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Indoor area after a mold remediation that looked good but was not successfulAirborne Mold Spore Count Number Guide

What is the Acceptable Level of Airborne Mold Spores?

Airborne mold spore count report interpretation.

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

Here we define the acceptable level of mold in buildings following mold testing or post-cleanup mold clearance tests in buildings.

Using real-world examples we describe different mold test reports, mold counts or levels in air, and we explain what those counts mean. We discuss how to use mold inspections and mold test results to decide if there is a mold problem in a building and how to decide "what to do next".

Page top photo: when a mold "remediator" simply sprays encapsulant all over loose debris it's not likely to be a durable clean-up job. Even the smallest disturbance of a surface like the one in our photo risks stirring up indoor air contaminants below the sprayed surface.

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

- Daniel Friedman, Publisher/Editor/Author - See WHO ARE WE?

Building Airborne Mold Contamination Levels

Stachybotrys spores (left) and structure (right)In our photo the red arrow points to our Burkhard personal air sampler or PAS in use sampling the concentration of outdoor airborne particle levels during

an AIR QUALITY STUDY San Miguel de Allende [separate web article] where we found high levels of non-fungal granular debris, principally soil dust.

Here we discuss: acceptable and unacceptable mold counts. What does an airborne mold spore count number actually mean?

What is the Acceptable Level of Mold in Buildings? Mold Clearance Inspecting and Testing Guide. How does a building "pass" a clearance inspection?

How should we interpret mold spore counts, levels, and mold test results or reports. Examples of mold test results and their interpretation for all different levels of indoor mold

Article Contents

This article is part of our series: ACTION GUIDE - WHAT TO DO ABOUT INDOOR MOLD which provides an easy to understand step-by-step guide for dealing with toxic or allergenic indoor mold and other indoor contaminants: what to do about mold "mildew," moisture, in your house or office, building-related illness, involving your physician, treatment, sick building investigators, reduction of irritants, and special products to help clean buildings and air.

What are Considered High Levels of Indoor Airborne Mold Spores?

Editor's note: we have arranged the questions and answers immediately below roughly in order of the level of indoor mold spore counts that were reported by the reader or their "mold test" person.

For examples of different ranges of levels of airborne particle concentrations we use actual questions posed to us by clients or by InspectApedia readers.

Question: are "high" levels of Penicillium/Aspergillus spores and Basidiospores dangerous? Are they likely to have caused cancer?

Had testing done in a home where the occupant developed lung cancer.

Would high levels of the spores basidiospores and pen/asp group be a contributing factor? - Cyndi, 6/21/2012

Reply: We need to Define "high levels of mold", Aspergillus flavus carcinogenicity, Basidiomycetes?

Cyndi,

You have not defined "high levels" of mold, nor whether you meant high levels in air or on surfaces.

And if in air, there are many variables that can increase or decrease the actual airborne particle levels, and thus human exposure, by orders of magnitude, such as fans on or off, windows open or shut, active or still conditions in the building and more.

To prove that a specific mold exposure caused a specific illness is difficult enough that it's rarely attempted; people, their individual health sensitivities, lifetime exposures, genetics, and other variables are wide in extent. Burge cited at least 4 tests that would have to be met - and that are generally cost prohibitive.

Hazardous mold: distinguish between causing illness and aggravating an existing illness for sensitized people

Indeed there are some fungi and toxins associated with them that are considered potential carcinogens. For example, (you did not speciate your molds) Aspergillus flavus produces an aflatoxin that is a known carcinogen.

Quoting G. A. Payne et als: "Aspergillus flavus is an opportunistic pathogen of both plants and animals, and it produces one of the most potent naturally occurring carcinogens known." [4]

It is entirely reasonable to think that high levels of Penicillium or Aspergillus fungal spores found indoors in the air at high levels (or on surfaces that can send high levels of spores into building air), would pose a serious health risk to someone who is already immune compromised, undergoing chemotherapy, for example.

Basidiomycetes is the name of a very large group of fungi, including edible mushrooms. Basidiomycetes in buildings are associated with wood rot; they can produce spores that are very common in outdoor air, sometimes at high levels outdoors or inside and from outdoor as well as indoor original sources. [5]

A cautious approach would be to presume that a high level of basidiomycetes found indoors could be allergenic, and it is likely to indicate wet conditions, possibly extended wet conditions that would have invited a plethora of mold genera/species to grow in the building.

Depending on the mold test that you had performed, I would certainly not conclude that the mold families/genera you report are the only, nor even the most significant molds that may actually be present in the building.

Airborne Mold Spore Counts over 150,000 spores per m3

Question: Pen/Asp spores were found indoors at 161,351 per m3. Why would air tests show mold and surfaces not show any results? What do I do next?

Great site. I have a little guest house that was tested and the results showed a high level of Aspergillus penicillium in a hallway between bathroom and bedroom near a back door. The air sample in the hallway showed 161,351 per m3 and a raw count of 2.269.

This was an air sample. There were other samples taken that were surface samples one in a dining area cabinet and one behind the bathroom toilet and both of those showed no spores. There was also an outdoor sample and...no spores. The back door which is where the small hallway is with the high samples is left open most of every day.

Is it possible that spores come in from outside and cause the high air sample reading there. There are no water sources in that area and no visible mold anywhere. Why would the air show results but the surfaces not show any results? I am unsure as to what to do next. The test was over $500 and I don't know how to proceed now.

I surely don't want mold around but am not sure if it is something inside the guest house due to the nonexistent source of water in that area. Any advise would help. - Jim

Reply: Small mold spores move through widely through a building like a gas and may be detected away from the actual physical mold colony or source

Jim that's a great Penicillium/Aspergillus question.

Penicillium and Aspergillus spores are very tiny - they can be down to even around one micron. So they are very highly mobile in air, and pass through a building just about as easily as a gas. Therefore you could have a large Pen/Asp mold reservoir somewhere other than where the air test was conducted - say in a wet crawl space over which someone installed fiberglass insulation into the floor above.

A large but more "hidden" mold reservoir can put a high level of Pen/Asp into building air but there could be little or no mold on building surfaces where the air test was conducted.

When I find those conditions I usually also find that there are spore chains, not just individual spores, in the air sample, and I find the same spores in settled dust samples from the same building area.

The mold spore level in your report is quite high - much higher than would be explained by a normal outdoor air mold source.

In that case a thorough expert inspection is needed to find the mold reservoir source and to write an appropriate mold remediation plan.

Airborne Mold Spore Counts over 50,000 spores per m3

Question: 88,000 toxic black mold spores per m3 - My outdoor was 764 mold spores per m3. Why is is such a dramatic difference

Ok maybe you can help me understand my mold test report results. I had air samples indoor and outdoor of my home. We had several plumbing issues that gave us three floods in three bedrooms.

The landlord did not follow proper procedures and resulted in crazy results. My outdoor was 764 cu and my indoor was 88,000 cu of black toxic mold. Why is is such a dramatic difference and is this unheard of? - Patrice

Reply: Indoor and outdoor mold tests in air are looking at completely different environments

Patrice your indoor mold levels are

- not unusual for a flooded building with a large problem mold reservoir; I've seen higher still. Furthermore, the "count" is probably misleading in that there are almost certainly other genera/species besides "black toxic mold" and some of those may be more harmful and more ubiquitous in the indoor air


- something that needs to be tracked down to the physical source by a competent onsite inspection, history taking, and perhaps some modest invasive inspection of cavities that were flooded.

The reasons for the dramatic difference include that we are comparing completely different environments - an indoor air test (or was it a surface test?) in a relatively enclosed space with a large reservoir of a few species of wet-building-molds growing therein will give a much higher reading of those mold spore levels.

Outdoors, all molds are present everywhere, all the time. But they are generally more dilute in outdoor air - after all it's a bigger space than inside your home. We do, however, sometimes see elevated levels of particular molds outdoors, for example certain basidiomycetes shortly after the start of rainfall, and other mold spores seasonally and depending on weather conditions. Near the woods at some times of the year Ganoderma spores may dominate an air sample, for example.

So while it's usually comparing apples and oranges to compare indoor to outdoor mold levels, we might check outdoor air just to double check that something found indoors is really coming from indoors, not outside.

Reader follow-up:

Ok thank you so much I will read more. I've been up all night trying to figure out if we are ok but it is def the owners responsibility to take care of this. Just want them to do it correctly. Thank you for the advice and clearing up some things for me.

I believe all landlords/owners should have knowledge of your website it might help them in long run. This is a serious issue and a lot are not educated. I had to go through this to learn myself. But thanks alot. You are very kind.

Question: Basidiospores 530 per m3, Penicillium/Aspergillus 1,100 spores per m3, Stachybotrys 86,000 spores m3 - been in a motel for a week

My results were Basidiospores 530 cu and Penicillium/Aspergillus types at 1,100. My last one was Stachybotrys at 86,000 spores which gave me overall 88,000 total. So it was the black that was mostly found.

Have five children in home and smallest always sick on why hired specialist myself. Our home is only 1300 sq ft.

Been in hotel room for a week now so guess they are having issues with fixing I assume. So is that extremely high as specialist making it to be. Also can I save our clothes by washing since contaminated? - Patrice

Reply: What does a high indoor airborne mold spore level of Stachybotrys chartarum mold spores really mean

Patrice, I appreciate your numbers, but I emphasize that depending on how a test is conducted and variations in building conditions, airborne mold counts vary by several orders of magnitude, from minute to minute.

So it is absolutely not reliable to treat them as very accurate and it is much more important to look at the results qualitatively - your numbers show the presence of high Stachybotrys -that is a mold that's hard to disturb (big sticky spores) but may be found airborne if someone has been doing demolition. The Pen/Asp spores are smaller, easily airborne, pervasive, and can be an equally or worse health hazard.

Stachybotrys is a water-loving mold. It likes wet drywall, for example. And more, because Stachybotrys mold spores are black, big, warty fellows, they are both easy to see on building surfaces and easy to see in a surface, dust, vacuum, or air sample for mold.

A result is that "black molds" are often over-reported and light-colored, hard to see and small mold spores are often under-reported.

Watch out: Since the same conditions that caused a Stachybotrys mold colonization in a building are highly likely to produce other mold genera/species too (we almost never find just one kind of mold in a building), and since some of those other (harder to see and under-reported) molds can be equally or even more harmful, a proper building survey is in order when high levels of Stachybotrys are found, and it would be a mistake to pay attention only to that infamous "toxic black mold" - there are plenty of other "toxic or harmful" molds that aren't black.

I emphasize that you cannot fix a mold problem by an air test because air tests alone don't reliably tell you where the physical problem exists nor do they diagnose the cause of mold growth - both of these must be accurately understood.

You need a competent onsite visual inspection to find the location and extent of mold to be removed as well as to identify its cause.

If you see ACCURACY OF AIR TESTS for MOLD you can read several articles that detail the reasons for wide variation in airborne tests (as well as "culture" tests)

Airborne Mold Spore Counts Over 20,000 spores per m3

Question: Our Pen/Asp group reading was 41,300 m3 spores per cubic meter. Should we be concerned?

Question: Just had a mold test done. We've been having health issues since November 2010. Our Pen/Asp group reading was 41,300 spores per cubic meter. Should we be concerned? Where can we get help? - Steven

Question: Just had a mold test done. We've been having health issues since November 2010. Our Pen/Asp group reading was 41,300 spores per cubic meter. Should we be concerned? Where can we get help? - stephenterrill@gmail.com 7/1/2011

Reply: A visual building inspection, indoors and out, is justified by high indoor mold spore levels

A high indoor Pen/Asp level suggests that there is an indoor mold reservoir to be found and cleaned up; in particular if the examination of the sample found spore chains, not just individual spores, that would be a compelling argument for indoor mold contamination that needs action.

Because both Penicillium and Aspergillus spores are small they travel easily throughout building air and can indeed be a health concern. But frankly I must say it's troubling to read that you paid for mold testing but could not get a clear answer from the folks you paid.

Most likely what's appropriate is a competent visual inspection of the building to find the most likely mold reservoir locations and further inspection and maybe testing to confirm what's in those spots. That way you'll know what needs to be cleaned, the extent of cleanup, and the leak or moisture source that needs to be corrected as well.

See MOLD / ENVIRONMENTAL EXPERT, HIRE ? for help in understanding when it's appropriate and cost-justified to hire an expert to find an indoor mold problem source and write a mold remediation plan.

RE:"Our Pen/Asp group reading was 41,300 spores per cubic meter. Should we be concerned? Where can we get help?"

A high indoor Pen/Asp level suggests that there is an indoor mold reservoir to be found and cleaned up; in particular if the examination of the sample found spore chains, not just individual spores, that would be a compelling argument for indoor mold contamination that needs action. Because both Penicillium and Aspergillus spores are small they travel easily throughout building air and can indeed be a health concern.

But frankly I must say it's troubling to read that you paid for mold testing but could not get a clear answer from the folks you paid. Most likely what's appropriate is a competent visual inspection of the building to find the most likely mold reservoir locations and further inspection and maybe testing to confirm what's in those spots.

That way you'll know what needs to be cleaned, the extent of cleanup, and the leak or moisture source that needs to be corrected as well.

Airborne Mold Spore Counts Over 10,000 spores per m3

Question: Indoor Penicillium/Aspergillus mold spore count was 12,000 spores m3 of air. Should we be concerned?

Mold testing showed Penicillium Aspergillus outdoor 240 indoor 12,000 should we be concerned

also after clean up is re growth a problem? - Karen Kruger

Reply: 12,000 Pen/Asp spores/m3 of air is high and justifies an actual investigation of your building

Karen,

Indoor air particle counts are highly inaccurate even if the number is precise, because of significant variation of the level of indoor particles from minute to minute and because of the great many factors that can make orders of magnitude difference in test results.

Details are at ACCURACY OF AIR TESTS for MOLD

That said, an indoor count of 12,000 Pen/Asp spores per cubic meter of air is on the high side and suggests that there is an indoor mold source or reservoir. If the lab technician reported the presence of spore chains, not just individual spores, that is confirmation of a nearby mold source.

Air tests for mold without an expert visual inspection of the building to identify visible mold reservoirs or conditions that make a hidden reservoir likely are not worth much as they are often expensive without being diagnostic. It's likely that a proper investigation is justified, needed to find the problem and define the extent of cleanup. See MOLD EXPERT, WHEN TO HIRE for help in deciding if and when it's appropriate to hire an expert.

If a mold cleanup job is properly performed, the cause of mold growth is corrected too. Following that course of action, if you later find mold problems in the building, they're a new problem, not a re growth problem.

Finally, didn't you pay someone to conduct the mold tests you describe? Why can't the person you paid answer questions for you? I would think twice about hiring someone who simply collects samples and sends them to a lab, with no expertise, no interview, no case history taking, and no expert inspection of the building. And with no support to their clients and no questions asked or answered.

Airborne Mold Spore Counts over 5,000 spores

Question: Asp/Pen 7707

two rooms tested & that did not include the basement where it is covered in mold all over the place of all kinds, not to mention discovering asbestos too! Child's room test:

Asp/Pen 7707,

Cladosporium 54,

Basidiospores 2134,

Periconia/smut/myxo 54,

Curvularia/Pithomyces 54,

Stachybotrys 27,

other unidentified Hyphae 54

total count 10030.

Kitchen test: Asp/Pen 8801, Cladosporium 81, Periconia/smut/Myxo 934, Curvularia/Pithomyces 161, Other unidentified 134, Hyphae 321 Total 10459. Kitchen was tested because basement is really bad & kitchen at top of stairs reeks of odor & visible mold in walls, cabinets, carpet, dishwasher, & bathroom with black mold within shelving just off kitchen behind fridge area.

Air quality was not done in basement but should have been since it is sever down there on everything! Landlord told me to run the fans in basement & ceiling fan in kitchen w/windows closed, dehumidifier running & turn up the heat to dry it all out. Told by Environmental specialist bad idea.

To late. Daughter has sever allergies & has excessive long lasting bloody noses, headaches, rashes, amebic dysentery, stomach pains, ear aches, sinus infection.

I have had headaches,dysentery, ear aches, sinus infection, vomiting, both of us have had fevers. Other rooms have mold evidence & photographed such as dining rm, living rm - on flr, furnishings, belongings etc. 14 rooms I could not air quality test every one on limited budget.

Previous tenants moved out because of the same reason. Daughter & I exposed to this for a year at I am sure different levels. How worried should I be besides worried about daughters asthma. Landlord just wipes things with mold cleaner when here as if it fixes issue & it just grows back & stinks! Help? Advice? - Lee 9/23/11

Reply:

Lee,

I agree that from your description it sounds as if there is a serious mold problem in the building.

Particularly that Aspergillus/Penicillium count of over 8000 is high enough for an indoor Pen/Asp mold count that I'd be looking for the mold reservoir.

MOLD APPEARANCE - WHAT MOLD LOOKS LIKE  might be helpful but keep in mind that there could be a mold reservoir that's not immediately visible such as contamination in building walls or ceilings or in its HVAC system.

Watch out: just turning up the heat to "dry it out" will never cure an indoor mold contamination problem, and as I've seen first hand in the field, in fact if we try heating and drying a space before doing what's actually needed - which is find and remove the mold and fix its cause - we might actually see a surge of airborne mold spores, making the building more dangerous than before.

Our advice for tenants is

at RENTERS & TENANTS GUIDE TO MOLD & INDOOR HAZARDS

- there we give specific suggestions on how to proceed in a case like yours

Question: What does a colorless mold spore count of 6000 mean?

I am trying to locate a lawyer...environmental specialists ....and what a 6000 spore count means - Anonymous 7/18/2012

Reply: Nothing without more specifics.

Unfortunately a spore count of 6000 means absolutely nothing without a context.

It's like saying "no soap, radio"

Indoors? Outdoors?

Reader follow-up: mold spores were "colorless" than that tell us the genus

it said colorless, can it be taken to the 'genus' stage

Reply: No

Can "colorless mold spores" alone as a description of airborne mold be translated to a specific genus on the basis of that information alone.

No.

There are about 1.5 million mold genera/species, about 75,000 that have been named and studied, and thousands of those are "colorless" or hyaline, spread across an enormous range of family, genera, and species.

For example, colorless mold spores might be a surge of basidiomycetes common at very high levels in outdoor air after start of a rainfall, unidentified spores - the lab had no idea what they were, or Penicillium sp. or Aspergillus sp. mold spores at high levels and including spore chains - that would indicate a nearby fungal contamination indoors.

We discuss this range of toxicity among mold spores at

MOLD TOXICITY VARIATION

or for a more broad understanding see

MOLD CLASSES, HAZARD LEVELS

MOLD LEVEL IN AIR, VALIDITY discusses the general validity of counts of airborne particles.

Also ACCURACY OF AIR TESTS for MOLD explains why variations in test conditions can cause 1 to 3 orders of magnitude variation in the airborne particle count that is detected in a given test indoors.

In light of that point, let's not confuse precision (the number of digits in a number of airborne particles) with accuracy. We don't know what was in the 6000, and we don't have a clue about whether an accurate number would have been 60, 600, 6000, 60,000, or more. In fact it's a credit to the lab who produced the report you saw that the number was rounded to 6000 and not given as 6129 or something.

We don't know whether the count includes one spore type or hundreds of them, the spore size, toxicity, species/genus, nor what, if anything it indicates about the presence or absence of a mold contamination problem in the (unknown in all respects) building. You might want to take a look at

See MOLD EXPOSURE STANDARDS for notes on numbers and exposure levels for "generic" mold spores - an approach that fails to recognize the wide variation in allergenicity or toxicity of individual species..

A mold "test" or "count" without an expert inspection and occupant interview, especially at comparatively low numbers in the few thousands of something that is unidentified - we don't know from your number if we're talking about one spore type or 20, is not very helpful.

About your request to find an environmental expert, based on just the spore count you gave, you should review

MOLD / ENVIRONMENTAL EXPERT, HIRE ? for help in deciding when to hire someone.

At page top the link titled EXPERTS DIRECTORY includes links to listings of mold consultants, attorneys, etc.

InspectApedia has no business nor financial relationship with any expert, consultant, or product discussed at the website.

Airborne Mold Spore Counts under 5,000 spores per m3

Question: Total mold spores around 3500 in a house used to grow marijuana, or around 2300 with high Pen/Asp

Question: We are looking at buying a house that was previously used as a marijuana grow up. It has been cleaned up and City declared occupancy okay. Mould counts downstairs (where the grow up was located) are 31 raw count, spore count % total 38As/23Ba/8Co/15PA/15SPM total spores per m3 416.

The upstairs (living area) are 34 raw count, spore count % total 21As/50Ba/29Cl, total spores per m3 448. These are the numbers after cleanup by the environmental company. The room has been fixed up and all problems solved. Are we safe with these numbers to continue to purchase this house? - Paula 7/14/2011

Question: Great site. I have a little guest house that was tested and the results showed a high level of aspergilus penicillium in a hallway between bathroom and bedroom near a back door. The air sample in the hallway showed 161,351 per m3 and a raw count of 2.269. This was an air sample.

There were other samples taken that were surface samples one in a dining area cabinet and one behind the bathroom toilet and both of those showed no spores. There was also an outdoor sample and...no spores.

The back door which is where the small hallway is with the high samples is left open most of every day. Is it possible that spores come in from outside and cause the high air sample reading there. There are no water sources in that area and no visible mold anywhere.

Why would the air show results but the surfaces not show any results? I am unsure as to what to do next. The test was over $500 and I don't know how to proceed now. I surely don't want mold around but am not sure if it is something inside the guest house due to the nonexistent source of water in that area. Any advise would help. - Jim 7/18/11

Question: How can living room be higher than basement ? I bought a home where former owner grew pot. We did most of the renovations ourselves. Had air test done, and those were the results. I was very disappointed to see these high numbers. How bad is this ? - Lizabelle 11/4/11

Reply:

Paula: I can't make any sense out of those mold counts and have no idea how the tests were performed - so it would be quite iffy to have an opinion about the mold risk in the home you describe. I'd start by insisting on some clarification from the folks you paid to inspect and test the home.

If that "expert" can't help you then you didn't get much useful for their fee and you will need to find someone competent who will actually address the questions involved rather than just "perform a test"

Jim: that's a great Penicillium/Aspergillus question.

Those mold spores are very tiny - they can be down to even around one micron. So they are very highly mobile in air, and pass through a building just about as easily as a gas.

Therefore you could have a large Pen/Asp mold reservoir somewhere other than where the air test was conducted - say in a wet crawl space over which someone installed fiberglass insulation into the floor above. A large but more "hidden" mold reservoir can put a high level of Pen/Asp into building air but there could be little or no mold on building surfaces where the air test was conducted.

When I find those conditions I usually also find that there are spore chains, not just individual spores, in the air sample, and I find the same spores in settled dust samples from the same building area.

In that case a thorough expert inspection is needed to find the mold reservoir source and to write an appropriate mold remediation plan.

Lizabelle:

About finding higher mold spore counts upstairs than in a basement, there are plenty of plausible explanations of which I cite two strong ones:

1. the mold spore reservoir is often but not always in the building basement. Leaks into building walls or ceiling or a flooded wet carpet, are examples of possible local upstairs mold reservoirs. If such mold reservoirs are found they will need to be removed.

2. if there was previously a highly contaminated building basement and that area was cleaned, it is possible that the cleaning contractor did not provider adequate negative air and dust control, blowing moldy dust upstairs where even though mold may not be growing on surfaces, there could then be a high level of moldy dust that shows up in screening tests for mold.

This is a very very common event in my experience. If this is the problem, additional HEPA vacuuming, cleaning, wiping, are in order, followed by a follow-up test.

Reader follow-up:
45 counts=2400 basement & 49 counts-2610 livingroom. Should I be concerned about these numbers ? I bought in 2008. Cleaned up in 2009. If these spores are now in my walls, ceiling. How much work is involved to get the entire house cleaned up ? I am very-very concerned. Thank you - Lizabelle

Reply:

Lizabelle,

You are asking an important question that could involve significant cost and disruption to your home, while providing no information other than mold test results. ON that basis alone it would be improper and unethical for anyone to advise you of just what to do, of how much work is needed, or even of the risk level.

At MOLD EXPERT, WHEN TO HIRE we provide some help in deciding when it is probably appropriate and justified to go further in investigating a building for the possible presence of a mold problem.

Please take a look at that information and then use the comments box on that page if you have further questions and I'll do my best to be more helpful.

Beyond that step, since you paid someone to perform the "mold tests" on your home, if that person is not helping you to interpret the meaning of the test results then you are not getting what you paid for, and in fact are not getting much of value at all. (in my OPINION)

Reader followup:
I just received the report (11/04) I did speak to them, and they are to come by (again) to see if he can locate the source. I thought maybe, this sight would shed a little more light on my situation. Your remarks have been helpful. I am "no"t prepared to demolition walls & floors. And was hpoing for a form of TREATMENT that existed to help situations, such as mine. - Lizabelle

Reply:

Lizabelle,

take a look at MOLD SPRAYS, SEALANTS, PAINTS

(I, too, wouldn't rush to do anything dramatic or costly, but I would not simply "treat" mold by some air or superficial means; the proper steps are

1. decide if there is a problem meriting further, even invasive inspection of building cavities

2. if step 1 finds a problem mold reservoir them mold is remove, physically cleaned, not just "treated" lest the process be ineffective, incomplete, and leave harmful particles (even dead mold spores can be harmful)

3. find and fix the cause of mold growth so that you don't have to repeat the process

Reader remarks:

They are suggesting a "Decamination process" No price mentioned yet. With this process, I need to empty my home of all plants and animals for 24hrs.

I have many plants, a dog & a bird. Relocating for 24hrs would be hard. They have not "pushed" this process on me, but I am considering it. I live in a bungalow, and there is alot of "area" to cover. Also, there is a sumpump in the basement, would this be a cause ? Thanks - Lizabelle

Lizabelle- follow-up:

A "mold decontamination process" that does not find and remove the problem mold as well as fix its cause, risks leaving harmful material in the building, wasting your money, and depending on the process used, possibly creating a new indoor hazard (such as overuse of ozone).

The cost of a proper mold cleanup (if one is actually justified at all) is indeed significant, so the temptation to look for and buy a magic bullet is understandingly tempting. Magic doesn't work well off of the stage however.

Question: Mold spore trap results in an office were Penicillium/Aspergillus 4270 spores / M3 and 2130 Cladosporium spores / M3 with low outdoor levels: are all molds equally toxic?

I recently did a spore trap air quality test my 400 sq foot office, the test consist of a machine that cycled air for 5 minutes and contents were shipped to lab. The results were Inside: Pen/asp raw count 80 with 4,270 spores/cu.m and cladosporium raw count 40 with 2,130 spore/cu.m in addition other smaller count molds.

The outside levels are much lower pen/asp raw count 18 with 960 spores/cu.m and cladosporium raw count 8 with 427 spore/cu.m in addition other molds such as basidiospores.

I had been very concerned over the past five years i had occupied this office because I had become increasingly ill with so many symptoms. I had a urine test done that detects mycotoxins in the body and it came back that i was being exposed to moderate levels of Trichothecene which had caused a severe chronic systemic infection.

After reading the previous questions on your site, I feel like the levels in my building are low.

So my question to you is will some infestations carry more mycotoxins or do all bad/toxic molds produce these toxins. I am just puzzled since there are no guidelines to how much mold is safe. Thank You - Nikki

Question: I have just received the air samples back. i have a total mold spore count under a kitchen sink of 2400. Is this cause for concern? - Chuck Helmke 7/6/2011

Reply: Modest mold spore counts indoors may still indicate a problem, and yes, mold spore toxicity varies widely among species and even within individual species; difficulty with mold exposure guidelines

About rather low but still-indicative airborne mold spore counts:

You must consider that there are many reasons why there is enormous variability in the level of indoor particles in a building from moment to moment, including particles such as mold spores. I describe these in an article found

at MOLD TEST METHODS, ACCURACY

I have found several orders of magnitude in the airborne particle level just from moving the spore trap up or down at different heights in a room, waving a notebook in the air, rapping on metal ductwork, turning a fan on or off.

So a mold test that seems to indicate a problem (such as the one you cite) is a RELATIVE indicator - that is, it would be absolutely nonsense to claim that the Pen/Asp spore count of 80 spores collected over five minutes was an accurate measure of the actual mold exposure in the building.

When there is an indication of an indoor mold problem the most useful procedure is to inspect the building to find the problem source. Just testing alone is not sufficiently diagnostic.

About variations in mold toxicity or allergenicity

Nikki the toxicity or Pathogenicity or allergenicity of mold species varies widely from harmless to quite serious, and because individual human sensitivity to molds also varies widely, there is a big range of possible effect from exposure to mold depending

About mold exposure standards

Finally, you are right to be curious about the difficulty in writing mold exposure guidelines. We cite North American and world wide mold exposure standards at MOLD EXPOSURE STANDARDS but frankly any mold exposure "standard" can only be a very general guideline because of the following difficulties:

Details are at MOLD TOXICITY VARIATION and you'll also want to see MOLD EXPOSURE RISK LEVELS

Question: Are There FDA approved levels for mold?

Do you know anything about the FDA approved levels for mold? - Sabrina 2/28/2012

Reply:

Sabrina, the US FDA approves drugs and medications not mold. If you are looking for mold exposure standards, a very difficult topic, we provide a lot of detail at MOLD EXPOSURE STANDARDS and at MOLD EXPOSURE RISK LEVELS. (live links at the end of this article)

Question: My air quality mold test found Indoor Pen/Asp count of 3000 spores M3 and outdoor count of 800, with Chaetomium present. Ceiling fans were on during testing. How should post mold remediation clearance testing be performed? Should I see a pulmonologist?

I discovered an HVAC leak and on subsequent inspection discovered significant mold in one bedroom and baseboard water damage in the master bedroom. The air quality test came back with Chaetomium in the spare bedroom at 200 with 15 actual spores found and Pen/Asp in the master at 3000 with an out door count of 800. I see by prior postings that having ceiling fans on could have increased the values. Both rooms had fans on at time of testing.

QUESTION 1: A protocol is being written and I am getting mold remediation estimates but when the clearance is done should the fans be on or off? I want an accurate test but at the same time I am nervous about the clearance.

I have lived in the house for a few years and the master bedroom is mine. I am constantly sick with upper respiratory issues (caught H1N1 in '09 and Pertussis in '10), have asthma, receive allergy shots weekly, and have been plagued with unexplained rashes and skin irritation since the spring of this year. Mold happens to be one of my more severe allergies and I have read that Pen/Asp can actually grow in human tissue.

QUESTION 2: Should I contact my ENT or other doctor such as a Pulmonologist? - Chris

Reply: Repeat the same building air movement conditions during clearance testing as during original testing if at all possible, plus other suggestions for post mold remediation mold tests

Chris:

if the fans are ON during clearance inspection and testing that will be the most aggressive and thus cautious procedure. Keep in mind that when someone objects, you can reply that after all you do intend to sometimes turn on the fans, so it's reasonable to see what you'll be exposed to when you do.

If I were on site I'd probably collect samples under exactly the same conditions as the original test, for comparison purposes but I'd also try a second test with the fan on. If I get a high problem mold level with the fan on, some additional cleaning in that area would be appropriate.

Ask your primary care doctor for advice on consulting a specialist. (Sept 28, 2011) Chris said:

Question: 3,416 m3 mold spores - We are buying a house previously used to grow marijuana. What do these mold counts mean?

We are looking at buying a house that was previously used as a marijuana grow up. It has been cleaned up and City declared occupancy okay.

Mould counts downstairs (where the grow up was located) are

31 raw count, spore count

% total

total spores per m3 416.

The upstairs (living area) are 34 raw count, spore count % total 21As/50Ba/29Cl, total spores per m3 448. These are the numbers after cleanup by the environmental company. The room has been fixed up and all problems solved. Are we safe with these numbers to continue to purchase this house?
THANKS SO MUCH!!! - Paula

Reply: Mold test results that are vague or confusing deserve some interpretation and help by the person who inspected the building and performed the tests

Paula: I can't make any sense out of those mold counts and have no idea how the tests were performed - so it would be quite iffy to have an opinion about the mold risk in the home you describe. I'd start by insisting on some clarification from the folks you paid to inspect and test the home.

If that "expert" can't help you then you didn't get much useful for their fee and you will need to find someone competent who will actually address the questions involved rather than just "perform a test

I have to say that starting from a "raw count" of 31 mold spores /m3 of air, and one individual sample, and knowing nothing about how intelligently the sample was collected, even so, the raw count is so low as to be trivial and extrapolating results from a questionable test with trivial results is itself rather questionable.

Air tests for mold, used alone without an expert building inspection for visible mold and for conditions that are likely to have caused a hidden mold problem, are not reliable.

See MOLD LEVEL IN AIR, VALIDITY for details.

Question: Aspergillus/Penicillium was 852 and 2670.

I recently had my house tested. I have visual signs of mold in the attic that they did a tape test and was Stachybotrys *medium*. We did 2 Air samples in 2 of our bedrooms. Aspergillus/Penicillium was 852 and 2670.

Basidiospores was 704 and 370, Cladosporium was 407 and 296, Myxomycetes++ was 222 and 74. Stachybotrys was 74 and 37. Now we both went into the attic could that be the reason for the small traces of Stachybotrys in the air samples?

Yesterday I think I found the source of the Aspergillus/Penicillium.

I found a leak in one of the basement walls right where my Furnace is! I removed the panel and sure enough found black mold growing behind it! I did some tape samples that I will send out to find out if for sure it is the Asp/Pen. But where are the other ones coming from and should I be concerned? My wife has had bad cough with Phlegm for a couple months. I have had on and off stuffy noise for 2 years.

This is probably the cause! I'm removing the wall this weekend I sprayed it with MoldStat lastnight. Then I will fix the leaky wall. How long could these allergy symptoms last after I have cleaned up the mess? Do you think the attic is a huge concern?

Last year I fixed the moisture problem due to a leaky attic hatch and moisture escaping into the attic. I also added a fan that also turns on due to high humidity. I'm going to put some plastic down and spray the attic down with Moldstat and scrub the boards, dry them then remove the plastic. With my levels is there any long term health problems that could happen to us? - Joe. 12/2/2011

Reply:

please see the cases above and below this range.

Question: Pen/Asp mold count was 2,080 m3 with the ceiling fan on. No one has ever been sick. The inspector is saying we have a problem

The ceiling fan was on and the pen/asp lab test came back 2080 in our great room. No one is our house has ever been sick but the inspector is saying we have a problem.

Next - our basement had a count of 320 per cubic meter of air for Pen/Asp. Does this seem elevated ? - Coleman

Reply: Fans significantly increase the level of indoor airborne dust and particles but your count is not particularly high.

Coleman:

The absolute spore count is not extremely high, especially considering that a ceiling fan was on at the time of testing, but since we don't usually find any elevation of Pen/Asp spores in a home your result is sufficient justification for a more careful and thorough visual inspection and some follow-up.

Other factors such as visible evidence of a leak history into walls or ceilings, history of building leaks, flooding, and even an interview that finds that some occupants complain of indoor-air-quality issues when in the home and not when elsewhere all could suggest that further investigation is justified.

A general mold count of 320 spores per cubic meter is pretty low; but depending on exactly what is seen under the microscope, such a sample could still point to a nearby indoor problem mold source.

For example, Pen/Asp spore chains present in an air sample for mold almost certainly means that this is not outdoor mold but rather mold from an indoor source. That's because both Penicillium and Aspergillus genera produce their mold spores in long, fragile spore-chains.

The spore chains break up into individual mold spores very rapidly as the particles move through air. So when I find spore chains in an air sample I know there is almost certainly a mold source nearby.

A visual inspection for leaks or leak / moisture problem conditions along with a case history of building complaints is how we can decide how much investigation is warranted.

To decide if you want to investigate further see MOLD / ENVIRONMENTAL EXPERT, HIRE ?

Question: Pen/Asp spore count of 2080 with a ceiling fan on

The ceiling fan was on and the pen/asp lab test came back 2080 in our great room. No one is our house has ever been sick but the inspector is saying we have a problem. - Coleman 7/9/11

Reply:

Coleman, running a ceiling fan increases airborne particle levels by at least one order of magnitude over still air. It's a cautious and thus "aggressive" test approach.

The absolute spore count is not extremely high, especially considering that a ceiling fan was on at the time of testing, but since we don't usually find any elevation of Pen/Asp spores in a home your result is sufficient justification for a more careful and thorough visual inspection and some follow-up.

We'd need to know a lot more about the house, its age, materials, construction, leak history, occupants, and occupant complaints to have a view of what's needed.

Reader Follow-up:

Thank you for the quick response and we are getting it checked out. FYI - no visual mold present.

Next - our basement had an airborne count of 320 for Pen/Asp.

Does this seem elevated ? - Coleman

Reply:

A general mold count of 320 spores per cubic meter is pretty low; but depending on exactly what is seen under the microscope, such a sample could still point to a nearby indoor problem mold source. For example, Pen/Asp spore chains means that this is not outdoor mold but rather mold from an indoor source.

A visual inspection for leaks or leak / moisture problem conditions along with a case history of building complaints is how we can decide how much investigation is warranted.

To decide if you want to investigate further take a look at MOLD / ENVIRONMENTAL EXPERT, HIRE ?

Question: Pen Asp at 1810 spores/m3

Hi, This article is very helpful. My husband and I recently bought a 2 floor condo (2nd and third floor of a 2 family) with a basement. We have one half and the 1st floor occupants have the other side. Two years ago, during a large rain in Boston, water did enter the basement- more so on our side.

As our neighbors were remodeling their basement (shortly after we bought unit and moved in) they noticed mold on their side of the sheetrock which triggered us to get some testing. As it turns out, their side with the mold exposed has very acceptable levels compared to the outside and the company we used.

They have been using a dehumidifier religiously as well. Our side has not had a humidifier running for a couple months and more humid and did show higher levels of some molds, which I'd like to get an opinion on. There is no visual mold that we or the company who came in was aware of. Very minimal spots were on the sheetrock but were cleaned 2 months ago and have not come back:

The levels we see from our test that I'm nervous about are:

Pen/Asp group: 1810 counts/m3 (as compared to 53 for our neighbors and 267 outside)
Stachybotrys: 53 counts/me (as compared to 0 for neighbors and outside). I understand just one spore of this kind can be harmful.
Our total spore count was: 4470 counts/m3

Since we know the mold company is selling remediation services, its hard to know how severe our case is. This is a storage basement, not living space but still has contents we use on a regular basis.
Thank you for any insight someone could share. - Anonymous 8/9/11

Reply:

"testing" that finds "acceptable" mold levels might be misleading if it was an air test - an air test is at real risk of a false negative. Your total counts are low but that is not a real assurance - see ACCURACY OF VARIOUS MOLD TEST METHODS for details

In deciding if it's appropriate to hire someone to look more carefully into the question of mold contamination, take a look at MOLD EXPERT, WHEN TO HIRE

Airborne Mold under 500 spores per m3

Significance of Very Low or Zero Airborne Mold Spore Counts

Question: Low or meaningless "spore counts" - My home had low air test results for mold but found Stachybotrys. Is any level of Stachybotrys ok?

4 year old has been to doctors 200 times. Two year old has been to the doctors over 120. walked out of the house two months ago with the clothes on our backs. Had a air test ,had the Pen/Asp but also had stachybotrys. 2ND FLOOR Center raw count 5 Count/m3 106 % of total 33.4

The guy who took the samples and gave me the report said the mold levels in my home are acceptable. Is stachybotrys at any level ok? The children are now under the care of a informed Doctor and getting better. thank you for your time. - Mom

Reply: Low airborne mold spore counts and presence of mold in other tests might indicate an inadequate inspection and poor testing

Normally in a building that has been cleaned or has never had a water intrusion and indoor mold problem, we expect airborne mold spore counts from a properly-conducted test to be in the few hundreds of spores per cubic meter of air or less. And in a building not thought to have had an indoor mold contamination problem we don't expect to find spore chains of Aspergillus sp. or Penicillium sp.

Those raw counts you cite are very low, making me suspect that the inspection and test procedure have not homed in on the problem(s) in your home. Stachybotrys sp. is a big sticky spore that is not easily made airborne. I find Stachybotrys airborne most often when someone has disturbed a moldy surface such as moldy drywall during cleaning or demolition.

If you suspect that something in the home is causing or contributing to illness you should

  1. Confirm that possibility with your doctor
  2. If the doctor agrees that the indoor environment could be a factor, find a competent inspector who will actually examine the structure, not just collect tests.
  3. Many other factors can of course cause illness and respiratory complaints besides mold.
  4. See MOLD / ENVIRONMENTAL EXPERT, HIRE ? for help in understanding when it's appropriate and cost-justified to hire an expert to find an indoor mold problem source and write a mold remediation plan.

Question: how to interpret incomplete mold test report data

How do I interpret a report for indoor sampling for Aspergillus that says: m3/760; raw score 18 ; 22.5%? Thank you - Deborah 3/20/2012

Reply:

With respect, Deborah,

Surely you paid an "indoor air consultant" to come to your home, inspect, test, and collect what in your note appear to be air tests for mold (air tests alone, without a competent building inspection would be, to say the least, unreliable).

The person who conducted the tests knows the test conditions (still air, fans on or off, windows open or shut, other building and occupant factors) that are very important in deciding what added diagnostic information the test itself might offer.

Without that data, and from your single number alone, I think it would be unconscionable to pretend to risk your health and money on a simplistic answer of the meaning of the appearance of 18 individual mold spores in a sample. In sum, the test, alone, is meaningless.

Question: gobbledygook mold test results with low numbers

4 year old has been to doctors 200 times. Two year old has been to the doctors over 120. walked out of the house two months ago with the clothes on our backs. Had a air test ,had the Pen/Asp but also had stachybotrys.

2ND FLOOR Center raw count 5 Count/m3 106 % of total 33.4 The guy who took the smaples and gave me the report said the mold levels in my home are acceptable. Is stachybotrys at any level ok? The childern are now under the care of a informed Doctor and getting better. thank you for your time. - Mom 7/7/11

Reply:

Mom I do not understand your mold test - nor how any number of particles within a test can be more than 100% of the total number of particles found by the test. But I can say that betting a big expense on a raw count of five mold spores would be, in general, nonsense.

If your home has a problem with indoor air quality and indoor mold, or if there is reason to suspect such, those raw counts you cite are very low, making me suspect that the inspection and test procedure have not homed in on the problem(s) in your home.

See MOLD / ENVIRONMENTAL EXPERT, HIRE ? for advice on how to decide if you need an actual expert.

Question: Cladosporium at 550 spores - is it dangerous?

REcently had a mold test done on a home I am looking to purchase. The Cladosporium spore leves was 550 and the raw count was 83. What does this mean? Is it dangerous? - Sue 5/25/2012

Reply:

Sue, the mold count might be low - depending on what kind of test was performed and how it was conducted, and it might also be meaningless. You will want to ask the person you paid to inspect and test your home to help you interpret the meaning of the mold test lab report.

That person has key information that we do not - about the building interior, exterior, components, visible mold, leak history, and related data. In general, air counts alone, without a competent inspection, history taking, occupant interview, etc. are so unreliable as to be aptly criticized as junk science. See AIR TEST FOR MOLD: ACCURACY for an explanation.

Comment from Al:

Sue is the raw account was 83, and your total account was 550, this last number is based on the relationship ratio m3 and 1000 liters..remember 1 m3= 1000 liters,,,by looking the raw count # of 83, with a simple calculation you can find the total # based on 1 m3 or 1000 liters as a volumen.

Reply:

Thanks Al, well put. Keep in mind that on the face of it, it would be absurd to launch a very costly building treatment based on 83 actual airborne particles collected in a single sample, regardless of the equivalent airborne concentration converted to spores per cubic meter of air.

Especially since Cladosporium, the king of molds, is the most common, prevalent, widespread fungus around. It sounds as if a competent building inspection was not performed.

A practitioner who just collects an air sample for mold, sends it to a lab, and tosses the report over the wall to you for your own decision on what action is needed, has not performed a useful job.

Watch out about mold test and spore count accuracy: To calculate the equivalent airborne concentration of any particle we need to know the actual raw or physical particle count, the percentage of the sample or trace that was counted or examined, and the volume of air used to conduct the test - usually by multiplying the test duration by the liters per minute air flow rate of the particular sampler.

Depending on how the test was conducted, however, we can see several orders of magnitude variation in the actual "number" of the result. Therefore let's not confuse test precision (the number of decimal places in the number or answer) with test accuracy (is the test off by a factor of 10, 100, or 1000 from the true building conditions.

- Ed.

Question: Pen/Asp at under 500 spores/M3

I am a senior citizen and feel that I am not informed enough to know if i need to be concerned about the air sample i had done in my home. EMSL did an air sample in my family room and found
the following:

Aspergillus/penicillin in family room: Raw Count 22; Count/m2 464; % of total 38.7

OUTSIDE: raw count 1; Count/m2 21; % of total 0.2

A swab in my basement was taken because my ice maker in my kitchen leaked on a tile and a black spot looked like mole to me. Myxomycetes was "High"

Are those counts high? Do I need more extensive testing or professional remediation? - Viola Turner 8/22/11

Reply:

Viola, EMSL is the giant among mold test labs, having bought up lots of smaller labs around the country, and in my experience their training and expertise are very good. (Disclosure, we have no connection with EMSL but I know some of the principals). I don't doubt the lab work itself.

But an air test alone to screen a building for mold, without a competent building inspection and taking of history of building-related complaints, is just very unreliable. A very low computed mold count (such as yours) is not usually a problem indicator but it might or might not have meaning, depending on what's actually going on at the building.

I don't start with the assumption that an ice maker leak was or is the only leak concern at a building, nor did you say how much leaked, how much got wet, where water went - information that would help assess the risk of a hidden problem and help decide if invasive inspecting and testing were really justified.

And mold test swabs - do they mean anything? It depends. If the swab was examined microscopically it might give some interesting information, though in my experience swabbing crushes particles I'd like to use in the microscope to understand what's in the sample.

And if the swab was used to prepare a mold culture ... keep in mind that only 10% of all molds that exist will grow in any culture whatsoever, so your "test" as a mold screen is 90% unreliable when you open the package.

Surely you paid someone to come to your home and do some kind of inspection and testing. It'd be fair to insist that that person help you understand the meaning of the test results. If the "test" person says "I just collect samples and send them to the lab" then their help was not worth much, nor their test in my OPINION.

Finally, while it's doubtful that tests alone were a reliable screen of your home for problem mold, you might not really need such testing. See MOLD EXPERT, WHEN TO HIRE ) to figure out if you need further testing.

Question: When should we want or expect to find an airborne mold spore count of Zero mold spores m3

I am really afraid of indoor mold spore levels and suffer from allergies and asthma. Why can't I get my indoor mold levels down to absolute zero?

Reply: normal "clean" healthy outdoor or indoor air always contains particles including mold spores except in "clean rooms"

Only in a "clean room" such as facilities used to produce electronic computer chips or in certain hospital clean room applications will we see the indoor particle levels even approach very low levels. And even then particle levels won't reach absolute zero even when extensive HEPA air filtering is in use.

Common sources of indoor particles where there are people include skin cells, fabric fibers and low levels of inorganic debris such as soil particles.

As our mentor Dr. John Haines (NYS DOH mycologist, ret.) said repeatedly, "All mold is everywhere, all the time." By that John meant that mold spores and other dust particles (such as dust from the Sahara desert) travel widely, worldwide, in air.

Therefore many mold genera/species are just about always available to colonize an indoor building surface or material. Only if you ran your home like a computer clean room, never opening a window or door to admit outdoor air, could you even approach a near-zero indoor mold or other particle count.

A "zero level" of indoor mold particles is not a reasonable nor necessary nor appropriate target to assure healthy indoor air.

To avoid an indoor mold problem we don't need to try to remove all particles from indoor air. Rather we need to find and fix building conditions that cause indoor mold growth, such as leaks or high indoor moisture. Details are

at MOLD PREVENTION GUIDE.

...


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Reader Comments, Questions & Answers About The Article Above

Below you will find questions and answers previously posted on this page at its page bottom reader comment box.

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2022-11-18 by InspectApedia (Editor) - Watch out: NO spore count in an air sample should be taken as highly accurate or precise

That list is my OPINION and is an amalgam and a collection of a number of expert sources including:

Watch out: NO spore count in an air sample should be taken as highly accurate or precise. We find airborne count levels varying by 3 to 5 orders of magnitude depending on small changes in sampling conditions. Don't confuse precision in reporting (number of digits) with accuracy.

See more-detailed explanation at

ACCURACY OF AIR TESTS for MOLD - home

AIRBORNE MOLD COUNT VALIDITY

AIRBORNE MOLD COUNT NUMBER GUIDE - you are on this page

In particular, the greatest risk is of a false negative: failing to detect a significant but hidden harmful indoor mold reservoir. Something as simple as a change in humidity can result in enormous changes in the level of some genera/species of airborne mold.

We found this in a college library basement stacks area where our first air samples found very low levels of airborne spores despite visible thick green mold growth on very large collections of books in the library basement.

A day or two after a mold remediation company had installed large commercial dehumidifiers, the indoor RH had dropped dramatically and the Aspergillus sp. (which was the dominant but by no means only growth present) decided that the dry air meant "Time to release our spores".

Just walking past books the slight air current of one's passage left waves of green mold spore dust that we could actually see, and of course the airborne mold spore count soared.

On 2022-11-18 by Anon- where do these spore count levels come from?

Anonymous asked:

I have seen a list that describes when spore levels are generally considered to be a problem, and when an environment is considered to be clean.

I have copied an excerpt below. You may have seen it yourself, as it is commonly cited and the wording is identical from one website to the next.

I am unable to determine the original source of this list.

Can you advise as to whether it is from a particular document or guide, from a regulatory agency, or just generally accepted industry standard?

Regards, [Anon] 2022/11/18


On 2022-10-06 by Babette - Here's my mold test result - I'm sick as a dog

I am in a pickle here and sick as a dog with pneumonia from working at home in a rental in Florida. The air quality report just came back with 211,000 spores and trying to figure out what is really going on based on my health decline living in this place for nearly 5 months until I left and health still declining.

Here's the report. Thanks so much for any feedback. It's a wild goose chase getting any restitution in Florida.

Mold count report (C) InspectApedia.com Babette

On 2022-09-25 by InspectApedia (mod) - request an interpretation of the test results

Reply by InspectApedia-911 (mod) - air tests for mold are highly inaccurate

@Babette,

Unfortunately it really is a wild goose chase when we rely on air tests for mold - those are highly inaccurate. The variability that I have found in airborne mold levels is at least four orders of magnitude depending on exactly the conditions when it test is conducted. So a number like 400 might actually be truly 40,000 or 4 we don't really know.

What's appropriate when you have evidence that conditions in the home are making you sick is a much more thorough visual inspection by an expert who will consider not only your complaints but the nature of construction and the history of the building with any leaks or moisture problems.

That in turn should identify the places in the building where there's the greatest risk of hidden mold and that's where some further investigation is justified.


On 2022-09-23 by Tracy - Want help understanding mold test results

Mold count report (C) InspectApedia.com Tracy

Thank you for all of the information on this site! Would love some help understanding some recent mold test results.

This test was taken as part of home inspection for purchase of home. Home has been vacant for months with windows and doors sealed and limited coming and going to open doors or windows.

There is a hot tub in the living room with water cycling in it with the lid on and an air sample was taken above the hot tub. There are no visible signs of a leak or mold. The client plans to remove the hot tub in the spring. At the time, there were ceiling fans on in the room that are not normally running.

Are these results cause for alarm? By the numbers, should we be considering some type of remediation?

On 2022-09-23 by InspectApedia-911 (mod) - mold counts are notoriously inaccurate but look at the dominant indoor spore or particle numbers

@Tracy,

As you will read in this article series mold counts are notoriously inaccurate and can range from what's really there by four orders of magnitude.

However when those spores are the dominant ones found in any indoor test the result still is suggestive:

The Stachybotrys sp. is a water loving mold which is an indication that there's been a leak somewhere in the building.

The fact that Penicillium / Aspergillus spores are the dominant spore found indoors is a strong suggestion that there is or was a mold problem indoors.

What's needed when you find conditions like this, particularly building occupants are complaining about health or air quality related issues, is an actual competent thorough inspection of the building including a complete review of its leak history and occupant complaint history..

It disappointing that you've paid someone to perform what's perhaps an expensive test and yet you have to go to an independent source to ask for an interpretation of the test. After all, the people who came to your house have seen it and we have not. Surely they have more information than we do.

On 2022-09-25 by Tracy

@InspectApedia-911, Thank you for your response. The test was part of a home inspection where inspector was only in the home the one time and we did not receive an interpretation of results. In my search for information regarding this result, I have found varying answers.

I have appreciated your feedback and the info you provide on this site. It has made the most sense and brought the most understanding to what is turning out to be a not so definitive way forward. We will definitely pursue additional information regarding any leaks, spills, etc. Thank you!

Reply by (mod)

@Tracy,

As mentioned earlier, assuming you paid for this test to be done, it would be perfectly reasonable and expected to request an interpretation of the test results.

And while I [DF] am a bit critical of home inspectors who "add-on" "tests" to an inspection to improver their profit, at the same time in my OPINION a home inspector who is educated about mold and mold hazards ought to be able to do a better job than a mycologist at noticing the risk areas in a home: she'll surely know better than most people the clues that indicate a prior, present or risk of future leaks, water entry, high moisture, and so to be able to tell you the areas in the home most-likely to harbor a mold problem.

You said there were "no visible signs of a leak or mold" - if none were reported to you it's time for a more-expert look.


On 2022-08-05 by Nicole

Hi there this is a wonderful page and I already feel so much better informed reading everything. We recently did air sampling and a brown spot on the wall in the closet. Both came back with Penn/Asp.

The room itself isn’t very high but could that spot be causing the elevated level in the air? In other words should we treat that spot and assume we took care of the problem or should we be investigating for hidden water damage somewhere?

Mold count report (C) InspectApedia.com Nicole

On 2022-08-05 by InspectApedia-911 (mod) - should we be investigating for hidden water damage somewhere

@Nicole,

Take ANY mold "test" result with a heaping table spoonful of salt - that is, mold tests are not at all reliable as an accurate characterization of the actual species present (most species do not grow in culture and test procedures easily miss dominant mold genera/species that may be present but not visibly obvious)

and similarly, such tests are not an accurate estimate of the actual amount of mold in a building nor the amount of mold that's airborne.

Details are at AIRBORNE MOLD COUNT VALIDITY

Treating a spot of mold on a wall is not useful.

You need to find the mold - including mold hidden in wall or ceiling cavities

Remove the mold - (don't just "spray" or "treat" it)

Find and fix the reason it grew - leaks or high moisture.

Start at the most-suspect area and make a test cut into that drywall. Let me know what you see on the cavity side of the drywall and in the wall cavity.


On 2022-07-23 by Trishia - Our inspector used a thermal camera to detect water intrusion

Weird situation here : house was being built during hurricane and windows were left open during storm. I checked on house 3 days after rain stopped and noticed many wet areas in Sheetrock and subfloor. Builder promised to fix — but they did not.

Fast forward 5 years : my son has severe asthma (only started after moving in) so I get the house tested for mold. Inspector used a thermal camera to detect water intrusion — nothing found. I did air quality tests on two rooms I had pictures of wetness during build and significant numbers for Pen/Asp came back.

My question : since I know these certain areas were wet, that is what we are basing the remediation on. However, how do I find out if there is hidden mold in other areas of the home? I didn’t take pictures of each space (hindsight is 20/20)

I have thought of doing air tests of each room, but after reading through this site, it seems that won’t tell us where it is. I know the HVAC is contaminated and I will remove all carpet — but I am at a loss for how to discover all of the actual source. I know the builder is going to fight me on this so I am trying to get as much information as possible.

Any advise is appreciated!!

On 2022-07-23 by InspectApedia-911 (mod) - thermal camera to detect water intrusion is unreliable: risk of missing mold or damage from leaks into areas now dry

@Trishia,

I'm sorry to say that we've seen this problem before.

It's a fundamental error of mold inspection to think that thermal scanning will find mold from prior leaks.

Once the water has dried there's no temperature difference. Thermal scanning sees temperature not mold.

Similarly, air testing is fundamentally unreliable. Not only are there four orders of magnitude variation in the difference between a mold count and the mold that's actually present, but there's a high probability of a false negative when the mold is in the building cavity.

Simple changes such as in relative humidity as well as changes in the pattern of air movement in a building make big changes in the level of airborne mold even when the mold is on exposed surfaces where it could reasonably be detected.

Air testing will not be helpful in your case. Furthermore even if you were lucky and air testing suggested that there was a mold problem you would still have to make further investigative steps to find where the mold was.

What we have to do now is follow the water. That means go to every area that may have been wet, perhaps every window that may have been open, and go to the most suspect area nearby such as immediately below the windowsill and immediately above the floor below the window, and make a small test cut opening into the wall.

I find usually a 2 inch by 4 inch opening is plenty big enough to see whether the back of the drywall is moldy and to see whether there's mold on the framing or on the interior surface of the wall sheathing. If we inspect all of the most suspect areas we will either find mold or we will have a reasonable basis for stopping the search.

Where mold is found by visual inspection of test cuts into wall or ceiling cavities, the specification for remediation will be to remove drywall until we have at least a one stud or joist bay or one foot of clear surface area of surface that had no mold contamination.

You also need to remove any insulation that has been wet and of course to inspect the exposed surfaces in those cavities.

Try some test cuts, ask for the questions as needed, and keep us posted.


On 2022-07-15 by CJ - is it safe to restore the flooring in our building based on this mold test?

Leak in sealed off laundry where we have only been going in and out through the garage door access. Demo’d all visual mold. 3 days of an industrial air scrubber. Air test results show 1249 penicillium (1370 outside), 161 stachybotry, 363 of hyphal fragments (81 outside), 725 cladosporium (4753 outside), 121 ascospores (524 outside).

Are we safe to re-floor. Testing company says yes but my research says no. Our HVAC run from this room.

On 2022-07-16 by InspectApedia-911 (mod) - Watch out: your HVAC system itself might have become contaminated with mold

@CJ,

It sounds to me as if your HVAC system itself might have become contaminated and I can't tell whether the cleanup is complete or not based simply on a brief text message. I also don't know what materials are involved or what the existing floor materials are. So it's hard to give you a safe yes or no answer.

Running the air scrubber right before doing any tests, of course, skews the result and testing itself is potentially unreliable especially if the results are negative. That is to say it's easy to get a false negative.

It's critical than to have an actual physical visual expert inspection of the scope of damage and the scope of work to be sure that the cleanup has been complete. In my opinion, reliance solely on a test to decide that is foolhardy and unreliable.


On 2022-06-16 by Sasha - what's your opinion of these mold test results - after dog and cat peed on the carpet

In my rental unit, past tenant had their dog n cat pee on the living room carpet, and we replaced it after a month of their move. Current tenants insisted on mold testing and got it done. It came back at Stachybotrys 13 Count, have attached the test result.

What's your opinion on it? Please advice. We are getting air purifier as a precaution measure. Any other advice? Thanks a lot in advance!

Mold test results Sasha

On 2022-06-16 by InspectApedia-911 (mod)

@Sasha,

No one can make a reliable assessment of mold contamination based on a mold report like that one - by itself.

We don't normally find Stachybotrys spores indoors unless there has been water (a leak of some sort, not cat pee) and some mold contamination.

But from the report alone we don't know if that's left-over from a cleanup job or if there is some justification for inspecting further.

An air purifier can not possibly fix an indoor mold contamination problem as it can not remove the source.

IF there is a moldy area less than 30 sqft it's a handyman job.

If there's a larger area it's appropriate to hire a professional.

Relying on air tests alone is unreliable. You need to actually inspect the building.

No panic is needed, just proceeding with some thought.

On 2022-06-21 by Sasha

@InspectApedia-911, Thanks for your advice.
Thinking of the source.. carpet was professionally cleaned, and for some reason in the issue area (living room) where the Urine damage was there didn't dry for a long time, and we replaced the Carpet after 3 weeks of this cleaning along with the new carpet pad, and floor was treated with kilz.

So prabably this 3 weeks would have caused for this Stachybotrys? There are no other leaks or water stagnation. So, indeed this would have been a residual from the cleanup?

If the source is resolved, and there is no other issues, after the clean up, how long should one wait to get the test done? Appreciate your time and advice very much! Thanks.

On 2022-06-21 by InspectApedia (mod) - removal of moldy carpet and padding could indeed have left some moldy dust

@Sasha,

If you removed moldy carpet and padding, that could indeed have left some moldy dust in the building that might be detected in a follow-up "air test".

Notice that your indoor test found Aspergillus/Penicillium spores at some elevation - a more-serious possible cause of mold-related illness if present at high / persistent levels.

If you are absolutely certain that there are no other leaks and never have been leaks over the life of the building, and if there are no building air quality complaints or worries, this would be a place to stop. Else you'd investigate further and with more-care than a simple air test.


On 2022-04-01 by Donna - Have mold in home. This is a result of a air test and i dont understand it: Pen/Asp raw count 20

Have mold in home. This is a result of a air test and i dont understand it

Bedroom: penicillium/Aspergillis Raw count: 20, Cladosporium:raw raw count: 62, unidentified/hyphal fragments:raw count 25

Living room: cladosporium Raw count: 40

Thank you

On 2022-04-01 by Inspectapedia Com Moderator - Get your money back if all you were told was "raw spore counts"

@Donna,

The "raw count" number is the actual number of mold spores that the microscopist counted in the sample.

That number is converted into an estimate of the actual airborne concentration by by calculating what percent of the sample was examined and how much air passed through the sampler during the collection interval.

Those calculations allow the technician to tell you the airborne concentration of spores per liter of air.

Watch out: without those calculations the "raw counts" mean absolutely nothing. You cannot conclude anything.

And of course that's before considering that the actual level of airborne particles in a space varies enormously over time, so at its very best, such a "count" is only a momentary sample and not the whole story.

That means, in particular, that a low "count" or exposure level found by such a "test" could be wrong, while when the "test" finds a high level of exposure it's probably right that there is a significant problem to be found.

Mold "air tests" alone are spectacularly un-reliable and in-accurate. What is airborne - measured as particle counts - varies by up to 4 orders of magnitude depending on very small changes in how the test was conducted (someone walking by, someone moving a notebook, someone turning a fan on or off or opening or closing a window or door).

So an air test alone is not useful. If you have reason to suspect indoor mold contamination what's needed is an onsite expert inspection of the entire building, not a "test".

Details are at ACCURACY OF AIR TESTS for MOLD

and at AIRBORNE MOLD COUNT VALIDITY

Only when test results show extremely high indoor airborne mold levels is the test likely to be meaningful. So yes there may be a mold problem in your home but I can't say for sure with just the data you have at hand.

Before spending more on this question take a look at

MOLD / ENVIRONMENTAL EXPERT, HIRE? - when to hire an expert


On 2022-02-07 by derrick

Hello ,I had a mold test done on a building I rent. As I suspected mold might be present, I missed the call so they could go over the report with me ,I just need to know is this space safe to be in
Thanks

Mold test results Derrick

On 2022-02-08 by Inspectapedia Com Moderator - basic questions to ask about a mold test report

@derrick,

It is impossible to answer your question about safety from a test alone. And if the expert you hired won't call you again to interpret their "mold test report" for you then in my OPINION you should demand your money back.

Unfortunately a mold test of any kind, taken by itself, without an expert inspection of the entire building and an interview of the occupants and an awareness of the buildings leak history and occupant health is simply not something that has any meaning.

The basic questions you would ask are: is there visible mold, does the building have a history of leaks, and are the occupants at particular risk, sufficient to justify a thorough visual inspection. My point is that screening tests for mold using a culture or any other method are, taken alone, unreliable.

If you see more than 30 square feet of mold in your building the you already know it needs professional attention. If you don't but you have the other risk factors that we discussed in this article series, then you probably want to hire an expert. Take a look in the index to related articles and you will see an article titled

MOLD / ENVIRONMENTAL EXPERT, HIRE?


On 2022-02-03 by Paul L. - my post mold cleanup showed that the numbers decreased - raw count of 3 Cladosporium outside

I live in the Northeast where we recently were hit with heavy snow and freezing temperatures. I recently had a mold clearance test taken after completing the remediation. Note: The original test was taken in September.

All areas showed a decrease in mold counts as hopped for unfortunately the outside weather at the time of taking samples was 12 degrees with snow on the ground. This resulted in an outside/background report showing a total of 3 raw count Cladosporium.

Thats it! no other fungal spores were present. So even though the mold levels are way down in comparison to the original test, it still red flagged all my inside tests as being Elevated. What can I do to get a better test comparison in cold weather conditions?

On 2022-02-03 by Inspectapedia Com Moderator - shouldn't be relying simply on a test for mold to clear a mold remediation job

@Paul L.,

As you will read in this article series, Airborne tests for mold contamination, used alone without a thorough and expert visual inspection, are very unreliable. I see up to four orders of magnitude variation in test results based on even small changes in test conditions.

And of course anyone with experience knows as you have commented that when there's snow cover you're not going to get much mold and outdoor air. Comparison doesn't really make much sense.

So in my opinion you shouldn't be relying simply on a test for mold to clear a mold remediation job. You want to know that the mold was found and removed and it's cause corrected.

In my opinion that requires a visual inspection of the work area before the building is restored.


On 2022-01-29 by Krystal Causey - are these mold count numbers saying it's dangerous for us to be living in our home?

My mold report reads

Ulocladium raw count 126/Per m3 1700
Penicillun/Aspergillus raw count 288/Per m3 150,000
Cladosporium raw count 1 Per m3 53
Hyphal fragments 53
Limit of detection 13
Sample volume(liters) 75
Background debris 2
Skin cells 80-4,000

We live in a 1496 Sq foot house. Are these numbers dangerous for us to be living in our home? We have a 3 month old, a 2 year old and a 13 year old plus our animals living here. My husband and I both sleep with cpaps. There is "black mold" in multiple areas of our home.

We purchased Sept. Of 2020. The seller did not disclose the mold issue... or we wouldn't have bought the house. I just want to understand how much jeopardy my family is in, living here.

On 2022-01-30 by Inspectapedia Com Moderator - need more than mold test alone to determine risk

@Krystal Causey,

I really want to be helpful but unfortunately a mold test of any kind, taken by itself, without an expert inspection of the entire building and an interview of the occupants and an awareness of the buildings leak history and occupant healthful durability is simply not something that has any meaning.

If the person whom you hired to perform the test for carpeted for you then you should ask for your money back as it's not really helpful.

Watch out: But ***IF*** those numbers mean that the lab calculates that you have an airborne Penicillium/Aspergillus count of 150,000 per cubic meter of air, that is a very high level that is almost certainly unsafe; you could develop serious mold-related illness.

The basic questions you would ask our is there visible mold, does the building have a history of leaks, and are the occupants at particular risk, for which you say yes, sufficient to justify a thorough visual inspection.

My point is that screening tests for mold using are culture or any other method are, taken alone, unreliable.

And the expert whom you paid probably a significant fee to "test" your home for mold won't take time to explain the report to you and advise you accordingly, get your money back and find a better consultant.

If you see more than 30 square feet of mold in your building the you already know it needs professional attention. If you don't but you have the other risk factors that we discussed in this article serious then you probably want to hire an expert.

Take a look in the index to related articles and you will see an article titled

Mold expert, when to hire

 

Thank you to our readers for their generous comments

Hi there this is a wonderful page and I already feel so much better informed reading everything. - On 2022-08-05 by Nicole

 

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