More on the Interpretation of Mold Air Samples

Are you staring at the results of a mold test and struggling to figure out what it all means?  Let me try to help you.


The most common method used for mold air testing is uses a spore trap cassette. Because there is always a background amount of airborne mold spores, a key step in collecting air samples is to have a “reference” sample collected from the outdoor air at the time of the indoor testing. Since there are no guidelines on acceptable mold levels in the air, an outdoor sample is the best tool for interpreting the results of the indoor samples. Without the outdoor sample, you are limited in what you can gather from the results of the indoor samples.


There are various D.I.Y. air tests you can pick up at your local hardware store requiring you to place out a petri dish for several hours. Most of those tests are not very helpful in giving you any sort of usable data to evaluate the air in your home and as a general suggestion should be avoided.


Interpreting mold levels can be tricky. If you would like feedback on your mold air sampling results, please comment below and I will do my best to give any feedback I can in my free time. The views expressed in the blog post and comments are my own, and not necessarily those of Indoor Science. If you need a more immediate response regarding your results you can book a 30-minute phone consultation for $98 by clicking here.

Dylan McIntosh

Dylan McIntosh

Dylan McIntosh is a Senior Project Manager that performs indoor air quality assessments, industrial hygiene testing, and laboratory mold analysis. Mr. McIntosh holds a Bachelors of Science degree in Biology from the University of Illinois - Springfield. Dylan is an ACAC Council-Certified Microbial Investigator (CMI) and an Pan American Aerobiology Certification Board (PAACB) Certified Spore Analyst. In his words… “Throughout my life, I always had a dream of becoming an astronaut. That dream hasn’t worked out (yet) so I started a career in the next best thing, indoor air quality! In my free time I enjoy outdoor activities with my dog, cooking, and being involved with A Special Wish - Chicago; a local charity.”

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225 thoughts on “More on the Interpretation of Mold Air Samples

    Hello, I received the following mold reports and was hoping to get some insight into how to interpret the results. I suffer from seasonal allergies and am sensitive to mold and pollen. Should I be concerned about purchasing this house based on the attached results?


    1st sets of numbers = Control exterior
    2nd sets of numbers = basement interior
    raw ct. ; % red; spores/m3
    Ascospores 14 25 750 ; 0 0 0
    Basidiospores 98 25 5,200 ; 3 25 160
    Cladosporium 8 25 430 ; 2 25 110
    Curvularia 0 0 0 ; 1 100 13
    Epicoccum 0 0 0 ;2 100 27
    Ganoderma 2 25 110; 0 0 0
    Nigrospora 1 100 13; 0 0 0
    Other colorless
    Penicillium/Aspergillus types†
    Rusts 0 0 0 ; 4 100 53
    Smuts, Periconia, Myxomycetes
    Background debris (1-4+)†† : 2+ (outdoor) 3+ (indoor)
    Hyphal fragments/m3 : <13(outdoor) 27 (indoor)
    Pollen/m3: 27(outdoor) 27(indoor)
    Skin cells (1-4+): < 1+(outdoor) 3+ (indoor)
    Sample volume (liters): 75(outdoor) 75 (indoor)
    § TOTAL SPORES/m3 6,500 (outdoor) 360 (indoor)

    MoldSCORE™: Spore Trap Report
    Outdoor Sample: Control exterior
    raw count : spores/m3 : mold score
    Generally able to grow indoors*
    Alternaria ND ;< 13
    Bipolaris/Drechslera group ND; < 13
    Chaetomium ND ;< 13
    Cladosporium 8 ; 430
    Curvularia ND ;< 13
    Ganoderma 2 ;110
    Nigrospora 1 ;13
    Penicillium/Aspergillus types† ND; < 13
    Stachybotrys ND ;< 13
    Torula ND ;< 13

    Seldom found growing indoors**
    Ascospores 14; 750
    Basidiospores 98 ;5,200
    Rusts ND ;< 13
    Smuts, Periconia, Myxomycetes ND ;< 13
    Total 6,520

    Location:Basement Interior
    raw count : spores/m3
    Generally able to grow indoors*
    Alternaria ND ;< 13 ; 100
    Bipolaris/Drechslera group ND ;< 13; 100
    Chaetomium ND; < 13; 100
    Cladosporium 2 ;110; 105
    Curvularia 1; 13; 105
    Epicoccum 2; 27; 111
    Nigrospora ND ;< 13; 100
    Penicillium/Aspergillus types† ND ;< 13; 100
    Stachybotrys ND ;< 13; 100
    Torula ND; < 13; 100

    Seldom found growing indoors**
    Ascospores ND; < 13 ; 100
    Basidiospores 3; 160; 100
    Rusts 4 ;53; 121
    Smuts, Periconia, Myxomycetes ND ;< 13; 100
    Total 360(spores/m3);116(mold score)


    These numbers to me do not indicate elevated mold levels in the air of the basement. There is a small detail which is a little strange, the hyphal fragments in the basement are a little higher than I usually see indoors.

    I am a teacher who has had many health issues that I believe are related to mold in my portable classroom. Here are the results of the air quality test:
    Sample type: Air-O-Cell

    Analysis: Direct Microscopy; FALI Method IAQ 101; Modified ASTM D7391

    Volume: 75.0 L
    Ascospores – ND S/m3
    Basidiospores – 170 S/m3
    Cladosporium – 420 S/m3
    HYPHAL FRAGMENTS * – 35 S/m3
    Penicillium / Aspergillus – 770 S/m3
    Rusts/smuts/myxomycetes – 13 S/m3

    Inside w/AC on
    Ascospores – ND S/m3
    Basidiospores – ND S/m3
    Cladosporium – 8200 S/m3
    HYPHAL FRAGMENTS * – 490 S/m3
    Penicillium / Aspergillus – 380 S/m3
    Rusts/smuts/myxomycetes – 40 S/m3

    Can you help me interpret this??? I am very concerned as I was very sick for 7 months!!!
    Thank you!!!!


    In my opinion, I see that there is an elevated level of Cladosporium inside. This is a common mold type which can grow indoors in spaces with evevated humidity. I have also seen this type growing on A/C coils and drain pans.


    In the mold lab report, I saw Pen/ASP Group present on 51-75% of sample area.
    Sample media Type: Tape lift.

    The dry wall of the shower may have a leakage behind. The ceiling of the shower is easily to get mold. The ceilings mold are removed so no sample. This sample is got by opening a small part of the dry wall and taped the area. Is the Pen/ASP mold behind the dry wall the cause of the mold often appearing in the ceiling?
    The Pen/asp are currently only found behind the drywall. Will it penetrate thru the drywall and present in the shower room?

    Thank you


    Microscopically Pen/Asp appears like a field of dandelion seed heads. When they are disturbed the spores release into the air, and Pen/Asp have a lot of spores! If the materials are chronically damp then it is possible to have mold growth on both sides, the extent of the growth is dependent on the extent of the moisture in the material. The only way to see if the mold is affecting the air quality is to have air samples collected.

    Thank you Dylan,

    Does this report ” Pen/ASP Group present on 51-75% of sample area” means I have toxin mold which impacts health? Do you know where I can find link on what human impact will Pen/ASP have?
    Another question, not all ASP/Pen are toxic. Which lab can identify the species of the ASP/Pen on my dry wall, and what the cost is? I want to find out if they are toxic.
    Thank you



    I am not a healthcare professional, so I can not comment on possible health effects. All we can take away from that result is that there is Asp/Pen growing on the surface. Most commercial environmental microbiology labs can speciate Asp/Pen, some national labs are EMSL, EMLab P&K.

    The purpose of this blog post is to provide interpretation of air sampling lab reports, so I just ask that comments please stick to this theme.

    Thank you Dylan. I don’t know why my inspector didn’t take a air sample of the bathroom, but just taped a sample directly on the mold from the opened bathroom dry wall. I really want to find out if the air is contaminated since the mold is behind the dry wall.
    I called the lab , IMS Laboratory, which tested the sample, to check if they can speciate ASP/PEN. But they just told me to talk with my inspector on it.
    I am calling EMSL and the other labs you recommended to find out who can do it and may do another test again.

    Hi Dylan I could really use your help. I live in a relatively new building…its about 7 yrs old. For about 1 year I’ve smelt mold/ must in my son’s bedroom. I initially attributed it to him being a teenager but the smell got stronger and stronger. I investigated and found mold growing on clothes in his closet, mold growing on the side of his bed, his desk, books on shelf, head phones and just randomly throughout his room. I brought it to management’s attention and they dismissed it bc they couldn’t find a source of mold or water. They tried to blame it on me for not opening windows or ventilating my unit (which I do every day). My family started getting sick so I decided to hire a professional to do a spore trap report and I got the following results.

    Control/ outside: Penicillium/ Aspergillus = 75 spores per cubic meter. Raw Count 3

    Bathroom: Pen/ Asp = 18,000 spores per cubic meter. Raw Count 450

    Master Bd Rm: Pen/ Asp = 12,600 spores per cubic meter. Raw Count 315

    Guest Bd Rm: pen/ asp = 73,000 spores per cubic meter. Raw Count 1818

    Living Room: pen/ asp = 9,000 spores per cubic meter. Raw Count 235.

    Living Room: Basidiospores = 2600 spore per cubic meter. Raw 65

    Management believes I am at fault for the elevated mold levels bc they cannot find water intrusion. Is it possible we are doing something to cause mold growth? We open windows every day and also have a double heppa air purifier. I would appreciate your expertise here.

    Also, we live in San Francisco, CA so we don’t have AC and the humidity level in our unit was 68 % and temp 78 degrees when the testing was done( we had a heatwave). On average the humidity is 62% and temp 74 degrees indoors.


    The results in your comment show elevated levels of Asp/Pen. Finding out what is causing the mold to grow is much more difficult than just collecting the air samples. Since the mold was found growing on items in the room, and not just the building materials, that to me is a sign of some sort of humidity issue. Now, this could be hand in hand with water intrusion, I can not determine that. I would recommend hiring a mold inspector that will do more than just air samples to figure out the issue. It would be good to have an infrared and moisture meter scan done either during or directly after heavy rain. I would also suggest monitoring the humidity levels in the rooms, and if the humidity is consistently over 60% it may be worth running dehumidifiers.


    I’m selling my house in Northern IL and have been asked by the buyers for a mold remediation credit for high aspergillus in the basement bathroom. There is no visible mold and a different mold inspector I had come out couldn’t find any moisture at all with a handheld detector. The drywall in a storage area behind that bathroom did get wet once 6 years ago. The humidity inside was 48% according to the report.

    Could you give me your interpretation of these lab results? The only indoor sample was taken right by the toilet.

    Location Outside Basement
    Detection Limit (spores/m3) 40 40
    Hyphal Fragments 2 80 3 120
    Pollen 3 120
    Spore Trap Used M5 M5

    raw ct. spores/m3 % raw ct. spores/m3 %

    Alternaria 3 120 <1
    Ascospores 14 560 4 1 40 1
    Basidiospores 33 1320 9 9 360 13
    Cladosporium 273 10900 76 16 640 24
    Epicoccum 2 80 <1
    Penicillium/Aspergillus 5 200 1 40 1600 59
    Rusts 27 1080 8
    Smuts/Periconia/Myxomy 1 40 <1 2 80 3
    Colorless/Other Brown
    Background debris (1-5) 3 3
    Sample Volume(liters) 25 25

    Raw ct Spores/m3 Raw ct Spores/m3
    TOTAL SPORES/M3 358 14300 68 2720


    Yes, I would say these results show a slightly elevated level of Aspergillus/Penicillium inside the basement. However I do also notice that these samples were collected for a shorter time than most, the industry standard for the sample volume is 75L and these samples only collected 25L. We can see elevated levels of Asp/Pen in basements with no visible mold or water damage sometimes due to chronic high humidity. It is important to remember that the inspector’s readings only show conditions at that exact moment, so just because they did not find moisture and the humidity was acceptable during the inspection that does not mean that if outside conditions are different that they would get the same results.

    Thank you! I understand that it’s only slightly elevated but we will probably let them have the credit.

    What you said about moisture presence being partially dependent upon outside conditions makes sense.

    It’s very generous of you to share your expertise on the internet. Thanks again!

    Hi Dylan!

    We’re recovering after Harvey flooding down here in Houston. Thankfully we only had 8″ or so of water in the home we were renovating and were able to get in pretty quickly and tear out all of the sheetrock. We just had our fist post-remediation mold test and we have elevated levels of Chaetomium. We had two indoor readings – this was the higher of the two.

    Particle Identification / Raw Count (Count/m³) / % of Total
    Alternaria – – –
    Ascospores 1 / 200 / 6.1
    Aspergillus/Penicillium 10 / 2200 / 66.7
    Basidiospores 3 / 700 / 21.2
    Bipolaris++ – – –
    Chaetomium 1 / 200 / 6.1

    Our inspector was citing the elevation likely originating from one area behind a built-in cabinet – which we plan to remediate further at his suggestion. We also had two large holes in the slab from where we were doing under slab plumbing and I suspect those were also contributing to the readings. Those are now being filled in with concrete. Otherwise, the home is bare bones so I’m at a loss where the readings are coming from.

    Can you help me understand what an acceptable level of Chaetomium is?

    Any tips to tackle Chaetomium remediation?



    Chaetomium mold is a type that is considered a water damage indicator, and it is not found in the outdoor air, so therefore any amount of Chaetomium is likely to be considered “elevated” by an inspector. My opinion the numbers on your test is likely just residual spores in the air from the remediation, and if you have the remediation company run the air scrubbers for a few more days it should take care of it. Another possibility is that there might be some settled construction dust which could be holding residual spores. If the home has visible work dust I would have them vacuum them up. I doubt there is missed growth anywhere in the house, because as you say it is bare bones, this is likely just leftover spores in the air from the tear out.

    Hi: we are currently in the process of buying a new home. As part of our home inspection, we had an air quality test conducted. During the inspection, there was no visible mold or evidence of moisture/mold found anywhere in the home. However, the AQT came back with positive results for stachybotry. Raw Count: 4, read: 100%, spores m/3: 53. Since this test, the selller had a mold assessor come to the home for a visual mold inspection- he was able to find one small area of mold (which wasn’t swabbed), and a water stain under the kitchen sink. Still not reassured, we (us & seller mutually) brought in another 3rd party remediation company that looked behind walls using a camera. He only looked in areas common for moisture problems: finished basement, attic, near plumbing, etc. they found a couple sources of a potential problem, but when swabbed none were positive for staychbotry.
    His results were:
    Aspergillus: spore estimate = moderate; mycelial estimate: many
    Mycelium: spore estimate = ND; mycelial estimate = many
    Curlvularia: spore estimate = ND; mycelial estimate= rare
    Myxomycetes: spies estimate = ND; mycelial estimate = rare.
    I have a 1yr old baby, and I am pregnant with baby #2. I am very concerned that we are unable to locate the source of the stachybotry. The seller seems to believe that it may have been carried from the outdoors to the indoors on someone’s shoes (or similar). Is this possible? Should I be alarmed?

    Any advise or information you could provide would be greatly appreciated- thank you in advance!

    Thank you,
    Nervous mommy

    Whenever we see Stachybotrys in air samples that is a warning to us. Stachybotrys is not found in outdoor air samples very often and is an indicator of water damage inside the home. You could have another air sample collected to see if that Stachybotrys level was just an anomaly. If Stachy shows up on that air sample I would say that strongly supports some sort of indoor growth.

    Thank you very much! One other question, if you don’t mind. Based on the stachybotry results, are you able to determine if the stachybotry problem seems wide spread or more of an isolated problem? Is that a high reading? And do you believe stachybotry to be dangerous to human health?

    Thanks so much again!

    Hi there. We had a water leak in our guest bedroom (interior wall). The home builder removed/replaced wall and part of flooring but we didn’t use mold remediation company, so I am little concerned. Our recent mold test indicated penicillium/Aspergillus in a higher level than all the other types of mold but lower than outdoor levels. Would something like an air scrubber resolve this? Also, should I re-test after a certain period of time, to ensure levels are dropping? If so, what time frame do you recommend?

    Thank you – Alicia

    Sample Type/Volume: Z5 -25L (Spore Trap)

    Particle Identification / Raw Count (Count/m³) / % of Total

    Cladosporium: 4/ 160 / 9
    Other Ascospores: 1/ 40 / 2
    Other Basidiospores: 5/ 200 / 11
    Penicillium/Aspergillus: 24/ 960 / 53
    Smuts, myxomycetes: 11/ 440/ 24
    Total Spores: Count = 45/ 1800 / 100

    Guest Room:
    Cladosporium: 3 / 120 / 13
    Other Ascospores: – – –
    Other Basidiospores: 2/ 80/ 8
    Penicillium/Aspergillus: 18/ 720 / 75
    Smuts, myxomycetes: 1/ 40 / 4
    Total Spores: Count = 24/ 960/ 100

    Unless you still see visible mold growth around, I would say these air samples are acceptable. If you were still concerned with the numbers you could run an air scrubber to clear the airborne mold from the air. You could retest after running the air scrubber for a few days, just make sure the scrubber is turned off before testing. I would also suggest running the sample for at least 75L, as opposed to the 25L that was done for the above testing.

    I have recently been affected by Harvey but the rental I was living in with my kids showed signs of mold 2 weeks prior from substantial wind driven rain… I have a copy of the air quality report and would like your opinion…. I have been to the doctor recently and three is concern about the effects on my lungs and body in general… would you be able to help read these air report?

    I have recently put a contract on a lake house but these were the mold results and I don’t understand them. Do these levels seem like an issue to you? Please help.
    AB Identification Number: EH092717-14-1 EH092717-14-2
    Sample Identification Number: 2157808 2157843
    Date Collected: Sep/26/2017 Sep/26/2017
    Description: Basement Outside Air
    Sample Type: Spore Trap Spore Trap
    Sample Condition: Intact Intact
    Volume/Area Sampled: 25 L 25 L
    Reporting Limit: 40 40
    Spore Identifications Raw Count Spores/m3 Raw Count Spores/m3
    Acremonium-like ND BDL ND BDL
    Alternaria 1 40 ND BDL
    Arthrinium ND BDL ND BDL
    Aspergillus ND BDL ND BDL
    Aureobasidium ND BDL ND BDL
    Botrytis ND BDL ND BDL
    Cercospora-like ND BDL ND BDL
    Chaetomium ND BDL ND BDL
    Cladosporium 116 4640 1596 63840
    Coprinus ND BDL ND BDL
    Curvularia 1 40 2 80
    Drechslera/Bipolaris Helminthosporium/Exserohilum ND BDL ND BDL
    Epicoccum ND BDL ND BDL
    Fusarium ND BDL ND BDL
    Ganoderma ND BDL ND BDL
    Memnoniella ND BDL ND BDL
    Nigrospora ND BDL ND BDL
    Penicillium ND BDL ND BDL
    Penicillium / Aspergillus – like 3052 122080 43 1720
    Pithomyces 1 40 ND BDL
    Scopulariopsis-like ND BDL ND BDL
    Spegazzinia ND BDL ND BDL
    Stachybotrys ND BDL ND BDL
    Tetraploa ND BDL ND BDL
    Torula ND BDL ND BDL
    Trichoderma-like ND BDL ND BDL
    Ulocladium ND BDL ND BDL
    Ascomycetes-unspecified 22 880 19 760
    Basidiomycetes-unspecified 24 960 316 12640
    Hyphomycetes-unspecified ND BDL ND BDL
    Zygomycetes-unspecified ND BDL ND BDL
    Myxomycetes/Perconia/Smuts/Rusts ND BDL ND BDL
    Miscellaneous structures
            Hyphae Present Present
            Clamydospores ND BDL ND BDL
            Perithecia ND BDL ND BDL
            Sclerotia ND BDL ND BDL
    Background Particulate Density Medium Medium
    Total Spore Count 3217 128680 1976 79040

    These results show a major elevation of Aspergillus/Penicillium indoors. The indoor sample shows an elevation of almost 100x, strong evidence that there is some mold growth and moisture issues in the home.

    Hello Dylan-
    I’m another Harvey victim, down here in Houston. We had water intrusion through our weep holes and under the floor. All flooring has been removed and most built-ins, EXCEPT kitchen cabinets. We just got results from the air sampling. My concerns are the Cladosporium, Penicillium/Aspergillus, and Stachybotrys levels inside.

    Outdoor control: (raw ct./spores m3/%)
    Cladosporium 16 / 640 / 20
    Pen/Asp 15 / 600/ 19
    Stachybotrys 0

    Cladosporium 2 / 8 / 7
    Pen/Asp 26 / 1040 / 90
    Stachybotrys 1 / 40 / 3

    Prior to testing, I cleaned all surfaces with antimicrobial cleaner, sprayed visible mold with disinfectant, and ran an air scrubber w/HEPA filter for 72 hours. The walls behind the refrigerator and dishwasher (both are on either side of the kitchen cabinets) were dry by the moisture sensor readings, and no visible mold.

    Our questions now are
    1) are these dangerous levels of mold?
    2) without any visible signs of mold, should we deduce that the mold source is behind the cabinets?

    Many, many thanks for your input.

    The single spore of Stachybotrys is not a statistically relevant result, so I can not say one way or another in relation to that. THe Aspergillus/Penicillium levels insde are slightly high, but it is not as high as you would see in a home with major mold issues. It is likely the small amounts of mold you see growning in the home are what is contributing to the levels in the air. I have no concern over the Cladosporium levels indoors.

    We’re trying to interpret an ERMI analysis with results in spores eq/mg dust on a house we are considering purchasing. No outdoor samples were collected. A 5 mg sample was collected with a vacuum on carpet in two rooms from the second and third floors (not the basement). Here are the results for species that were not “ND” from EPA 36 Species Identification Group 1:

    Aspergillus penicillioides: 48
    Aspergillus restrictus: 12
    Aspergillus versicolor: 45
    Eurotium (A.) amstelodami: 55
    Aureobasidium pullulans: 102
    Cladosporium sphaerospermum: 19
    Paecilomyces variotii: 9
    Penicillium spinulosum: 16
    Penicillium variabile: 2
    Wallemia sebi: 23

    The ERMI Value = 2.6
    ERMI Interpretation = Level 3, which states Relative Moldiness. Further investigation needed to determine if sources of mold exists.

    Group 2 sum of the logs indicated low relative moldiness.

    Any advice on how to remediate, if needed? There are no visible signs of water/mold. The inspector, using a thermal camera found no signs of moisture but he recommended adding a dehumidifier to the basement, which is 90% finished. The house is two years old.

    Unfortunately, an ERMI test is not suited to answer the questions you have. All we can do to interpret the results is what it says in the report, that there may be indoor mold/moisture issues but further investigation is needed. An ERMI test looks at the likelihood a property has had water damage and mold growth at some point in the past, it does not evaluate the current conditions of the space. ERMI testing cannot be used to determine if remediation is needed, you need a good visual assessment and moisture testing.

    HI Dylan,
    Thanks so much for helping out and offering insight into these tests. I own a rental unit (I used to live in it). Some of the ladies who now live in the unit asked a company to do an Air-O-Cell / 75.0L spore collection test. They presented this document to us as evidence that our house has mold issues and are demanding a reduction in rent as well as an early termination of the lease. We are obviously seeking legal assistance for that. However, we have NO IDEA what these levels even mean. We have a certified Class A builder who specializes in water remediation doing all work. He found (2) spaces in what is called the front room – which has a sump pump due to previous water penetration – that has water infiltration from the foundation. He found NO foundation issues in the bedroom but did find that the tenants were not using the dehumidifier or using the bathroom exhaust fan during and after showers. It was his opinion that the front room elevated results were because of foundation issues and he has repaired the foundation by excavating around the area. He found nothing to repair in the basement master bedroom. These are the results of the test:

    Master BEDROOM:
    fungal types identified / raw count / spores/ m3 / % of total:

    Peniscillium/Aspergillus 152 / 2,022 / 94%
    Ascospores 2 / 27 / 1%
    Basidiospores 6 / 80 / 3%
    Total Spore Count 160 /2,129 / 100%

    Front room:
    Penicillium/Aspergillus 536 / 7,219 / 95%
    Acospores 1 / 13 / <1%
    Basidiospores 11/ 146 / 1%
    Cladosporium 11/ 146 / 1%
    Epicoccum 1/ 13 / <1%
    Penicillium/Aspergillus —/ —–/ —–
    Polythrincium —/ —–/ —–

    Penicillium/Aspergillus —/ —–/ —–
    Acospores 16 / 213 / 10%
    Basidiospores 78/ 1,037/ 52%
    Cladosporium 47/ 625 / 31%
    Epicoccum —/ —–/ —–
    Penicillium/Aspergillus 6 / 80/ 4%
    Polythrincium 2 / 27 / 1%
    TOTAL 149/ 1,982 / 100%

    Penicillium/Aspergillus —/ —–/ —–
    Acospores 7 / 93 / 17%
    Basidiospores 16/ 213/ 39%
    Cladosporium 8 / 106 / 19%
    Epicoccum —/ —–/ —–
    Penicillium/Aspergillus 10 / 133/ 24%
    Polythrincium —/ —–/ —–
    TOTAL 41/ 545 / 100%

    Specifically, I'm trying to understand what do these numbers MEAN? Does this mean that there is a huge problem of mold that cannot ever be removed despite my contractor removing drywall (with no visible evidence of any mold damage – simply some dampness associated with a water leak) and no seen or visible mold issues anywhere?

    If it helps, on the first day of the repair work, he measured humidity in both rooms that have issues. Room #1 – the master bedroom, which is mostly below grade level, measured at 52% humidity with no dehumidifiers being run at all. After dehumidifiers being run for only 8 hours, the humidity level measured at 38%.

    In the front room, where there was a sump pump and known water infiltration (hence the sump pump), the humdity measured at 56% before work began (with no dehumidifiers) and measures at 42% now that work has been completed (with no dehumidifiers).

    I thank you in advance for your kind assistance.

    All mold issues can be remediated to a pre-loss state, so if the work is done correctly and moisture issues are identified and solved the mold from this issue will not persist. There is an elevation in the bedroom and front room of Aspergillus/Penicillium. The bedroom levels are slightly higher than what we can see in the outdoor air from time to time, the front room is higher but not off the charts relative to how high these numbers can be in homes with major issues.

    Hi Dylan,

    Thank you for helping people interpret the data. We recently had a test done and here are the findings. Any input from you would be really well received. Thanks!

    Sample Type/Volume: Allergenco D 75L

    Particle Identification / Raw Count (Count/m³) / % of Total

    Alternaria 16/213/3%
    Ascospores 32/427/6%
    Aspergillus/Pen 104/1387/19%
    Basidiospores 3/40/ <1%
    Cladosporium 355/4733/64%
    Curvularia 1/13/<1%
    Epicoccum 6/80/1%
    Ganoderma 4/53/<1
    Nigrospora 2/27<1
    Pithomyces 5/67/<1
    Rust 9/120/2%
    Smut/Myxo/Per 15/200/3%
    Total Spores 552/7360

    Ascospores 3/40/<1
    Aspergillus/Pen 317/4227/81%
    Basidiospores 3/40/ <1%
    Cladosporium 62/827/16%
    Ganoderma 3/40/<1
    Pithomyces 1/13/<1

    Total Spores 389/5187

    Ascospores 22/293/6%
    Aspergillus/Pen 95/1267/26%
    Basidiospores 3/40/ <1%
    Cladosporium 234/3120/65%
    Ganoderma 3/40/<1%
    Smut/Myxo/Per 4/53/1%

    Total Spores 361/4813


    I am seeing an elevation of Aspergillus/Penicillium in the basement sample. We can see this type elevated in basements frequently and would suggest monitoring humidity levels in the basement if you do not have signs of visible mold or a history of water issues.

    Hoping you can help interpret these findings. We had a leak from our bedroom window, cleaned up the same day, removed and replaced carpet. No signs of visible mold. These samples were taken the week after.
    Thanks in advance!
    Bedroom sample:
    Aspergillus/Penicillium 71 sp/m3
    Cladpsoriurm 329 sp/m3
    Smuts/Myoxomycete/Periconie/Rust 3082 sp/m3
    Strachybotrys 71 sp/m3

    Outdoor sample:
    Aspergillus/Penicillium 165 sp/m3
    Cladpsoriurm 1035 sp/m3
    Smuts/Myoxomycete/Periconie/Rust 6235 sp/m3
    Strachybotrys 24 sp/m3


    Typically if you take care of wet materials in 24-48 hours you minimize the risk of mold growth. These results look good to me for the indoor space.

    Ian, please help… I am a young mother who developed sudden health problems (severe joint aches that migrate) that correlate with purchasing anolder home that was uninhabited for several years in the north east part of the country. The unfinished basement show signs of moisture and has a strong musk and we have been trying to clean it for the past 1.5 years. We got rid of anything that had the appearance of mold. My symptoms have never gotten better despite a clean bill of health with a doctor and specialist. My instinct tells me that it’s the house and I am making myself sick thinking that I’m leaving and I’m varmint that’s poisoning me or my children. I am young and prior to this was an athlete and healthy. I am at my wits end with feeling discomfort all the time. I recently had a mold expert who seemed very knowledgeable and he sent me our lab results tonight which did not come with the explanation. Please note that the children and the master bedroom is on the second floor. Aspergillosis/pen 2000 count/m3 in kids room and 27,800count/m3 in basement


    I can’t make too many conclusions with what you provided. I will say that the 27,800 in the basement seems elevated, but without an outdoor sample I do not have any context on how high it might be.

    Hi, Dylan!

    I just received these results on a potential new home with a note that the levels are not elevated. I would love to hear your thoughts as well, as I have long-term issues with asthma.

    Fungal Spore Type Spore Count Spore Count/m³ Spore Count Spore Count/m³ Spore Count Spore Count/m³
    Alternaria — — 1 13 — —
    Arthrinium — — — — — —
    Ascospores 8 107 — — — —
    — — — — — —
    Basidiospores 4 53 — — — —
    Bipolaris/Dreschlera — — — — — —
    Chaetomium — — — — — —
    Cladosporium 8 107 10 133 5 67
    Curvularia — — — — — —
    Epicoccum — — — — — —
    Fusarium — — — — — —
    Memnoniella — — — — — —
    Nigrospora — — — — — —
    Oidium/Peronospora — — — — — —
    Pithomyces — — — — — —
    Polythrincium — — — — — —
    Rhizopus/Mucor — — — — — —
    91 1210 18 240 27 360
    Spegazzinia — — — — — —
    Stachybotrys — — 1 13 — —
    Stemphylium — — — — — —
    Torula — — — — — —
    Ulocladium — — — — — —
    Unidentified Mitospores — — — — — —
    Total Fungal Spores 111 1480 30 400 32 427

    Everything seems normal in these results, however a slight yellow flag with the detection of 1 spore of Stachybotrys. It is likely this result is just an anomaly since it is very low, but Stachybotrys is a water damage indicator type.

    Hi and thanks in advance for any help you can provide!
    I had my daughter’s dorm room tested after she had some severe medical issues.
    The air tests didn’t seem too bad. The outside air had much higher levels than inside. For example, aspergillus/penicillium inside was 110 spores/m3 with a raw count of 8 and 100% read. Outside was 350 spores/m3 with a raw count of 26 and 100% read.
    Total spores inside were 270 spores/m3.
    The other part of the testing was swab and dust sampling.
    Swabs of the back interior wall in which the paint was bubbling and peeling off the concrete blocks show 1600 spores/unit with a raw count of 3 of chaetomium; and 98000 spores/unit with raw count of 94 of brown hyphae ID unknown.
    Finally, with dust sampling we found 2.724 ppb of ochratoxin A (present if greater than 2 ppb); and 2 spores/mL of rhizopus stolonifer.
    Is any of this something to be concerned about?

    The swab showing Chaetomium is a yellow flag, and if you were to open up the wall you may find mold growth inside the wall. The air samples seem okay, and the lack of Chaetomium in the air sample is a good sign. For the mycotoxin testing, there is not a lot of information on interpreting what is acceptable levels, so unfortunately I can not add anything for the dust sample.

    Thanks for doing this Dylan, we appreciate it more than you can know.
    Just closed on a house, seller lied on disclosure form about water damage. Just got this done, thoughts?

    Location: Outside

    Exposure: 15.00 l/min. for 5.00 min.
    Reporting Limit: 53 Spores/cu. m

    Sample Identification Raw Count Spores/cu. m Percent(%)
    – Fungi –
    Cladosporium 113 6,030 45.76%
    Basidiospores 95 5,070 38.47%
    Ganoderma 15 800 6.07%
    Epicoccum nigrum 9 480 3.64%
    Ascospores 7 373 2.83%
    Alternaria 4 213 1.62%
    Cercospora group 1 53 0.40%
    Pen/Asp group 1 53 0.40%
    Rust 1 53 0.40%
    Smuts/Periconia/Myxomycetes 1 53 0.40%
    Total Fungi 247 13,200 100.00%

    – Other –
    Hyphal Fragment 2 107 100.00%
    Background Item Level
    Dust / Debris Very Low
    Hyphal Fragments Very Low
    Opaque Particles Very Low

    Location: Basement

    Medium Type: AllergencoD

    Sample Identification Raw Count Spores/cu. m Percent(%)

    – Fungi –
    Pen/Asp group 74 3,950 45.16%
    Cladosporium 42 2,240 25.61%
    Basidiospores 37 1,970 22.52%
    Ganoderma 6 320 3.66%
    Ascospores 3 160 1.83%
    Epicoccum nigrum 1 53 0.61%
    Stachybotrys 1 53 0.61%
    Total Fungi 164 8,750 100.00%

    – Other –
    Hyphal Fragment 2 107 100.00%
    Background Item Level
    Dust / Debris Medium
    Hyphal Fragments Very Low
    Opaque Particles Very Low

    Location: Living Room

    Sample Identification Raw Count Spores/cu. m Percent(%)

    – Fungi –
    Cladosporium 77 4,110 46.43%
    Basidiospores 52 2,770 31.29%
    Ganoderma 10 533 6.02%
    Pen/Asp group 8 427 4.82%
    Ascospores 7 373 4.21%
    Epicoccum nigrum 5 267 3.02%
    Rust 3 160 1.81%
    Alternaria 1 53 0.60%
    Cercospora group 1 53 0.60%
    Curvularia 1 53 0.60%
    Nigrospora 1 53 0.60%
    Total Fungi 166 8,850 100.00%

    – Other –
    Hyphal Fragment 2 107 100.00%
    Background Item Level
    Dust / Debris Low
    Hyphal Fragments Very Low
    Opaque Particles Very Low

    With these samples, there is an elevated level of Pen/Asp in the indoor samples. The levels are higher in the basement, this is a type we see elevated in basements a lot. We can see elevated pen/asp with a range of moisture issues, so it could be from leaks, humidity, issues, flooding, ect.

    I had a mold inspector come to view a condo i was looking to purchase. He found no visible signs of mold nor with one of those wall metering things. An outdoor and indoor sample (air trap method) of the attic area where the hvac and water heater are located. Elevated levels of penicilium/aspergilus (273/m3 outside to 3820 inside) and stachbotrys (0 to 624) came back.

    The inspector had just come from a remediation project. Is it possible the levels were so high because he was just in a contaminated area and might have had mold on him from that project thereby affecting the test he was performing?

    You are correct that it is possible for a contractor to affect a sample if they have been in moldy areas, but the levels on the samples you sent are much higher than what I would expect to see if the mold was on the clothes/equipment. However, it is not standard practice to collect an air sample in an attic, in many climates attics are naturally ventilated, so this can result in high levels of settled spores in attic dust that can get reintroduced to the air and create false positive readings. Since the inspector did not find visible mold in the area I would put more weight on that than the air samples in the attic.

    Good morning:

    Thank you for this great site. I just bought a house and did a mold/moisture test. We just installed new roof. Prior roof was leaking, and there are water stains on ceilings in some areas, though moisture detector did not detect active moisture in those portions. The only areas with active moisture are efficiency and family room near door/baseboard. Can you please provide me your opinion on the following mold test results:

    Volume Sampled of each: 75L

    Raw Count- 9
    Count/m3- 120
    %- 60
    Raw Count- 4
    Count/m3- 53
    %- 27
    Raw Count- 1
    Count/m3- 13
    %- 7
    Raw Count- 1
    Count/m3- 13
    %- 7
    Total Spores:
    Raw Count- 15
    Count/m3- 200
    Hyphal Fragments- N/A

    Living/Family Rooms:
    Raw Count- 8
    Count/m3- 107
    %- 80
    Raw Count- 1
    Count/m3- 13
    %- 10
    Raw Count- 1
    Count/m3- 13
    %- 10
    Total Spores:
    Raw Count- 10
    Count/m3- 133
    Hyphal Fragments:
    Raw Count- 1
    Count/m3- 13

    Master Bedroom:
    Raw Count- 5
    Count/m3- 67
    %- 4
    Raw Count- 11
    Count/m3- 147
    %- 8
    Raw Count- 57
    Count/m3- 760
    %- 42
    Raw Count- 9
    Count/m3- 120
    %- 7
    Raw Count- 21
    Count/m3- 280
    %- 16
    Raw Count- 14
    Count/m3- 187
    %- 10
    Raw Count- 7
    Count/m3- 93
    %- 5
    Raw Count- 2
    Count/m3- 27
    %- 1
    Raw Count- 9
    Count/m3- 120
    %- 7
    Total Spores:
    Raw Count- 135
    Count/m3- 1800
    Hyphal Fragments:
    Raw Count- 2
    Count/m3- 27

    Raw Count- 7
    Count/m3- 93
    %- 100
    Total Spores:
    Raw Count- 7
    Count/m3- 93
    Hyphal Fragments:
    Raw Count- 1
    Count/m3- 13

    Thank you!


    I see an elevated level of Asp/Pen and Cladosporium in the bedroom samples. These levels are slightly elevated, as we can see levels higher than this in the outdoor air from time to time. The Stachybotrys levels in the efficiency sample is concerning to me, this to me shows that there is likely some sort of indoor growth in this area.

    Dylan, we just moved into a rental house with some previous water damage (obvious staining on walls). We decided to have the air tested and found chaetomium in most rooms (low levels, all under 150), and even Stachybotrys (2 rooms with under 10 and master bathroom with 80 count). Penicillium and aspergillus are all under 200. There are some water stains on the walls. The landlord has agreed to fix the roof but not going to do anything about damaged drywall other than repainting it. Some areas are soft and they’ll cut them out. Those areas that are hard and not warped will be just painted over with oil based primer. Will that be enough? With low counts in air samples , do we need to insist on mold remediation or should we just take a “wait and see if it comes back after the roof repair” approach?

    Any level of Chaetomium and Stachybotrys in air samples is an indication of indoor mold growth. It is likely that there is some level of mold growth inside those wall cavities that have evidence of moisture issues. Repairing the roof might address the moisture and stop future issues from coming up, however, it will not remove what is already present. All affected materials should be removed by a qualified mold remediation professional in my opinion.

    Sorry, I was concentrating so hard to make the numbers look presentable that I forgot to put the backstory haha.
    In March the former owner of the house had a hot water heater break & flood two small rooms. I had numerous companies come out giving different opinions on what needs to come up, like drywall and flooring vs just carpet (not the laminates or cedar closet walls) and just wipe it w/ anti mold solution, run dehumidifier and get Heppa filter.
    But there is no visible mold, and half the people had positive moisture readings and the other half didn’t. Only one person used an IR cam and didn’t see any moisture either.

    Thanks again,

    I ripped up some carpet. Nevermind. It’s soaked underneath. :(
    Thanks though :)
    This is a wonderful service you’re providing.

    Hi Dylan,

    We recently had some flooding in our neighborhood from hurricane Irma. We we’re lucky and there was only a little bit of flooding in our place. However in weeks to follow the moisture in the house was noticable. We had an inspection and the following lab report was provided; recommending remediation. I am pregnant and I’m wondering how safe these levels are for a newborn upstairs and how long remediation should/would take. Also any opinion on how effective the Dyson airblade purifiers are? Thanks!
    Raw ct – spores/m3 – %
    Alternaria: -null-/2ct-80m-2%/null
    Ascospores: 30ct-750m-9%/7ct-280m3-7%/3ct-120m3-8%
    Basidiospores: 54ct-1350m3-17%/4ct-1603-4%/1ct-40m3-3%
    Cladosporium: 162ct-4050m3-50%/13ct-523-12%/4ct-160m3-11%
    Curvularia: 15ct-375m3-5%/12ct-480m3-11%/1ct-40m3/3%
    Penicillium/Aspergillus: 47ct-1180m3-15%/69ct-2760m3-64%/27ct-1080m3-75%
    This last one is a little concerning.
    I really appreciate your time.

    You are correct in that the Pen/Asp levels in the home are slightly high. We can see Asp/Pen levels that high outdoors on occasion, and in homes with major issues we can see these levels 10,000+. The levels are not very high, so remediation shouldn’t be a very big ordeal, however, I have not seen the property so I do not know what exactly needs to be addressed. I am not a licensed health professional so I can not comment on “safe” levels for health. I don’t have any experience with the Dyson product, all I can say is that it advertises to filter particles at HEPA levels, which for a consumer purifier as good as you can expect.

    Our home flooded during Hurricane Harvey. Water levels reached 2-3 feet in the house and stayed in the water for about 48 hours. Demo was done within 4 days, drywall was cut to 6 feet high. We had a professional company come in and do the dry-out with industrial blowers & dehumidifiers until the moisture readings were below 17 throughout the house. They treated all exposed wooden beams twice with moldicide.
    We are just about to begin the re-build process and got a mold test last week, just to make sure everything was ok. We were shocked when we received the results this morning and it said we had “Elevated Mold Conditions” and “Mold Remediation Recommended.”
    I will do my best to present the numbers as they are in the report. Please tell me if I should be tremendously concerned, or if this might be fairly simple to remediate.

    Thank you!

    Master Bedroom
    Basidiospores 2 – 80 – 29%
    Cladosporium 1 – 40 – 14%
    Pen/Asp 2 – 80 – 29%
    Stachybotrys 2 – 80 – 29%
    Background Debris 3
    Sample Volume (liters) 25
    TOTAL SPORES/M3 7 280

    Living Room
    Basidiospores 7 – 280 – 35%
    Cladosporium 7 – 280 – 35%
    Curvularia 1 – 40 – 5
    Pen/Asp 4 – 160 – 20%
    Stachybotrys 1 – 40 – 5%
    Background Debris 3
    Sample Volume (liters) 25
    TOTAL SPORES/M3 20 800

    Family Room
    Basidiospores 2 – 80 – 20%
    Cladosporium 4 – 160 – 40%
    Pen/Asp 3 – 120 – 30%
    Stachybotrys 1 – 40 – 10%
    Background Debris 3
    Sample Volume (liters) 25
    TOTAL SPORES/M3 10 400

    Basidiospores 3 – 120 – 43%
    Cladosporium 1 – 40 – 14%
    Pen/Asp 2 – 80 – 29%
    Stachybotrys 1 – 40 – 14%
    Background Debris 3
    Sample Volume (liters) 25
    TOTAL SPORES/M3 7 280

    Basidiospores 1 – 40 – <1%
    Cladosporium 1 – 40 – <1%
    Pen/Asp 297 – 11900 – 98%
    Stachybotrys 2 – 80 – <1%
    Tetraploa 1 – 40 – <1
    Background Debris 3
    Sample Volume (liters) 25
    TOTAL SPORES/M3 302 12100

    Outside Control
    Ascospores 6 – 240 – 9%
    Basidiospores 35 – 1400 – 50%
    Cladosporium 15 – 600 – 21%
    Curvularia 1 – 40 – 1%
    Nigrosporia 1 – 40 – 1
    Pen/Asp 6 – 240 – 9%
    Spegazzinia 6 – 240 – 9%
    Stachybotrys 1 – 40 – 10%
    Background Debris 3
    Sample Volume (liters) 25
    TOTAL SPORES/M3 70 2800

    The only things that stick out to me in these numbers are the Pen/Asp in the garage sample, however, air sampling in a garage is not standard industry practice since there is so much outdoor air exchange (unless this is a garage which has been built out as a living space). There is Stachybotrys present in all the samples, including outdoors, so this might be another reason for their suggestion. Since the indoor levels are so close to the outdoor level I would interpret those results as being acceptable.

    Thank you for your reply. By “acceptable” do you mean that you would feel comfortable living in a home with these numbers? Would remediation be suggested? I had a remediation expert out today and he said he saw no evidence of visible mold and wouldn’t even know where to begin remediation. There is nothing obvious to treat. He suggested maybe air scrubbers. What do you think?

    Running air scrubbers will filter out the particles in the air, and would hopefully remove any of the residual Stachybotrys spores. I can’t make any specific remediation suggestions since I have not assessed the property for visible mold and moisture. That remediation contractor seems trustworthy in that he did not try to sell you on any unnecessary treatments. Even without any Stachybotrys spores outside the indoor levels are still low.

    I just looked at my results again… I made a mistake by reporting Stachybotrys outside. There was NO Stachybotrys outside, but everything else is correct. Does that change your assessment?

    Hi Dylan: We had sampling done and it turned out that we have 1200 aspergillian/pen in our living room and 800 in our bedroom when AC is on. Outside reading was 80 We were away for 15 days when it was very hot in CA. Could this have caused it? Had all ducts cleaned as they were really dusty. Can we get rid of this by turning air on and airing out home or do we have to have a big remediation done? What is an acceptable level? Thank you so much. Your site is the best in trying to comprehend all of this!


    There is not a concrete number for acceptable levels of mold in the air, we have to use the exterior levels as a baseline. The heat will not cause mold growth, there has to be some moisture for the mold to grow. This moisture could be humidity that might have been an issue when you were away. 1200 and 800 are not extremely elevated so I would not expect to need a large remediation, I would suggest doing a detailed cleaning of the home and possibly run a HEPA air purifier for some time to lower the levels in the air.

    Air Sample Analysis through EMLab P & K MoldSCORE in Naperville showed a moderate likelihood of indoor Penicillium/Aspergillus fungal growth, with a Mold Score of 155 (Below 150 they consider low likelihood). How can we clean this up? Is it possible to zero in on a concentration of it, or do we just have to clean the whole house again from ceiling to floor? Any suggestions are appreciated. Let me know if you need more info on our situation. Thanks!

    I am not familiar with their “moldscore” and how they assign those values. I can say that 350 spores/m3 of Cladosporium is not a high level. Outdoors we can routinely see levels over 1000. If you don’t have a history of moisture issues in the home and do not see visible discoloration I would suspect that these results are coming from the outdoor air, and it was just an anomaly that the outdoor levels were very low at the time of your testing.

    Sorry for the confusion… We had 350 spores/m3 (13 raw ct) of Penicillium/Aspergillus inside, and <7 spores/m3 (0 raw ct) outside. This came out to a MoldSCORE that was considered "moderate likelihood of indoor fungal growth". Cladosporium wasn't an issue in our house. It was found more outside than inside, as you said is usual. So, is 350 spores/m3 of Penicillium/Aspergillus in the normal range in your opinion? If not, any suggestions on what formula we can clean the house with? Thanks for the help!

    Yes, I would consider that to be a background amount unless you have had moisture issues in the home or see visible mold growth.

    We’re under contract on a house, built in 2006. There hasn’t been flooding but there were some drainage issues into the window well one very wet year that they fixed. I am very mold sensitive and recently went through a protocol to heal Chronic Inflammatory Response Syndrome from likely mold exposure in a house in Atlanta. Not wanting to go through it again, we had a mold test (air samples) done with the inspection, and here are the results. I’m not sure how to proceed, since there is the presence of Chaetomium in the basement. I don’t know if that should be a deal-breaker? Does it require remediation? Thanks for your help!
    spores/m3, raw ct, outside spores/m3, outside raw ct
    Penicillium/Aspergillus types: 270, 5, <13, 0
    Cladosporium: 320, 6, 590, 11
    Basidiospores: 160, 3, 320, 6
    "Marker" spore types (Chaetomium): 40, 3, <13, 0
    "Other spore types (Smuts, Periconia, Myxomycetes): 210, 4, 53, 1

    They lab provided a "MoldSCORE" for each of these, and listed the "Marker" type as MODERATE. The report said the following: "The MoldSCORE™ was in the MODERATE range for the following area(s): 2514 6000 (basement). A moderate MoldSCORE™ means that the results are inconclusive, and suggests that a more detailed inspection by a trained professional may make sense if there are any other reasons to believe that mold growth could be a problem in this room." Any advice would be appreciated! Thanks!

    The Chaetomium in the basement is a sign that there has been moisture issues in the basement. I would make sure that the basement is assessed very thoroughly to make sure that there are no ongoing moisture issues. I would proceed very carefully knowing there has been at least 1 moisture event in the past, and we are seeing Chaetomium in the air samples.

    I’m a teacher at an elementary school. Aside from my own illnesses that I’m concerned is coming from the building, 1400 kids are in this building as much as I am. The last IAQ test was done in 2014 & I’m having some trouble deciphering what it means. The test consisted of non-culturable spore trap air samples collected from a classroom and a hallway. These are a few of the results I have questions about from the classroom test.
    Pen./Asperg. Raw Cnt-14 Mult.-4 Spores/m3-373 57%
    Basidiospores Raw Cnt.-6 Mult.-4 Spores/m3 -160 24%
    Cladosporium Raw Cnt.-2 Mult.-4 Spores/m3 -53 8%
    Pithomyces Raw Cnt.-3 Mult.-1 Spores/m3 -20 3%
    Ascospores Raw Cnt.-1 Mult.-4 Spores/m3 -27 4%

    Are any of these numbers something to be concerned about?

    It is very difficult to give any meaningful analysis without knowing the outdoor levels at the time of the testing, but generally speaking these all look to be normal.

    Hi Dylan, thank you for your time. We renovated the basement into a separate living space this year. 2 months ago, an outside house was left on and it flooded the newly renovated area. A dehumidifier has been working since and the cork flooring was just pulled up 1 week prior to the air quality test. Here are the spore trap results from 10/30:
    Renovated area:
    Cladosporium: 10 raw count, 530 spores/m3
    Pen/Asp: 291, 16000
    Stach: 0
    In basement but right outside of renovated area, unfinished:
    Cladosporium: 10, 530
    Pen/Asp: 43, 2300
    Stach: 0
    Clad:6, 320
    Pen/Asp: 51, 920
    Stach: 0
    Clad: 7, 370
    Pen/Asp: 6, 320

    Your thoughts?

    The Pen/Asp levels are highly elevated in the basement. I would suggest cutting into some of the walls near the source of the leak for discoloration, i suspect there is some hidden mold growth in the space.

    Also some mold is visible along the baseboards of the renovated basement area where the cork flooring was removed. The moisture meter reported dry. Also there is some mold stains on the basement wall in the unfished area, probably from a leak from heavy rain 2 years ago. No visible mold or growth on other things.

    The visible mold growth should be cut out an removed. Any mold in the space should be removed. Running an air scrubber during and after the removal will clear the elevated levels in the air

    Hi Dylan: We have been on your site for weeks now, have had companies come in with quotes for remediation, but even you said levels were not high. We have just a few questions, but would like to call you or Ian. I thought I saw where there was a charge, but we don’t mind. Would that be possible? Thanks so much!

    Hi Dylan! I recently got back air test results and the following 3 types were show to be at elevated levels:

     213 count/cubic meter of air, compared to 40 Outside
    o Acceptable level is 200 count/cubic meter of air
     Curvularia
     760 count/cubic meter of air, compared to 40 Outside
    o Acceptable level is 200 count/cubic meter of air
     Pithomyces
     747 count/cubic meter of air, compared to 67 Outside
    o Acceptable level is 200 count/cubic meter of air

    Everything I’ve read online seems to indicate that Curvularia and Pithomyces are plant/grass/leaf related molds and we have no indoor plants? I’m confused as to how the levels could be so elevated in our hallway? Do you know what would likely cause these specific types to be so high? Or what you would recommend as a next step for these specific types?

    Thank you!


    These molds are all usually considered to be outdoor mold types. It is really unlikely to find these types growing indoors. If you don’t have any moisture issues or visible mold growth I would suspect these are coming from outdoors. I am not sure were the “acceptable level” numbers for these molds are coming from, background mold levels are very dynamic so it is almost impossible to assess “acceptable levels” like that, and I would not put much weight into that. Typically an outdoor sample is collected to be used as a control for the naturally occurring mold at the time of the testing.

    Hi there was wondering if its safe to stay in the home we are in right now. my step son has recently developed asthma since we started living in the home a year and half again. so i decided to get the air quality testing done since there is a leaking pipe in the home.

    Living Room
    Ascospores 10 (133m3) 4%
    Aspergillus/Penicillium 60( 800m3) 23%
    Basidiospores 163 (2173m3) 63%
    Cladosporium species 26 (347m3) 10%
    Total 259 (3453m3)

    Master Bathroom
    Ascospores 4 (53m3) 7%
    Aspergillus/Penicillium 10 (133m3) 17%
    Basidiospores 28 (373m3) 47%
    Cladosporium species 17 (227m3) 28%
    Nigrospora species 1 (13m3) 2%
    Total 60 (800m3)

    Ascospores 5 (67m3) 8%
    Basidiospores 17 (227m3) 28%
    Cladosporium species 38 (507m3) 63%
    Total 60 (800m3)

    Due to how much individual sensitivities affect how people react to mold, I can not say if it is “safe” or “healthy” inside a home. I am also not a medical professional so it is best to leave that determination to a qualified person. I can say that the levels inside the home do look mainly normal. there is a slight elevation of Asp/Pen in the living room, however, you can experience levels higher than that outdoors at some points in the year. If there was a large mold issue in the home affecting the air quality I would expect much higher levels in the home. With that being said it is very important to address any moisture issues in a home as quickly as possible to help mitigate the risk of mold growth happening.

    Hi Dylan,

    Great sight and appreciate you sharing the knowledge with common folks.

    How would you assess the following:

    Outside Air
    Type: Raw / per m3
    Ascospores: 20 / 1100
    Basidiospores: 84 / 4500
    Cladosporium: 20 / 1100
    Pen/Asp: 16 / 850

    Office Area
    Alternaria: 3 / 40
    Ascospores: 8 / 430
    Basidiospores: 21 / 1100
    Cladosporium: 13 / 690
    Pen/Asp: 10 / 530


    These results are a textbook example of a normal indoor environment. I don’t see any issues with mold in these results.

    Good Evening,

    I hope all is well, we recently had a mold test and we are extremely worried. We were told that we had elevated levels of Chaetomium in our Master Bedroom . I will do my best to present our results, would you be able to give me your opinion on the level of concern we should have and if Remediation is needed.

    Volume Sampled of each: 75L

    Master bedroom
    RawCt- Spores/M3 – %

    Basidiospores- 24- 312 -47%
    Ascospores- 3 -39 -6%
    Chaetomium- 1 -13- 2%
    Cladosporium- 9-117 -18%
    Penicillium/Aspergillus- 12- 156- 24%
    Smuts/Periconia/Myxomy- 1 -13- 2%
    Zygomycetes- 1- 13- 2%
    Background Debris -3
    Total Spores/M3 – 51 -663

    Control (Outside)

    Ascospores 21- 273- 6%
    Basidiospores 156- 2030 -42%
    Cladosporium 171- 2220- 46%
    Epicoccum 1 -13- <1%
    Penicillium/Aspergillus 18- 234- 5%
    Smuts/Periconia/Myxomy 6- 78- 2%
    Zygomycetes 1 -13- <1%
    Background Debris -3
    Total Spores/M3- 374- 4860

    A result with a single spore of Chaetomium is a difficult thing to interpret. It is possible that the spore is just an anomaly, we can see a spore in the outdoor air every once in a while, or it is also possible that the inspector may have been at a property with a mold issue before coming to your home and brought the spore in on his clothing or equipment. It is also possible that the spore is coming from internal growth.

    I would say if your property has a history of moisture issues, then I would have the air samples collected again. If the Chaetomium shows back up, or another water damage indicator mold is found I would say that is evidence that there may be some underlying mold issues. If your home has not had any issues with moisture, since the rest of the results look good, I would lean more on the side if the result not being statistically significant.

    Hi Dylan, I have read that Stachybotrys is not often found in air spore traps because the spores are heavy and earthbound. Given this should I be particularly concerned about the findings in my basement.

    Asp/Pen 41 – 1600 – 78.4%
    Basadio 5 – 200 – 9.8%
    Clado 3 – 100 – 4.9%
    Epicoccum 1 – 40 – 2%
    Stachybotrys 3 – 100 – 4.9%
    Totals – 53 – 2040 – 100%

    Asp/Pen 17 – 670 – 69.1%
    Basadio 5 – 200 – 20.6%
    Clado 3 – 100 – 10.3%
    Epicoccum ND
    Stachybotrys ND
    Totals – 25 – 970 – 100%

    Asp/Pen 9 – 400 – 10.1%
    Basadio 38 – 1500 – 37.7%
    Clado 50 – 2000 – 50.3%
    Epicoccum ND
    Stachybotrys ND
    Totals – 99 – 3980 – 100%

    You are correct, Stachybotrys spores are heavy and covered with a sticky coating. In nature, the spores have adapted to stick to insects and other things that might come across growth in the outdoors. We don’t often see Stachybotrys spores in outdoor samples for that exact reason. Your results do show that Stachybotrys is present in the basement, but it also shows an elevated level of Asp/Pen. I would suspect that there is some history of moisture in the space and likely hidden mold growth somewhere.

    Hi Dylan! I had a bathtub overflow and immediately (with 20 minutes) mopped up the water that had gotten on the floor by the tub. Unfortunately it seems that had seeped under the baseboard into the bedroom immediately on the other side of the wall. The bedroom carpet was wet for about 1-2 days. I put towels on the floor and immediately turned on an air purifier + a fan. I also put baking soda on the floor to speed the drying and ensure no odors. I had a mold test done and these were the results of the air samples. I live in the downtown Seattle area.

    Alternaria (raw, spores/m3)
    Bedroom: 0
    Bathroom: 1, 10
    Outside: 0

    Ascospores (raw, spores/m3)
    Bedroom: 226, 2260
    Bathroom: 294, 2940
    Outside: 405, 4050

    Basidiospores (raw, spores/m3)
    Bedroom: 4, 40
    Bathroom: 8, 80
    Outside: 53, 530

    Cladosporium (raw, spores/m3)
    Bedroom: 23, 230
    Bathroom: 12, 120
    Outside: 12, 120

    Myxomycetes (raw, spores/m3)
    Bedroom: 1, 10
    Bathroom: 0
    Outside: 1,10

    Penicillium/Aspergillus (raw, spores/m3)
    Bedroom: 26, 260
    Bathroom: 55, 550
    Outside: 13, 130

    Total Spores (raw, spores/m3)
    Bedroom: 285, 2900
    Bathroom: 371, 3700
    Outside: 485, 4900

    Thank you so much for your help!! I mainly want to know if I should be concerned–if yes, should I invest in professional remediation or could I instead handle this on my own (and if so, how)?


    I don’t see anything particularly concerning with these results. The Asp/Pen levels are slightly higher than the outdoors, but typically in homes with Asp/Pen growth I see much higher levels than that (levels like 5,000 spores/m3). Unless you see visible mold growth, I would say there is no need for remediation based off these results.

    Here are the pre remediation numbers:

    Exposure: 15.00 l/min. for 5.00 min.
    Reporting Limit: 53 Spores/cu. m
    Sample Identification Raw Count Spores/cu. m Percent(%)
    Pen/Asp group 1 53 0.40%

    Pen/Asp 74 3,950 45.16%
    Basidiospores 37 1,970 22.52%

    Living Room
    Basidiospores 52 2,770 31.29%
    Pen/Asp group 8 427 4.82%

    Post remediation numbers:

    basidiospores 6 320 85.8%
    cladosporium 1 53 14.2%

    living room
    pen/asp 4 213 57%
    basidiospores 2 107 28.7%

    pen/asp 9 480 69.2%
    basidiospores 4 213 30.7%

    good enough?

    Hi Dylan,

    Happy Thanksgiving, and thanks for operating this site. I found some mold in my attic after a humid fall (Richmond, VA) and called to have an inspection. Since they were here, I asked for an air test. There was minimal surface growth in the attic, but they also tested two bedrooms and found concentrations of mold well above what I would expect, given that we’ve never had a moisture problem (7 years in the house) and have no visible signs of mold apart from the attic.
    The troubling counts:
    Basidiospores: 400/m3, 600/m3 (1000/m3 outside)
    Cladosporium: 200/m3, 1600/m3 (!) (1000/m3 outside)
    Penn/Asp: 1000/m3, 800/m3 (400/m3 out)

    The Cladosporium number scares the heck out of me–these are in our children’s bedrooms! More importantly, I’m just befuddled, as there’s no sign of mold in these rooms. We’re going to call a few mold remediation companies, but any guidance is appreciated. Thanks again.


    I suspect that you might have some humidity issues inside the home. The slightly elevated levels of Cladosporium and Asp/Pen on these results are similar to what can be seen in homes with chronically high humidity. These levels are not a major red flag, we can commonly see levels higher than this in the outdoor air in the spring and summer. High humidity could also explain the mold growth in the attic in the absence of leaks.

    Thanks so much, Dylan. I don’t feel like it’s humid in the house right now (with the heat on), but it was definitely humid enough all summer and fall here in Richmond. Other than to check the humidity (and maybe a dehumidifier), is there anything we can do to get rid of what’s already there? Thanks again!


    I would also try to figure out what is causing the mold in the attic. It is possible that some of the mold in the attic is affecting the air quality in the living spaces. Some common issues in attics are bathroom exhaust venting into the attic and lack of attic ventilation.

    These are my EMRI results for various rooms in the house. As far as I can tell they are considered “safe”. Although Aspergillus penicillioides has a 70 spore count. Also I read if you have even 1 spore of the toxic mold that could indicate a problem so I wanted to double check. Thanks
    Fungal ID \ Sample ID MAC-522/EC-Home: LR, Lndry, BRs, Kit
    Aspergillus flavus/oryzae 1
    Aspergillus fumigatus 2
    Aspergillus niger 25
    Aspergillus ochraceus 3
    Aspergillus penicillioides 70
    Aspergillus restrictus* 7
    Aspergillus sclerotiorum <1
    Aspergillus sydowii ND
    Aspergillus unguis 3
    Aspergillus versicolor ND
    Aureobasidium pullulans 51
    Chaetomium globosum 1
    Cladosporium sphaerospermum 18
    Eurotium (Asp.) amstelodami* 95
    Paecilomyces variotii 2
    Penicillium brevicompactum <1
    Penicillium corylophilum 14
    Penicillium crustosum* 1
    Penicillium purpurogenum <1
    Penicillium spinulosum* ND
    Penicillium variabile 6
    Scopulariopsis brevicaulis/fusca <1
    Scopulariopsis chartarum <1
    Stachybotrys chartarum 2
    Trichoderma viride* <1
    Wallemia sebi 13
    Sum of the Logs (Group I): 13.95
    Acremonium strictum <1
    Alternaria alternata 1
    Aspergillus ustus 33
    Cladosporium cladosporioides 1 390
    Cladosporium cladosporioides 2 15
    Cladosporium herbarum 4
    Epicoccum nigrum 71
    Mucor amphibiorum* 13
    Penicillium chrysogenum 6
    Rhizopus stolonifer 29
    Sum of the Logs (Group II): 11.09
    ERMI (Group I – Group II): 2.86


    The responses in this blog post are all related to air samples using a spore trap cassette, which is not the same as an ERMI test. You can not use the same interpretation for air samples for ERMI testing. Because of how vastly different ERMI testing is compared to air sampling, and the lack of interpretation guidelines for ERMI testing, there is not a lot a consultant can determine with just looking at ERMI testing.

    Hi, I am prospective buyer of a house and we recently performed a home inspection and noticed some water damage in the basement. So they performed a mold test below are the results. The water leak was in the attic furnace and traveled down the walls to the basement. My question what does these results mean? And can this be fixed to the point where the mold would be completely removed and not come back. I am just concerned because I have 2 small children

    A)Penicillium/Aspergillus types** mold score of 300; 34,000 spores/m3; raw ct 629; outside <13 raw ct 0

    B) Cladosporium species spores mold score of 100; <13 spores; raw ct 0; outside 320 raw 6

    C) Basidiospores mold score of 100; <13 spores ; raw ct 0; outside <13 raw ct 0

    D) "Marker" spore types*** mold score of 100; <13 spores ;raw ct 0; outside <13 raw ct 0

    E) "Other" spore types***,****mold score of 100; <13 spores; raw ct 0; outside 106 raw ct 2


    I see a clear elevation of Asp/Pen in the sample. The most important part of remediation is making sure the moisture issues are corrected. In a situation like this, where the moisture is coming from floors above, it is possible there would be other areas of mold growth hidden in the walls since the route that the water flows from the attic to the basement could cause unsuspecting materials to get wet.

    Hi, Dylan. We have had extensive latent water damage pursuant to roof damage from Huricane Irma. We have had the roof tarped (repair scheduled for early 2018) and remediation of the water damage. We were given the following results after completion of “tape” testing of areas of the refrigerator wall and base plate and kitchen sink wall (both spots that are now dry, but where there remains discoloration):

    Aspergillus/Penicillum-Like 2,064/cm2
    Chaetomium 31/cm2

    Chatomium 59,980/cm2
    Hyphal Fragments 90,860/cm2

    We are being told that we need to move put of our home for four weeks for “sterilization” and mold removal. Your thoughts?

    No one can determine if you should move or remain in your home based on surface samples. It is impossible to estimate exposure using these tape lift samples. All that can be gathered from these tests are that the discolored area from which the tests were collected from are in fact mold growth. The best way to see what you may be exposed to is to collect air samples from inside the home.

    Hi Dylan,
    My air test report from Hayes Microbial Consulting says Indoor: Cladosporium Raw Count=5, Count/M3=67, % of Total>99%. Reporting Limit: 13 spores/M3.
    Outdoor: Cladosporium Raw Count=3, Count/M3=40, % of Total=11.6%. There are some other types outdoor.
    Is the indoor level dangerous? What’s this numbering system compares to other reports that use 000’s?

    Thank you very much.

    Cladosporium is one of, if not the most common type of mold in the world. This is only a low amount, and the difference between the two is negligible. Unless you have moisture issues in the home or visible mold growth I do not expect that there is a mold issue in the home. It is likely that the internal Cladosporium levels are from the outdoors.

    The “count/m3” or “spores/m3” is the industry standard on reporting mold concentrations in the air, I am not aware of what the other numbering system you are referring to.

    My husband & I have contracts on a home. Along with our inspection we bought the radon & mold tests. Below are the results from the mold tests. I have no idea if these numbers are good, bad, or indifferent. Any help would be great.

    Spore trap anlys, Spore trap anlys, Spore trap anlys
    COC / LINE # 1098879-1 1098879-2 1098879-3
    SAMPLE TYPE & VOLUME Z5 – 25L Z5 – 25L Z5 – 25L
    COLLECTION DATE Dec 21, 2017
    ANALYSIS DATE Dec 27, 2017
    Raw / pores per M3 / % of total
    Other Basidiospores 4-160-50 / 4-160-13 / 2-80-7
    Penicill/Aspergillus 4-160-50 / 26-1,000-81 / 25-1,000-93
    Pithomyces. — / 1-40-3 / —
    Smuts, myxomycetes — / 1-40-3 / —
    TOTAL SPORES 8-320-100 / 32-1,240-100 / 27-1,080-100
    MINIMUM DETECTION LIMIT* 1-40 / 1-40 / 1-40
    BACKGROUND DEBRIS Light / Light / Light
    Cellulose Fiber 1-40 / 1-40 / —


    I see an elevation of Aspergillus/Penicillium in both the indoor samples. The levels are only moderate, not extremely elevated. However, I would say it is cause for further investigation to figure out what is causing this elevation indoors.

    Hi and thank you so much for your help

    My mom had water damage in her bedroom and linen closet that was remediated. The walls were pulled out to the studs and sealed, air fans were run in the rooms.

    I have Lymphoma and am immunocompromised so I want to be everything has been appropriately remediated. I want to be able to visit with my mom. :-)

    The report was given to me with no context as to whether the results were normal or if further remediation needed to be done.

    Please advise as to what you think. You can find the report here:

    I thank you in advance for your help.


    This report is telling me there is still some work to be done. The Aspergillus/Penicillium levels in the indoors, specifically the closet sample, are elevated. I can’t say if there are still moldy materials in place, or if there just needs to be a detailed cleaning and air scrubbing to remove residual spores from the air. That determination can only be made by a qualified professional who physically assesses the problem.

    I would make sure that everything is addressed, as Aspergillus is a type which can cause infection in immunocompromised people. You can find info on Aspergillosis here:

    We are in contract for a home but we requested a mold inspection and air samples because we have two small children, one of which already has asthma. The finished basement showed some positive results- we intended to use this room as a playroom for our kids and now def not so sure. The inspector noted a small area in the basement laundry closet which had visible mold. The sellers also did admit to home having basement water during two different hurricanes, and a bathroom leak on second floor all of which had mold remediation at the time. I’m concerned this house has a chronic water problem. What do these results tell us?
    Aspergillis/Penicillum 760 count/m
    Basidiospores 300 count/m
    Chaetomium 100 count/m
    Cladosporium 200 count/m

    Living Room:
    Aspergillis/Penicillum 200 count/m
    Basidiospores 40 count/m
    Chaetomium 30 count/m

    Basidiospores 200 count/m

    THere is a slight elevation with the Asp/Pen levels in the home. The presence of Chaetomium to me points to either water events that were left unaddressed for a period of time (i.e. a flood that was not dried quickly) or chronic moisture issues (i.e. a crack in the foundation which allows water in when it rains). Either way, there has been mold growth in the home that either was not remediated or was not remediated completely.

    I just had a mold test done for a potential buyer who has allergies and sensitivity to mold.
    Spore Trap Analysis
    Exterior Control: Pithomyces Raw Count – 4
    Spores per m3 – 27 Percent of total – 50
    Rusts Raw Count – 4 Spores per m3 – 27 Percent of total – 50

    MBedroom: Chaetomium Raw Count – 16 Spores per m3 – 110 Percent of total – 100

    Can you explain this to me. There is mold in the MBedroom but not any that’s outside and only one mold? I’m not sure I understand the numbers either for the mold in the MBedroom.

    Thank you.

    Chaetomium is a mold that is not often found outdoors. When we find it in indoor air samples it is a marker for chronic moisture problems inside a home. To me this is saying there is or has been in the past some sort of water issue inside the master bedroom.

    I just got licensed to do Mold Inspections in south Texas and my first lab results look insanely high. First off this was from Hurricane Harvey and the house has been basically locked up with exception of home owner coming and going occasionally to do the demo. HVAC was ran for about a week or so after house flooded, then was shut off. Aspergillus/Penicillium outside was 56 raw, 2500 count/m3, indoor downstairs was 10,500 raw, 464,000 count/m3; second floor 7280 raw, 322,000 count/m3. Very little surface mold. Home owner did the demo himself with friends and gutted the whole 2 story house to the studs and sheating from 1st floor to roof rafters (they have spray foam insulation). The mold remediator, I will be working with has never seen anything this high before. Brand new bio pump, i visually calibrated with supplied rotometer. Do those numbers seem plausible, given the circumstances?

    These results are on the high end for Asp/Pen. I have seen Asp/Pen levels this high before, and the highest I have seen was over 1 million spores/m3. With an event like a hurricane and flooding, combined with homes being closed up for some time it can allow for really high mold levels inside the home, even if the visible growth seems minimal. If the home currently is bare down to the studs I would suggest using a HEPA vacuum on all the surfaces in the house, making sure there is no residual dust or debris from the demo still settled inside the house. Air scrubbers should also run, I would suggest having box fans running at the same time to keep spores airborne so the air scrubber can do its job.

    Hello. We are selling our house, and the inspection came back with “elevated” penicillum/aspergillus in 2 adjoining rooms. (The inspector took air samples.) One reads 1,440 and the other 1,880. We had a roof leak, and the entire valley and flashing were replaced above the two rooms 3 months ago. First, are these levels dangerous, and second, could moisture from the previous roof leak contribute to the readings? No visible mold and no smell of any kind in the home. Thanks, Bill


    I can’t comment on if these levels are safe or not, as I am not a medical professional and there are no published guidelines for safe levels of mold indoors. I don’t have many conclusions to draw from those results, as there is no data for the outdoor air at the time of the testing. The outdoor levels are used as a baseline in figuring out the “normal” amount of mold indoors. In very general terms these levels seem to be slightly higher than we would expect to see normally indoors. Any moisture event can lead to mold growth, it only takes ~ 24-48 for mold to start growing after a moisture event. Even after the moisture has been dried out and the issue fixed, the mold that did grow can persist in the space.

    Hi! I received the following mold report for an upstairs home office/former bedroom in Tampa FL and was hoping to get some insight into how to interpret the results. Humidity levels are usually 45 to 60% and the room is carpeted. Had recent wind driven rain from Hurricane Irma in Sept. After washing the windows in the room with a squeegee have had an earthy occasion odor in the room. Ordered a de-humidifier. Thank you so very much!

    Miguel, I can not access the report. Please adjust the privacy settings so I can see it if you would like me to comment on the results. Thanks!

    Outside: asp/pen 80

    Inside: asp/pen 1,400
    Cladosporium 500

    After 4 hr inspection found no leaks and also used a meter with no moisture readings.

    Would appreciate any feedback we are closing on the home in March. Some mold specialists have told us to do micro-scrubbing and some have said its not high enough to worry about. My daughter has asthma really bad. Any thoughts on this would be so appreciated. Thanks for your time.

    Moisture is dependent on the current conditions. If it has not rained in a few days, for example, things may appear dry. However, if you were to check during a rainstorm you might be able to find moisture. The asp/pen levels are elevated, however, it is not very high. This may be from possible mold growth indoors, but it is possible there isn’t an issue.

    Thank you for replying we got a quote from a company after showing them the results and they also did a clinical inspection (although it haf not rained). Can i get your thoughts on their recmd treatment?

    Hepa vacuum floors and top of cabinets, Set up 3 large air scrubbers and 1 dehumidifier, return
    next day to fog the home lightly with hydrogen peroxide, return on day 3 or 4 to vacuum the floors
    again, remove all equipment, and lightly fog the home again. (4 days run time on equipment)
    Humidity needs to be maintained well below 60% (close to high 40’s low 50’s), recommend a large
    (90 pint/day or greater) dehumidifier from home depot or lowes with a built in pump to encourage
    this environment. A second unit may be necessary in the master suite. Should only be a seasonal
    requirement as more run time on the ac system in the summer time should yield desired humidity.
    TOTAL $2,200.00
    Total $2,200.00

    *we had another quote from a company that was $2900 but included wiping down every surface from ceiling to floor with a bentonite solution as well as the air scrubbers and hepa vacuums.
    We just dont know if this much detail is needed to decrease the numbers as it is more money as well. But we also arent sure if the 2200 quote will fix the problem.

    Thank you so much for your time

    Hi Dylan,

    We live in MA and during a rain storm a few months ago the rubber roof ripped off our apartment and we had a number of (what I would call significant) water leaks throughout the apartment during the storm (2 hours or so). We collected as much water as we could in buckets/pots, used towels to clean up anything else, and ended up using a large air mover and dehumidifier moved throughout the house for the next few days. There is a crawlspace between the roof and our ceiling. In there there is insulation, HVAC ducts and the furnace.

    We asked the landlord to get a mold test done since nothing else was done and we were concerned that there could be mold issues from this not being properly taken care of. The results of the test were:

    (Raw / sp/m3)
    Room 1: 16 / 780
    Room 2: 45 / 2200
    Room 3: 70 / 3400
    Room 4: 30 / 1360
    Room 5 (Bathroom): 58 / 2800
    Outside was 0/0 (I believe this is to be expected during winter months).

    On our report these were the only spores that were identified as “slightly elevated” / “elevated”. There were some others found but apparently the counts were low so as to not be as much of a concern (most were one or two spores in the raw count).

    We haven’t seen any visible evidence of mold, nor any musty smells in the apartment.
    Any thoughts on this?



    The levels, particularly in Room 2 and Room 3, are slightly elevated. Mold is a microorganism, so it is possible for there to be some light growth which may not be visible to the eye. I would suggest doing a detailed cleaning of the property using a HEPA vacuum, and maybe running a HEPA air scrubber for a day or so.

    raw ct spores/m3 %
    Basidiospores 27 1080 40
    Cladosporium 9 360 13
    Penicillium/Aspergillus 30 1200 44
    Smuts/Periconia/Myxomy 2 80 3

    Mold is in the basement. These are the reading from a room on the 1st floor. Thanks.


    Without an outdoor air sample, I can not give any meaningful analysis of these results. The Penicillium/Aspergillus levels may be slightly elevated, however, it is possible for outdoor levels to be that high so I can not be certain.

    Cladosporium Raw Count 1 Spores per M3 40
    Penicillium/Aspergillus Raw Count 4 Spores per M3 160

    Anything to worry about?

    Hey Dylan- I’m a realtor and deal with Bank owned foreclosures only. I have a buyer who’s lender has requested a mold test. The only result of the cassette air test that seemed out of line was for Aspergillus/Penicillium at 2910 vs outdoor at 40. There is no odor but a small area of visible mold/mildew on a wall. We are in Fort Lauderdale, FL. House is vacant. I can email the report or section. Love to have your opinion. I feel like I’m being punked!

    You have an elevated level of mold on the air sample, and also confirmation of visual mold growth indoors. Seems to indicate a moisture issue of some sort. I would suggest having a detailed inspection to make sure there are not any other issues that are not as apparent.

    We would not be able to comment on if an area is safe for someone to inhabit. Individual mold sensitivities are so varied in the population, and we are not medical professionals we would not be able to comment on the health risks of a space.

    Hi! I received the following mold report for an upstairs home office/former bedroom in Tampa FL and was hoping to get some insight into how to interpret the results. Humidity levels are usually 45 to 60% and the room is carpeted. Had recent wind driven rain from Hurricane Irma in Sept. After washing the windows in the room with a squeegee have had an earthy occasion odor in the room. My wife has been sick more with colds and allergies. Had roof near window patched where roof meets 2nd story wall where the smelll seemed to come from. Ordered a de-humidifier and smelll has pretty much disappeared but we have had no rain in about a week or so. Thank you so very much for your thoughts!

    Moving into new home at end of march. 1200-1400 Pen/Asp inside with outdoor at 80. No visible mold or smells. Checked by 3 different people (one being our very ocd inspector). Humidity 60%. Have talked to 3 diff companies and have had 4 diff options. Can i get your suggestion on what to do please? The last 2 options would be for 3-4 days before we moved in.
    1. Just add humidifier and high filtration filters to AC (we plan on doing this reguardless)
    2. Fog with hydrogen peroxide. Air scrubbers. Hepa vacuums $2200
    3) fog with bactrin and air scrubbers $800
    Thanks for yoyr time.

    Hi Dylan,

    My wife and I are looking to purchase a home that has undergone mold remediation in mid 2016, but still shows signs of some mold. What do you think of the results below? Also they have always ran a dehumidifier in the basement. home is in a major city with a wooded back yard and a small creek.

    Alternaria: Raw -1* — Count/m^3- 40*
    Ascospores: Raw -39 — Count/M^3- 1600
    Aspergillus: Raw -39 — Count/M^3- 1600
    Basidiospores: Raw -468 — Count/m^3- 19800
    Cladosporium: Raw -54 — Count/m^3-2300
    Curvularia: Raw -30 — Count/m^3-1300
    Epicoccum: Raw -1 — Count/m^3-40
    Ganoderma: Raw -2 — Count/m^3-80
    Myxomyetes: Raw -4 — Count/m^3-200
    Pithomyces: Raw -12 — Count/m^3- 510
    Rust: Raw -4 — Count/m^3-200
    scopulariopsis: Raw -1 — Count/m^3-40
    Unidentifiables: Raw -4 — Count/m^3-200
    Arthrobotrys: Raw -2 — Count/m^3-80
    Botrytis: Raw -1 — Count/m^3-40
    Cercospora: Raw -1 — Count/m^3 – 40
    Oidium: Raw -1 — Count/m^3 – 40
    Total Count: 28210

    1st Floor:
    Basidiospores: Raw -1 — Count/m^3- 40
    Pithomyces: Raw -1 — Count/m^3- 40
    Total Count:80

    Alternaria: Raw -1* — Count/m^3- 10*
    Basidiospores: Raw -17 — Count/m^3- 720
    Cladosporium: Raw -7 — Count/m^3-300
    Pithomyces: Raw -1 — Count/m^3- 40
    Cercospora: Raw -1* — Count/m^3 – 10*
    Total Count: 1120


    Hi Dylan,

    I decided to get an air quality report after I started developing odd symptoms: dizziness, sinus issues, breathing issues and most recently red and itchy eyes. The symptoms started about 1 month after I moved into this condo which is on the first floor but there are no visible signs of mold anywhere. The Cladosporium count seems particularly high indoors 2550 vs outdoors 900, do you think this could be causing me health problems? Thanks for your time.

    Lab Sample Number:
    Client Sample ID:
    Volume (L):
    Sample Location:

    Indoor Living Rm

    Outside Back North

    Spore Types Count/m3 Count/m3 – – –
    Alternaria 20 – – – –
    Ascospores 200 630 – – –
    Aspergillus/Penicillium 480 680 – – –
    Basidiospores 390 1800 – – –
    Bipolaris++ – – – – –
    Chaetomium 7* – – – –
    Cladosporium 2550 900 – – –
    Curvularia 7* – – – –
    Epicoccum – – – – –
    Fusarium – – – – –
    Ganoderma – 20 – – –
    Myxomycetes++ 7* 7* – – –
    Pithomyces – – – – –
    Rust – – – – –
    Scopulariopsis – – – – –
    Stachybotrys – – – – –
    Torula – – – – –
    Ulocladium – – – – –
    Unidentifiable Spores – – – – –
    Zygomycetes – – – – –
    Cercospora 20 – – – –
    Nigrospora 7* 20 – – –
    Pestalotia/Pestalotiopsis 20 – – – –
    Total Fungi 3708 4057 – – –
    Hyphal Fragment 200 40 – – –
    Insect Fragment – – – – –
    Pollen – – – – –
    Analyt. Sensitivity 600x 22 22 – – –
    Analyt. Sensitivity 300x 7* 7* – – –
    Skin Fragments (1-4) 2 1 – – –
    Fibrous Particulate (1-4) 1 1 – – –
    Background (1-5) 2 1


    I can not say if these levels are high enough to cause health effects. The Cladosporium level indoors is slightly elevated to the outdoor sample. However, you are frequently exposed to similar levels as the indoor sample in the outdoor air. We can see outdoor Cladosporium levels at times higher than 3,000 spores/m3.

    Results from ATL Aerobiology state that there are elevated concentrations of aspergillus and penicillium where 37 times greater than the outside baseline sample. What on earth does that mean? Thanks!

    I would need to know the actual data, 37 indoor and 1 outdoor compared to 37000 indoor and 1000 outdoor are vastly different but yet both 37 times greater.

    We got our daughters bedroom tested and these are the results. No indication clinically or smell.


    Chaetomium 80/0
    Cladosporium 200/2200
    Curvulari 200/0
    Pithomyces 80/0

    Thank you for your time amd expertise with helping us all out


    The presence of Chaetomium always raises some eyebrows. With levels that low, it is hard to make any concrete interpretation. The best thing to do would be to run another test in the area to see if the Chaetomium shows up again, and if so at what level. Your results are very very low (the analyst only counted 1 spore of Chaetomium) and we do not see any other water damage indicators so it is possible that your result is just an anomaly.

    Hi Dylan,
    Thanks so much for your work here – I am so confused about the spore trap analysis results we received in a recent mold test and am really grateful for any insights you have on what they mean, including if you think it is safe to stay living in the house while we deal with any problem.

    Our house is straw bale construction, with a natural lime/sand render, which is not sealed. No current moisture was detected. I have included the outdoor air sample and all the indoor samples taken.

    The master bedroom internal wall void sample was taken in a small hole that goes right into an small area of exposed straw bale (no idea on what counts would be typical in a straw bale!).

    The roof void sample was also taken in quite an enclosed space as we don’t really have a standard roof void – just enough space for some insulation sandwiched between the external roof and the internal roof lining.
    The numbers may not add exactly to the total spores as the test results for individual molds only showed as raw count and I had to multiply them up to indicate spores/m3. I’ve put the spores/m3 in brackets after the raw count.

    Re the lounge room sample, we do have an old feather filled lounge suite that our dogs have slept on for a few years, and wondering if that could be at least part of the explanation (throwing it away today!) in that room at least.

    Sample Description Number/ID Outdoor Control
    Sample Serial Number 25739916
    Background Debris Rating 1-Low (minimal or no effect on analysis)
    % of Slide Area Counted 100%
    Total Spores and Hyphae
    Total Mould Concentration of Spores per Cubic Metre (spores/m^3)
    Ascospores 1 (67)
    Aspergillus/Penicillium-like 4 (267)
    Cladosporium 3 (200)
    Smuts/Myxomycetes/Periconia 2 (133)
    Trichoderma 1 (67)
    Hyphal Fragments 2 (133)
    Unidentifiable Fungi or Spores 3 (200)

    Sample Description Number/ID Lounge
    Sample Serial Number 25739953
    Background Debris Rating 1-Low (minimal or no effect on analysis)
    % of Slide Area Counted 100%
    Total Spores and Hyphae
    Total Mould Concentration of Spores per Cubic Metre (spores/m^3)
    Ascospores 7 (467)
    Aspergillus/Penicillium-like 1 (67)
    Smuts/Myxomycetes/Periconia 4 (267)
    Stachybotrys/Memnoniella 2 (133)
    Trichoderma 3 (200)
    Ulocladium 7 (467)
    Hyphal Fragments 7 (467)
    Unidentified Fungi or Spores 2 (133)

    Sample Description Number/ID Dining/Kitchen
    Sample Serial Number 25739906
    Background Debris Rating 1-Low (minimal or no effect on analysis)
    % of Slide Area Counted 100%
    Total Spores and Hyphae
    Total Mould Concentration of Spores per Cubic Metre (spores/m^3)
    Aspergillus/Penicillium-like 6 (400)
    Chaetomium 1 (67)
    Nigrospora 1 (67)
    Pithomyces 1 (67)
    Smuts/Myxomycetes/Periconia 2 (133)
    Trichoderma 2 (133)
    Hyphal Fragments 1 (67)
    Unidentified Fungi or Spores 2 (133)

    Sample Description Number/ID Master Bedroom
    Sample Serial Number 25740162
    Background Debris Rating 1-Low (minimal or no effect on analysis)
    % of Slide Area Counted 100%
    Total Spores and Hyphae
    Total Mould Concentration of Spores per Cubic Metre (spores/m^3)
    Alternaria 1 (67)
    Ascospores 3 (200)
    Aspergillus/Penicillium-like 5 (333)
    Cladosporium 2 (133)
    Nigrospora 1 (67)
    Smuts/Myxomycetes/Periconia 2 (133)
    Trichoderma 4 (267)
    Hyphal Fragments 4 (267)
    Unidentified Fungi or Spores 1 (67)

    Sample Description Number/ID Master Bedroom Internal Wall Void
    Sample Serial Number 25739950
    Background Debris Rating 1-Low (minimal or no effect on analysis)
    % of Slide Area Counted 100%
    Total Spores and Hyphae
    Total Mould Concentration of Spores per Cubic Metre (spores/m^3)
    Ascospores 6 (400)
    Aspergillus/Penicillium-like 6 (400)
    Nigrospora 1 (67)
    Hyphal Fragments 11 (733)
    Unidentified Fungi or Spores 12 (800)

    Sample Description Number/ID Master Bedroom Ensuite
    Sample Serial Number 25740175
    Background Debris Rating 1-Low (minimal or no effect on analysis)
    % of Slide Area Counted 100%
    Total Spores and Hyphae
    Total Mould Concentration of Spores per Cubic Metre (spores/m^3)
    Alternaria 1 (67)
    Ascospores 4 (267)
    Aspergillus/Penicillium-like 3 (200)
    Chaetomium 1 (67)
    Smuts/Myxomycetes/Periconia 1 (67)
    Hyphal Fragments 1 (67)

    Sample Description Number/ID Daughter’s Bedroom
    Sample Serial Number 25740009
    Background Debris Rating 1-Low (minimal or no effect on analysis)
    % of Slide Area Counted 100%
    Total Spores and Hyphae
    Total Mould Concentration of Spores per Cubic Metre (spores/m^3)
    Ascospores 5 (333)
    Aspergillus/Penicillium-like 1 (67)
    Smuts/Myxomycetes/Periconia 1 (67)
    Hyphal Fragments 1 (67)
    Unidentified Fungi or Spores 1 (67)

    Sample Description Number/ID Study
    Sample Serial Number 25739930
    Background Debris Rating 1-Low (minimal or no effect on analysis)
    % of Slide Area Counted 100%
    Total Spores and Hyphae
    Total Mould Concentration of Spores per Cubic Metre (spores/m^3)
    Alternaria 2 (133)
    Ascospores 7 (467)
    Smuts/Myxomycetes/Periconia 1 (67)
    Trichoderma 2 (133)
    Hyphal Fragments 2 (133)

    Sample Description Number/ID Loft
    Sample Serial Number 25739961
    Background Debris Rating 1-Low (minimal or no effect on analysis)
    % of Slide Area Counted 100%
    Total Spores and Hyphae
    Total Mould Concentration of Spores per Cubic Metre (spores/m^3)
    Ascospores 4 (267)
    Aspergillus/Penicillium-like 1 (67)
    Pithomyces 1 (67)
    Hyphal Fragments 3 (200)
    Unidentified Fungi or Spores 4 (267)

    Sample Description Number/ID Roof Void (accessed via Loft)
    Sample Serial Number 25739999
    Background Debris Rating 1-Low (minimal or no effect on analysis)
    % of Slide Area Counted 100%
    Total Spores and Hyphae
    Total Mould Concentration of
    Spores per Cubic Metre (spores/m^3) 5200
    Ascospores 2 (133)
    Aspergillus/Penicillium-like 37 (2467)
    Chaetomium 5 (467)
    Cladosporium 8 (533)
    Dreschlera/Bipolaris-like 1 (67)
    Epicoccum 16 (1067)
    Pithomyces 1 (67)
    Smuts/Myxomycetes/Periconia 1 (67)
    Hyphal Fragments 3 (200)
    Unidentified Fungi or Spores 4 (267)

    Sample Description Number/ID Bathroom
    Sample Serial Number 25739951
    Background Debris Rating 1-Low (minimal or no effect on analysis)
    % of Slide Area Counted 100%
    Total Spores and Hyphae
    Total Mould Concentration of Spores per Cubic Metre (spores/m^3)
    Ascospores 1 (67)
    Cladosporium 1 (67)
    Trichoderma 2 (133)
    Unidentified Fungi or Spores 1 (67)

    I just want to preface this by saying here in Chicago, we do not have straw-bale construction at all, so our experience with it is very limited.

    With this type of construction, it is really hard to say what might be growth due to moisture issues in the home or growth that was in the straw bales prior to/during construction. You do have some water damage indicating molds (stachybotrys, chaetomium, ulocladium, trichoderma) in a few samples, but they are at a very low level. The roof void sample does seem to have the highest level of Asp/Pen, but again it is hard to say if this is from moisture or from the natural construction of the home.

    HI Dylan, thanks so much for your reply. Is it possible to send you our full report and pay for some additional guidance? The link on this page to book an appointment doesn’t seem to be working. And wondering what thresholds your company uses to assess acceptable mold levels – there seems to be so much variation!

    Hello – received the following results. Any major concerns while i wait for feedback from the inspector? Live in ranch home with walkout basement; about 2/3 of the basement is fixed up (carpet on floor, drywall walls (used Styrofoam insulation and of course put up a vapor barrier, and ceiling tile) – we are almost never down there. Had an inspector come out to check air condition and he took a sample outside, basement (fixed up area) and upstairs living room. I am original owner and never had any water damage / leaks (that i know of). Inspector found no visible evidence of mold.

    Outdoor raw ct. / spores m3 / %
    Basidiospores 6/240/32
    Cladosporium 3/120/16
    Pen/Asp 10/400/53
    Background Debris 3
    Sample Volume 25
    Total Spores 19/760

    Basement raw ct. / spores m3 / %
    Alternaria 1 / 40 / 2
    Basdidopores 11 / 440 / 24
    Cladosporium 3 / 120 / 7
    Pen/Asp 29 / 1160 / 64
    Smuts/Periconia/Myoxmy 1 / 40 / 2
    Background Debris 3
    Sample Volume 25
    Total Spores 45/1800

    Living Room raw ct. / spores m3 /%
    Basdidopores 4 / 160 / 18
    Cladosporium 2 / 80 / 9
    Pen/Asp 15 / 600 / 68
    Smuts/Periconia/Myoxmy 1 / 40 / 5
    Background Debris 3
    Sample Volume 25
    Total Spores 22/880

    When the weather gets really cold the windows sweat in the basement (even get ice). Basement does seem to have higher humidity upper 50 to low 60s although when i run the dehumidifier it takes out some water but doesn’t seem to make much of a difference in %. Appreciate in advance any thoughts you may have!

    it seems like you have a slight elevation of Aspergillus/Penicillium in the basement. I would attribute that to the condensation issues you have mentioned in the basement. I would suggest you increase your dehumidification efforts in the space to keep that humidity down, especially in the colder months.

    Had a mold spore air cast of outside and inside in crawl space it showed a mold Spore count of 2400 which I was told was and three times the level it was supposed to be I have course I’m going to use a HEPA vac and sporicidin as recommended by my mold hygienist are these values correct or is the expected crawl space mold Spore count supposed to be 800 or below in a three-bedroom residence?

    Air sampling in crawl spaces is not recommended, and there are no recognized industry guidelines for air sampling in a crawlspace.

    Hi, I have been in an area that mushrooms continue to grow through the floor. The company that tested did air sampling and testing of one ceiling tile. They insisted that sampling the floor where the mushrooms grow is not useful because flooring is dirty. I noticed specifically that Cladosporium results were higher inside than outside.
    Here are the results of the sampling:
    Cladosporium outside
    Raw ct 22
    Spores/m3 590

    Cladosporium inside
    Raw ct 91
    Spores/m3 610

    Penicillium/Aspergillus outside
    Raw ct 2
    Spores 13

    Penicillium/Aspergillus inside
    Raw ct 2
    Spores 13

    Please help to interpret. Thanks!


    I suspect you may have mistyped your results, there is no way that the raw count outdoors is ~4x lower and only 10 spores/m3 lower than the indoor measurement.

    Regardless of those results, for mushroom growth to happen indoors there has to be very high moisture consistently. Mushroom growth indoors is a huge red flag for major moisture issues in the space.

    Thanks for your reply Dylan! I have a picture of the report that I’d like you to see. Is there a way I can send this to you? Thanks again!

    Hmmm, it is interesting that the lab only read 25% of the outdoor sample for Cladosporium, but 100% of the indoor sample.

    The results of 590 and 610 are essentially the same, and I do not see any issues there.

    What is odd to me is that the Basidiospore levels indoors were so low. Mushrooms produce basidiospores in HUGE amounts, so if you had mushroom growth indoors I would expect to see those levels off the charts on the indoor samples.

    Thanks again! These results are from air sampling. Not sure why they only reported 25%. Would surface sampling on the floor where the mushrooms grow be more reliable?

    In my opinion with the presence of mushrooms, sampling is going to be not necessary. You need to have someone come assess specifically what is happening moisture wise that is allowing for this fungal growth. Moisture is responsible for mold growth in buildings, and for mushrooms to grow you would need extreme moisture issues.

    Hi Dylan,

    Below are screen shots of a recent test at my 2 bedroom basement apartment. My roommates and I have been waking up groggy, tired (even after 10 hours of sleep), stuffed up when waking up and headaches. I seem to be getting the worst out of all, with lungs burning and difficulty breathing. There was also an incident when I had awoken from sleep and on the brink of passing out. I felt like I could not breath enough air (the first this has ever happened to me). I slept over a friend’s house after the last episode to see if it may have been health issues unrelated to my home. I woke up feeling refreshed with none of the symptoms. A visual inspection from my landlord’s pest control guy said there were no signs of mold, which prompted me to get these air test. I wanted to get the most accurate result possible so 24 hours before the inspector came I closed all windows and turned off all fans. The results are disappointing, for it seems that everything is within “normal parameters”. Could you please take a look at our test results and see if there is anything our inspector missed?


    Bedroom 1 & 2, Bathroom



    I do not see any indication of a mold issue in the results you provided. There are many things that can cause similar issues, I would suggest assessing the space for other common IAQ issues like CO2, CO, RH %.

    I had mold remediation done last week. The kitchen showed Aspergillus/Pencillium like at count of 853/m3 and raw count of 16, before the mold guys started. After mediation, the count went to 1,067/m3 and raw count of 20. It was not detected in the outside air. I had a dishwasher that had leaked a couple of years ago and we had to replace some tile. I know the mold company stirred things up by having the windows open and filtering the air out the basement window. I’m sensitive to mold and my Marcon test in Dr. Office showed over 20,000. I have lyme co-infections (Bartonella and Babesia) and just recently removed all my mercury fillings (9 total, 5 visits with all the precautions). I’m desperate to get rid of this problem so my health can get better. The mold guy can’t seemed to see any signs of mold in the kitchen. Is this a mold that can be killed with bleach water, having a mask and gloves on? How can I find where this problem is?

    My suggestion would be to have them run air scrubbers longer, and do a thorough cleaning of the work area with HEPA vacuuming. If the remediator can not find any remaining physical mold growth then the levels are likely just due to spores remaining airborne after remediation.

    Killing the mold is not the goal of remediation. The goal of remediation is the removal of mold. Even dead mold that is in a space can cause effects in people.

    The level count of Aspergillus/Penicillium is 8230 in my attic and only 300 on background/outdoors. Is this something to be alarmed with?
    The level count of Basidiospores is 11,200 in my attic and only 2100 on background/outdoors. Is this something to be alarmed with?
    The level count of Cladosproium is 19,100 in my attic and only 2200 on background/outdoors. Is this something to be alarmed with?
    All other indoor results are in normal range of comparison background results, so why would attic levels be so much higher?

    This is a perfect example as to why collecting air samples from an attic space is not appropriate. Most people are not vacuuming or cleaning their attic spaces regularly like you would a living space in the home, so the normally occurring mold from the outdoors will settle out of the air and collect into dust over time. And since the mold is not removed from the space, the normally occurring mold spores can collect into very high levels. With an inspector moving around the attic, this will stir up a lot of the dust (and the mold spores that have collected into this dust over time) into the air and this can lead to air samples in attics coming back with very high levels even without any evidence of a mold issue in the attic. Because of this, no one is able to confidently interpret attic air samples.

    Of course, it is possible there is a mold issue in the attic, and these numbers are due to that. However, a mold issue in an attic should be visibly identified and confirmed with surface samples, in my opinion, an attic air sample can not solely be used to determine that an attic has a mold problem.

    Hello, I received the following mold reports and was hoping to get some insight into how to interpret the results. I suffer from seasonal allergies and am sensitive to mold and pollen. I lived in that house for 8 years, and I had rhinitis caseosa, and since I moved out one year ago, my rhinitis caseosa dissapeared, well all the hay fever symptoms dissapeared. Here’s the result ( old house built near 1908, and having some leak issue in the attic, and the basement ( never repaired when we stayed there for 8 years) :

    Outside : 40 Cladosporium SP

    Inside, Basement 1 : 10 000 Cladosporium sp, 2500 Aspergillius/Penicillium SPP
    Basemant part 2 : 42 471 Aspergillius/Penicillium SPP, 800 Cladosporium, 40 periconia
    Laundry room : (who’s up the Basement 1 ) : 2600 Aspergillius/Penicillium SPP, 1720 periconia, 280 Cladosporium, 40 unknown.

    Also, here’s two result for the UFC/m3 for the basement : over 11 142 Aspergillius/Penicillium SPP
    Laundry soom : 4991 UFC/m3, 1854 Aspergillius SPP, 63 Penicillium SPP, 63 cladosporium, 45 mycelium, 27 unknown…

    Tx !


    The results to me are consistent with an area that has had some minor moisture issues over a period of time. We are seeing both an elevation of Asp/Pen levels in the basement as well as Cladosporium. None of the other types are of concern in the samples. Asp/Pen and Cladosporium are both mold types which are common in the outdoor air as well as indoors. These levels are clearly elevated so I suspect there is some significant moisture in the basement

    I recently had a mold test done in my home which shows a spore count m/3 of 50 outdoors and 200 indoors. The raw spore count was from 1-8. There isn’t an obvious large patch of mold but we now know it’s there. Is remediation appropriate for this level of spore count. Is there a way to do it for mold in the air? Thanks!


    I need more information to make any sort of interpretation. I would need to know the types and amounts of mold present in the samples.

    Hi! Please help! We are in contract with a house and one of the bedrooms is in the basement we were going to use for our 2 kids so the results of this mold test I have been anxiously awaiting. Now that I have results I can’t understand the results. Also no one is getting back to me and we planned to talk the realtor tomorrow about what we thought of the inspection with the overall house. The kids and I homeschool and are inside the house a lot, I’m pregnant, and my son and I have some mold allergies. As far as interior should I be concerned of the penicillium level of 380? Also about 5 other particles that are lower but were identified? What are things we can do to help with the mold if we want the house.

    Here are the results:

    Aspergillus/Penicillium raw count 380 and % of total 8.1% This appears to be interior. It has a symbol of concentration 10x or more above background and there are about 4 other particles that ranked as spores reported to cause allergies in individuals. The other 4 are:

    Ascopores raw count 3, count 40, 8% of total
    Basidispores raw count 2, count 30, 6.1% of total
    Cladosporium raw count 3, count 40, 8.1% of total
    Myxomycetes raw count 1(cubic meter)count 4 (cubic meter)

    Thank you and I’m not sure if I’m asking correctly but I would like someone’s opinion that understands the report. I would love to send the report but can not copy and paste it in here.

    Please let me know your thoughts.

    It seems that you may have mistranslated some of the results from the report into your comment. You said the Asp/Pen raw count was 380 and is 8.1% of the total. Did you mean to say it is 81% of the total? What is the Asp/Pen level in the count/m3 column (this is usually the column after the raw count)? Did you have an outdoor sample collected at the time of the indoor samples?


    We are in the process of purchasing a condo on the 2nd floor that has been unoccupied for several years. The seller disclosed that about 2 years ago there was a backup of the main which caused some flooding in the kitchen area that went unnoticed for quite a while. He had the flooring in the kitchen replaced and remediation done. He did not notice until a month ago that the water damage went under the cabinets and wall through to the entry way wood floor. He recently had the entryway flooring pulled up and 18 inches of drywall removed then had mold remediation done. They fogged the whole condo. We had an air quality test done 48 hours later (before drywall and flooring replaced) with the following results: Chaetonium 40/530/72 and Penicillium/Aspergillus 16/210/28. The control test outside showed no results for either of those molds. What would you recommend?

    Lisa D

    The results indicate that there is still an issue in the air. Fogging is not an appropriate measure for remediation, you need to have the physical mold growth removed under a containment and also have air scrubbers operational during the remediation. Going forward you should have HEPA vacuuming of the affected areas and air scrubbing done to remove any residual mold in the air or settled onto surfaces.

    Hello! I just received results from our air testing in the crawlspace and a bedroom where the air smells intermittently humid/musty more often than not. We have an obvious problem in our crawlspace (and I worry about our attic but did not have it tested). These are the numbers that stand out (count/M3):

    Alternaria species– 320 (outside), 120 (crawlspace), 520 (bedroom)
    Ascospores– 1250 (outside), 80 (crawlspace), 160 (bedroom)
    Aspergillus/penicillium– 920 (outside), 29200 (crawlspace), 360 (bedroom)
    Cladosporium– 5400 (outside), 1280 (crawlspace), 2640 (bedroom)
    Epicoccum species– 80 (outside), 120 (crawlspace), 160 (bedroom)
    Torula species– 40 (outside), 120 (crawlspace)

    I noticed that for epicoccum, numbers are higher than outside in the bedroom. For cladosporium, counts are higher in the bedroom than in the crawlspace. Our remediation includes cleaning up and putting a vapor barrier in the crawlspace but does not address the bedroom where there is no visible mold. Should I be concerned with these numbers inside? I live in IL. Thank you!

    The numbers indoors to me all look fine, Epicoccum and Alternaria are typically outdoor mold types and do not grow indoors very often. It isn’t recommended to collect air samples inside of a crawlspace, the samples can be artificially high and tend to lead to false positives. A thorough visual inspection of the crawlspace should be performed to determine if there are any moisture or mold concerns.


    I will add that we are considering leaving our home temporarily during remediation but don’t know if that is necessary since most/all of the problem is only known to be in the crawlspace. I am afraid to take the risk with 94% aspergillus penicillin in the crawlspace.

    I wanted to ask you for a second opinion. I had an additional mold test done after a remediation company gutted my bathroom due to a leak. They cleaned and treated the mold. The area was already cleared with an air sample. I was concerned about contamination in the hallway outside of the bathroom so I had an additional air test in the bathroom, outside, and in the hallway. The testing company says I should do further remediation, I am not sure this is warranted.

    Results in spore count/M3

    Ascospores 1/40
    Basidiospores 5/200
    Chaetomium 1/40
    Cladosporium 1/40
    Pen/asper 1/40

    Ascospores 6/240
    Basidiospores 36/1440
    Chaetomium 2/80
    Cladosporium 13/520
    Pen/asper 31/1240
    Smuts/pericona/myxomy 7/280

    Alternaria 2/80
    Ascospores 6/240
    Basidiospores 85/3400
    Chaetomium 14/560
    Cladosporium 30/1200
    Penn/asper 19/760
    Rusts 1/40
    Smuts/pericona/myxomy 115/4600
    Stachybotrys 2/80

    I don’t think the remediation did great job regarding keeping the hallway clean as I saw drywall bits on the floor indicating they hadn’t bagged everything, but they did a decent job of cleaning and applying biocide to all surfaces of the bathroom. Perhaps all that is needed is a cleaning and disenfecting of the hallway and hepa filtering since there is no longer a moisture issue

    The hallway sample is pretty clear that there has been some cross contamination outside of the bathroom. Standard clearance testing would test both inside the area of the remediation and an adjacent area to make sure there has not been any contamination like this. A detailed cleaning of the hallway with HEPA vacuuming/HEPA air scrubbing should be enough to get the space back to a pre-loss state.

    A-01 Kitchen 06/23/17 1,133 1,000 Aspergillus/Penicillium
    120 Chaetomium
    13 Pithomyces
    A-02 Garage North Wall
    (Wall Check)
    06/23/17 2,800 67 Alternaria
    2,400 Aspergillus/Penicillium
    333 Chaetomium
    A-03 Outside 06/23/17 853 40 Ascospores
    413 Aspergillus/Penicillium
    267 Cladosporium
    27 Epicoccum
    67 Pithomyces
    40 Ulocladium
    Samples highlighted in bold red text indicate elevated and or abnormal counts of mold spores
    Tape Sample Results
    I.D. Location Date
    Y or N
    Spore Type
    T-01 Garage North Wall 06/23/17 Yes +4 Alternaria
    +4 Aspergillus/Penicillium

    Would these levels of indoor mold be hazardous to our health?. The numbers inside are significantly higher than outside


    I am not a healthcare professional and am not able to assess if a space is “healthy” or not. The presence of Chaetomium, and the levels of Aspergillus/Penicillium in the space are elevated. This indicates to me that there have been some significant moisture issues in the home and likely substantial mold growth.

    We recently discovered visible mold on some drywall in our basement. We had a mold inspector come out and take some samples and here are the findings I am most troubled with. We had a reading in the basement of 9360 for Stachybotrys and 19,700 for Penicillin/Aspergillus which is visible on some wood support beams.
    Further results indicate mold in the two upper levels of the home as well with a reading of 160 and 120 respectively for Stachybotrys and 560 and 960 respectively for Penicillium/Aspergillus. The control result of Stachybotrys was 200 while the Penicillium/Aspergillus was 440.

    We have been told that we should not stay in the house until all the mold has been remediated. They are suggesting that all the contents of the basement be removed, that porous items should be discarded and that any hard surface items would be boxed and taken to a facility and cleaned and returned. That the upper levels of the home will be air scrubbed and all surfaces need to be wiped clean with I think an antibacterial

    Do these results seem dependable since the Stachybotrys is higher outside than on the two upper levels of the house?

    Is it really necessary to remove EVERYTHING from the basement? And, if they air scrub the upper levels of the house and wipe down all surfaces, what about all the furniture, carpet, clothing, etc?

    I am a little nervous being in the house but don’t seem to have any health issues so far other than mild allergy symptoms. It will be another week before we can get the remediation done and I would like to stay in the house if it is not dangerous to do so.

    In my opinion, I think the outdoor Stachybotrys levels are artificially high. You can see this often when people take air samples outdoors after being in an area with high levels of mold. The spores can attach to clothing, equipment, etc and end up on the outdoor sample. It is very rare to have any level of Stachybotrys outdoors. The levels in the upstairs levels are likely caused by the very high levels in the basement.

    Unless there is visible mold growth on surfaces, you likely don’t need to discard of all the items in the basement. One of the leading guidance documents used by remediation companies, IICRC S520, would consider these items “condition 2” and recommends cleaning of both porous and non-porous items.

    Items in the upstairs areas can also be cleaned, including carpets, furniture, and clothing. Usually, a HEPA vacuuming or laundering fabric items would be sufficient along with HEPA air scrubbing in the areas.

    During a recent home inspection on a 2-year old home in Northeastern Florida, I received a report that indicated curvularia spores at a concentration of 188/m3 (raw count was 28) in one of four rooms sampled (the master bedroom). Other rooms were normal. There is no visible indication of moisture intrusion or mold, indoor moisture readings were normal. Sample type was Air-O-Cell 150.0L. Is the level indicated high enough to warrant concern?

    Curvularia is almost always a type that is from the outdoor air. While it is not impossible, it would be very strange to see this mold type growing on building materials indoors.

    i used a DIY mold test kit and sent off samples to a lab. results showed “Low” PEN/ASP growth. It’s in a very small area.
    Is that a dangerous mold?
    I”ve heard a mold expert say that the best elimination for it is hydrogen peroxide. Is that correct?


    I assume this was a swab test kit that was sent to the lab?

    All molds can cause allergic reactions in sensitive individuals, beyond that it is impossible to assess any health risk (pen/asp is a group of hundreds of different species, each with different potential health issues).

    Our suggestion for people wanting to clean mold from a surface is to use a solution of dish detergent and water.

    Hi Dylan,
    Our family moved into a home 3 months ago. Ever since, we have had a toilet leaking water from the base of the toilet onto the floor, a bathtub leaking from somewhere unknown from the base of the tub, our ac unit constantly drips onto our carpet and 2 bedroom windows leak water from the top of the frames inside the home and down inside the wall. We have had fungal infections, headache, fatigue and upper respiratory issues. I am sensitive to allergies and we have a disabled child that is also sensitive and susceptible to infections. We also found mold in our toilet tanks and underneath our kitchen sink within the frame of the cabinet and replace our ac filters about every 3 weeks because myself and 2 contractors ive had in the home have seen mold on them. Our home is evident of previous water damage prior to us. It also feels humid inside the home. So, we had mold air testing done. Here is what EMLab results shown per 75L:
    Chaetomium 1/13
    Cladosporium 1/53
    Skin cells 4000-8000
    Pollen <13
    Background debris 3
    Basidiospores 3/160
    Cladosporium 3/160
    Pen/asp 2/110
    Hyphal fragments 53
    Skin cells 13-67
    Pollen 110
    Background debris 3

    Any and all input you provide will be helpful. I have one contractor contradicting the other and i just want a healthy and safe environment for us with the best possible remediation to these issues. I have been leaning towards a fog after speaking to a few sources. What are your thoughts on that?

    I don’t have access to the google docs you linked, please adjust the permissions so I can view them.

    These numbers have a single spore of Chaetomium mold, this result to me raises eyebrows, but with only a single spore we can not make any determination since a single spore is not statistically significant. I will provide more info once I can view the other report.

    As of today, it was discovered there are a couple leaks in the roof as well. At this point the ac unit and windows are still leaking. We are also now dealing with hives and our family doctor has requested blood work to see the levels of mold in our system. Since this has now been nonstop for 4 months, do you think i should get another air test completed?


    These are the results of our previous air quality test. I know you said crawlspace tests are not typically accurate, but there was visible mold. An air scrubber was used, the mold was cleaned, the joists and subfloor was sealed, and a vapor barrier was put down yesterday. Today I can still smell the humid odor that prompted me to have testing done. The odor is intermittent on different days. We also have some rotting around the far edge of our roof/gutters but no visible leaks. Some days I can smell the odor around some window frames (we don’t have trim up right now). We ripped drywall out around a corner of a frame and see no mold, even behind the insulation. The tester said he cannot test inside exterior walls. I am not really sure where to go from here. Any tips? Thank you!

    Note: On the day air testing was done, I could not really smell the odor inside our home.

    Alternaria species– 320 (outside), 120 (crawlspace), 520 (bedroom)
    Ascospores– 1250 (outside), 80 (crawlspace), 160 (bedroom)
    Aspergillus/penicillium– 920 (outside), 29200 (crawlspace), 360 (bedroom)
    Cladosporium– 5400 (outside), 1280 (crawlspace), 2640 (bedroom)
    Epicoccum species– 80 (outside), 120 (crawlspace), 160 (bedroom)
    Torula species– 40 (outside), 120 (crawlspace)

    Good Morning,

    We moved to Florida in February and since that point I have developed this horrible fear/obsession with mold. I had a mold inspector come out after we discovered our window was leaking and found some minor mold behind the baseboard. We removed the drywall around the leak and did not find any further issues. When the inspector he collected air from three different areas within the same sample, in the room with the leaking window, the laundry room where we our washer had flooded and we had water remediation come out, and our bedroom.

    I have the following results:
    Sample Type & Volume: Aim Impaction – 168L
    IDENTIFICATION/ Raw Count / CFU per m3 / Percent of Total
    Cladosporium 5 / 30 / 13
    Non-sporulating fungi 24 / 140 / 60
    Penicillium 11/ 65 / 28
    TOTAL SPORES 40 / 235 / 100

    As I said, we have removed all effected drywall and have treated the underlying concrete blocks and wood studs with Concrobium anti-microbial. The inspector said these results are good, no single type above 30 and cumulatively under 50, I just want to ensure this is accurate with the collection in different locations and to make sure these levels are safe, we have two under two in the house.

    In addition to treating the area, we have been running an Alen HEPA air filter in there since the discovery, we also purchased additional Alen HEPAs for our babies’ bedrooms.

    I really appreciate your opinion and I have enjoyed reading your other responses, they are very informative!


    This inspector collected what is called “viable” air samples. These numbers shouldn’t be compared to most of the other numbers I discuss in this post. However, accurate testing should be compared to an outdoor sample. The arbitrary numbers they list (none above 30, total below 50) are not an industry standard and I am not sure where they are getting that from. Also, it should be noted that viable air sampling does not detect non-living spores, and many water damage indicator species will not grow on standard sampling media.

    So should I be concerned about these results? I was given the impression the viable air sampling was the more accurate measure to conduct mold testing.

    Viable sampling has benefits and drawbacks, but for most residential situations it is not the best option. Without having control samples to compare it to I really can’t add much more than the numbers seem acceptable.

    Here are the results of our air quality test. Volume sampled: 75L.

    Spore Type – Raw Count/ Count/m3

    Ascospores – 11/147
    Aspergillus/Penicillium like – 10/133
    Bipolaris/Dreschlera – 1/13
    Cladosporium – 26/347
    Ganoderma – 1/13
    Pithomyces – 1/13
    Total – 50/667
    Hyphal Fragments – 1/13
    Debris Rating: 3
    Detection Limit: 13

    None detected: alternaria; arthrinium; basidiospores; botrytis; chaetomium; curvularia; epicoccum; fusarium; memnoniella; nigrospora; oidium/peronospora; rust; smut/myxomyces/periconia; stachybotrys; torula; ulocladium.

    Alternaria – 2/27
    Ascospores – 2/27
    Cladosporium – 2/27
    Curvularia – 8/107
    Epicoccum – 1/13
    Pithomyces – 5/67
    Torula – 1/13
    Total – 21/280
    Hyphal Fragments – 3/40
    Debris Rating: 3
    Detection Limit: 13

    Ascospores – 3/40
    Cladosporium – 2/27
    Curvularia – 4/53
    Epicoccum – 1/13
    Pithomyces – 2/27
    Smut/Myxomyces/Periconia – 1/13
    Total – 13/173
    Hyphal Fragments – 1/13
    Pollen – 2/27
    Debris Rating: 2
    Detection Limit: 13

    Cladosporium – 5/67
    Curvularia – 2/27
    Pithomyces – 1/13
    Total – 8/107
    Pollen – 2/27
    Debris Rating: 3
    Detection Limit: 13

    We were told that the results show that our air is relatively clean, but the hyphal fragments were slightly elevated. A HEPA air filter was recommended. I am concerned that the results show mold spores indoors that were not found outdoors. I have not been able to find any visible mold. Is there a way to locate the source of the mold? Please let me know if any of the results are concerning. Thank you for your time.


    I don’t see any issues with your results. I would even say the hyphal fragments are fine. The types found indoors that are not found outdoors are all typical outdoor mold, and I wouldn’t have any concerns with these types and the levels found in your indoor samples. Outdoor sampling is only a snapshot in time, it is possible to have types that show up on the indoor sample which likely came from the outdoors even if they do not show up on your outdoor sample.

    Hi Dylan,

    I was wondering if any of these numbers stand out to you? The guy who did the tests didn’t say much about the results. We are renting an apartment. Also we were going To have the air ducts cleaned, but they didn’t look that bad and when the guy looked in the plenum part of the AC, he found mold and said he couldn’t clean the ducts because the spores would spread. The aletmebt said they will replacement the plenum. Do you know if that is sufficient?

    Master bedroom
    Aspergillus/penicillin raw count 8 and 349 per m3

    Cladosporium 1 raw count and 44 per m3

    Ascospores 1 raw count and 44 m3

    Basidiospores 18 raw count and 785 per m3

    Background particulate per cubic meter 125,938 ( soil, talcum, cellulose , carbon, and insulation found)

    Background particulate (soil and carbon )- 21, 364 per cubic meter

    Aspergillus/ penicillin -raw count 26 and 1135 per m3

    Cladosprium 17 raw count and 742 per m3

    Ascospores 44 raw count and 1920 per m3

    Basidiospores 109 raw count and 13, 080 per m3


    The mold levels and types all seem fine. The background debris in the indoor sample seems abnormally high, but if they were inspecting the ducts/HVAC equipment before testing that could cause a temporary spike in particulate matter in the air.

    Hey Dylan,
    Trying to get my head around what these numbers mean:

    Raw Ct/Per m3

    Basidiospores 1/53
    Cladosporium 14/750
    Penicillium/Aspergillus types 15/800
    Others 19/1,000

    What you mentioned above is how I understand tests, which is without a baseline test from the outside it is hard to know whether these numbers are out of wack unless they are super high inside?


    You are correct that it is hard to get a good grasp on results without an outdoor sample. Another factor would be what types are considered in the “other” category.

    These results seem to be okay, but without knowing that info it is hard to get a solid interpretation.

    Hi, Dylan! I’m in Southern California and have received the following results from a mold test. There were issues under three sink cabinets.
    Bathroom One: Cladosporium = 3,500 /// Penicillium/Aspergillus = 5,000
    Bathroom Two: Chaetomium = 4,000 /// Penicillium/Aspergillus = 1,500
    Kitchen: Chaetomium = 2,000

    What is the level of concern? Would a reading under a cabinet typically be zero?
    Thanks, so much!

    Are these surface samples or air samples?

    Typically with air samples there will be some background level of mold, even under a cabinet. However, surface samples typically will only have a few settled spores on a clear surface.

    Chaetomium is a water damage indicator and is not a typical background type in air or surface samples. This is a red flag to me.

    Hi Dylan,
    Is it common for total spore levels to go up after remediation?? I had a plumbing leak behind drywall in a bathroom. Drywall was removed and the walls were explosed. A mold air test was done and it found 0 spores/m3 of penicillium/aspergillus types but 490 spores/m3 of smuts, periconia, and myxomycetes. Mold remediation was done and now the penicillium/aspergillus is 3300 spores/m3 and the smuts is 0!! They removed alot of drywall. Is this normal?? Now they want to remove mire drywall!! Thanks, Adam

    smuts, periconia, myxomycetes are almost always found outdoors, so I wouldn’t pay any mind to these levels. The Asp/Pen levels indicate to me that they need to do a better job cleaning the air.

    Curious what these professional test reports mean ( sample volumes = 75L) :

    indoor- pencillium aspergerillus spore count basement = 4267 1st floor = 13 outdoor = 693
    indoor cladisporium spore count basement =1493 1st floor = 53 outdoor = 15840


    Those results to me indicate an indoor source of Penicillium/Aspergillus in the basement. The Cladosporium levels seem okay to me since the outdoor levels are so high.

    I’m a pastor, so my housing is provided as part of my employment. The parsonage we are expected to live in has a very bad odor. My wife experiences burning eyes, throat constriction, headache as soon as she enters the building. We have had an air quality test done, and I am trying to understand the results. The numbers feel really low to me, yet, we know there is a problem of some sort.

    I’m just going to mention the levels we were told to pay attention to. . . .
    Raw Count Count/m3 % of total
    Outdoor Totals 97 3880
    Living Room Total 48 1920
    Bedrooms Total 50 2000
    Basement 1 Total 13 520
    Basement 2 Total 1 40

    Outdoor 49 1960 50.5
    Living Room 30 1200 62.5
    Bedrooms 33 1320 66
    Basement 1 11 440 84.6
    Basement 2 1 40 100

    Outdoor Nothing reported Nothing reported Nothing Reported
    Living Room 5 200 10.4
    Bedrooms 3 120 6
    Basement 1 Nothing Reported Nothing Reported Nothing reported
    Basement 2 Nothing Reported Nothing reported Nothing Reported

    Outdoor Nothing Reported Nothing Reported Nothing Reported
    Living Room Nothing Reported Nothing Reported Nothing Reported
    Bedrooms 1 40 2.0
    Basement 1 Nothing Reported Nothing Reported Nothing Reported
    Basement 2 Nothing Reported Nothing Reported Nothing Reported

    Also present, but not directed to worry about levels: Ascospores, Basidiospores (outdoor only), Cladosporium, Epicoccum, myxomycetes (outdoor only)

    Thanks for any help. I want to make sure that we are properly understanding the report before we make any decisions. And I want to make sure the house is safe for my family.

    These results all look normal to me. One small thing is the Chaetomium in the bedroom, but it is too low to really conclude anything from that. You may need to have someone do a detailed moisture inspection and or cut into wall cavities to check for hidden mold growth. The typical “musty” or “earthy” odors associated with mold growth isn’t actually mold spores, but a by-product of their metabolism called mVOCs. It is possible to have hidden growth and no elevation on air sampling.

    Hi Dylan,

    We have three multi-split air conditioners that generated some mold inside of them and had to be taken apart and deep cleaned. We just had a mold test done in the house afterwards (air and dust) and the inspector was recommending that we hepa vacuum all surfaces (walls, floors, etc), wipe them down with a wet cloth and then hepa vacuum again, in addition to cleaning all personal belongings. He was concerned about the dust test that gave an ERMI score of 1.9 I wanted to get your opinion on the items below that he was most concerned about before spending thousands of dollars:

    The dust test showed the following items of concern:
    Stachybotrys chartarum Stac 14 spores/mg dust
    Aureobasidium pullulans Apull 3,110 spores/mg dust
    Penicillium glabrum Pspin2 78 spores/mg dust
    Cladosporium sphaerospermum Cspha 26 spores/mg dust

    The air test did not show any of the above issues of concern.

    Do you think this type of deep cleaning is warranted for this result? The AC units have been thoroughly cleaned and I am keeping a close eye on them and will do this as a routine maintenance from now on. We have no evidence of any issue anywhere else in the house and it is a small house (850sqft).




    ERMI testing has been designated by the EPA (who developed the test) as for research use only, and it is not an adequate test for making suggestions for remediation one way or another. That being said, an ERMI score of 1.9 is fairly low as it is and with the air samples showing no issue all the more reason to suggest that no additional cleaning should be needed.


    We have just completted remediation and here are our results. Since it is normal to have safe levels of mold, we are having trouble drawling the line in the sand saying the problem is gone, the mold counts that exist now are natural. Hoping you can give us some insight if we can draw that line!

    Basidiospores 1010
    cladosporium 468
    penicillium/aspergillus 585

    Thank you!


    It is almost impossible to make any conclusions without an outdoor reference sample for comparison. I can say that in my area (Chicago) these results are below the typical outdoor levels for this time of year and would most likely not indicate an issue indoors.

    I am looking at purchasing a house, dependent upon mold remediation. They only tested the basement since it had an obvious smell to it and visible mold on the joist – Spore Trap ASSESSMENTReport™ Air-O-Cell(™) Analysis of Fungal Spores & Particulates (Methods MICRO-SOP-201, ASTM D7391). The upstairs has been completey remodeled. The testing showed highly elevated aspergillus/penicillium counts: Outside – Raw Count = 27, Count/m3 = 570, % of total = 1.9. Basement – Raw Count = 585, Count/m3 = 12300, % of total = 90.2. I am even more concerned that is shows curvularia in the house and not outside. The outside reading is 0. The inside reading is Raw Count = 1, Count/m3 = 7, % of total = .1. It is recorded as being slightly elevated, but since the effects of this type of mold can be so much worse for immunocompromised people (of which I am one) I would like to know what extra steps we need to take. Also found was Ganoderma. Outside – Raw Count = 1, Count/m3 = 20, % of total = .1. Basement readings are Raw Count = 2, Count/m3 – 40, % of total = .4. The company that we are bringing in does treatment with hydrogen peroxide since I can’t be around chemicals. Is this sufficient treatment? They said that they will come back and test/ re-treat every week until things are remedied.

    Thank you for performing this service for people.


    The Aspergillus/Penicillium levels are what I would be concerned with. Curvularia and Ganoderma are almost exclusively found outdoors, and the very low levels they found in the home are not concerning to me. Outdoor conditions are dynamic, meaning that in your outdoor sample there was not any Curvularia, but if you were to take another sample you may have some. I am not aware of any specific health effects Curvularia poses to immunocompromised people, however, Aspergillus can cause infections called Aspergillosis in immunocompromised people so the issue should be addressed.

    The goal of remediation is to physically remove the mold, not kill it with chemical treatments. I would strongly suggest a remediation company that will perform the work according to IICRC S520, and also hiring someone to assess the moisture issues that is causing mold growth in the first place.

    Dear Dylan,
    My son’s Kindergarten classroom was recently tested for air quality in August. I requested a copy of the full report but am struggling to interpret the data. The “quiet” test found 2,100 total Penicillium/Aspergillus types (105) and the “disturbed” found 2,500 total types of Penicillium/Aspergillus types (120). The quiet fungal count of fungal structures was 420 and disturbed was 480. Can you please let me know if these numbers pose any health risks? I am seriously considering placing my son at a different school but want to make this decision with as much accurate information as possible. He has a history of allergies and asthma runs in the family.
    Thank you very much for your time.

    To have any sort of interpretation I would need to have information from the outdoor air at the time of sampling. 2,100/2,500 can mean different things depending on the naturally occuring outdoor conditions.

    my home mold test result shows counts per square centimeter, all results I see on the internet are per square meters. How high aren this results? Aspergillus/Penicillium-Like Raw count 24. Count/cm2, 960
    and Cladosporium raw count 64,763. Count/cm2, 2,590,520

    This is likely a surface sample, or a passive sample (usually a petri dish left out), and not an air sample. You can not directly compare these results to that of true air sampling which reports in spores/m3