Article Summary: After writing Mold Testing, I decided I needed a simpler way to explain the reasoning behind taking two side-by-side Swiffer samples in order to determine if a building is moldy. This method circumvents variables that otherwise can lead to poor results. Don’t listen to Inspectors that claim ERMI is only for research purposes or can only be used in limited situations. This is nonsense and I’ll explain why.August 26, 2015
I’ve read a few opinions of mold inspectors indicating that ERMI testing isn’t valid. Arguments made range from hiding behind the Office of the Inspector General (OIG) statement that ERMI was only intended for research purposes to the more thoughtful but still ill-informed position that ERMI can only be used in homes to determine if there is a potential mold issue – that it should not be used to evaluate the success of a mold remediation project. The later group of inspectors fails to realize the full potential of ERMI testing while the former are either too afraid or too biased to engage ERMI at all. In either case, those with CIRS suffer greatly from this failure to fully engage the benefits of ERMI.
What you don’t see from any of these wayward inspectors is an attempt to discredit the ERMI methodology itself. After all, the testing was developed by the EPA and has a 99.7% accuracy. If you send in a sample, any quality lab like MycoMetrics will determine the exact amount of DNA present for each of the 36 molds scored on the ERMI report. The science behind the DNA methodology is rock solid.
What these inspectors drone on about are facts like the original testing was done on carpeting of homes and the fact that there was never an official release as to the meaning that could be assigned to given results. In Mold Testing – A Better Way, I describe how to circumvent nearly all the concerns related to testing methodology. This is done by comparing side-by-side outdoor and indoor mold samples. Using this method, we can readily determine if a building has a mold issue. It doesn’t matter if the building doesn’t have carpeting, is newer, or has a contributing outdoor source. All it takes is a little common sense and a desire to actually help those with CIRS to realize this.
In terms of what levels cause health issues, I refer you to ERMI & Politics. Dr. Shoemaker has meticulously collected ERMI scores and correlated it with patients that suffer from CIRS. In general, if the ERMI is above 2, those with CIRS will suffer. Alternatively, if the HERTSMI-2 score is above 11, those with CIRS must stay out. He has thousands of records to back up this claim. Granted there is a gray area for those that don’t have CIRS, but for those of us that are literally dying an excruciating death from mold toxins, it is an absolute travesty to not use ERMI to the fullest as I and Greg Weatherman have outlined.
Side-by-Side Out & Indoor Swiffer Sampling Detects Toxic Indoor Mold
Refining ERMI Testing
An ERMI mold report lists 36 mold scores expressed as the number of mold spores found in each milligram of dirt. These 36 molds are divided into two categories, Group I and Group II. There are 26 molds in Group I that consist of molds commonly found inside water-damaged buildings. There are 10 molds in Group II that consist of molds almost exclusively found outside. In the picture, I’ve depicted the movement of outdoor airborne debris into a building. Along with this outdoor debris, the building itself always produces some of it’s own internal dust and dirt.
Not surprisingly, outdoor airborne debris consists of molds from Group I, Group II, and various types of dust and dirt. In other words, given the wide range of decaying matter and conditions outside, there will always be some Group I molds and some Group II molds mixed in with various bits of dust and dirt. In the picture, this debris lands in the containers set out specifically to collect airborne debris. One container is outside and the other is inside. Even though it’s all mixed together in real life, I’ve separated the various constituents to help visualize the relative ratios. (You can read details of how I recommend collecting samples in Mold Testing – Improved Swiffer Cloth Method.)
When windows and doors are opened, a fraction of this mix of outdoor airborne debris enters the building. Although the amount of this debris is much less inside, the overall ratios of the Group I, Group II, and dirt entering from outside remains the same. In the picture, I’ve reduced the width of the indoor container while keeping the heights of the outdoor dust/dirt and Group II molds the same to indicate there is less debris indoors but some ratios remain the same. Specifically, if you compare the height of the green Group II molds to the height of the dark brown outdoor dust and dirt, they remain the same. This is true regardless of the overall amount of airborne debris that gets in through the windows and doors and regardless of whether the building has water damage.
It’s also helpful to realize that the occupants and items inside the building produce their own dust and debris. Furniture, people, pets, and so on all produce dust and debris. I’ve shown this as a layer of lighter colored brown dust and dirt in the inside container. In a home that doesn’t have any water damage, this indoor dust and debris is free of any additional mold spores. In a moldy home like the one shown, it will also have various Group I molds mixed in too. Although it’s not a critical point, the addition of indoor dust and dirt will lower (dilutes) the values listed on the indoor ERMI report. This relates to the fact that ERMI scores are listed as the number of mold spores per unit of dirt (milligram).
Getting back to the example, even though the amount of Group II molds and outdoor dirt entering the building will be less, the ratio of the Group II molds compared to dust and dirt levels will be unaffected by any Group I molds. Regardless of whether the building is moldy or not, Group II molds relative to dust and dirt amounts remains unaffected. This is due to the fact that buildings just don’t make outdoor Group II molds even if they’re water damaged. This is a key point. By establishing the ratio of outdoor Group II molds to indoor Group II molds, we have a point of reference to determine if any Group I molds are in excess. If we find that one or more Group I molds are not in the same ratio as the Group II molds, the only way that this can happen is if the building is producing Group I molds. In other words, the building is moldy.
Said again, The key to why collecting and comparing an outdoor Swiffer sample to an indoor Swiffer sample (see Improved DNA Testing) lies in the fact that the ratio of outside Group II mold counts compared to inside Group II mold counts can be used to determine if any of the Group I molds are in excess – if the building is moldy. In the example below, the ratio of outdoor Group II mold counts compared to indoor Group II counts is roughly 10:1. However, the ratio of some outdoor to indoor Group I molds are significantly less than 10:1. Where did these extra Group I molds come from that lowered the 10:1 ratio? We know they didn’t come from outdoors. Therefore, they must have come from within the building itself as a result of water damage. The building is moldy.
Abbreviated Moldy Building ERMI
|Outdoor Swiffer Sample (spores/mg)||Indoor Swiffer Sample (spores/mg)||Outdoor/Indoor Ratio|
|Group I: Wallemia Sebi – 1800||Group I: Wallemia Sebi – 930|
|Group I: Aspergillus Niger – 400||Group I: Aspergillus Niger – 420|
|Group I: Stachybotrys Chartarum – 12||Group I: Stachybotrys Chartarum – 1|
|Group II: Alternaria Alternate – 9000||Group II: Alternaria Alternate – 860|
|Group II: Cladosporium – 7000||Group II: Cladosporium – 680|
|Group II: Mucor Aamphibiorum – 300||Group II: Mucor Amphibiorum – 29||
This ratio is much lower for two Group I molds indicating the building has water damage.
Does this mean that if you only took a single ERMI sample that the results are useless? Certainly not – see ERMI Basics. In most cases, a single ERMI is quite telling. However, in some situations that I discuss in Mold Testing, the results can infrequently be misleading. A single ERMI is better suited to determine if a building is OK for those with CIRS to occupy. Side-by-side testing is better for determining if the building has water damage and also eliminates troublesome variables. Equally important, this is an attempt to bring some clarity to all those mold inspectors that just can’t seem to be able to wrap their minds around the fact that ERMI can be used to tell if any building is moldy both before and after remediation. The common sense logic is irrefutable.