How to interpret your mold air sampling results.

Due to popular demand, we have now added a service to interpret mold results for clients all over the globe. We provide review, interpretation and recommendations based on your mold results from other vendors and contractors. If you would like to engage this service, please use the contact us page or the link below to open an email, send us a copy of your results and we will respond with further information on how we can provide this service. This service will provide you with our most up to date published interpretations and site specific written interpretations on letterhead. 

Many have asked me about how to interpret indoor air quality results. Since there is very little to be found regarding mold test results and air sampling interpretation on the web, I have decided to share this information with the world.

The following information is unofficial and opinionated in nature and is to be used as a guide to help understand mold concentrations. I have developed this guide through many hundreds of successful mold remediation projects. This guide shall not be considered a final conclusion of mold remediation requirements.

Mold Spore Level Guide:

DISCLOSURE: The information contained in this document is unofficial and opinionated in nature and is to be used as a guide to help understand mold concentrations. This guide shall not be considered a final conclusion of mold remediation requirements and does not guarantee end results. Furthermore, this guide shall not be used to anticipate end medical result, always consult with your physician if you are experiencing a medical condition.

The Most Relevant Mold Species:

Penicillium/Aspergillus – The most common mold species to show up in Indoor and outdoor air samples. Most of the hundreds of sub-species are allergenic with only a few that are toxic. This group of species will grow with only the humidity in the air as its water source (even in relatively clean, mold-growth-free, indoor environments). Levels vary based upon activity levels, dustiness, weather conditions, outside air exchange rates, and other factors.

Basidiospores – Basidiospores are extremely common outdoors and originate from fungi in gardens, forests, and woodlands. It is rare for the source of Basidiospores to be indoors. However, Basidiospores may be an indicator of wood decay.

Cladosporium – One of the most commonly found molds outdoors and frequently found growing indoors. Spores from Cladosporium are generally present in outdoor and indoor air, even in relatively clean, mold-growth-free, indoor environments. Levels vary based upon activity levels, weather conditions, dustiness, outside air exchange rates, and other factors.

Curvularia – A common allergenic mold. Curvularia can grow on a wide variety of substrates.

Chaetomium – A common water marker that usually indicates wet paper and/or drywall. Chaetomium growth can be widespread, cellulolytic and very commonly found on damp sheetrock paper.

Stachybotrys – A common water marker and the most common toxic mold species. Stachybotrys is rarely found indoors, but when found, is an indication of a problem. Stachybotrys can be considered elevated at a very low concentration. Stachybotrys is commonly found indoors on wet materials containing cellulose, such as wallboard, jute, wicker, straw baskets, and other paper materials. Stachybotrys are widely considered the most hazardous form of indoor mold and are mycotoxin producing and must be removed. Whenever Stachybotrys are present, air sampling is highly recommended for clearance confirmation. For more information on Stachybotrys please visit: www.apsnet.org/publications/apsnetfeatures/Pages/Stachybotrys.aspx

Memnoniella – A similar species to Stachybotrys and is treated similarly. Memnoniella can grow on a wide variety of substrates.

Hyphal Fragments – An indicator of fungal growth. Hyphal fragments are the fruiting structures of mold (such as a tree has branches and a plant has stems). Hyphal fragments typically settle quickly, therefore, the presence of high amounts of hyphal fragments (above 100/m3) suggests an active fungal growth is nearby.

Single Clump and Clumped Spores – Clumped spores are heavier than a single spore. Clumped spores typically settle quickly, therefore, clumped spores collected in media suggests an active fungal growth is nearby.

Conidiophore – Are similar to hyphal fragment but also bears spores. Conidiophore typically settle quickly, therefore, the presence of conidiophore suggests an active fungal growth is nearby.

Mold Spore Level Guide:

Identification of an active fungal growth or indoor reservoir can be extremely difficult without scientific testing, also known as scientific confirmation. Swabs, tapes and bulk samples are considered the lowest form of scientific confirmation as it only addresses a small localized area of confirmed mold growth. Swabs, tapes and bulk samples are capable of identifying mold types, but do not indicate the size of a mold contamination due to their localized testing. From A Swab, tape or bulk sample a lab technician can state the rate of growth or concentration based on the parts of mold structures found.

Some dry or dormant molds found on building materials can be tested by swabs, tapes and/or bulk samples, however, may be nonviable and may not greatly impact or contaminate the air.

Air sampling is considered the highest level of scientific confirmation as it not only confirms the presence of mold spores and types, it also indicates the quantified amount of mold spores in the air. This information can then be interpreted to understand the potential impact to health as mold spores caught in the air can be inhaled into the lungs. Mold spores found in the air are typically viable, meaning if conditions are favorable, they are able to grow.

Air sampling must be compared to an exterior control sample. An exterior control is compared to interior samples for elevations in spore types and or the presence of spore types absent in the exterior. The results of this comparison can be used to assist in identifying if an active fungal growth or indoor reservoir exists.

  • 0-50 spores – These are trace levels of mold concentration and are typically not an issue. Considered extremely clean. Stachybotrys and Memnoniella can be considered elevated at this level and any level above this point.

  • 51-500 spores – Very low levels of mold concentration. Still considered extremely clean.

  • 501-1500 spores – Low levels of mold concentration. Considered acceptably clean. Penicillium/Aspergillus & Cladosporium spore concentrations can be found at this level and can be normal. This mold concentration level does not necessarily require remediation. Normal cleaning and wiping of surfaces can help to reduce spore concentrations below this level.

  • 1501-3000 spores – Slightly elevated levels of mold concentration. Spore concentrations at this level may indicate an indoor reservoir exists. Exterior control results must be compared to indoor samples to identify if cross contamination from the exterior is playing a role. If water or moisture intrusion or visual mold contamination is not found during the assessment, hyphal fragment concentration >100/m3 will help confirm likelihood of a nearby active fungal growth. These levels can be caused by a dusty home or lack of upkeep. Normal cleaning and wiping of surfaces can help to reduce spore concentrations below this level.

  • 3,001-4,500 spores – Moderate levels of mold concentration. Unless there is a corresponding concentration in the exterior control, this is the level where some form of cleanup may be required. If visual mold contamination is identified, then cleanup of that area is required. If water or moisture intrusion or visual mold contamination is not found during the assessment, hyphal fragment concentration >100/m3 will help confirm likelihood of a nearby active fungal growth. These levels can be caused by a very dusty home or extreme lack of upkeep. Vigorous cleaning and wiping of surfaces and an increase in ventilation can help to reduce spore concentrations below this level. If the area is relatively clean, a hidden fungal growth may exists. Mold mapping techniques can be used to identify the location of a hidden fungal growth. Most people with normal immune function can tolerate this level, however, severely sensitive people may experience symptoms during prolonged exposure.

  • 4,501-10,000 spores – Moderate to high levels of mold concentration. Unless there is a corresponding concentration in the exterior control, this is the level where cleanup is typically required. If visual mold contamination is identified, then cleanup of that area is required. If water or moisture intrusion or visual mold contamination is not found during the assessment, hyphal fragment concentration >100/m3 will help confirm likelihood of a nearby active fungal growth. These levels can be caused by a very dusty home or extreme lack of upkeep and lack of ventilation to the area. Vigorous cleaning and wiping of surfaces, increase in ventilation and fungal fogging can help to reduce spore concentrations below this level. If the area is relatively clean, a hidden fungal growth most likely exists. Mold mapping techniques can be used to identify the location of a hidden fungal growth. Relative humidity may be elevated above 60%. This is the level where some people with normal immune function may experience symptoms during prolonged exposure.

  • 10,001-25,000 spores – High levels of mold concentration. Unless there is a corresponding concentration in the exterior control, this is the level where some form of cleanup is required. Hyphal fragment concentration will be elevated above 100/m3. Fungal growth size can range from >10sf and larger. If visual mold contamination is identified, then cleanup of that area is required. If water or moisture intrusion or visual mold contamination is not found during the assessment, a hidden fungal growth is near. Mold mapping techniques can be used to identify the location of a hidden fungal growth. Relative humidity may be elevated above 60%. This is the level where most people with normal immune function will experience some form of symptoms during prolonged exposure. Restrictions to these areas may be implemented.

  • 25,001-75,000 spores – Very high levels of mold concentration. Cleanup will be required and most likely requires a Professional Mold Remediator. Hyphal fragment concentration will be elevated above 100/m3. Fungal growth size is typically >100sf. Relative humidity is typically elevated above 60%. This is the level where nearly all people with normal immune function will experience symptoms during prolonged exposure. Restrictions to these areas may be implemented.

  • 75,000-1,000,000+ spores – Extremely high levels of mold concentration. Professional Mold Remediator will be required. Hyphal fragment concentration will be extremely elevated. Fungal growth size is >100sf. Relative humidity will be elevated above 60%. Mold exposure at this level is considered hazardous for human occupancy, vacate the area.

The above levels are based on total mold counts.

Building Biology Sporetrap Interpretation Method:

 

Reference: www.Healthybuildingscience.com

Plant and Organic Matter:

Houseplants and indoor gardens can increase exposure to indoor mold. Potting soil is composed of an abundance of organic matter, when plants are watered organic matter becomes an ideal location for mold to grow. Clients with many plants should be aware of the possible negative impacts to indoor air quality when improperly cared for. Contact your local Horticulturalist for more information on properly caring for your plants to minimize mold.

Testing Protocol:

Bald Eagle Inspection Services, LLC only uses testing devices which are in normal and accurate working condition. The pumping equipment is a digital Zefon Bio-Pump Plus. This equipment is highly accurate and requires no cleaning prior to sampling. There is no possibility of cross contamination from prior test locations. The pump equipment can be field calibrated and is calibrated at each sample location.

The collection media is Zefon Air-O-Cell cassette, calibrated at 15L/Min. All exterior samples are collected at 10 minute sampling time for a total volume sampled of 150L. All interior samples are collected at 5 minute sampling time for a total volume sampled of 75L. Sampling procedures are as per Zefon International Air-O-Cell cassette Laboratory and User Manual guidelines.

All samples are sent FedEx overnight to a certified and accredited laboratory for professional analysis. Results are delivered within 24 hours of receipt by lab.

Please feel free to contact me with any further questions.

Bald Eagle Inspection Services, LLC provides experienced and extremely high quality Mold Inspection services serving all areas of Upstate New York, including Saratoga Springs, Malta, Ballston Spa, Clifton Park, Rensselaer County and upper Albany County. If you or someone you know is interested in a mold inspection, please visit Bald Eagle Inspection Services, LLC for more information.

The wording and formatting of this document is protected by 2017 copyright law (C). All wording and formatting of this document is property of Bald Eagle Inspection Services, LLC. Plagiarism of any wording or formatting of this document is taken seriously and is not acceptable without the expressed written consent of Bald Eagle Inspection Services, LLC. Written content and formatting is considered intellectual property of Bald Eagle Inspection Services, LLC. Any use of this intellectual property must be properly cited as (property of Bald Eagle Inspection Services, LLC – (518) 488-2538) ALL RIGHTS RESERVED.

22 thoughts on “How to interpret your mold air sampling results.”

  1. The mold test result shows Aspergillus/ Penicillium count of 2554, Chaetomium 10949 and hyphal fragments 1460. The air quality Alternaria 13, Aspergillus 2347 and Cladosporium 80.
    The mold remediator says we need to open the drywall. There’s no trace of mold on wall, just behind the baseboards where he took the swab.
    Should I go ahead with remediation?

    Reply
    • These levels fall under the high level category. I would follow your assessors recommendations. At these levels you should have a post remediation retest to confirm levels have returned to normal. If you choose to do the job in steps you still have a check and balance in the post remediation testing.

      Reply
  2. What a lab interpretation method should be taken for the air sampling test conducted in a house?
    – Spore trap standard
    – Spore trap with OBP summary
    – Spore trap full report
    – Spore trap horizontal

    Thank you in advance

    Serguei

    Reply
  3. Had major water damage in bathroom and kitchen: water mitigation began 8 days later: Air sample showed Chaetomium at 11200 and Pen/Asp at 7920 in bathroom, Chaetomium at 4160 and Pen/Asp at 2400. Mold remediation was recommended. Building Management sent in their own mold assessor who said his company does not believe in air samples, did visual inspection and saw no mold but saw effervescence on bathroom wall tiles, moisture meter on bathroom ceiling showed slight moisture, other walls dry. Took some patch samples of wood floor which showed water damage and wall samples.

    Which approach is correct? How do I know if I really have a mold problem?

    Thank you in advance.

    Sylvie

    Reply
    • Sylvie,

      Thanks for the comment. I can tell you that those air sample results are above desired levels in all areas.

      Personally whenever there are cavities involved I do like to take air samples because the sampling can indicate what is going on in an area. You can get a good idea of magnitude of the damage based on the air samples. I also like to take a post remediation air sample. I would be looking there to verify that the sampled results have come back down to a normal level. This strategy can indicate if more hidden mold exists. Some states will tell you that sampling is not required to perform a mold assessment, its not, but I believe it does provide a better quality service. An assessor that doesn’t believe in air sampling may not be trained on how to perform them. They can greatly improve discovery. As the contractor stated, he didn’t see any visual mold, but I would assume based on those numbers that mold exists.

      If you would like me to help you out, feel free to fill out a request form on my website at http://www.baldeagle.biz

      Reply
    • Sylvie,

      Thanks for the comment. I can tell you that those air sample results are above desired levels in all areas.

      Personally whenever there are cavities involved I do like to take air samples because the sampling can indicate what is going on in an area. You can get a good idea of magnitude of the damage based on the air samples. I also like to take a post remediation air sample. I would be looking there to verify that the sampled results have come back down to a normal level. This strategy can indicate if more hidden mold exists. Some states will tell you that sampling is not required to perform a mold assessment, its not, but I believe it does provide a better quality service. An assessor that doesn’t believe in air sampling may not be trained on how to perform them. They can greatly improve discovery. As the contractor stated, he didn’t see any visual mold, but I would assume based on those numbers that mold exists.

      If you would like me to help you out, feel free to fill out a request form on my website at http://www.baldeagle.biz

      Reply
  4. Thank you for great info. I had air sample done and it showed 16760 total fungi in the crawl space and 10560 exterior. The interior and exterior where measured for 5mi. 75L. Would this be considered high for the crawl space? Thank you Stacey

    Reply
    • The 5L for 5min (total 75L) indicates the person conducting the test ran it as if the area was considered livable interior area. Typically I wouldn’t air test non-livable spaces and would rely on a visual. However, yes, these numbers do indicate high levels of mold contamination. I would expect to see mold growth someplace. The questions is, can that mold make its way to the interior environment. I would suggest testing there.

      Reply
  5. I received an air report for Chaetomium in the basement at 53 count/m3, and 13 count/m3 on the first floor near the HVAC return (There was also Aspergillus/Penicillium at 433 count/m3 in the basement – which was elevated above the outside baseline which was 227 count/m3). Those were the only two molds elevated above outside control. The basement has carpet, and we noticed a small amount of water intrusion in the corner. Generally the basement did not smell very musty, except near the corner with a bit of water. The HVAC air handler for the first floor is in the basement, so I wonder if the ducts are contaminated since we saw Chaetomium on the first floor near the return.

    Wondering how big of an issue this is – we didn’t see any visible mold anywhere in the basement. Was curious if getting rid of the carpet in the basement could clear up the issue (we could do air sampling afterwards to determine), or if we should immediately clear out the carpet as well as the drywall in the basement.

    Reply
  6. Hi I’m currently in the process of purchasing a home and I had a mold inspection done. The results are :
    Aspergillus/Penicillium (raw count 8)(count 200 ) of the master bedroom compared to the exterior of: Aspergillus/Penicillium (raw count 3) (count 70)
    This is normal right??
    The overall total fungi numbers are : (raw count exterior 33) (count exterior 660) vs. (interior raw count 18) ( count interior 460)

    Reply
  7. What size air sample are you using for the concentration levels above? Or am I misunderstanding the text above? I got a DIY mold test kit that used a small petri dish to collect an air sample. It has mold spores in the gel. However, I’m not sure if your number ranges above are designed for such a small surface area, and the larger numbers seem like there would simply not be enough surface area of a petri dish to have that many spores collected. I counted roughly 25 spores in the 2inch diameter petri dish.

    Any help or comments are greatly appreciated.

    Reply
  8. My air quality test results revealed Penicillium/Aspergillus with a raw count of 230, spores/m3 at 1,541, and % of total at 73. There appears to be no mold visible but I am looking to purchase this home and want to be sure how to proceed with the results and get your input as to why those levels are so high. The home is sitting vacant and all closed up with the A/C running. Also, the home is very dirty inside and carpets are in need of being torn out. Anything you can tell me would be very helpful. I would like to put it on the sellers to correct so your recommendations on how to remediate will help me.

    Reply
    • If you did purchase the house, this is what I would do:
      I’d check the air-handler. If dirty, have it cleaned. Then throw the carpet out and thoroughly clean the house.
      If there is no mold visible and no moisture intrusion, chances are that the levels will come down after the cleaning and carpet ripout.

      Reply
  9. I do interpret results for a fee of $100. You would need to email me the results I will review them and if I can provide an interpretation I will respond with a link to make a payment. Once payment is received I would provide a written interpretation on my latter head within 24 hours.

    Reply
  10. Hello,
    I had a mold test done the results were interpreted as passed However I hav been having headaches and repritaory problems during mold remediation and after testing.
    Is it recommended to repeat the mold test?

    Reply
  11. We had our house tested and the bedrooms were fine. Under the house was terrible and penicillium/Aspergillus was as follows- outside air 433, kitchen 4853. There was a leak that occurred 3.5 years ago in the ceiling of the kitchen and recently my son overflowed the upstairs sink affecting the same (or very close) ceiling subfloor. There are no visible signs of mold from the previous leaks-should we rip up the ceiling? We just got the mold in the crawl space remediated. Could the mold remediation under the house help the levels in the kitchen?

    Reply

Leave a Comment

Call Now Button