How to interpret your mold air sampling results.

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 opinionative 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:

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 from several locations at once, 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 identify if an active fungal growth or indoor reservoir exists.

 

  • 0-50 spores – These are trace levels of mold concentration and are 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 – Medium 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.
  • 4,501-10,000 spores – Medium 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%.
  • 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%.
  • 25,001-75,000 – Very high levels of mold concentration. Clean up 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%.
  • 75,000-1,000,000+ – 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%.

The above levels are based on total mold counts.

Any use or distribution of this document must include citation and credit per the following copyright statement: 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 - www.baldeagle.biz - (518) 488-2538) ALL RIGHTS RESERVED.

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 www.baldeagle.biz for more information.