Healthy Indoors Magazine
Issue link: https://hi.healthyindoors.com/i/1095622
26 | March 2019 The Spore-Trap Trap By Jack Springston, CIH, CSP, FAIHA T hose of you who know me know that, for years now, I have had issues with the ongo- ing proliferation of certificates and certifica- tions in the indoor air quality (IAQ) and mold profession. By last count, the American Council for Accredited Certification (ACAC) has 12 different contractor and investigator certifications related to IAQ, and another 8 certifications relat- ed to mold and moisture control. In addition to ACAC, there are a multitude of other groups and organizations who also issue their own somewhat dubious certifications related to IAQ and mold. You say you want to be a "Certified Formaldehyde Sampler" and do testing in homes with laminate flooring? No problem, just step right up, pay us a bunch of money, take one of our training classes, and, wham, now you are certified! With the enactment of the New York State mold regulations, for example, I think it's safe to say we will be seeing a whole new generation of 2-, 3- and 4-day wonders who will be able to point to their state issued licenses and proclaim that they are mold "experts". In New York, the new mold assessor des- ignation is responsible for determining the clearance criteria of mold remediation projects. It is a certainty that, not knowing any better, many of these newly minted "experts" will choose to collect spore trap samples and assign some sort of arbitrary criteria without ever understanding the shortcomings and pit- falls of this methodology. Flow rates and inertial impaction Standard spore trap sampling devices function by pulling air through a sample slit, which accelerates the particles in the air stream, and then fling those particles at a small glass slide that is covered with a sticky sampling media (think fly- paper or a glue trap). The device works on the principal of inertial impaction, which I described in some detail in my June 2015 article for Healthy Indoors ('Ghosting and things that go Bump'). Short version – when air sharply turns and bends, particles in the air stream tend to keep moving in a straight line and bump into stuff. The bigger the parti- cles, the more likely they will hit the surface and stick. The smaller the particles, the more likely they will bend with the air and pass right by. Each manufacturer has their own optimal flow rate for their samplers and cassettes, which is designed to try to ensure that as many small particles as possible will be captured. If the flow rate is too slow, then