Roaring Brook News

Demystifying Mold - Part I

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Data showing indoor sites with significantly higher levels of total spores or of individual spore types, as compared with the outdoor reference control, indicate a likely indoor source increasing the amounts of these spoors. Such a source is called an amplification source. An amplification source could be a heavy entrapment of dirt and dust due to poor housekeeping, or the growing of mold in either accessible or inaccessible areas of the building (for example, within the walls). In some cases further investigation and/or sampling may be required to locate amplification sources.

It must be understood that samples of airborne mold spores are brief snapshots in time. A sample is usually taken in five to ten minutes, and only captures what is in the air at the time of sampling. It does not indicate the levels of mold spores present at other times. Although air sampling for mold is a useful tool, this is why a result similar to that of the control sample must not be used as an absolute measure of safety or as an indicator of the absence of mold in a building. The following phrase applies when viewing the results of air samples for mold spores: The Absence of Evidence is Not Evidence of Absence.

Once located, all amplification sources, no matter how large or small, should be cleaned or remediated.

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Some of the information presented in this article was gathered from the EPA and from others citing the EPA.

Air Sampling for Mold

Air samples for mold are generally taken for either of two reasons:

1. To gather evidence to support the presence of an elevated level of mold spores due to a known growth source.

2. To find areas of hidden or uncertain indoor growth sources of mold.

However, there are other reasons for sampling, which include:

· Wall cavity checks to search for mold growing within wall cavities.

· Post remediation (clean-up) samples to demonstrate lower airborne levels once the mold source or sources are removed.

Looking at Air Sampling Data

When viewing air sample data, we typically compare indoor sites having known or suspected mold contamination with an outdoor reference control. Normally, the levels of mold spores indoors should be the same or lower than the levels outdoors, and the distribution of spore types should be very similar to that of the outdoor sample.

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