Mold Standards for Exposure & Testing FAQs:

Questions & answers about specific mold exposure levels, standards, or measurements & reports of "mold counts" versus various current & proposed mold standards as well as the very substantial shortcomings in any mold exposure standard whatsoever.

This article series also explains at what level is allergenic or toxic mold considered a problem in buildings? How do we obtain an accurate and meaningful measurement of mold exposure indoors?

Mold Counts & Standards: questions & answers, Mold Count FAQs about What mold spore levels indicate contamination in buildings ?

These questions & answers about interpreting mold counts or airborne mold level counts were posted originally

at AIRBORNE PARTICLE & MOLD COUNT NUMBER GUIDE - be sure to see that article for an orderly approach to the question of "what does my mold test result mean?"

[Click to enlarge any image]

On 2019-10-11 by (mod) -

I trust that you will not pay the final bill before you've had an independent clearance inspection and testing have been made comfortable with the result

On 2019-10-10 by Leilani

I have 1600 mold spores in my half basement after mitigation and removal of the mold. My 2 kids and I have been staying with friends and hotels for 4 wks now. The mitigation and removal my insurance is not covering and have a bill for $7900.

Question: respiratory problems vs allergic response

(Oct 29, 2012) Scott

Hi can you advise if exposure to mould spores, mycotoxins and fragments can cause respiratory problems without the person showing an allergic reaction to the mould?

Reply:

In my opinion, certainly yes, if you mean other types of allergic response such as itching; but you should discuss this with your doctor, not online.

Question:

(Jan 24, 2013) Saeed Sheikh Muhammad

Now-a-days I am interested to find out the referece values of yeast & mould in Nut candies & Nut paste for food analysis.

Question: CB points out problems with mold related illness, misdiagnosis, and very sensitive transmission of mycotoxins

(Feb 5, 2013) CB

Wowza-- keep it up! This is one of only two websites I've read in 9 months that is completely free of misinformation, disinformation, errant conclusions or pure arrogant ignorance. I'm a physician, early 40's, brought to my knees over 6-8 years by the insidious progression of complex multi-system mycotoxicosis.

After being misdiagnosed by over a dozen docs (including the infamous Mayo), it was desperation, near death, the internet and one laboratory that helped save my life. However, the diagnosis was just the beginning.

While there is effective treatment, it is expensive and difficult to access.

To avoid a huge tangent, I'll just say that there are IV therapies that are extremely effective at clearing circulating and tissue-bound mycotoxins, as well as those that decrease excessive mycotoxin-induced neural inflammation and restoration of depleted GABA stores (but big Pharma doesn't want us to know about these--since the ingredients are commonly described as "not approved for, intended to diagnose, nor treat any illness").

Back on point.

Time, lots of struggling and trial and error, and exorbitant expense have ultimately led us to our epiphany: while molds and their antigenic structural components largely correlate with the "asthma/allergy spectrum," their mycotoxins are a separate, MASSIVE, grossly-under-recognized human health issue. Residual mycotoxins are being retained on fibers of clothes, linens, carpet, insulation, furniture......

And "transfer" from these does occur. In the absence of a DESPERATATELY-needed mycotxin-specific organic compound detector, we've had to indirectly learn some lessons.

With over 100 symptom- and timing-based urine mycotoxin levels in several people, we've documented non-contact airborne transfer from clothing (worn by a person from an effected building) to multiple people who simply spent an hour in the same room with them.

We've documented skin-skin transfer and animal hair-human transfer. Multiple individuals had elevated Tricothecene levels after 40 minutes

...

(Feb 5, 2013) CB said: hot tub had Tricothecene levels above 40 ppb--

in a private hot tub (the hot tub water was subsequently tested, and low-and-behold had Tricothecene levels above 40 ppb-- i.e. more than 200 times the toxic threshold). This exposure resulted in one party having a Tricothecene level that peaked 4 days later at 46 times above the toxic threshold, and severe neurocognitive, GI, and rheumatologist symptoms that precluded a full work schedule for weeks).

I've had numerous tests at my house and office, and thorough necessary remediation efforts at both. Two issues have arisen over the past 4-5 months.

First, recurring symptoms and correlative elevated mycotoxin urine levels led to identification of suboptimally-remediated sources of mold in attic insulation (despite supposed negative post-remediation evaluation).

Second, and subsequently, recurring symptoms/elevated toxin levels led to realization that certain areas of carpet were (very likely) retaining mycotoxins in the absence of persistent/recurrent mold (the carpet in question never, itself, had a primary mold issue; and repeat air sample tests of the "intentionally-disturbed" carpet were not remarkable.

yet consistent temporally-based illness issues suddenly resolved upon replacing the carpet). Man, we really need some tech geeks and a couple of engineers and PhD's to develop a real-time VOC meter for mycotoxins.

Anyway, I apologize for the verbal diarrhea. But wanted to say thank you for your efforts, open-mindedness, quest for truth and accuracy, and passion.

While the upper and lower airways suffer well-established collateral damage from antigenic mold particles, mycotoxins are silently causing profound issues including, but not limited to: Autoimmune, neurodegenerative, psychiatric, rheumatologic, endocrine, immunodeficiencies, cardiovascular, dermatological, etc.

One huge confounding variable is that everyone claims to be a mold expert, and 90% don't have a clue that they don't have a clue. My other massive concern is the current dangerous arrogant ignorance of the US medical field regard

Reply: My dog was a certified mold inspector

Thank you for these helpful remarks. I've moved your comments into the article for preservation.

I agree with your concern that "mold experts" vary widely in expertise as well as in avoidance of conflict of interest.

My dog was a certified mold inspector by the way - it was easy to send in some money and get a diploma for her.

A weekend nor a week do not an expert make, of a dog nor of a human being. You can quote my OPINION on that.

Question: buyers inspection said there's mold: is this a concern?

6/25/2014 Jack

I am in the process of selling my house. The potential buyers had a building inspection done. The inspector found what looks like dust on the floor joists in the basement.

This is not a surprise since I have used the basement as a work room for wood working. A mold inspection was done and the only thing reported was Aspergillus/Penicillium *High*. At the bottom of the report the company defines "Category: Count/per area analyzed

Rare: 1 to 10 Low: 11 to 100 Medium: 101 to 1000 High: >1000"

Is this proof of a situation which we should be concerned about or not?

Thanks for your help,
Jack

Reply:

Jack,

I don't know what that "high" means - spores per inch, spores per cubic meter of air, spores in a culture, spores on a swab, spores in the mind of the inspector or what. Also waving a notebook changes the number by several orders of magnitude if air testing was performed, so such tests are wildly inaccurate, especially if they do not detect a problem.

However high levels of indoor Aspergillus/Penicillium is worth looking into. It may have nothing to do with wood dust from a shop. A more intelligent assessment would look at the building leak history, figure out the locations of highest-risk of mold contamination, and examine those areas directly.

Follow the water:

 look carefully at the home's leak history and what materials have been wet. Inspect those areas, invasively if necesary. If examining the highest-risk points in the home do NOT find an actionable mold contaminated area to clean-up, you've done about as much as is reasonable.

That doesn't guarantee that there is no mold problem to find and remove, but the approach can argue that there is no current information that appears to justify further invasive inspection, demolition, etc.

Don't panic - which leads to wasting money, but proceed with some caution.

Question:

(June 25, 2014) Jack

I am in the process of selling my house. The potential buyers had a building inspection done. The inspector found what looks like dust on the floor joists in the basement. This is not a surprise since I have used the basement as a work room for wood working. A mold inspection was done and the only thing reported was Aspergillus/Penicillium *High*. At the bottom of the report the company defines "Category: Count/per area analyzed

Rare: 1 to 10 Low: 11 to 100 Medium: 101 to 1000 High: >1000"

Is this proof of a situation which we should be concerned about or not?

Thanks for your help,
Jack

Reply:

Jack a detailed answer is now in the article above.

Question: meaning of a 24-count of mold colonies - serious health worry?

(Aug 11, 2014) TROY WILSON said:
IS A 24 COLONY COUNT FOR PENNICELLIUM MOLD SERIOUS FOR HEALTH CONCERNS

Reply:

A culture test, if it was based on particle settlement out of air, is fundamentally unreliable as a building test for mold contamination.

See MOLD CULTURE TEST KIT VALIDITY

Also see MOLD CULTURE TEST ERRORS

Question: reading of 180 CountM3 for Stachybotrys

(Sept 27, 2014) Kal said:
Should I be concerned about a reading of 180 CountM3 for Stachybotrys?

Reply:

The count alone is of little meaning but the presence of the mold you cite indicates a building that has been water damaged and probably has or previously had mold contamination.

Question: indoor spore count of 950000 cladosporium

(Mar 26, 2015) Anonymous said:
If there is an indoor spore count of 950000 cladosporium,... what can you advise about this level for an office area?

Reply:

The count you cite is very high for any indoor mold - indicating a building that has been water-damaged and is worth inspecting for mold contamianation, though of course it has little more meaning without knowing more about the test, how it was conducted, and about the building.

Question: 104,000 cu.m of pen/asp group?

(Apr 26, 2015) jim said:
what to do with 104,000 cu.m of pen/asp group?

Reply:

The count you cite is high for an indoor mold - indicating a building that has been water-damaged and is worth inspecting for mold contamianation

I would start by asking the person who performed the test what it means, where the problem mold is located (assuming that's what she or he says the test means), and what caused it, followed by removing the mold and fixing the cause. If the person you hired is not going to answer such questions I'd ask for a full refund of whatever fees I'd paid.

Question: acceptable standards for toxic mold spore counts,levels or measurements in California

(May 27, 2015) Anonymous said:
what are the acceptable standards for toxic mold spore counts,levels or measurements in California

Reply:

Anon

While your question is perfectly understandable, you need to know that any quantitative answer to that question would be complete nonsense. "mold spore counts" is far too vague a term. We need to know the way that a test was conducted, the test conditions, the mold genera and species and other critical facts before we can make any sense out of a "count" or "level" of mold

. For example waving a notebook in the air during an " air test" for mold can make several orders of magnitude difference in the count level, and further, the toxicity of mold spores varies from none to high depending on the genera and species of mold and even further on the local growth conditions. For example a potentially harmful mold spore may or may not actually contain high levels of mycotoxins depending on just what material on which the mold is actually growing.

As an additional example, "mold spores" vary not only in harmfulness by genera and species and growth substrate but also sheer physical size. It makes no sense to equate one Stachybotrys chartarum spore (large and heavy) with one Aspergillus niger spore (tiny and light). The total volume of these particles is enormously different - at least by a factor of ten.

And where each spore might go in the body is different. A tiny particle can be breathed deeply into the lungs - while a large particle is likely to lodge in the nose (or eye or on the skin). So their possible vectors of harm vary enormously.

And "counts" of mold taken by some methods such as growing spores on a culture plate are further misleading since 90% of molds won't grow on any culture at all. You're 90% "wrong" when you open the test, and that's before considering differences in settlement rate out of air based on particle weight or variations of what's in the air as air disturbance, temperature, humidity, and other factors change.

A simple "mold count" out of context is balderdash. Or should I say, Baloney whether the count was in California or Charleston.

Question: Please advise if these Mold numbers are safe.

(July 8, 2015) Please advise if these Mold numbers are safe. Urgent for buying a house Please !!! said:
I am going to buy a house. The Mold inspection report gave me the following numbers. The inspector is not really telling me in common language if this is good to go or not. I am confused. Any advise would be deeply appreciated !!! I have to get back to the seller by tomorrow regarding any remediation , if needed.

OUTSIDE: (Raw Count, Spores/m3, % )
-----------------

Alternaria (8, 53, 5)
Cercospora (4, 27, 3)
Chaetomium (- - - )
Cladosporium (28, 190, 18)
Epicoccum (- - -)
Ganoderma (8, 53, 5)
Oidium/Erysiphe (4, 27, 3)
Other Ascospores (48, 320, 31)
Other Basidiospores (40, 270, 26)
Penicillium/Aspergillus (8, 53, 5)
Smuts, myxomycetes (8, 53, 5)
TOTAL SPORES (156, 1046, 100)
Cellulose Fiber (4, 27, - )
Pollen (- - - )

ROOM#1: (Raw Count, Spores/m3, % )
-----------------

Alternaria (- - -)
Cercospora (- - -)
Chaetomium (52, 350, 59)
Cladosporium (12, 80, 14)
Epicoccum (8, 53, 9)
Ganoderma (4, 27, 5)
Oidium/Erysiphe (- - -)
Other Ascospores (- - -)
Other Basidiospores (- - -)
Penicillium/Aspergillus (- - -)
Smuts, myxomycetes (12, 80, 14)
TOTAL SPORES (88, 590, 100)
Cellulose Fiber (24, 160, - )
Pollen (8, 53, - )

ROOM #2: (Raw Count, Spores/m3, % )
-----------------

Alternaria (- - -)
Cercospora (- - -)
Chaetomium (- - -)
Cladosporium (- - -)
Epicoccum (4, 27, 6)
Ganoderma (4, 27, 6)
Oidium/Erysiphe (- - -)
Other Ascospores (12, 80, 19)
Other Basidiospores (20, 130, 31)
Penicillium/Aspergillus (4, 27, 6)
Smuts, myxomycetes (20, 130, 31)
TOTAL SPORES (64, 421, 100)
Cellulose Fiber (12, 80, - )
Pollen (- - -)

Reply: time to get your money back

My advice is to ask for a full refund of whatever you paid your "mold inspector"

- first, if s/he cannot explain the report's meaning to you then they're not providing a useful service they're simply taking tests and sending lab results;

- second- a proper "mold inspection" includes an actual inspection of the property, not just a lab test since tests alone are very very unreliable, especially when they don't seem to indicate a thing.

A competent inspection examines the building structure, materials, leak & moisture history, areas of highest risk for hidden mold contamination, presence of visible indications of leaks or mold, and other factors in order to make a reasonable risk assessment. An occupant history, building history, and other data may also be pertinent. For example was there ever a roof leak, plumbing leak, sewer backup, flood.

Question: how bad is wet rug mold for my dogs?

(Aug 6, 2015) Andrea said:
I saw that my new rug was soaked with rain water in my cellar. I pulled the rug back and got black mold on my fingers. I put a fan on till it dried not cleaning it first. The mold is about 1" wide and 10' long. It has been three days and I slept in the room while the fan was on. Now I realize that I was breathing in airborne mold. How bad is that for you and my two small dogs 10 and 18 pounds?

Reply:

That fan was not the best approach to dealing with a wet moldy rug as you are likely to increase the level of airborne mold that might be irritating or harmful. Better is to remove wet moldy carpets, remove the water, and fix the water source or leak.

I can't assess the health risk you ask about: it depends on too many variables including the specific mold genera/species present, the airborne concentration, the duration of exposure, and the health condition of the people or other animals who were exposed - those are questions to take to your doctor and your vet, with some urgency if any of you are experiencing health complaints that your doctor opines could have an envriomental cause or contributor.

Question: house under purchase has to pass a "mold inspection"

(Sept 16, 2015) gazer1023 said:
We just received our air quality test results back from a house we intend to purchase. The results state that there are 647 Raw Count/4335 Spores/M and % of total 94% for Penicillium/Aspergillus. Part of our offer to purchase is that the house has to pass inspection. In my research I think this is a big fail and we need to insist they clean up the problem before we purchase. Lastly, the furnace is in the room of the basement that tested positive so should we insist on the vents being cleaned as well. This is our dream home and is a ton of $$ we want to make sure we understand what to ask for. Thank you!

Reply:

Pass or fail based on a physical count of 647 mold spores is in my opinion nonsense. However the high percentage of Pen/Asp spores in the indoor sample is indeed a red flag that would justify a more competent inspection to find the mold reservoir and to determing what cleanup and leak cures are needed.

Question: interpret the mold counts in my Condo - miserable skin rash

(Dec 9, 2015) Elizabeth said:
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

Question: mold test air-counts in Montreal home

Dec 13, 2015) Terence

My wife and I have put an offer in for a house in the Montreal area. I requested two pre-purchase inspections (building inspection and air quality test). We had no suspicion as a reason to order the air quality test, but we just wanted to make sure. Since it is a pre-purchase inspection, the test had to be non-invasive.

We received the air quality tests back Friday evening (and I had to let the agent know by Friday if we were taking the house). The test has numbers on it, and three line items are highlighted in red, however no further explanation is given. Therefore I have no context in which to take the results. I don't know if the results are a bit high, moderately high, very high, or extreme.

The building inspection did not reveal any particular problems with the house that would alert us. The house was built in 1973, and the previous occupants were very dirty people. There is carpet everywhere, including an area rug directly on the floor in the basement. The house has three bathrooms, one of which was recently redone. The other two bathrooms, the kitchen, and the flooring are all going to be completely redone. The HVAC system and chimney will also be professionally cleaned.

Penicillium/Aspergillis - Basement (Raw Count 31, concentration 1771 spores/m3) // Outdoor (Raw Count 2, concentration 27 spores/m3)
Markers (Stachybotrys/Chaetomium, Globossum) - Basement (Raw Count 16, concentration 914 spores/m3) // Outdoor (Raw Count 0)
Other Spores (Ascopore, Fragments, Arthrinium, Other Dark Brown) - Basement (Raw Count 28, concentration 1600 spores/m3) // Outdoor (Raw Count 0)

I got an extension from the real estate agent until Monday. We are due to meet her Monday morning at 10:30. The period given when you pre-purchase inspections is simply not enough to investigate air quality issues.

Reply: ask for your money back from a "mold tester" who cannot or will not answer questions nor interpret his or her "mold test" report results

Terence:

Start by demanding your money back for your "air test"

Any building inspection or test for which the professional you hired won't or can't explain what she or he found and can't say what it means to you is simply taking your money for doing nothing of value.

Any "air test" without a thoughtful and thorough inspection of a building for its leak history, condensation history, moisture history, construction materials, flood or sewer backup history and a myriad of other important factors, is completely unreliable - in particular if the test does *not* detect a problem. About the most one could say of such as test is "we didn't detect anything but we can't assure you that there is no problem"

Question: living with brown mold

(Dec 29, 2015) C MCKEON

I am unsuccessfully trying to live in what i believe to be brown mold for several years.

My health deterioting and have discarded a lot of my lifes treasures because i cannot clean them. I have been quoted tests from $1,000.00 to $5,000.00. My finances will not allow it as i am a senior on fixed income. Any suggestions would be appreciated.

Reply:

CM

Worse still, many people will charge you $1000. and just do a "test" that is of almost no use. Even if such a mold "test" confirms that there is a mold problem in the building you won't know where it is, why it is there, what cleaning is needed to remove the mold and what repairs are needed to prevent its recurrence. This is to say that a superficial approach, even if expensive, is not useful.

If you have more than 30 sqft of contiguous mold growing indoors you need a professional to define the cleaning needed and another to remove the mold and repair its cause. Small areas of mold can be cleaned using normal household cleaning methods.

Search InspectApedia.com for "WHEN TO HIRE AN EXPERT" for details that will help you decide if/.when hiring a professional is really needed.

Otherwise, search InspectApedia.com for HOW TO FIND MOLD, or WHAT MOLD LOOKS LIKE or FIND HIDDEN MOLD or HOW TO CLEAN UP MOLD for extensive detail on what to do about indoor mold.

Question: how to understand mold test count ranges in Florida mold test report

(Feb 5, 2016) Danny

Hello, I was hoping for some help in understanding these ranges on an air test that was recently done in my bedroom as well as the kitchen/living area.

We live in South Florida and found water damage caused by a leak in our roof that has caused mold to grow in the walls which is now being dealt with and a mold remediation company came and did the air test, the results of which are below. Any and all help would be appreciated thank you, I am especially worried because what the inspector referred to as a small amount of stachybotrys was found and I know that's considered "toxic black mold".

Bedroom:
Ascospores: Raw Count= 6, Count/m3=40, %=14
Aspergillis/Penicillium-Like: Raw Count= 29, Count/m3=193, %=66
Basiodiospores: Raw Count=1, Count/m3=7, %=2
Cladosporium: Raw Count=7, Count/m3=47, %=16
Stachybotrys: Raw Count=1, Count/m3=7, %=2
Total Spores: Raw Count=44, Count/m3=293
Hyphal Fragments: Raw Count=2, Count/m3=13
Debris Rating: 3
Detection Limit: 7

Kitchen:
Ascospores: Raw Count= 6, Count/m3=40, %=23
Aspergillis/Penicillium-Like: Raw Count= 8, Count/m3=53, %=31
Basiodiospores: Raw Count=2, Count/m3=13, %=8
Cladosporium: Raw Count=6, Count/m3=40, %=23
Smut/Myxomyced/Periconi: Raw Count=4, Count/m3=27, %=15
Total Spores: Raw Count= 26, Count/m3=173
Pollen: Raw Count= 1, Count/m3=7
Debris Rating: 3
Detection Limit: 7

Reply: example of a useless "mold test" report and questionable use of mold swab testing

Danny,

With apologies for having to say so, these counts don't mean a darn thing when taken alone. An air test for mold without a thorough visual inspection for leaks, water leak or moisture history, occupant complaint history, etc. is simply not diagnostic and not prescriptive - it's just numbers tossed over a wall.

None of your counts were "high" and may not indicate a water-damaged or mold-contaimated building - at least that's what some would say. But I have to argue that we can't conclude anytying from just numbers only. Simply turning a fan or or off, opening a door, walking through a room during an air test for particles can change the particle counts by 1 to 4 orders of magnitude.

Furthermore, the "toxic black mold" scare is misleading. There are plenty of harmful indoor molds that are not "black mold". However we do not usually find much Stachybotrys Chartarum (a popular "toxic black mold" enjoyed by mold test folks) indoors. High levels of it may indeed indicate that there has been water or mold contamination;

But for example your bedroom count found ONE single mold spore - that could have come in a window or on someone's foot. It's meaningless. All mold spores are everywhere, all the time. It's the concentration that's important. One spore, alone, with no other information, is not important.

Finally look at the absolute number of spores. It would be nonsense to make any major or costly or health-related decisions based on the detection of five or six particles of any sort in indoor air.

If the inspector who took your money refuses to tell you what she or he thinks the report means, I'd demand a full refund.

(Feb 8, 2016) Danny said:
Thank you

We did indeed have water damage and mold inside the walls, the leak has been fixed amd we will get started on the removing the mold this week. My wife has been experiencing symptoms, it seems to have exacerbated her asthma and is now undergoing treatment.

I'm glad to know the air results numbers weren't "high". He also took a swab from one of the baseboards, he swabbed directly on the mold. These were the results:

Aspergilius/Pencillium-Like: Raw Count=212, Count/m3=329, %=6
Chaetomium: Raw Count= 2,991, Count/m3=4,635, %=91
Cladosporium: Raw Count=82, Count/m3=127, %=2

Thank you so much for your help.

Reply: limitations of swab tests for mold

Swabs, unfortunately, mash up and destroy forms useful for microscopic identification of molds. Swabs only make sense if we are going to culture a sample. Culturing is 90% wrong in all cases when testing for mold since 90% of molds won't grow on any culture at all.

There is no question but that there is a troubling relationship between mold exposure, allergies, and asthma. It's a problem for me, too.

NONE of the mold tests, samples, swabs, are very helpful if we don't find the actual location of the mold problem as well. That needs to be found and removed.

While all molds might show up indoors, certain ones are "red flags" such as Aspergillus/Penicillium which is easily airborne, small, breathed deeply into lungs, often harmful, and is a common genera of molds in water damaged buildings.

You want to know that the mold reservoir has been found and removed and that no significant moldy dust or cross-contamination was left in the home. If on spending time in the home your wife's symptoms seem worse, I'd consider that justification for a closer look at the home environment.

2015/02/09 Danny said:
Thank you so much

The leak has been found and fixed and a mold remediation company is coming this week to open up the walls and decontaminate.

Reply:

MOre than 30 sq.ft. of continguous mold merits professional cleaning that involves dust containment, negative air, post remediation inspection, etc.

Article Series Contents

• MOLD EXPOSURE STANDARDS
  • ASTM Mold Standards
  • Australian Mould Guidelines - separate article
  • California Mold Disclosure Law - separate article
  • MOULD STANDARDS CANADA - - separate article
  • European Union Mold Standards
  • New York City Mold Guidelines - separate article
  • OSHA Guide to Workplace Mold - separate article
  • World Health Organization Mold Bulletin - separate article
• AIRBORNE MOLD COUNT NUMBER FAQs-2

"Mold Levels" warning: single number "mold levels" are unreliable as a measure of health risk in buildings for several reasons including at least the following:

1. Particle levels vary: the actual level of indoor particles in air varies by several orders of magnitude over very short few-minute intervals, making reliance on any single measurement questionable, particularly if the measurement does not show evidence of a problem.
   
   Simple mechanical disturbance like turning on or off a fan can completely change individual measurement results. Short term measurements are therefore inaccurate.
2. Human sensitivity varies: because of wide variation in individual human reaction and risk to mold, variation in allergenicity, pathogenicity, and toxicity among mold genera and individual species, and even additional variation in these levels depending on specific environmental conditions such as the substrate upon which a mold is growing (its food), quantitative risk-levels are better used as an overall indication of building cleanliness before and after a mold cleanup, and not as an absolute level of risk to building occupants.
3. Particle toxicity varies: There is very wide variance among the toxicity of individual mold species, ranging from none to probably highly toxic, pathogenic, or even carcinogenic.
4. Spore size or mass varies widely from less than 1 u to over 200u, so a large spore contains potentially more harmful material than a small spore of the same "toxicity," making a "count" that does not identify the particle and particle size ambiguous
5. Mold spore toxicity varies, even within an individual species, depending on what substrate the species is growing on in a particular instance, e.g. wood vs. drywall. For background on how and why molds can be toxic, see this World Health Organization Mold Bulletin.
6. Viable vs. non-viable "spore counts" vary in significance: procedures that use cultures to identify "viable" spores may omit high levels of non-viable spores which nonetheless remain highly toxic.
   
   Methods that rely on culturing have a high risk of identifying a mold which is present but is not the dominant or even the most problematic mold in the building, while completely failing to disclose a problem mold which is present but which simply does not grow in the culture media used, or is overgrown by another species in that media. For more details see Mold Spore Counts: are indoor fungal spore counts valid?for further explanation.

See ACCURACY OF AIRBORNE MOLD SPORE COUNTS for more details about these issues. That said, here is a sampling of some indoor air mold spore exposure level criteria and comments

...

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

Or see AIRBORNE MOLD COUNT NUMBER FAQs-3 - more-recent FAQs about interpreting mold counts

Or see these

Recommended Articles

• ACCURACY OF AIR TESTS for MOLD - home
• AIRBORNE MOLD SPORE COUNT GUIDE - home
• AIRBORNE PARTICLE LEVELS vs IAQ - home
• AIRBORNE MOLD COUNT VALIDITY
• MOLD EXPOSURE RISK LEVELS
• MOLD EXPOSURE STANDARDS - home
• MOLD LAB REPORTS
• MOLD LEVEL REPORTING
• MOLD TESTING METHOD VALIDITY
• VISUAL INSPECTION & HISTORY of MOLD

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AIRBORNE MOLD COUNT NUMBER FAQs-2 at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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

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Citations & References

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

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