Spore Trap Air Sampling
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Introduction

Fungal spore trap air samples are collected using a sampling cassette attached to a high volume
vacuum pump.  Air is drawn through the cassette and the contents of the air are deposited upon a
sticky glass slide which is then analyzed by an analyst who identifies fungal types and quantity.  
Spore trap sampling is a tool that provides a snapshot of the types and concentration of airborne
fungal spores (viable and non-viable) present in the indoor environment at the time of sampling.
Qualtest, Inc. provides spore trap analysis for a variety of sampling cassettes including Micro5,
Allergenco, Air-O-cell, Burkhard and Cyclex D.  Analysis includes identification to genus or group
of all fungi present, quantification to spores/m3 and % of each spore type. A general assessment of
background debris is determined.

Advantages

    •  Useful for initial site testing, especially if fungal growth is not visible.
    •  Can reveal presence of hidden mold.
    •  Easy to use and handle in the field .
    •  Low chance of sample contamination.
    •  Provides rapid turn around time.
    •  Rush analyses available upon request.

Disadvantages

    •  Some fungi that produce wet spores can be missed.
    •  Spore viability cannot be determined.
    •  Fungal spores cannot be cultured.
    •  Fungi cannot be speciated to the species level with this method.
    •  Some spores cannot be differentiated due to similarity in size and color.

Recommendations

    •  Recommended flow rate is 15 lpm.
    •  The sampling time is dependent on the density of particulates in the environment.

    Clean "office" or outdoors with no visible dust.                                   10 minutes
    Indoor environment, high activity & personnel.                                     5 minutes
    Heavy dust or dirt visible in air.                                                               3 minutes
    Indoor environment, drywall renovation or heavy industrial dust.      1 minute

    •   Obtain an outdoor sample to be used as a comparison to the indoor samples.  
    •   Sending a blank cassette for analysis periodically is a good practice.

Spore Trap Results Interpretation

To date there are no standardized methods for analyzing spore traps. There are at present no strict
numerical guidelines which are appropriate for assessing whether the contamination in an area is
acceptable or not.

  •  Keep in mind that the results of the total spores (raw counts) are used only for screening
purposes and that the spore concentration has a statistical deviation depending on the
analyst.

  •  The amount of fungal spores present in an air sample is highly variable. Changes in airflow,
humidity, light level and temperature can all trigger a spore's release. A single air sample will
often underestimate the fungal contamination in the air.

  •  Compare total concentrations of fungal spores from outdoor and indoor samples. Generally,
indoor fungal spore concentrations are lower than that of the outdoors. This comparison is
not valid when the outdoor sample was taken during or immediately after precipitation. It
probably is not valid during some winter months where outdoor fungal counts are usually
below that of the indoors.

  •  Compare fungal spore types from indoor and outdoor samples. Fungal spore types from  
indoors and outdoors should be generally similar. When you compare indoor and outdoor
spore types you should consider the following:

           a.   Fungal species are present in the indoor sample and not in the outdoor sample.

           b.   The predominant fungal species found in the indoor sample is different than the
                  predominant fungal species in the found outdoor sample.

           c.   If there is a difference in the fungal spore diversity between indoor and outdoor
                  samples, this may be an indication of indoor amplification.

  •  Look for indicator fungal spores. Some fungal spores, when detected in indoor environments,
are good indications of water damage.

  •   Spores of Chaetomium, Stachybotrys, Memnoniella and Ulocladium are likely
associate with water-damaged buildings.

  •   When Aspergillus/Penicillium-like spores found in indoor samples are significantly
higher than that of outdoors, this would indicate that it is a water-damaged
environment.

  •   Cladosporium species are common outdoors, however, they grow well indoors on
surfaces with high moisture contents.

  •  When Basidiospores are detected in air samples, they are likely to come from outdoors.
However, basidiomycetes may grow on indoor wood products causing wood decay if
there is a high moisture related problem.

  •  Rusts, smuts and Oidium spores when detected in air samples, they are likely to come
from outdoors or indoor house plants infected with fungal diseases.

  •  Use Chaetomium, Stachybotrys and Ulocladium as indicators of fungal contaminants
for a mold remediation project.

  •  A negative finding does not prove the absence of fungal spores in the air sample, but      
indicates that the spores were not detected.  A combination of results of air samples
and visible inspection is recommended in drawing conclusions.  

  •   Non-microbial particulate levels may mask fungal structures, giving false low counts.
The non-microbial particulate (debris) levels are rated as follows:

  •  Low: 0-25% of slide covered, this may show slightly decreased counts.

  •  Moderate: 26-75% of slide covered, actual counts may be from 1-4 times higher
than reported.

  •  Heavy: >75% of slide covered, actual counts may be from 4 - 10 times higher
than reported.
Fungal Sampling Information
Non Fungal Sampling
Information
Chain of Custody (Normal)
Qualtest, Inc.   2458 Alton Parkway   Irvine, CA   92606 Phone: (949) 838-0378
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Qualtest, Inc.
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