As part of determining whether an indoor environment is contaminated with excessive amounts of mold and requires remediation, Indoor Environmental Technologies (IET) routinely performs both air and surface mold sampling. While there are many types of mold sampling methods, IET has found this approach effective for interpretation in a building.
Mold Sampling Methods
Air sampling using a “spore trap” sampler. Considerable information can be obtained about the environment from which the air sample was taken. For example, determining the types and concentrations of mold spores and other particles in the sample.
Surface sampling using a “tape-lift” method. This method can determine what molds are growing on a surface, if mold is present at sub-visible concentrations, or if mold spores have been settling out of the air in an unusual quantity.
Note: This very brief discussion is Mold Sampling 101. There are many exceptions and complications not discussed here.
Are Mold Samples Always Needed?
If visible mold growth is present, a mold sample is not really needed to determine, in most cases, that it is mold. However, laboratory confirmation might be useful in some cases, particularly in a lawsuit or insurance claim.
A person can normally detect visible mold growth just using their eyes. However, it should be remembered that mold that has reached the “visible” stage in its growth is well along in its life cycle. Microscopic mold needs to be quite dense on a surface before it becomes visible to the naked eye.
Purpose of Collecting Mold Samples
The main purpose of collecting air and surface mold sampling as part of our assessment is to determine things that the naked eye is not capable of discerning. Among them, whether…
- mold particles or spores have been released from areas of visible growth into the general environment so that occupants are being exposed.
- mold growth is present at sub-visible concentrations. This is especially important in cases where the source of moisture was elevated humidity rather than liquid water.
- mold contaminants have spread beyond areas known to be affected into adjacent spaces. Also whether it appears they have been entrained through the air conditioning systems.
- mold settling on surfaces indicates an ongoing issue. This is especially useful because air sampling provides only a “snapshot in time” of mold concentrations. Surface samples from horizontal surfaces often provide some indication of the extent to which mold contaminants have been released into the air over an extended time.
It is even possible to say, with considerable truth, that most mold sampling is done to determine whether areas are not contaminated and therefore do not require mold remediation. These areas then of course require protection against cross-contamination.