How to read a mold report

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 results, always consult with your physician if you are experiencing a medical condition. Mold screening and/or indoor air quality testing is only good for the time and date which the sample was taken. Because sampling is considered a snapshot in time, in some cases retesting at a later date may be advised.

Common Mold Species

Ascospores (ascomycetes) – A common spore type found everywhere in nature. Ascospores are attracted to humid conditions.
Penicillium/Aspergillus – A common mold species found 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 a moisture 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. Basidiospores may be an indicator of wood decay.

Cladosporium – One of the most commonly and frequently found molds 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.
Epicoccum – A common spore type found on decaying plant matter, but indoors Epicoccum can grow on many different substrates including paper, textiles, and insects.

Toxic Mold Species (Toxic spores should always be eliminated)

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. A known water marker. For more information on Chaetomium please visit: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC262481.

Fusarium – Commonly found in soils and can be associated with plants. Most species are harmless, however, some species found indoors can cause skin infections. A known water marker. For more information on Fusarium please visit: https://pubmed.ncbi.nlm.nih.gov/11964778.

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

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: https://www.apsnet.org/edcenter/apsnetfeatures/Pages/Stachybotrys.aspx

Ulocladium – Ulocladium can be found on a variety of materials including Soil, dung, paint, grasses, fibers, wood, decaying plant material, paper, drywall and textiles. A known water marker. For more information on Ulocladium please visit: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3279772.

Miscellaneous Particles

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 suspended 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 not an issue. Level of health concern or air quality conditions per EPA Air Quality Index would typically align with “good”. 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. Level of health concern or air quality conditions per EPA Air Quality Index would typically align with “good”. Still considered extremely clean.
  
• 501-1500 spores – Low levels of mold concentration. Considered acceptably clean. Level of health concern or air quality conditions per EPA Air Quality Index would typically align with “good”. 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 – Moderate levels of mold concentration. Level of health concern or air quality conditions per EPA Air Quality Index would typically align with “moderate”. 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. Retesting at 4 months is recommended to verify spore levels are stable or have improved.
  
• 3,001-4,500 spores – Slightly elevated levels of mold concentration. Level of health concern or air quality conditions per EPA Air Quality Index would typically align with “unhealthy for sensitive groups”. 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 exist. 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. Retesting at 4 months is required to verify spore levels are stable or have improved.
  
• 4,501-10,000 spores – Elevated to high levels of mold concentration. Level of health concern or air quality conditions per EPA Air Quality Index would typically align with “unhealthy for sensitive groups”. 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. Level of health concern or air quality conditions per EPA Air Quality Index would typically align with “unhealthy”. 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. Level of health concern or air quality conditions per EPA Air Quality Index would typically align with “very unhealthy”. 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. Level of health concern or air quality conditions per EPA Air Quality Index would typically align with “hazardous”. 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, vacating the area.

The above levels are based on total mold counts. To better understand the health impacts of total mold counts, Bald Eagle Inspection Services has aligned total mold counts with the EPA AQI. For more information regarding Air Quality Index (AQI), please visit the EPA’s website at: https://www.airnow.gov.

Building Biology Sporetrap Interpretation Method: