**When performing this test, you ONLY want dust samples from places that have 4-6 week old dust. Clean the areas you inspect first and wait for 4 weeks to collect the sample.

The US Environmental Protection Authority developed ERMI to provide a straightforward, objective, sensitive and standardized way to assess mold and indoor air quality investigations. The USEPA developed the ERMI as a ranking system based on dust samples collected from homes, the ERMI will help predict the moldiness of homes.

Based on widely published data from EPA researchers and the 2006 HUD American Healthy Home Survey, the test has been developed as a tool to evaluate the potential risk of indoor mold growth and associated health effects to occupants. Upon purchasing the ERMI, you will get a HERTSMI -2 along with it.

In order to most effectively use this tool, the ERMI obtained needs to be compared to a national database. Indices were determined using this method for 1,096 homes across the U.S. as part of the 2006 HUD American Healthy Home Survey. Individual indices, ranked from lowest to highest were used to create a national Relative Moldiness Index (RMI) Scale.

In initial studies by the USEPA, the concentrations of different mold species in “moldy homes” (homes with visible mold growth or a history of water damage) and “reference homes” (homes with no visible mold) were compared. Based on those results, mold species were selected and grouped into those with higher concentrations in moldy homes (group 1) and those with lower concentrations (group 2). To calculate the ERMI the individual concentrations of the mold species detected are log-transformed and the sum of group 2 logs is subtracted from the sum of group 1 logs.