Recent FAQs on airborne mold spore count reports or numbers - set #4.

Frequently-asked questions about how to interpret the mold test number that is returned by your mold test consultant or mold test lab.

This article series discusses the possible significance of different levels of indoor airborne mold spore counts and mold test reports.

Building Mold Contamination Levels

These questions and answers about how to interpret the mold count returned by various mold tests were posted originally

at AIRBORNE PARTICLE & MOLD COUNT NUMBER GUIDE - topic home. Be sure to see the advice given there.

On 2020-03-26 - by (mod) -

Bruce:

Air tests for mold are fundamentally unreliable in that the "number" can vary from the actual mold level by up to 4 orders of magnitude.
A "1" might be 1,000, for example.

However, finding ANY airborne Stachybotrys chartarum indoors means that there either was or is currently a wet building area (often drywall) and there was or is a mold reservoir in the building that needs (or needed) to be found and removed.

It's not the count itself but rather the fact that S. chartarum isn't normally growing indoors and therefore it's an indicator of building leaks and mold. It may not be anything near the most-dangerous mold indoors but it's an indicator of moldy conditions. Details are

at AIRBORNE MOLD COUNT VALIDITY

On 2020-03-24 by Bruce

I just received a building mold report showing one of the offices having a count of 24 for Strachybotys. Is this a number I should be concerned about? Lab details say limit of detection is 24 c/m3. I think that is not a count to be concerned about.

On 2020-02-27 - by (mod) -

Kristie

In the article AIRBORNE PARTICLE & MOLD COUNT NUMBER GUIDE take a look

at AIRBORNE MOLD UNDER 500 SPORES PER m3

and realize that mold counts are fundamentally inaccurate - the true mold level can vary by 4 orders of magnitude from the "count" given - "mold spore count tests" without a through inspection and interview and analysis of the building by an expert are of limited use.

On 2020-02-2 by Kristie mold count of 427 for cladosporium

I have a mold count of 427 for cladosporium
And 373 for smut count


I live in an apartment where mold was found on the windows and there are two water stains on the ceiling on which has mold on it but both stains are bone dry. I had a home inspector in and he said there is mold in the attic as well... He told me even if he remidiated the apartment it could come back because of the attic...I'm trying to get out of my lease...should I have more testing done? Since I only had the air tested.

On 2019-12-15 by Anonymous

A "low mold count" if it's a report of an "air test for mold" is, used alone, in my experience and opinion, singularly unreliable as a building screen for mold contamination.

IN this article series (see the INDEX to RELATED ARTICLES found at the end of this article ) we give a number of technical and practical explanations that make clear that there is so much variability (4 orders of magnitude) in counts of airborne particles depending on details of when where and how such a "test" is conducted as to make especially low or zero counts of particles unreliable.

What is needed if there is a concern for mold contamination is a thorough visual inspection and occupant interviews by an expert.

All that griping having been made clear, there is no reason whatsoever that we would expect any mold test, count, screen, or other arm-waving, to detect all possible mold spores anywhere. There are millions of mold genera/species.

On 2019-12-15 by (mod): what do low or no numbers mean in a mold test?

Jenny:

As there are a couple of million genera/species of mold, there is no chance that any mold test checked for all possible mold spores that could be present in air.

However your mold test should report what molds were observed - at least as long as the lab technician considered the presence of spores to be at all significant in the sample.

Keep in mind that depending on how a mold sample is prepared and how it is examined under the microscope, spores may be present but not detected. A very small change in focus, for example, can make hyaline and small Aspergillus spores appear or "disappear"

On 2019-12-15 by JennyR

Hi there. I'm attaching a mold report for an elementary school in Illinois. I have a couple of questions.

First, if there are no readings for certain molds, is it more likely that they did not test for those molds or that they did test but did not detect any of those types of spores?

My second question is: Is it possible that mold readings such as these could elicit symptoms in people. We've had several teachers complain about both having symptoms and smelling mold smells in certain parts of this building, ongoing for several years.

But, looking at the report, the counts look low compared to what I'm reading in the other Questions/Answers in this thread.

On 2019-11-09 - by (mod) -

Apologies MaryAnne but nobody can form a useful opinion about a mold test "count" alone; I have no idea how the 'test' was conducted, where, when, under what conditions.

The truth is that IF for example you had someone conduct an AIR test to count airborne mold spores, these "mold counts" can vary by 4 orders of magnitude by very small changes in "test conditions". So your 132 might be 0.0013 spores per cubic meter of air or 132000 spores per cubic meter of air.

I do agree that we don't want high levels of Pen/Asp in a building and I agree that finding Chaetomium indoors in other than incidental levels (that flew in a window) is taken to mean that there has been water damage and that there's probably mold contamination somewhere.

So unless those are "left over" mold spores from an otherwise documented, expert, thorough mold investigation and cleanup already performed, you will want to have someone competent do something more useful than "a mold test" - like an actual thorough inspection to identify actual mold reservoirs: how big, where, why, how much remediation is needed, and what's the cause.

It's also my OPINION that if you pay someone to perform a "mold test" and that person cannot tell you what the test results mean, you should demand your money back as a meaningless test is also useless.

Bottom line: find the mold, remove it, fix the cause.

On 2019-11-09 by MaryAnne

Hi there,
We had a house test at the following levels for Penicillium/Aspergillus:

(2nd floor) raw count: 132, spores/m3: 884, % of total: 74
(basement) raw count: 141, spores/m3: 945, % of total:

45.

The basement also tested for Chaetomium at the following levels- raw count: 14, spores/m3: 94, % of total: 4.
My question is, what should be our next steps? It does not appear that these levels are terribly high however the report does state high levels of debris in the sample likely caused significant interference with the accuracy of spore counts & counts are probably higher than reported. We want to be sure we are not in danger and are also concerned as we are looking to buy this house and fear that it will be very costly to remediate this problem.

On 2019-11-05 - by (mod) -

If you have found and removed the actual mold contamination it wouldn't be a shock to find some Airborne mold spores remaining in the building. However with adequate cleaning and a complete job simply ventilating with fresh air ought to drop that number down extremely low.

If it doesn't one suspects that the cleanup has been incomplete. Are we can really talk about is whether the job has been done correctly, that is I would not bet your health and money on guessing at your exposure level by e-text.

On 2019-11-04 by Amanda

We had a airborne/ surface sample test done after mold was found under our kitchen sink and on basement walls. The basement walls came back with chaetomium (very heavy) and under the sink, aspergillus/penicillin (heavy). The air sample from the kitchen one showed levels of 1493 count/m3 of chaetomium and 67 count/m3 of aspergillus. My question is should we be alarmed staying in our house if we have an 8 month old? The technician said we would be fine but I want a second opinion. Why is the basement mold so airborne in the kitchen?

On 2019-11-01 - by (mod) -

Andrea:

I have collected our conversation about dental office IAQ, mold, contaminants and an improper hole cut into a floor now found at AIRBORNE MOLD COUNT NUMBER FAQs-6

https://inspectapedia.com/mold/Mold-Air-Test-Number-Count-FAQs6.php

On 2019-10-29 by Andrea

I guess what I really should ask just so I feel validated in my mind. Would the level of Aspergillius/Penicillium mold spores found in our office make us sick? tjw number again was 23400 with a humidity level of 88% in the basement then pulling to our room by a fan and HVAC dampers closed.

On 2019-10-30 by (mod) - possible unsafe air in a dental office

Thanks for adding an interesting point. Aside from fire safety we're also allowing anything in the lower floor which could be hazardous to move upstairs.

You will see in this article series that are tests for mold look very precise but in fact a very inaccurate. Test results can vary from actual by 4 or more orders of magnitude. So the most you can say when you have a high number is yeah that looks like a problem or yes that's consistent with a moldy building.

I can't really assess the new one can really assess the actual exposure level of one individual in the building but I've considerably more data. You can take the number high enough that it indicates a building problem and potential Hazard rock bands zooming the test was done by someone reasonable confidence

On 2019-10-29 by Andrea

I guess what I really should ask just so I feel validated in my mind. Would the level of Aspergillius/Penicillium mold spores found in our office make us sick? tjw number again was 23400 with a humidity level of 88% in the basement then pulling to our room by a fan and HVAC dampers closed.

I have since called OSHA Indiana and they stated that the hole in the floor is against fire code.

On 2019-10-29 by (mod) -

It sounds as if an on-site expert is needed perhaps two experts to address first the location of and cause of mold contamination in the building so that the mold can be removed and it's cause corrected, and second a more competent person to review the heating ventilating and cooling system to make sure that it is working correctly. Frankly it sounds a little crazy to me to install what you described as a improper fan and then try to solve the problem by cutting a hole in a floor.

On 2019-10-29 by Andrea

I work in a dental office and have been feeling very sick. After passing Out, vomiting and being disoriented enough to be sent home one day I did some investigating. Discovered the HVAC dampers we’re stuck closed in our room resulting in no fresh air hot or cold was entering our room.

Also have been noticing that when we turned the Vent fan on in the room it was getting humid and hot. When the vent fan was on we were feeling sick and having to evacuate to go outside for fresh air. Discovered that when a handyman out in the vent fan, he has put one in that was way about the air exchange rate for the room causing the door to be unable to close. He then proceeded to cut a hole in the floor which led to the basement to help with the vacuum pull the vent fan Was causing. The hole helped the door shut but in turn brought hot humid air into the room when ever the vent fan was turned on.

Meanwhile we were having to evacuate every-time we were working in there WHEN the vent fan WAS TURNED ON. As workers where called to fix the HVAC system they also installed a down draft air system at each of our work stations adding up to 4 total in the room. Thinking this new vent system would be the answer.

We began working again in the room. Same results happened and we had to evacuate.

Once again I did some investigating. This time I covered up the hole in the floor that led to the basement with a couple towels. We did the same work we always did. Do NOT have to evacuate!! Meanwhile the workers down stairs must have thought it was warm and humid which could have possible coNd Orion’s of mold growth. Our manager informed us that there would be an air quality test taken in our office.

The results are in. Sump pump room was at 88% humidity and Aspergillus/Penicillium mold spore count reading was 23400 ppm.

I have been to the doctor through out this with all my sick symptoms fatigue, weight gain, rashes, ringing in both ears, de-myalinization in my brain, anxiety to go into that room again.

I have now been snubbed at work. I’m guessing because my boss thinks I may take legal action. I have in no way ever expressed to her of doing this. I don’t sleep very good anymore being consumed by how this situation has effected my life.
Any advise you could give I would gladly take on where to go from here.

Feeling sick just getting this in writing,
Andrea

On 2019-10-15 by (mod) -

From the limited information in the posts below, my best opinion is what I've already stated, plus the general guidelines in AIRBORNE PARTICLE & MOLD COUNT NUMBER GUIDE.

Ripping into a building based on just a single inspection or test point may be justified but it's also a pig-in-a-poke; What's needed is an actual, competent inspection by an un-biased expert who has no conflicting interests, and who can define the initial scope of work needed and can explain the basis for that. Indeed it's likely that a contaminated wall cavity needs to be remediated in a building, but some further guidance is needed such as

- remove visibly mold-contaminated or previously wet drywall and insulation until a 2-ft or 1 stud bay (etc) boundary of clean materials has been found

- clean the affected cavities

- restore the building

- identify and correct the cause of the mold

- protect surrounding areas from cross contamination

- determine whether or not it is safe and appropriate for occupants to be in other building areas before, during, and after the work pending a final clearance inspection

On 2019-10-15 by Marilu

Thankply.
The results are reported in spores per cubic meter from what we were told. Could you give your opinion based on spores per cubic meter?

There is no visible water damage on walls or on roof or near AC unit or in the attic. Three windows/sliding glass door have some minors cracks and look like there was some water intrusion at some point but everything is dry now per inspector. So we had a Hygienist come out and they recommended thatbwe allow them to cut into the wall and remove a sample under the 3 areas that looked the worse. We had a full inspection done and they recommended sampling in other areas but we could not afford so much so we narrowed it down to the windows/sliding glass doors that looked most problematic.
The report recommends remediation by removing the wall the affected areas and other measures.

Now with this additional info could you re read my 1st list of questions and share your thoughts?
Thanks so much.

On 2019-10-15 by (mod) - please interpret my mold test sample results

Sampled how? Vacuuming? Was there an inspection done? What's the leak history and mold remediation history of the home?

One can not assume anything about the actual mold levels - quantitatively - from this sort of test, and worse, we have not a shred of data on the scope of the mold problem in the home. Such tests are a not a substitute for an actual inspection that identifies a mold problem and describes the work necessary to remove it and fix its cause.

Furthermore the "counts" you gave are "raw" and don't describe mold exposure levels; the measure of Spores per cubic meter is more useful, though that too varies by many orders of magnitude depending on exactly when, where, and how a "mold test" is conducted.

However, all that griping stated, any indoor "mold test" that finds a that harmful molds such as Stachybotrys chartarum and Penicillium or Aspergillus indoors are either the dominant particle found in sampling or are present at elevated levels (as yours appear to be) means that you've confirmed that there is a problem.

Marilu nobody who actually knows anything about building mold contamination and health-related concerns would be foolish enough to claim that they know the actual risks to the building occupants from so little data and with not a shred of information about the home and its history.

We have no idea how much mold or MVOCs in the wall cavity tested is entering the occupied space.

But I have to say that this smells suspicious to me. If a building had a previous mold problem and if that mold was properly removed and its cause corrected, I would not expect to detect other than the smallest trace levels of mold inside building wall, ceiling or floor cavities.

What prompted you to have this test done?
Why a wall cavity test?
Why in that specific wall location?
What is the history of the home? What work was done, by whom, with what credentials, and what independent inspecting and test were done to confirm that such work, if performed, was proper and complete?

On 2019-10-15 2 by Marilu

We just had wall cavity samples taken from above the baseboard in 3 areas of a new home we're renting. Levels for Asp/Pen are 160k, 150k and 470k. Levels for Stachy are 1800, 12k and 0. Chaetomium levels are 22k, 15k and 7500.
We were homeless until finding this house. We are mold injured already and have no where to go. We don't think the landlord will remediate but will show them the report.

Are these levels high enough to warrant us to leave?
Until we figure out what to do, could we seal the affected walls using 6mm plastic sheeting to help mitigate contaminants blowing into the air from inside of the wall cavity, when the AC is on? The walls are dry, no current water stains or leaks.
How dangerous are these levels for our family? - [Click to enlarge any image]

On 2019-09-21 by (mod) -

Bill

Air test "counts" vary by up to 4 orders of magnitude depending on just how the "test" is conducted, so a count of 45 might be actually .004 or 45,000. So on the face of it, while the absolute count looks low, I can't make much out of it. NOT MUCH can be taken from such a test; if there is justification then what's needed is an actual onsite inspection by an expert. Testing may be profitable but it's not so useful by itself: it's not diagnostic (doesn't always give an accurate yes or no to the problem question, doesn't tell us where the problem is, doesn't tell us what needs to be done)

In my OPINION if you paid someone to do this "test" and she - who has seen and inspected the site - or he won't answer questions about it, it's time to get your money back.

On 2019-09-19 by Bill

forgot to ask question.. Is that a dangerous reading?

On 2019-09-19 Bill

I had an air test done and reading came back with Aspergillus Penicillium raw count 45 & 600/m3 and Cladosporium raw count 16 & 213/m3 in a bathroom with open drains in shower and sink. I don't know if it matters, but it rained that day as well.

On 2019-09-21 by (mod) - is my air test count of Aspergillus Penicillium raw count 45 & 600/m3 a dangerous reading?

Bill

Air test "counts" vary by up to 4 orders of magnitude depending on just how the "test" is conducted, so a count of 45 might be actually .004 or 45,000. So on the face of it, while the absolute count looks low, I can't make much out of it. NOT MUCH can be taken from such a test; if there is justification then what's needed is an actual onsite inspection by an expert.

Testing may be profitable but it's not so useful by itself: it's not diagnostic (doesn't always give an accurate yes or no to the problem question, doesn't tell us where the problem is, doesn't tell us what needs to be done)

In my OPINION if you paid someone to do this "test" and she - who has seen and inspected the site - or he won't answer questions about it, it's time to get your money back.

On 2019-09-19 by Bill

forgot to ask question.. Is that a dangerous reading?

I had an air test done and reading came back with Aspergillus Penicillium raw count 45 & 600/m3 and Cladosporium raw count 16 & 213/m3 in a bathroom with open drains in shower and sink. I don't know if it matters, but it rained that day as well.

On 2019-09-05 by (mod) -

Anon

No one who has an ounce of sense would pretend that she could tell you if a building is safe or not by mere e-text and a report of an uncertain "mold test"

However there are some basic guidelines that are reasonable:

1. If there is a large visible mold reservoir (more than 30 sqft of contiguous mold) in the building then professional remediation is warranted AND such an area would be a possible health risk for anyone.

2. If the area smells moldy there's mold contamination present, even if it's not visible - of unknown dimensions

A building that has been exposed to one or more leaks, floods, wetting events, over its life, if those results have not been expertly examined and remediated as needed, is certainly at risk of having hidden mold reservoirs.

The fact that some people in a particular environment do not suffer or complain about mold or other environmental irritants or concerns is not diagnostic. People vary in their sensitivity to specific things in their environment.

3. People at extra risk: elderly, asthmatic, immune-impaired, or otherwise at extra medical risk where there could be environmental contaminants or even mere stressors, should not be in a moldy environment.

You should ask your doctor for guidance about your personal risk and experiences.

4. Keep in mind that there can be other risks in any building, environmental or others, that are not noticed - don't let worry about a single one lead to being inattentive. Falling down the stairs is the most common injury.

5. I don't know what to make of four cancer diagnoses among workers at a particular site; what's the total population? Who are the population and what are their individual health histories, work histories, environmental exposures over their lives, types of cancers, relation of their cancers to environmental factors, etc. Just "cancer" alone isn't sufficiently diagnostic to form a reliable opinion about the relationship of cancer to workplace.

6. I strongly advise you and your building management: DO NOT rely on "mold testing" alone as an assurance that there is or is not a mold contamination problem in the building. Mold "test" results can vary by four orders of magnitude based just on small variations in how and where and when such "tests" are performed, and some popular "tests" such as culture or settlement plates an be 90% "wrong" from the onset as most molds won't grow in culture.

If there is a suspicion of a mold problem an expert and thorough visual inspection, taking of building history, review of occupant complaints, is what's needed - conducted by someone of sufficient expertise in building science, environmental hazards, inspection, testing, building materials, air movement, mycology, and the identification of other likely environmental contaminants.

In the ARTICLE INDEX you'll find more details on the reliability of mold tests, proper mold inspection and remediation procedures, etc.

On 2019-09-05 by Anonymous

Are there immediate health concerns to being in the space until it is removed? We are being told that they are looking into it, but it will take a while to come up with a solution and implement it. We have a horribly designed old building with a roof design that just can't be sealed. We have had water intrusion in the walls for years.

Now the floor supports are crumbling and the corners of the building are sinking into the crawl space. My office is next door to the corner office. We have wood floors, actually an old gym converted into offices, so it is an old basketball floor, from the 50's.

I ask all this because I had a benign brain tumor removed in April. It was very fast growing, from nothing to the size of a walnut in 2 years or less. (based on previous MRI and discovery MRI) When they found it they sent me to the ER to have it removed immediately.

This happened to me after three other employees in my section of the building were diagnosed with other cancers over the previous 3-4 years. So, before returning to work I requested some environmental testing be done. They agreed, however, my employer feels that the mold tests show nothing concerning. They will work towards repairs and removal, but say there are not health concerns in the mean time.

If these are unsafe conditions I could use some assistance with documentation to make my point.

On 2019-09-04 by (mod) - no concerns for exposure inside the office because it is "only in the crawl space"

In my OPINION saying there's no concern when there is an actionable mold reservoir (more than 30 sqft merits a professional) is in a crawl space is foolish and erroneous;

Some mold genera/species such as Aspergillus or Penicillium that are often found in such areas are such tiny spores that the can move like a gas up through the building to contaminate occupied space, as can MOVCs.

Of course wipes giving concentrations make no sense to me either. But if the space is moldy the mold needs to be removed and the cause cured.

On 2019-09-04 by LB

I received test results that a surface wipe of the crawl space of my office has a concentration of 365,760 spores/cm2 (cm - not m). and reads as 93% Asp/Pen. I am told that there are no concerns for exposure inside the office because it is "only in the crawl space". Would this hold true? It is hard to understand the measurements of cm vs m and surface wipe vs air sample.

On 2019-09-04 by (mod) - understanding ASHRAE mold readings and MYCOMETER mold readings

Anon:

I don't recognize "ASHRAE READING"

But from your description you need a professional remediation job;

Don't make the mistake of thinking that "black mold" is the concern; ANY mold of ANY COLOR indoors, with a couple of rare exceptions, is a potential hazard and needs to be removed: pink, purple, green, yellow, red, orange, white or ... black mold.


Renee: How to Interpret MYCOMETER Readings

A "mycometer" is an instrument, designed to measure mold concentrations on building surfaces by detecting certain enzymes produced by molds.

In my OPINION no reading will be completely intelligible:

EVERYTHING depends on exactly where you sample ANY surface for mold.

Having operated both a forensic & mold lab for years as well as conducting field investigations since the 1980s, I had the luxury of being able to perform more comparative testing and mold detection experiments than would normally be affordable, as I could work at my own expense.

One of the outcomes was the observation that sampling surfaces such as moldy drywall JUST A FEW INCHES APART can find entirely different mold genera species - principally because different molds may prefer different levels of moisture in the same building material: in this case the paper on gypsum board or "drywall".

So what on earth should we conclude from any "number" assigned to a mold-surface-contamination reading?

I can't make much sense out of such readings, particularly if the readings are low, since there's too good a chance of a false negative result - had you but moved over an inch you'd have found something different.

However in very general terms, any mold test of any sort that reports - on whatever scale they think is impressive and good marketing - that finds what that particular "testing" approach considers HIGH, is most-likely an indication that there was a meaningful or "significant" mold contamination found AT THAT SPOT AT THAT TIME.

Without a thoughtful and thorough building inspection by an expert, such a test result is not very helpful. It's not diagnostic. It hasn't told us

1. is there a significant building mold reservoir that needs attention? or did the test expert simply put her sensor on the one spot, of perhaps five square inches (thus trivial) of mold in the whole building?

2. If there is a significant building mold contamination problem, WHERE is the mold contamination, how much demolition and cleaning are needed, and what caused the mold and thus what other repairs are needed to avoid a repeat of the mold problem.

So ultimately you need to hire someone who will actually do the work needed.

FYI Mycometer's main location is
Mycometer A/S
Dr. Neergaards Vej 3
DK-2970 Horsholm, Denmark
Tel.: +45 3916 1072
info@mycometer.com
www.mycometer.com

Excerpting from that company's website we list the INTENDED PURPOSES of a MYCOMETEr

Mycometer-surface Applications
Post remediation verification (PRV)
Documenting the efficacy of the cleaning of surfaces for mould growth
Documentation of mould growth
Documentation that discoloration is NOT mould growth
Delineation of mould growth where it is non-visible. How much should be cleaned?
Documenting the cleaning of HVAC systems

Results categories have been established empirically, and provide criteria for clean, dirty and contaminated. Clean is the defined as the background level meaning the level found on visual clean surfaces in well maintained building with no mould and moist problems. Contaminated is defined as samples containing mould in higher concentration than what can be found on dusty and dirty surfaces in well maintained building with no mould or moisture problems. The interpretation criteria are in accordance with the most influential international guidelines such as those from WHO, New York City Department of Health and US-EPA. All mould growth, independent of species can affect health and should be removed.

End of excerpt

NOTHING in that documentation gives details about interpreting numbers of such test results.

Finally in my OPINION if the "expert" you hired to do your "mold inspection" (I use quotes because in my view those terms are highly suspect) will not answer the question you posed to me here then you should demand your money back.

On 2019-09-04 by (mod) -

I don't recognize "ASHRAE READING"

But from your description you need a professional remediation job;

Don't make the mistake of thinking that "black mold" is the concern; ANY mold of ANY COLOR indoors, with a couple of rare exceptions, is a potential hazard and needs to be removed: pink, purple, green, yellow, red, orange, white or ... black mold.

On 2019-09-04 by Anonymous

ASHRAE reading 64.4%
I think we have black mold many years and fire retardant sheet is dry rotted and blowing black dust through vents

On 2019-09-04 by Renee

What is considered a high mycometer quantification count? Our building reads 87 MAV/m3. But us simple layman are clueless in what this means

On 2019-08-28 by (mod) -

Frankly it means almost nothing.

"Mold test kits" that rely on culture are testing just about 10% of all the molds that could be present. The other 90% of molds won't grow in culture.

"Mold test kits" that use culture plates are also relying on particles (such as mold spores) that fall out of the air onto the plate; the rate of "fall-out" various enormously by particle size, mass, or weight, air currents, location of placement, etc.

So no such "mold colony count" will be an accurate actual representation of the environment where the "test" was conducted.

ALL we can say is that some Penicillium mold spores grew in the culture plate. Penicillium sp. mold might be present indoors at a problem level; if so it will certainly not be the only mold present, and other molds, including more-harmful ones, could be present.

Unfortunately IF there is reason to suspect your building is mold contaminated, an expert visual inspection, history taking, occupant interview etc. are what'd be needed, and that has to be performed by someone who is expert in mycology, building science, air movement, construction methods and material, etc. Don't just hire someone who stops by to drop off a mold test.

On 2019-08-28 by Cheri

Received a result of mold test kit. says 29 colonies of Penicillium and 100 % detection level. What does this mean?

Question: should a cancer patient avoid mold?

(Aug 25, 2012) jerry dupuis,[ dupster1@mnsi.Net said:

I have been told a person with , 'cancer ' should never be exposed to mold spores,
We have black mold in the building, and she is not aware of this hazard , is this true,?
We have staff exposed every day as well as swimmers and work out teams, i am concerned, jerry

Reply: yes

In my OPINION cancer patients and anyone else who has a compromised immune system is very likely at greater risk of illness if exposed to allergenic, toxic or pathogenic substances, including mold at other than incidental, typical outdoor levels.

People at extra risk in areas where there is mold contamination include at least:

• People with compromised immune system such as cancer patients undergoing chemotherapy
• People suffering from asthma or from mold allergies
• Elderly
• Infants and the very young
• People with any respiratory illness

Question: I have black mold

(Oct 13, 2012) ruth auerbach said:

I have black mold and also eferfescence we were tested at 800 in an airborne check
should we leave the house until it is fixed

Reply:

Ruth knowing so little about your home and the test I can't say if you should stay in the home or not. Insist that your test consultant help you interpret the test. If no inspection was performed the test is unreliable.

Question: how accurate are mold test labs

(Oct 24, 2012) Khalid said:

I know that mold has high variability but What is the precision and standard deviation for the lab?

Reply:

Good question. Most forensic labs including mold test labs not only pass certification testing but also participate in a "round robin" examination of a lab sample so that the labs can compare results and lab techniques, improving everyone's accuracy.

Forgive me for begging the question but as you put it it's not useful. Given that how the mold sample is collected can result in several orders of magnitude difference in the number of particles collected, meaning that the ability of the sample to accurately represent the test environment can be off by a factor of 10,000 times, the accuracy of a lab count is not a worry.

Please see these two key articles that will answer your question more meaningfully

ACCURACY OF AIR TESTS for MOLD

ACCURACY vs PRECISION of MEASUREMENTS

RE: Khalid's excellent question:

I know that mold has high variability but What is the precision and standard deviation for the lab?

Khalid, the variability in lab precision in mold counts indeed varies by technician, microscope adjustment and calibration, slide preparation, mountant used, magnification at which a sample is examined, and other measures such as the percentage of the trace or sample that is actually examined and counted in the lab

However the choice of test method, particularly where air tests for mold or culture tests for mold produces variation of at least several orders of magnitude in the results. Waving a notebook in the air during a collection of airborne particles, for example, can increase the count by a factor of 100 to even 1000. And using a culture to test for mold in buildings fails to account for the fact that 90% of molds don't grow in culture, or among those that do, a genera/species that likes the culture more than one of its neighbors may quickly reproduce, overgrow its neighbor, and falsely appear as the dominant mold when it was in fact an incidental bystander.

These arguments conclude that mold count variability caused by methodological method choices will generally overshadow variation in lab precision. Test lab managers know this. I have argued against providing "precise" particle counts. But their understandable reply is that test labs respond to market pressures. "If we dont' give counts our legal customers will just go to another lab that does" is a common retort.

All of this means that the importance of an expert visual inspection, noting building history, components, risk areas, visual hazards, and noting occupant complaint history and similar factors are very important in assessing building mold contamination risks, and that without these steps, mere quantitative "mold count" tests are not so reliable.

On 2019-05-24 by Todd

Thank you. Very informative website and level headed responses to questions.

On 2019-05-21 by (mod) - you wouldn't attempt a mold remediation based on an air test alone

I don't want to try to second-guess your on-site expert, but certainly you wouldn't attempt a mold remediation based on an air test. Someone with eyes needs to find the problem and Define the scope of work needed.

On 2019-05-21 by Todd - Aspergillus/Penicillium 153 raw 40% 2000 spores/m3

Hi,

Got the results below from samples in garage. There is a crawl space connected to garage that we can feel is damp / moist when we open the crawl space door. Looks there is a small puddle of water in there as well (probably from the soil from recent rains). Visible mold not seen, but don't think very corners of crawl space were visible inspected. Mold inspector recommends remediation. Thoughts? Thanks!!!

Outside:
Aspergillus/Penicillium 27 raw 9% 360 spores/m3

Basidiospores 66 raw 21% 880 spores/m3

Chaetomium 1 raw 0% 13 spores/m3

Cladosporium 159 raw 51% 2100 spores/m3

Unidentified Conidia 2 raw 1% 27 spores/m3

Garage SE Corner:

Aspergillus/Penicillium 198 raw 61% 2600 spores/m3

Basidiospores 48 raw 15% 640 spores/m3

Chaetomium 0 raw 0% 0 spores/m3

Cladosporium 69 raw 21% 920 spores/m3

Unidentified Conidia 2 raw 1% 27 spores/m3

Garage N Side at Crawlspace:

Aspergillus/Penicillium 153 raw 40% 2000 spores/m3

Basidiospores 60 raw 16% 800 spores/m3

Chaetomium 1 raw 0% 13 spores/m3

Cladosporium 108 raw 29% 1400 spores/m3

Unidentified Conidia 15 raw 4% 2000 spores/m3

Total Fungal Spores: 4200, 4300, 5000, respectively

On 2019-01-27 by (mod) - Do I have to get rid of everything?

Your question cannot be answered from a mold test report. However in general I can tell you that you only have to get rid of things that cannot be cleaned

On 2019-01-27 by Audrey

I was wondering how dangerous this is my house. We are currently renting and they are willing to fix the leak in the roof and clean up the mold but what about everything in the room or throughout the home. Do I have to get rid of everything?

IMAGE LOST by older version of Comments code - now fixed. Please re-post the image if you can. Sorry. Mod.

On 2017-06-10 by (mod) - How dangerous is tree mold in a mobile home?

Lucy,

I'm sorry but I don't know what tree mold is nor why it would be found inside a home of any sort.

If you paid someone to make an inspection or to perform a test and that's what they have told you then I question what that person is doing and what they know about indoor mold contamination.

There are molds that might be allergenic or potentially more harmful if they are present in a large Reservoir inside your home. Perhaps you can tell me more about what you have seen and where it is and I can comment further.

On 2017-06-09 by Lucy Collins

How dangerous is tree mold in a mobile home?

On 2015-12-12 by (mod) - get your mold test money back if the consultant won't explain the results

Elizabeth,

If you paid someone to perform an inspection and test for harmful mold in your home and that person cannot explain the meaning of the report you received, you should start by demanding a full refund.

These counts mean almost nothing without an expert visual inspection of the building for mold, leak history, related conditions.

On 2015-12-10 by Elizabeth

Hello, i'm looking for help in interpreting mold counts done in my condo. i've had a miserable rash for 9 months that no one can explain, and i finally thought to have mold testing. also a runny nose, hair loss and weight loss. my pillow is around 10 yrs old, so that may be a problem - i've thrown it out. my skin symptoms are concentrated face/neck/upper back. mold air counts were done w/ the pillow still in my bedroom (in case that matters.) thank you!!!!


Basidiospores MASTER BEDROOM raw count 30 spores/m3 390 % 11 OUTDOOR raw count 221 spores/m3 2870 % 59

Cladosporium MASTER BEDROOM raw count 21 spores/m3 273 % 7 OUTDOOR raw count 121 spores/m3 1570 % 32

Penicillium/Aspergillus MASTER BEDROOM raw count 231 spores/m3 3000 % 82 OUTDOOR raw count 30 spores/m3 390 % 8

Smuts/Periconia/Myxomy OUTDOOR raw count 2 spores/m3 26 % <1

background debris (1-5) master bedroom 3 outdoor 3

sample volume(liters) master bedroom 75 outdoor 75

total spores/m3 master bedroom raw count 282 spores/m3 3660 outdoor raw count 374 spores/m3 4860


-elizabeth

Question: how to interpret airborne mold count levelsk, 1833 Aspergillus/Penicillium outdoors & 8553 indoors?

My workplace has a mold problem and a air sample analysis was done in August. I just got a copy of it as my doctor requested it. Question is - report shows outside level of 1833 or 4.2% Aspergillus/Penicillium and inside count of 8553 or 97.0% per cubic meter of Aspergillus/Penicillium.

What do these numbers suggest? All 6 employees are having health issues.
Thank you for any insight!! - My work has mold

[Click to enlarge any image]

Reply:

My Work:

The numbers you quote suggest an indoor mold contamination problem. Did you ask the mold expert who performed the test to interpret the data, inspect the building, give advice? If not, you folks didn't get much of value.

See AIRBORNE PARTICLE & MOLD COUNT NUMBER GUIDE and also see MOLD EXPOSURE STANDARDS

Question: Are there health risks to building occupants during duct cleaning & ceiling replacement?

My company is having the building cleaned, the ductwork replaced and ceiling tiles replaced. They have been telling us that there is no health risk to us working in the building. The report that I was given really doesn't say how bad the air quality is. I am just a small fish at the bottom of a very large corporate pool and told I have a job to do. - Anonymous

Reply:

Anon:

There may be OSHA or other regulations that should guide cleaning or renovation work in your building, and if hazardous materials are present that is surely the case. More generally, if the cleaners in your building are taking steps to control the release of dust during the work, such as setting up containment, using negative air machines, or HEPA vacuuming, or if the work is being performed in areas whose air and dust does not readily enter the work area, the risk to occupants is of course reduced.

Dust containing just about anything can be a respiratory irritant and for people at extra risk such as asthmatics, can be more of a problem.

At MOLD / ENVIRONMENTAL EXPERT, HIRE ? we outline some considerations that can help you decide if further investigation, testing, or analysis of your work area are appropriate.

Question: Following a death due to mold exposure in a building, how long can the spores live after the source has been removed?

How long can the spores live after the source has been removed? How serious is the contamination of personal items in the home and how long after the source is removed, are they safe if ever? More specifically, we are dealing with exposure to a home 4 years after a death occured in the home due to mycotoxicosis of asperigillus and stachybotrys. The original source of the mold was not in this home, but rather at a work place.

A year after the death, family members and a caregiver came down with symptoms and now test positive for the same toxins the family member died of. They claim the house is cross contaminated and abandoned it. 3 years later, we were hired to clean out the home and just found out this information. 3 years ago at the time of the abandonment, the house was tested and found to be 16 times the normal levels of the mold spores.

Unknowingly, we brought items into our home, donated items to friends and charity, and cleaned the entire home with out face masks or respirators. A 3 year old child and pregnant woman were also exposed. Should we be concerned? - Tracey

Reply: dead mold spores may still be a problem; but small or sub-acute levels of moldy dust without an actual mold growth reservoir are not normally a problem

Tracey:

Mold spore viability varies by species and condition; some spores can become very dessicated (dried) and remain in place for months or even years, later returning to active growth if conditions of moisture, temperature, and other factors are favorable.

Further, some mold spores may remain toxic, for example containing mycotoxins, even if the spores are "dead" - in the sense that they would not return to active growth.

These are reasons that we emphasize that removing mold contamination is important and that "solutions" to mold contamination that focus on "killing mold" are a mistake.

The fact that you report a previous death in a home and illnesses in a home where the death was associated with mold contamination and that you later worked in such a home performing cleaning, does not alone provide enough data to assert that you caused serious cross-contamination in a second structure by having worked in the first one.

But I can imagine some potential problem sources including use of a non-HEPA rated vacuum cleaner to clean the moldy home - followed by use of the same equipment in another building; the second use risks blowing potentially harmful or irritating dust into the second building.

Conversely, just having dusty moldy clothing would not, for most people, be sufficient to cause a serious cross-contamination in another building. Washing or dry cleaning the clothing will generally be sufficient to remove that concern.

There could be an exception if the clothes were not cleaned. I had a case in which a woman became ill from exposure to high levels of Aspergillus in a leaky mold-contaminated modular home

. She was hospitalized, had become hypersensitive to airborne mold, and had apparently recovered. When she was scheduled to return home her husband brought her clothing that had been stored in a closet in (the moldy) home. When the clothes were brought into her hospital room she immediately developed a serious reaction. My investigation found hidden mold reservoirs in the source home.

If you continue to be concerned about having imported moldy dust into your home you should take these steps to reduce that concern:

Make sure that your own home does not have its own leaks, moisture problems, and hidden or visible mold growth reservoir, independent of any dust that you may have imported.

HEPA Vacuum and wipe dusty surfaces in the home

Wash or dry clean clothing that may have been exposed to high levels of moldy dust or other problem dust contamination

Change air filters in your heating or air conditioning system

See MOLD / ENVIRONMENTAL EXPERT, HIRE ? for more advice on how to decide if it is appropriate and justified to bring in an expert to survey the building for problem mold contamination or other IAQ worries.

Question: can you refer me to a mold inspector in Germany?

Can you recommend mold inspectors in Kaiserslautern Germany? I am in the US Military and recently moved here and think I have mold in my rental house.

Is the mold/musty smell caused by spores or are spores only released if they are disturbed - Brian

Reply: sources of mold experts and advice on choosing one

Brian, you should contact your base medical and health officers for advice on inspecting your home for health worries, and see MOLD / ENVIRONMENTAL EXPERT, HIRE ?

Moldy odors are produced by some, not all, species of mold, and even then, not in all conditions. The production of MVOCs (mold volatile organic compounds) that you smell in air depends on the genera/species of mold, the surface on which it is growing, and growth conditions such as moisture, temperature, light exposure. And similarly, mold spore release is a natural event that occurs depending on growing conditions as well as on mechanical disturbance such as during demolition or cleaning.

Question: Can you Interpret my Mold Test Report?

My Mother had some testing done for mold in her home. I was hoping that you could shed some light on this. This threw her into panic mode. She has had some sinus problems which could be related to this mold in home. I am reaching out to you so that we know how quickly this needs to be remediated. I have attached a Mold test report [edited to remove personal information - ed.] that I was hoping you could decipher or point me in the right direction of a company that I could reach out to here in Wyoming, Michigan where my Mother’s home is located.

I believe she does have some moisture problems as she has some peeling paint in most rooms of the main level. For years she has worried about the insulation in the attic but just too busy to get to the source of the problem. Thanks - A.R.

Reply:

We took a look at your mold test report and note that your mold investigator through visual inspection and lab report concluded that professional mold cleaning is needed at your home. As we have not seen your property much less inspected it, in my opinion the person whom you paid to examine the home should be the first one in line to answer your questions about how to proceed. If s/he does not provide the service of explaining what was found and what you need to do about it, we might wonder what you paid for. Certainly in our opinion it would be a unconscionable to have to hire a second person just to explain what the first one said.

We agree with the approach of answering a mold remediation need question through a combined building inspection for visual evidence of the location and extent of mold contamination, an interview with building occupants to establish the history of the home and possible occupant health concerns, limited testing to confirm that the mold seen is not just "cosmetic" is appropriate in some cases, and the combination of the experience of the inspector and lab results with the application of general mold level standards described by a reasonable and non-quantitative industry standard IICRC S520: Standard and Reference Guide for Professional Mold Remediation [9]

Watch out: you 'll want to be sure that the inspection of the home was thorough and that it identified both all areas that need mold remediation, the extent of remediation needed, and the causes of mold growth that need to be corrected. Without that level of information, in other words, a professional mold remediation plan, not just a "test report", you are at risk of wasting money by doing an incomplete job.

Question: Why are there no mold standards for the workplace?

Both, Need to know how we can get someone here to test our building for mold.

• In addition, why is there no standards for mold in the workplace?
• Building is located in New York we are in Suffolk County here on Long Island.
• We just being told that there are no standards for this type of things but they feel that it is safe for us to work.
• I have a few reports that they sent me but not sure, what they really mean.

Would you be able to help me/us?

Thanks again for getting back to me so quickly. - K.O.

Reply: Giving any single number for allowable mold exposure as a "standard" borders on junk science

Thank you for the interesting question - it helps us realize where we need to work on making our text more clear or more complete. A competent onsite inspection by an expert usually finds additional clues that help accurately diagnose a problem including addressing the question of whether or not there is in fact an indoor environmental hazard in your workplace.

Your statement that "mold was found..." itself is not diagnostic - I can find some mold in just about any building, new or old, anywhere in the world.

Whether or not that constitutes a health risk depends mostly on the size of the mold contamination, also on how mold spores may become airborne and move through the building, and of course the genera/species of the dominant mold present - ranging from harmless cosmetic to seriously harmful.

Presumptive questions

I am also interested in your posing of the question " why is there no standards for mold in the workplace?" Often people will pose a question in a manner that presumes a-priori something that is simply not true - a silly example is the old saw of a legal question "Are you still beating your wife?" which presumes the individual ever beat his wife at all in the first place.

Actually there are dozens of attempts at "mold standards", both quantitative (questionable as I explain below) and qualitative (sensible as I explain in AIRBORNE PARTICLE & MOLD COUNT NUMBER GUIDE) as you can see in theReferences or Citations section of this article. That said, here are some things to consider in answering your presumptive question.

Immediate action:

Take a look at MOLD / ENVIRONMENTAL EXPERT, HIRE ? for criteria that help decide if hiring an expert for a building is needed.

Basically, if you see more than 30 sqft. of non-cosmetic mold indoors in a building (a few indoor molds are cosmetic only) then professional mold remediation is in order, period, and your building management would be mistaken to conclude otherwise.

For cases where a large problem mold reservoir is not immediately visible and obvious, this article could be most helpful to you in deciding if there is reason to believe your workplace has conditions that make further, expert investigation appropriate.

Why single number mold standards are not accurate nor very useful

Mold "standards" that give an acceptable or unacceptable number of spores are really close to nonsense except at such very high levels as to be both unambiguous and not useful for less obvious mold contamination problems. In other words, at very high levels of problematic spores there is no argument that there is a problem to be found and removed. But that sledgehammer approach is not useful.

There are 1.5 million species that vary in toxicity to about 3 million levels if one adds the effects on toxicity of the substrate on which mold is growing.

You'd need standards for each mold species by type, weight, growing conditions. The health effects of inhaling a specific genera/species of spore are so widespread, that a single numeric standard would just be junk science.

Add to that the enormous variation in the "exposure level" found by different approaches to testing and the impact of varying building conditions, air movement, temperature, occupancy etc. looking for a standard is waiting for Godot.

Add to that factor a wide range of human or other animal response to mold exposure and a standard becomes still more difficult. I've instrumented some clients who responded with extreme distress to very low levels of airborne Aspergillus sp. (less than 300 spores/M3 of air) for example - an airborne mold level well below most accepted opinions of "what level of mold describes a contaminated building?"

Even the standard of comparing indoor to outdoor spore levels is highly questionable - since we can and usually are comparing numbers of completely different molds - an apples to oranges comparison.

However it is possible to combine an expert and complete outdoor and indoor and mechanicals system building inspection, interviews with building occupants, and some testing to guide a decision on what cleanup may be needed in a building. An experienced building diagnostician will consider some very general rules that help point to the presence of absence of a problematic indoor mold reservoir that needs to be found and removed and its cause corrected. "Testing" without a thorough inspection and interview is frankly not reliable.

What should be the approach to evaluating a mold-suspect building?

What is needed is an approach to deciding if there is an actionable problem in a building where obvious hazards (such as more than 30 sqft of problematic mold contamination) are not immediately apparent.

And the conditions of exposure matter too. A worker whose job requires spending hours a day in a moldy automobile such as the one illustrated at AIRBORNE PARTICLE & MOLD COUNT NUMBER GUIDE could be exposed to serious hazards even when the total square feet of moldy material could be as small as just the interior of the vehicle air conditioning system. Details of moldy automobile hazards are

at CAR MOLD CONTAMINATION

References to some helpful articles on mold standards, testing, expertise and need for an investigation

• At MOLD EXPOSURE STANDARDS you will see that we have collected the most comprehensive range of published "standards" or opinions about mold exposure levels.
• At ACCURACY OF AIR TESTS for MOLD you can see a thorough exposition of the sources of error in mold tests and reasoning that explains why reliance on testing alone is unreliable in evaluating a building for mold risk.
• At MOLD / ENVIRONMENTAL EXPERT, HIRE ? you can read some criteria that help decide if hiring an expert for a building is justified and appropriate.
• MOLD & ENVIRONMENTAL INSPECTORS and MOLD CLEANUP COMPANIES contains contact information for some indoor environment building investigators. However as you may need to call someone local to you, if you have the inclination to review the articles I've suggested above, you will be better equipped to avoid someone who lacks the appropriate expertise needed in building science, mycology, and the proper use of inspection and test methods and equipment.

Please keep me posted on how things progress, and send along photos if you can. Such added details can help us understand what's happening and often permit some useful further comment. What we both learn may help me help someone else.

...

Continue reading at AIRBORNE PARTICLE & MOLD COUNT NUMBER GUIDE - topic home, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Mold Count & Mold Level Articles

• ACCEPTABLE MOLD LEVEL
• ACCURACY OF AIR TESTS for MOLD
• AIRBORNE MOLD SPORE COUNT GUIDE - home
• AIRBORNE PARTICLE LEVELS vs IAQ - home
• AIRBORNE MOLD COUNT VALIDITY
• AIRBORNE PARTICLE COUNT VARIATION CAUSES
• AIRBORNE PARTICLE COUNT VARIATION EXTENT
• AIRBORNE MOLD SPORES CONCENTRATION BURSTS
• COUNT VARIATION - INDOOR vs OUTDOOR SPORES
• AIRBORNE PARTICLE COUNT VARIATION EXTENT
• FALSE NEGATIVE MOLD TEST RESULTS
• MOLD CULTURE TEST ERRORS
• AIRBORNE PARTICLE COUNTS in DUCTWORK
• AIRBORNE PARTICLE COUNTS vs SAMPLER HEIGHT
• AIRBORNE PARTICLE COUNTS vs WINDOWS, DOORS
• USES of AIRBORNE PARTICLE SAMPLING
• VISUAL INSPECTION & HISTORY of MOLD
• AIRBORNE MOLD COUNT VALIDITY
• MOLD CLEARANCE INSPECTIONS
• MOLD LEVELS IN BUILDINGS
• MOLD EXPOSURE RISK LEVELS

Suggested citation for this web page

AIRBORNE MOLD COUNT NUMBER FAQs-6 at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to MOLD CONTAMINATION & REMEDIATION

Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia

Ask a Question or Search InspectApedia

Questions & answers or comments about the meaning of various airborne mold spore count numbers, mold level reports and acceptable versus unacceptable mold levels found in buildings

Try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.

Note: appearance of your Comment below may be delayed: if your comment contains an image, photograph, web link, or text that looks to the software as if it might be a web link, your posting will appear after it has been approved by a moderator. Apologies for the delay.

Only one image can be added per comment but you can post as many comments, and therefore images, as you like.
You will not receive a notification when a response to your question has been posted.
Please bookmark this page to make it easy for you to check back for our response.
Our Comment Box is provided by Countable Web Productions countable.ca

Citations & References

In addition to any citations in the article above, a full list is available on request.

---

ADVERTISEMENT

---