Mold test vs. mold contamination detection:
Here we distinguish between tests to identify mold in a building and procedures to determine whether or not there is a mold contamination problem in a building.
Following that distinction we continue by listing the specific reasons to test for mold or cases when mold testing is appropriate and useful.
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- Daniel Friedman, Publisher/Editor/Author - See WHO ARE WE?
15th Annual North Carolina/South Carolina
Environmental Information Association Technical Conference
Myrtle Beach, SC
Daniel Friedman 23 September 2005, updated thorough 11/19/2013
Abstract: In this article series we explain the difference between a mold test and a procedure to reliably identify a mold problem in a building.
[Click to enlarge any image]
We describe the validity of nearly all of the popular mold testing methods currently in use, pointing out the strengths and weakness of each approach to mold sampling in the indoor environment, beginning with air sampling for airborne mold levels indoors.
We explain that a "mold test" in a building, used alone, without an accompanying expert inspection, may be of little use because of the potential for major errors in the test procedure and test mechanism and because even if the test successfully collects evidence of building mold contamination, the mold identified may not be the most serious mold contamination present.
Finally, even if a mold test could properly identify the presence of the most serious mold contaminants present, it may be insufficiently diagnostic to give any guidance whatsoever about where the mold problem reservoirs are actually located, the extent of cleanup needed, and the cause of the mold growth.
All of those questions will require an additional expert investigation, evaluation, and possibly further testing before a mold remediation plan can be prepared. Nevertheless, as we outline in topic 2 below (a separate paper) there are reasons to test for indoor mold.
This discussion of the usefulness and validity of mold tests is divided into two main topics:
Mold testing discussion can be divided into two main topics, the first of which is discussed in this paper.
We are "making up" this temporary distinction to make clear an important point.
[Click to enlarge any image] Photo: an Allergenco air sampler in operation.
Mold Testing a building for the presence or absence of a problematic level of mold is unreliable if by "testing" one means a simple air test, an arbitrary surface or vacuum test, a swab test, or any culture method used alone and without a careful and complete inspection of the property. In particular, failure to detect problem levels of problem mold with an air, culture, swab, PCR or similar test (used alone) is not sufficient to conclude that there is no problem.
1. Airborne particle levels vary widely over short time intervals. What's in the air in a building varies enormously, possibly by a factor of thousands, over just a few minutes, depending on things like the level of activity, mechanical disturbance of dust, fans being turned on or off, hot air heat or central air being on or off, and more subtle changes in humidity, etc.
See
ACCURACY OF AIR TESTS for MOLD
2. Mold Culture Tests whether from a "home test kit" culture plate or a swab are unreliable as a characterization of presence or absence of mold because
3. PCR tests are highly accurate in identifying individual molds, if you know what you're looking for. PCR is not reliable as a broad spectrum
scan to find what's in a building.
See
SWAB & PCR SAMPLING & TESTS for MOLD
Mold Problem Identification, as we are speaking here, is an important part of a building investigation for mold (or other allergen) problems.
By this we mean, an investigator should be charged to identify the presence of problematic mold, including no less than the following:
This information permits preparation of a remediation plan to specify the cleanup needed and the building repairs needed to avoid simply producing more mold.
Key in a Mold Problem Identification investigation is the actual visual examination of the building, its history, its leaks, and other physical evidence.
As a part of such an investigation, samples are collected of visible mold to distinguish cosmetic from problematic material, and other samples might be collected to examine the level of moldy dust settled in building areas where mold is not present. Additional samples may be collected for comparison baselines such from outdoor areas or from non-complaint areas in the problem building.
A thorough building investigation will include sampling or "tests" to identify the presence of mold and to identify the dominant problem molds by genera and often species.
By contrast, a quick and simple "mold test," particularly a random spot check, is of little value by itself: grabbing a 90 liter air sample or putting a settlement plate in a closet for an hour is not a reliable building characterization for mold, and a tape sample of the single square foot of mold in a building is unnecessary.
If there is no large mold area, no leak history, no at-risk occupants, in sum, if you simply have a little moldy area, just clean it up, and spend your "test kit" money on cleaning supplies or dinner out. Small amounts of mold can often can be cleaned-up by the occupant or owner provided that person has no special allergy or risk regarding mold.
Some states define
"small" as less than 30 sq. ft. of contiguous mold. Your own area may
use a different criterion. Larger areas of non-cosmetic mold are likely to
require work by a cleanup professional. If you think you need to hire someone,
seeMOLD EXPERT, WHEN TO HIREor more detailed help in deciding when and how
to proceed.
Settlement plates, culture media, or swabs which are later cultured, used alone for building mold risk analysis are invalid methods which risk both false
positive results (saying there's a problem when there is not) and false negative results (missing an important problem). More about this is in this
article and you can read in greater depth
at MOLD CULTURE TEST KIT VALIDITY .
What about other do-it-yourself tests? Amateur mold "testing" by a homeowner, using a tape lift of visible mold, perhaps with some good advice on where to look, might be an inexpensive way find out that the "black mold" on the floor joists is a "cosmetic-only" mold, thus avoiding the cost of a more expert professional building investigation/remediation.
However anyone using this approach should understand that it is incomplete and superficial: you might collect your sample from a spot which is not representative; you will not address the risk of hidden mold in building cavities; you will not have expert mold remediation advice; you will not have baseline data to support a later clearance test after cleanup, finally, you risk leaving another problem in the building.
These warnings should be considered carefully where large areas of mold are already visible or at-risk occupants are involved.
Of the mold samples sent to our lab by owners who have had no collection advice, we find that "black molds" seem to be over-represented and we suspect these are often not the real problem in the building. The mold the owner sees may be simply the indicator of moldy conditions.
Lighter, harder-to see molds in the Penicillium sp. and Aspergillus sp. families, for example, are under-represented in owner-collected samples (based on our field experience and on our review of statistics of samples sent to Dr. J. Haines at the N.Y. State Museum for identification) because these genera are often more difficult to see.
Can you please tell me what you charge for lab analysis of sticky tape dust samples?
[Click to enlarge any image] Photo: an indoor dust sample containing colorless Pen/Asp spore chains, fabric fibers, skin cells, mite fecals, and other fungal spores.
I would like to do dust samples in the living area, basement, and in the HVAC ducts.
I am suffering from a severe asthmatic condition that has worsened in the last few years despite the best efforts of several doctors. The problem affects me indoors and only seasonally when the house has to be closed up for AC or heat. Although the 70 year old home (I have lived in it since 1979) has never suffered water damage of any kind, I did have the humidity cranked up very high for several years during the winter months.
However, there is no visible mold except for a few darkened areas of insulation in the attic near areas where air leaked in from the living envelope. That insulation has been removed. The attic joists have been foamed to seal cracks around electrical boxes and the DWV pipes, and new fiberglass insulation added. HEPA vacuumed area during cleanup.
- Anonymous by private email, 2016/11/10
Thank you for asking about our testing services, Anon.
I've retired from performing environmental testing or inspection services to the public with a few pro-bono exceptions that you can review [at INSPECTION & TEST FEES ]
My fee for analysis of a tape sample of dust or suspected mold was $50. which will be similar to most labs. An onsite inspection, when justified at all, if done properly is going to cost more than $1000. + any lab costs. It's not something appropriate for all cases and often you can follow my website's advice to get a reasonable idea of what's going on in your building.
First let me offer a few suggestions and answers to your note:
The steps you've already taken are reasonable and probably inexpensive, though I suspect that some of them were not likely to have addressed a significant problem-particle reservoir if one is present.
And as I'll suggest below, if you haven't already done so, as an asthmatic there are simple things you want to do to reduce a building's role as a source of respiratory irritants such as removing wall to wall carpeting.
Start with your doctor: You should always consult with your doctor about his or her advice for reducing the contribution of your home or workplace to asthma problems. There is both general advice for reducing dust levels or cleaning, and specific advice about reducing exposure to specific allergens or asthma triggers.
As your suffering is seasonal it may be similar to my own, extrinsic asthma.
Before you spend money with anyone on testing samples you should consider whether or not there's a high risk of hidden problem dust (mold or other) reservoirs in the building and whether or not it's appropriate to hire an onsite expert. In my opinion no DIY mold "test", even settled dust or surface samples that I otherwise like, is a substitute for a thorough onsite inspection and occupant interview by an expert.
For your specific case I'd look at the general contents of settled dust to see if there are unusual levels of common irritating particles or even low levels of certain key indicator particles, and I'd look at the quality of HVAC air filtration and cleanliness of the building and its HVAC system such as cleaning up obvious dust reservoirs and removing common dust and allergen sources (carpeting, pets, rodents, visible mold contamination) before hiring an expert.
See MOLD / ENVIRONMENTAL EXPERT, HIRE ? for help in deciding if it's appropriate to face the cost of bringing in someone who knows how to address these concerns.
...
Below you will find questions and answers previously posted on this page at its page bottom reader comment box.
(May 18, 2012) PBI RESTORATION said:
WE HAVE TESTED MOLD FOR AIR QUALITY IN AN APT
IS AIR SAMPLER IN A 5 MIN PER AREA INCLUDING ONE OUT SIDE ACCURATE
ENOUGH TO DETERMINE IT SAFE
?
(Oct 16, 2012) Anonymous said:
we have found mold in the aseptic areas considered as Grade B category, I would like to find out where mold is coming from.. is it from operator who operate the air sampler or is it coming the air that circulate the aseptic area.
However, I would to know the root cause of mold contamination in the area. I need some clarification and advise from the expert how to investigate mold contamination in an aseptic areas - where it coming from? need your feedback
Reply:
Sorry,
I don't know what you mean by
aseptic areasNor by
Grade B category
...
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