Mold Testing ? Importance and Challenges

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Mold Research

Is mold testing necessary?

If mold is visible on the walls or roofs of a building, testing for mold is not necessary. Remediation experts can be called in to deal with the problem. On the other hand, if there is a reasonable doubt about the indoor air quality due to symptoms of mold exposure arising in the residents, yet no obvious signs of toxic mold are found, a mold consultant may have to inspect the premises.

Methods of Testing for Toxic Mold

  1. Non-viable testing involves collection of a specific volume of air samples with a sampling machine or a calibrated pump and capturing the airborne particles on a test slide or a patented cassette such as an Air-O-Cell cassette. The slides with the mold spores are examined in the lab under high magnification. If several samples are taken, magnified microphotographs can be used for visual comparison. To get a detailed picture, stains and polarized light technique may be used. Spore counting may be done when the sample is magnified between 400X and 1920X, to find the number of spores/M3.
  2. Viable testing is done by culturing the mold sample obtained by swabs, settlement plates or an Anderson sampler. Testing for different types of molds is done after culture. However, many types of toxic molds that are capable of causing symptoms of mold exposure, the black mold Stachybotrys in particular, have a large number of dead or non-germinating spores in samples taken indoors. This often gives inaccurate results and cannot be used as a measure of indoor air quality.

The Major Flaws in Indoor Air Quality Testing

  • Inaccuracy in sample collection

    Conditions prevailing at the time of testing affect accuracy as mold counts keep changing. Even slight disturbance can give false reading.

  • Lack of scientific basis for determining air quality

    Comparing the indoor and outdoor mold counts to determine the indoor air quality is unscientific as indoor toxic molds that cause mold exposure symptoms are different from many molds like basidiomycetes growing outside. It is like comparing oranges to apples.

  • Lack of consensus on safe and acceptable level of mold count

    ‘Safe levels’ are arbitrary and subjective. It depends greatly on the occupants of the building too. Immunocompromised people, infants and the elderly are more likely to present symptoms of exposure to toxic molds such as Stachybotrys.

  • Variation in toxicity

    Not all molds are toxic, and some molds like Stachybotrys and Aspergillus can cause worse symptoms of mold sickness than other less toxic molds. Even the same molds growing outside differ in toxicity from the ones growing indoors as mycotoxin ?production, the source of the neurological symptoms of mold poisoning, is a response to adverse environmental conditions.

  • How to Conduct Mold Testing for Best Results

    • A mold consultant having specific experience in the given field should conduct the test.
    • Inspection of the building and surrounding areas should be carried out in order to identify potential and real problem areas.
    • Building history with respect to incidents of flooding, leaks, plumbing problems should be studied carefully.
    • Occupants of the building should be interviewed to learn about their health problems and vulnerabilities. They can point out problem areas from musty smells and discomforts they have experienced firsthand.

Only a thorough study of the entire building along with air sample testing can give a reliable picture of the indoor air quality issues.

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