The Most Popular Mold Testing Methods

Below are the five most widely used methods of taking mold spore samples from the air during mold inspections. They are used by scientists, industrial hygienists, and mold inspectors.

These mold testing methods have been proven over and over by time, legal trial, and third party scientific lab verification for reliability taking into account many complex factors related to aerodynamics and physics. Surface sample methods just do not provide as much quantitative info as the following 5 air sample methods.

1) An Air-O-Cell non viable spore trap with pump calibrated and run at 15 LPM typically run from 1 to 15 min.

2) A Micro5 non viable spore trap with pump calibrated and run at 5 LPM for 1 to 5 min.

3) A CyClex non viable impactor with pump calibrated and run at 20 LPM for 1 to 10 min.

4) A CyClex-d non viable spore trap with pump calibrated and run at 20 LPM for 1 to 10 min.

5) A single stage viable impactor plate, such as an Andersen Impactor or one of it's exact duplicated clones (such as an Aerotech 6, or ems E6 with a pump calibrated and run at 28.3 LPM for 1 to 5 min.

The Cyclex from method # 3 above is not used as much as some other methods because it requires a larger up front investment on the part of the mold testing firm. $400.00 one time purchase of a reusable sampler as apposed to the free one time use plastic cassettes provided y labs. In addition to testing 200 liters of air with each sample the CyClex sampler developed by Environmental Monitoring Systems also has a cut off diameter (d50) the size of the smallest spores, this means tiny pen / asp spores just 2 or 3 microns across do not pass through the device and escape unnoticed. Also, the Cyclex typically samples 200 liters or 1/5 of a cubic meter of air, thats a good amount for an air sampler, the more air sampled the more statically reliable the results.

The first four methods above are non viable spore traps, this means that live and spores are collected in the sample device to give an idea of the total estimated number of spores per cubic meter of air. This sampling method does not miss spores. This is very important because often spores can be allergenic or potentially toxigenic, regardless of whether they are live.

The fifth method above is used for viable air testing. It is not as widely used by mold inspectors because like the CyClex it to has a higher initial investment in equipment around $500.00 for a stainless steel impactor plate with 400 tiny precession drilled holes, as apposed to a simple plastic air testing cassette provided for free by the lab. Also, viable sample results have a longer turn around time 7 to 10 days as apposed to about 3 days for viable methods. Viable sample means that only live mold colonies from live spores or live colony forming units are counted. Though this method does not allow the counting of spores, it is a very important and respected sampling methodology used by professionals for around from the 1950's to the present. It allows for the culture of live mold in the lab. Thus, entire colonies can be examined in the lab for more accurate identification of mold types, sometimes even to the species level.
Indoor v.s. Outdoor Mold Spore Levels

The most widely accepted guideline across the nation to help determine if indoor mold spore levels are indicative of a possible mold problem is the comparison of indoor and outdoor mold spore levels. Indoor mold spore levels should be similar to or lower than levels found outdoors, and the types of mold spores found in indoor mold test samples should be similar to types found in outdoor test samples. The below listed organizations and governing bodies support the above comparison method and have determined that indoor mold spore levels should be similar in number and type to outdoor mold spore levels and types: NYC DOH, ACGIH 1989, Canada M&H CO. 1991, ACGIH 1993, OSHA 1994, and Brazil 2000.

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