Why Air Testing for Mold is Not Enough

Not all mold inspection companies are created equally. Sadly, there are varying degrees of detail and depth in which companies assess the health of a home. Unfortunately, clients often come to us when another company has already tested their home for mold. As a result, a couple of things may happen:

1.) A previous inspector tells a client that they do not have an active mold issue because “air” testing did not show any mold. 


2.) “Air” testing showed a problem in one area but did not identify all the problem areas in the home. A remediation company remediated the questionable area, but the client is still sick. 

What happens when you look at a mosaic but are only one foot away from the art?

Indoor damp & air quality (IAQ) testing.

Can you tell what the mosaic is depicting? You cannot, right? However, if you step back about 10 feet, you can now see what all the small pieces in the mosaic represent in the whole work. 

Mold testing is like a mosaic. Homes with mold infestations usually have more than one issue. It is not very scientific to stop looking after you find one small part of the problem. If we hyperfocus on a tiny piece of the story, we miss the bigger picture. It is essential to step back and systematically assess the home holistically. Comprehensive testing beyond what is commonly known as “air” testing is necessary to get a complete picture of a severe mold issue. 

What is “Air” Testing?

When someone mentions the term “air” testing, what they are referring to is technically called “spore trap analysis.” Almost any mold inspection company uses spore trap analysis as their primary form of testing when testing indoor mold levels. 

This testing is done using an air pump that pulls spores from the air and “traps” them onto a slide. The inspector then sends the slide to a laboratory, where a technician will examine the spores on the slide under a microscope. The lab technician will do their best to identify what species of mold are present on the slide. Typically, results are reported in spores per cubic meter of air (spores/m3 ) along with the number and percentage of each spore type.

In most cases, the inspector will take what is called an “outdoor baseline” air sample. The lab will compare this sample to the sample taken indoors at one or more areas (usually each floor). This comparison aims to show which species of mold are native to the area where the home or dwelling is. For example, suppose the indoor air is comparable in levels and species to the outdoor sample without any glaring elevations. In that case, it is usually concluded that there is no severe mold problem that presents an issue in terms of air quality. 

The Pros and Cons of Spore Trap Analysis 

Every sample that is collected is a puzzle piece. Each sample is information that tells part of the home’s story regarding water intrusion and mold infestation. Our job as inspectors is to remain neutral, be scientific, and collect as much information as possible, giving the client as complete a picture as possible as to what is happening behind the walls of their home. 

To put it simply, spore trap analysis, or “air testing” as it is commonly referred to, is not inherently faulty testing. Instead, the issue becomes how this information is analyzed and presented to the client. If the inspector did no testing beyond spore trap analysis and told the client that the test did not show any mold and there is no mold issue, a great disservice has been done. 

That being said, spore trap analysis is always an excellent place to start. If the issue is found in air testing, which is essentially a broad overview, we know that it is a grave mold issue that presents a health concern. It can also serve as a good point of reference compared to other tests we might perform on the home. 

From our perspective, to find mold at even minute levels that might make a hypersensitive individual sick, air testing only tells a tiny part of the picture. For example, heavier molds such as Stachybotrys or Chaetomium globosom will rarely show up on air testing. Incidentally, these are known to be very toxic molds that make people very sick. 

These molds will, however, show up on surface testing, which comes in many forms. 

Other Types of Mold Testing 

Other tests that we commonly perform on a home to get a complete picture of the severity of the mold issue are the EPA 36 swab test, ERMI and HERTSMI surface testing, mycotoxin testing, and endotoxin testing. In addition, we routinely research and get the latest information on new testing that is available. Being up to speed on the latest advances in mold testing helps us minimize the chances that we may overlook an issue that would threaten our client’s health.

SURFACE TESTING (Source Testing)- Surface samples are typically taken from areas of visible suspect growth. They can be collected via sterile swab, tape lift, or by taking a piece of suspect material. The objective is to validate the presence of mold, identify the genera of mold present, and determine the spore counts. Direct examination shows precisely what is on the surface sampled. These samples are essential because they may reveal reservoirs of mold that have not yet become airborne.  

ERMI (Environmental Relative Moldiness Index) –  This test is carried out by a third-party lab called Envirobiomics. ERMI is an objective, standardized DNA-based method of testing that will both identify and quantify molds. This testing analyzes the moldiness index in dust that has settled in the home. In this case, we are not relying on the fact that the mold spores will be airborne when testing. This allows heavier molds to have a better chance of showing up on testing. The species of mold are split into two groups and given different weights as far as how toxic they are. A score is then given on the overall mold toxicity score. A score can be instrumental when comparing homes and deciding whether a hypersensitive individual should live in the home or vacate. 

HERTSMI-2 (Health Effects Roster of Type-Specific Formers of Mycotoxins and Inflammagens) – That’s a mouthful! The HERTSMI-2 is a more specific scoring system created by Dr. Ritchie Shoemaker of what he considers the most toxic molds. This scoring system is extrapolated from the ERMI test. In this scoring system, molds included are known to produce mycotoxins, which are among the primary triggers for cases of CIRS in water-damaged buildings. 

Mycotoxin testing – This testing is done by a third party called Real Time Labs. There is no way for an inspector or technician to know if a mold is producing mycotoxins or not unless we test for actual mycotoxins present. As mentioned above, it is the mycotoxins that the body is reacting to, specifically in cases of CIRS. Therefore, knowing if mycotoxins are present and at how high of levels can be very useful in determining whether a home is safe to live in or not. 

Endotoxin (Also done by Envirobiomics) – Endotoxins are derived from the cell walls of Gram-Negative bacteria (GNB). Gram-negative bacteria are found almost anywhere in nature. Their toxins are located within the outer layer membrane of the GNB cell wall. They do not have to be living; therefore, both viable and non-viable gram-negative bacteria contribute endotoxins. It has recently been discovered that endotoxins are a major contributing factor to cases of CIRS. 

Why This is Important to Hypersensitive Individuals 

Those with CIRS, as we shared in a recent article, are not only reacting to specific mold spores as a possible allergy but are having an inflammatory response to mycotoxins and unique combinations of spores mycotoxins, endotoxins, and other things present in their home. The inflammatory response is highly complex, and no two individuals respond to the same combinations in the same way. Because of this level of complexity, it is crucial to identify as many toxins present as the technology allows.

Furthermore, in cases of CIRS, the body is primed to react. Because of this, the body reacts more quickly with each exposure and with longer exposures. That means that it requires less of a toxic substance to cause a reaction. However, in time, the responses get more pronounced. For this reason, trace amounts of mold spores, mycotoxins, or endotoxins can make someone with CIRS quite sick. 

It is our job to find those trace amounts to protect those individuals that are hypersensitive. We take this job very seriously and aim to stay ahead of the curve, knowledgeable about any testing available to us that might help us in the CIRS’s patient’s plight of mold avoidance! 

For more tips, or if you are interested in learning how to prevent future mold issues or address current ones, please follow us on Instagram and Facebook. Also, if you have any questions or comments, feel free to leave them in the comments below or on our social media. 

And of course, please book your inspection today! We look forward to continuing the conversation. 


1. Aiha-assets.sfo2.digitaloceanspaces.com. https://aiha-assets.sfo2.digitaloceanspaces.com/AIHA/resources/FAQs-About-Spore-Trap-Air-Sampling-for-Mold-for-Direct-Examination-Guidance-Document.pdf. Published 2021. Accessed May 27, 2021.

2. ERMI Testing – Environmental Relative Moldiness Index | Surviving Mold. Survivingmold.com. https://www.survivingmold.com/diagnosis/ermi-testing. Published 2021. Accessed May 27, 2021.