Why Ambient Air Samples Aren’t Enough

Ambient air sampling is the most commonly used sampling method for the majority of mold inspectors to identify if there is a mold contamination. But just because most inspectors are doing it doesn’t mean it’s right. In fact, ambient air samples often provide a massive disservice because they create a false sense of security, that there is not a mold contamination in a home when there are often times there is.  

When discussing this topic it is important to specify ambient air sampling and source air sampling. Ambient air sampling occurs when an air sample is collected from the middle of a room to determine if there is a mold contamination impacting the area. Source air sampling occurs when an air sample is collected from a small isolated area to determine if there is a source of mold growth hidden in an area where no visible growth is present. 

Determining the source of poor indoor air quality, (such as Asbestos, Dust Mites, Strange Odors), requires sophisticated equipment and training. We provide a detailed approach to our property inspections and understand the right indicators to look for in a property that may indicate what is causing the indoor air quality issue. 

Reason 1: Ambient air samples are like a photograph

Ambient air samples are collected for a period of 5 minutes (or 10 minutes sometimes depending on the inspector). During that time, an air pump is pulling air from the surrounding area into the sampling media which contains a slide that can be viewed under a microscope.

The problem with this is that it is only accounting for whatever happens to be floating around nearby during that 5 minute time frame. This is problematic because the composition of the air around us is constantly changing. In fact, you can collect a sample in the same location 20 minutes later and get a completely different result. 

As an example of this, imagine the ambient air sample is being collected from a bedroom with carpeting, a bed, and curtains. If you collect the air sample from that room when it has been empty for hours, then many of the floating particles (and mold spores) would have settled on the surfaces. As a result, you’d likely get a low result on the sample results, because at that time those particles are not floating in the air. 

Now let’s say you collected the same sample in this same room, but immediately after someone got out of bed, opened the curtains, and walked around for a few minutes. This activity would have cause a large disruption in the room that would have resulted in many more particles becoming airborne. As a result, you’ll likely get higher readings on that sample result. 

Ambient air samples are highly variable and do not provide a historical perspective of a mold contamination that has impacted the space. For this reason, their results often provide a false negative. 

Reason 2: Ambient air samples don’t collect enough data

So let’s talk briefly about how an air sample is analyzed at the lab. As I mentioned above, air is pulled from the surrounding area into the sampling media which contains a slide that can be viewed under a microscope. When the lab technician analyzes the sample, they physically count the number of spores that are on the slide. This number is what is reported on the lab results. 

However, due to the physical element of the analysis, fine and ultrafine particulates are not accounted for in the sample. It is these incredibly small particles that may be the biggest issue when it comes to health effects as a result of mold and poor indoor air quality. This is because these incredibly small particles can bypass our body’s natural filtration system, infiltrate deep into our lungs, and even work their way into our bloodstream. 

So what are fine and ultrafine particulates? You can read more about them here, but there are many sources that contribute to these very small particles, one of which is mold. 

Mold colonies don’t only consist of spores. They are made up of entire growth structures which release spores as part of their metabolic process. But pieces of these growth structures can break away from colonies and become airborne. These particles carry the DNA signature of the mold colonies, and even carry mycotoxins (the toxic byproducts of certain molds). Furthermore, due to their incredibly small molecular weight, they can stay forever suspended in our breathing zone. And studies have shown that their quantities far exceed that of spores. 

The problem is that because these particles are not spores, they are completely overlooked when analyzed as part of an ambient air sample. Therefore, ambient air samples only provide a small piece of the picture when it comes to what you are potentially being exposed to as you walk around your home. Overlooking fine and ultrafine particles provides the occupant a huge disservice. 

Reason 3: The sample are misleading

Again, we talked about how a lab technician physically counts the spores collected from an air sample on a slide under a microscope. But this can become difficult if the sample is not properly collected.. 

When the air pump is pulling spores onto the slide, it is also pulling all kinds of other particles, such as pet dander, skin fragments, insect fragments, pollen, etc. All of these different particles cover the slide, and if too many of them are present, it “clouds” the slide making it very difficult to analyze. When this happens, the lab technician skips over the “clouded areas” and only counts what they can actually see. This can lead to an underreporting of results, and again, a false negative.

While ambient air sampling does have weaknesses and should not be used to determine overall air quality, Source Air Sampling is one of the most powerful sampling methods we have in terms of identifying sources contamination. The goal of these samples is not to determine cross-contamination or air quality, but rather pinpoint isolated locations of mold growth sources so a remediation protocol can be developed. 

Source air sampling is specifically effective at identifying hidden sources of mold growth in areas where we cannot see physical mold growth like behind walls and ceilings.

Just because most mold inspectors rely on ambient air samples doesn’t mean it is the best way to understand what someone may be exposed to in the home. Often times, ambient air samples show results that look completely normal, even when there are multiple sources of mold growth within the home. I can’t reiterate that enough. We see this all of the time. This causes people to believe their home is not contributing to their negative health effects… even if their doctor is telling them otherwise. 

The appropriate way to understand if mold has impacted the occupied living spaces is through dust sampling from surfaces that are not regularly cleaned. The sampling methodology is called ERMI, which utilizes an analysis call MSqPCR. This is a fancy way of saying DNA formatting of any mold species on the panel that may be present. 

This method is effective in all of the areas where we discussed ambient air samples area deficient. 

  • ERMI dust sampling is not a snapshot in time. If collected properly it can provide a historic view of what has impacted the home over several months or years.
  • ERMI dust sampling does not only account for mold spores. It also analyzes the fine and ultrafine particles that carry the DNA signature of the specific mold. 
  • ERMI dust sampling cannot be misread because the sample is not analyzed by the human eye. MSqPCR is a highly accurate and sensitive molecular technique for the detection of molds based on unique DNA sequences. 

The information contained on this site is for informational and educational purposes only. It does not represent a health diagnosis, therapeutic recommendation or prescription for treatment. We urge you to consult and obtain medical advice from a licensed, trained, and competent medical provider for concerns with health issues.