1	IAQ & Mold “Testing” Examining the Validity of Current Indoor Mold Sampling Techniques
2	About this presentation: Opinions based on observations of Field investigations 1978-2005 Sample contents 1986-2005 By same person making field investigation and lab analysis Influenced by academics in aerobiology, mycology, IH, engineering, sciences
3	Agenda - Shortcomings and Errors of Popular IAQ Tools Air sampling counts (spores/M³ of air) are inaccurate causes of particle level variation Tape samples – surface selection errors Vacuum samples surface vs. cavity vs. insulation Cultures not so great for screening
4	Why Investigators Look at Air
5	Collecting Airborne Particles
6	Measuring Airborne Particle Levels Scan a whole trace at low X Count >= 25% of trace at 480x or 720x (ID & count important particles) Calculate Spores/M³ of air for that trace (i.e. for that 6 minute interval) Spores/M³= (raw count/%of trace)x(1000/trace vol) Example 17,840 Aspergillus niger spores/M³ of air – BUT how accurate is this procedure?
7	Particle Trace Variation Successive 90L Samples 6 min. on, 6 min off
8	Particle Trace Variation Among Two successive 90L samples 6 minutes apart
9	Counting Spores/M³ of Air Problem: extreme variation in airborne particle levels occur over very short intervals Fallacy: interpreting specific “counts” i.e. “air tests,” as “exposure” without other building diagnosis, may be unreliable
10	How Far Off ? It depends … A precise count -- 11,543 spores/M³ may be highly inaccurate, off by a factor of 10 -- 115,430 spores/M³ 100 -- 1,154,300 spores/M³ This means at least 1-2 orders of magnitude of error, misrepresenting the actual longer term exposure level. Precise doesn’t mean accurate.
11	Some Causes of Short Term Airborne Particle Level Variation Spatial Variation e.g. 1 room, two close locations
12	Passive/Aggressive Sampling Procedural Variation Passive in Plenum
13	Convection Airflow Variation Building stack effects Building ventilation – passive (windows, temperatures)
14	"Mechanicals operation Variation -" Mechanicals operation Variation - A/C or heat on/off
15	More Causes of short term variation in indoor air particle levels Human/animal presence, even if “sitting still” Mechanical disturbance – walk on carpet Ceiling fans Local environment changes affect spore release (wind on bldg, rain, RH, temp. season, etc.)
16	Counts without diagnostic inspections? The absolute number is “wrong” The count interpretation based on building conditions is more important than the absolute number. Cannot interpret a count if there was no diagnostic inspection no recording of test conditions
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18	Comments on the Spores/M³ Table High spore counts may not correlate with high physical activity A previous event may produce high levels of moldy dust in an apparently clean area A large hidden mold reservoir may be present outside the remediation area Relative counts were important in this case Further investigation is needed
19	What do “Spore Counts” Mean when obtained as a simple “air test” It Depends. High (>10k problem spores/M³) = contaminated (somewhere) Medium = ambiguous Low = ambiguous (look at species and chains) Zero = ambiguous (Was the basement door shut?)
20	Diagnostic inspection + invasive measures + physical samples, e.g. tape, was very important here where the spore count was low
21	Air Sampling Conclusions Short duration indoor airborne particle counts of spores/M³ of air are Subject to extreme variation minute to minute for many reasons Not repeatable Precise does not mean accurate And Building conditions affecting the sample need to be documented Counts should be interpreted in light of a careful diagnostic inspection
22	Adhesive Tape Surface Samples Collect visible mold Exposed surfaces or by cavity invasion Collect settled dust Collect HVAC inlet, supply, filter debris Inexpensive, rapid, often definitive Spores, Conidiophores, Fungal hyphae Other diagnostic particles Examine non-viable or culture (maybe)
23	Tape Sampling Limitation Spatial Variation of Mold Genera
24	Tape Sampling Limitation Spatial Variation of Mold Genera
25	Tape Sampling Limitation Selection Error: Take Easy-to-See Mold
26	Tape Sampling Limitation Selection Error: Skip Hard-to-See Mold
27	Vacuum Samples (Air-O-Cel ™ or MCE Cassette) Some Good Uses Include Multiple surfaces – dust screening Carpet, furniture, soft-goods Support both viable and non-viable qualitative analysis
28	Important Vacuum Sample Building insulation – the under-estimated common large mold reservoir in buildings can be pinpointed
29	Vacuum Sample Limitations Surface vacuums leave important mold structures on the surface (use tape) Vacuums do not collect sticky and non-sticky spores with equal success (use tape) Small-bore wall cavity vacuums are unreliable (compared with test cut) Not enough air movement in cavity Short Air-O-Cel™ easily overloaded Long MCE samples, too few or too costly
30	Cultures to "Test for Mold" Settlement plates – “Home Test Kits” Rely on gravity, large spores fall faster
31	Cultures to "Test for Mold" Settlement plates False negative results (Chaetom. & S. chart.) Possible false positive results
32	More Culture Limitations Only 10% of all molds will grow on any culture Cultures as screens may be 90% wrong What grows in the culture is what likes it What does not grow may be what was important
33	Moldy Tea Results MEA grew Cladosporium DG-18 grew Aspergillus niger, A. flavus, A. glaucus and Penicillium sp.
34	Mold cultures Great to try to coax out and ID an unknown – if culturable Great for photographs – if culturable Great for detailed speciation studies – if culturable May identify a problem in a building, if culturable - else maybe not: 10% vs. 90%!
35	Polymerase Chain Reaction Works by amplification of nucleic acids (DNA cloning) Highly accurate identification to species Limited data base (being expanded) Ideal to look for a specific mold May not be useful as a broad screen –have to look for specific targets
36	Some Lab Limitations Expertise at fungal spore identification PAACB - the only fungal spore identification certification exam www.paacb.org EMLAP/Culture ID/Lab Procedures - AIHA Workload – who’s really examining the sample? Expertise in microscopy and slide preparation
37	Lab Limitation: Particle Level Variation Due To Microscope Adjustment
38	Conclusions: Mold-IAQ Investigation objectives should include Detect evidence of a hidden problem sufficient to … Justify (or not) invasive measures to … Find and Map Large Mold Reservoirs Permit writing a remediation plan And also Provide baseline comparison samples for follow-up
39	Conclusions: About Sampling Methods, Every tool is useful, but with limitations Air Samples: Spores/M³ of air may be precise but inaccurate Tape samples: collection points are critical Vacuums surfaces & insulation-yes, but wall vacs-doubtful Cultures: 10% chance (maybe more) Investigators should document building conditions affecting sample (simple “air tests” are ???)
40	"Fulltext version of this paper" Fulltext version of this paper: InspectAPedia.com/mold/Mold_Test_Method_Validity.php Both full-text and this Power Point version (illustrated) are © 2005 Daniel Friedman all rights reserved Contact: Daniel Friedman at InspectAPedia.com/Contact.htm
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