigerator).  I've tried talking to her, but she can't smell it.  Her husband has finally acknowledged the situation, but doesn't know where to begin.  The entire house and furnishings have been affected.  The basement had flooded about 1.5 years ago. The cause of the flood has been taken care of.  I've tried researching for a type of mold that attaches to everything…and I mean everything.  What suggestions do you have for me to give her?  I and other family members are concerned about what effect this is having on her and her husband's health.  Any help would be appreciated.   - Cheryl, Michigan

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Musty odors in houses and other buildings are not that uncommon.  They are particularly prevalent in houses with wet basements, very old houses with basements, houses with wet crawlspaces and mold-infested floor joists, houses in which water gets into walls through brick veneer, poorly-caulked windows and doors, poorly-maintained siding, etc. 

Mold odors are caused by volatile chemical compounds that are produced as the various fungal species grow on water-damaged or moisture-containing organic materials such as wood, paper, cotton, etc.  These compounds are typically higher molecular weight alcohols or ketones.  Scientists and mold experts refer to them as MVOCs (microbial volatile organic compounds). 

These MVOCs may include up to a dozen or so different compounds depending on the type or organisms present, the material they are growing on, etc.  Typically , a few compounds are responsible for most of the odor.  Our noses, our olfactory sense, can detect these substances in very, very low concentrations, that is, in the low parts per billion (ppb) range.  At such levels these compounds are not likely harmful to humans.  There is some limited scientific information that suggests that they can ,at relatively high concentrations, cause upper respiratory irritation in humans.  Such levels only occur in very heavily infested buildings.  I recall in a flooded house I once investigated that "my nostrils and sinuses were singing  " despite the fact that I had a very high quality respiratory designed to remove asbestos, lead and particles such as mold.  It, of course, could not and did not remove MVOCs present.

MVOCs vary in their odor properties.  Most smell "musty".  Some such as Chaetomium smell "earthy".  A number of wood-decay fungi smell "mushroomy.

MVOCs cling to surfaces such as clothing and possibly human skin.  I smell them on people (especially students who live in off-campus housing that is often poorly maintained).  I smell them on myself and in my car after I have conducted inspections of houses with very significant mold problems.

The reason that you aunt and uncle can't smell the mustiness is likely due to a combination of olfactory fatigue (one can not smell many odors even after a few minutes of exposure) and accommodation (or adaptation). After a while one gets used to it and does not notice anything out of the ordinary.

MVOCs do degas from the materials they cling to (that's why we can smell them).  They may cling to some materials for a couple of hours and others for days depending on the exposure.

In your aunt's home the MVOCs are likely to be a symptom of a mold infestation problem, rather than a problem in themselves.  The biggest health risks are exposures to mold spores associated with the infestation producing the musty odors.  These risks include chronic allergy, chronic sinutisis and in many cases asthma.

The house should be inspected by a competent mold professional in order to identify infested materials and then recommend remediation measures.  Once remediated, most if not all of the mustiness will be eliminated , as well as, potential health risks associated with exposures to mold spores.

Indoor Environmental Quality (2000), Thad Godish Ph.D., C.I.H

Direct E-mail 00tjgodish@bsu.edu

See our Mold Solution Buyers Guide for useful products in preventing and reducing mold to safe levels in your home or office.

First Published: Late-August, 2004
Updated: February 2007

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