ERMI mold testing samples are prepped by EPA licensed laboratories of which there are only 14 world-wide. AIHA does not have an ERMI accreditation process to date but may undertake this project within the next 1-2 years. Meanwhile, the EPA has an extremely rigorous licensing process, so look for the EPA license number before utilizing an ERMI laboratory.
In 2006, a tsunami struck the fungal sampling coastlands of USA...but hardly created a splash. The tsunami quietly seeped into the wetlands when the US EPA's Steven Vesper, Ph.D., announced the development of ERMI...the acronym for Environmental Relative Moldiness Index on August, 2006. The mold community welcomed ERMI with a yawn and a raised eyebrow. While a handful of laboratories have been promoting ERMI since last fall, its acceptance into the industrial hygiene and fungal detection disciplines has been tepid at best, and relegated to the more esoteric, high-end projects such as litigation support and celebrity cases where cost is less valued than precision and accuracy. It has grown at the glacial pace of Stachybotrys in Arizona.
Examples of Group 1 molds include A. flavus, A. fumigatus, A. sydowii, Aureobasidium pullulans, Chaetomium globosum, Penicillium brevicompactum, P. spinulosum, Stachybotrys chartarum, Trichoderma viride, Wallemia sebi and 16 others. Group 2 molds include Acremonium strictum, Alternaria alternata, A. ustus, Cladosporium cladosporioides (I & II), P. chrysogenum and 4 others.
For each mold species within the panel, the concentration (spores/mg of dust) is converted to its algebraic log then summed for the respective groups. The Group 2 log sum is subtracted from Group 1 to arrive at the ERMI value. This value called the Relative Moldiness Index Value is then placed on a chart scaled from -10 to 20. Within this range, EPA has developed four categories of homes ranging from Level 1 to Level 4...the higher the level, the most likely the home has a mold problem. Level 4 homes are predicted to have the best chance of exhibiting mold contamination.
What's even more impressive is that research by Dr. Vesper and others has been able to link homes with Group 1 molds to the likely development of asthma in children living in water-damaged homes. A relative moldiness index (RMI) as seen in ERMI was able to make this prediction. They concluded that: "The RMI values may be a useful tool for predicting the mold condition of a home. If Group 1 molds are discovered, water-damage remediation and mold removal might be considered as part of the total prevention plan in an asthmatic child's home."
EPA's Steven Vesper, Ph.D, found through exhaustive statistical analyses of bulk dust samples obtained in affected and unaffected homes that a distinction occurred by evaluating concentrations of groups of molds. HUD/EPA studied a statistically valid sample size of 1200 homes across the US determining the levels and types of molds present. Half of the homes were know to have extensive water damage and occupants suffered from significant respiratory illness. The other half were from unaffected homes where no respiratory distress or asthma were present. By contrasting the various mold populations in these two types of homes, he classified molds into two groups – Group 1 mold species (water impact molds) occurring in water-damaged, atypical homes; and Group 2 mold species found in all homes (common environmental molds). Group 1 molds consist of 26 species while Group 2 molds consist of 10 species for a total of 36 total mold species.
Mold testing samples are analyzed using Mold Specific Quantitative Polymerase Chain Reaction (MSQPCR — EPA Method SOP MERB-020, rev. 3, 7/11/02). Don't bother trying to remember that...just remember DNA sequencing. MSQPCR is a highly accurate and sensitive molecular technique for the detection of molds. It is objective and specific because it is a detection system based on unique DNA sequences. Just as humans have unique DNA sequences that provide statistical probabilities of 1,000,000,000:1 odds, so do environmental fungi. The DNA sequence for Aspergillus fumigatus is uniquely different from A. flavus and A. versicolor. As popularized by the criminal forensics program CSI, "DNA doesn't lie." It's as close to the statistical truth as possible with an accuracy of 99.99%.