Why doesn’t an ERMI test require an outside sample like a spore trap analysis?
A. The Group 1 molds accumulate in the home dust based on indoor conditions, but the Group 2 molds, which primarily come from the outdoors, accumulate in the indoor dust based on the outdoor environment. In the simplest terms, the accumulations of Group 1 and Group 2 molds in the dust are governed by different processes. For example, consider two homes identical in every way except in house-keeping habits—vacuuming, cleaning, HVAC filter changing, and so on. Cleaning was performed daily in the first house but yearly in the second. If a mold burden estimate was based solely on the total mold cell concentration in a dust sample, the mold burden in the two houses would appear to be different. However, for purposes of comparison, assume that both homes have identical water and mold problems. By subtracting the Group 2 molds from the Group 1 molds, we adjust the homes to the same “mold baseline” (as well as we can at this time).
