The United States Environmental Protection Agency (USEPA) developed an index for indoor mold analysis called ERMI (Environmental Relative Moldiness Index). The standard is based on a test using state of the art DNA testing (MSQPCR) to identify molds that are linked to water intrusion and various respiratory diseases. The results obtained from this test give each home an ERMI score, which can be compared to the 1,100 homes that were studied by the EPA.
Homes receiving a high ERMI score are more likely to have unwanted indoor mold growth than those that receive a low ERMI score.
What is an ERMI Score?
The ERMI panel includes 26 mold species known to thrive in water damaged homes and 10 species found in all homes, with or without water damage. Each species and group of species is enumerated from DNA extracted from dust samples,which are taken in both the living and sleeping quarters of the home. Concentrations of each of the 36 molds are used to derive an “ERMI score” that rates the moldiness of each sample against those tested by the US-EPA. These values range from approximately –10 (low moldiness) to 20 (high moldiness), with an average home having a score of 0.
1. What do the ERMI results mean?
ERMI samples are reported with both an ERMI score and the individual quantifications of each mold species found in the ERMI panel. An ERMI score is a guideline for determining levels of mold exposure for home occupants. The individual quantifications can also be useful in identifying the mold problem in a home. An ERMI analysis is a diagnostic tool and provides inspection details to aid in a home’s assessment by a qualified professional.
2. How do you identify the source of the mold problem when you take an ERMI sample?
An ERMI sample is a composite sample of dust, normally taken in the living area and master bedroom. This dust is a reservoir that will reflect any mold problems seen in a home. If the ERMI score indicates that there might be water damage within the home, further inspection might be required, especially if this problem is concealed.
3. How do you take an outdoor control?
The outdoor control is built into an ERMI sample, and no additional samples are necessary. The Group 2 molds are outdoor molds that are commonly found across the U.S., and this group is subtracted from the Group 1 molds.
4. How is the sample collected?
An ERMI sample is collected inside a dust collection device which is designed to attach to the end of a standard vacuum hose. Since an ERMI sample is a composite sample, dust is collected from two rooms of the house (usually the Living Room and Master Bedroom). Eighteen square feet over a period of five minutes should be collected from each room using the same collection device.
5. Does a high ERMI score indicate a health issue?
There are no implicit human-health recommendations with an ERMI score. Mold-exposure symptoms differ from person to person, depending upon the sensitivities of each individual and their levels of exposure to mold. An ERMI score should be used in conjunction with individual mold species quantifications and symptoms of home occupants to arrive at an action decision. An ERMI score is simply a guideline for determining levels of mold exposure for home occupants.