Particle Levels vs Sampler Height Variations When Air Sampling for Mold
PARTICLE COUNTS vs SAMPLER HEIGHT - CONTENTS: How does air sampler height affect mold counts or mold sample results?Airborne mold tests on and below a moldy game table demonstrate large variation in indoor mold levels. Use of spore traps and air samplers for indoor mold inspections is inaccurate. Just how accurate and valid is air sampling for toxic mold testing?
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This article discusses Mold or Airborne Particle Levels versus Air Sampler Height when testing for airborne mold.
This document is a brief tutorial which provides information about the accuracy of and sources of errors in tests for the level of allergenic and toxic mold in residential buildings: Are
spore counts valid? Are cultures and swab tests valid? These critical questions are discussed in this paper.
Variation in Airborne Particle Levels due to Placement Height of Air Sampling Device
How much difference does it make whether the air sampling machine is placed on top of or underneath a mold-contaminated table?
The photographs above show microphotographs of representative sections of an airborne particle sample trace in the same room in
a building, with a single variation: the left hand photograph of a mold spore sample shows just a few fungal spores was collected with our sample placed
on top of a basement pool table.
The right hand photo of a mold spore trap sample shows a very high spore concentration in the same room,
obtained when we placed our sampler on the floor below the (mold infected) pool table. In both samples we used passive methods.
Our photos above show a game table left in a basement where an airborne mold problem was suspected. The table looked "clean" but inspecting below (see our flashlight leaning on the left table leg?) shows thick yellow and green mold growth on the un-sealed chipboard structure.
stirred room air (say by turning on a fan or waving a notebook, it is likely that these "under table" mold spores would have been
distributed more uniformly in the building's indoor air and that they would have been present in an air sample at a much higher level than with passive spore trap air sampler use.
Many IAQ consultants place their air sampler at about chest or head height in a building, presuming that will best represent
the particles that will be inhaled by building occupants. This sounds reasonable except that mechanical disturbance of local indoor
dust will cause enormous variation in the actual particle level at any given time and will probably make the particle distribution
more uniform in the space.
Our field and lab experiments show one to three orders of magnitude (or more) variation in airborne spore counts at the same location depending on the use of passive or aggressive sampling methods.
How many mold reports document the details of sampling such as where mold was visible, where the sampler was placed, and what
possible variations in airborne particle level might obtain depending on details of how the sample was collected such as whether fans are turned on or off, the room was occupied or empty, windows open or shut, vacuum cleaners running, children playing nearby, etc. Virtually never
is this information considered, gathered, or reported by the industrial hygienist or other mold investigator in residential indoor air quality investigations.
How to Interpret Airborne Mold Tests in View of Air Sampling Inaccuracy
We conclude that if an indoor air test for mold such as using a spore trap or air sampling device detects a high level of problem mold spores (or other airborne particles) we believe that those results have meaning and indicate a problem - although that type of test alone is faulty because it is not prescriptive: we still have not identified the source of the problem so we still do not know what action is needed.
But if an indoor air test for mold does not detect a high level of airborne mold or other problem particles, we cannot rely on this procedure alone to reach a confident conclusion about the air quality in the building.
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Thanks to Susan Flappan, Flappan Consulting, moldetect.com, Overland Park KS, 913-402-1131, for contributing comments and some suggested text from ACGIH Bioaerosols: Assessment and Remediation 12/2006.
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Or choose the The Home Reference eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page "Promo/Redemption" space.
Carson Dunlop, Associates, Toronto, have provided us with (and we recommend) Carson Dunlop Weldon & Associates' Technical Reference Guide to manufacturer's model and serial number information for heating and cooling equipment Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.
Kansas State University, department of plant pathology, extension plant pathology web page on wheat rust fungus: see http://www.oznet.ksu.edu/path-ext/factSheets/Wheat/Wheat%20Leaf%20Rust.asp
"A Brief Guide to Mold, Moisture, and Your Home",
U.S. Environmental Protection Agency US EPA - includes basic advice for building owners, occupants, and mold cleanup operations. See http://www.epa.gov/mold/moldguide.htm
US EPA - Mold Remediation in Schools and Commercial Building [Copy on file at /sickhouse/EPA_Mold_Remediation_in_Schools.pdf ] - US EPA
US EPA - Una Breva Guia a Moho - Hongo [Copy on file as /sickhouse/EPA_Moho_Guia_sp.pdf - en Espanol
Associations: Sick House, Sick Building, SBS - Air Quality, Government, Private Associations and Information Resources
Atlas of Clinical Fungi, 2nd Ed., GS deHoog, J Guarro, J Gene, & MJ Figueras, Centraalbureau voor Schimmelcultures, Universitat Rovira I Virgili, 2000, ISBN 90-70351-43-9 (you can buy this book at Amazon) - The Atlas of Clinical Fungi is also available on CD ROM
"A Brief Guide to Mold, Moisture, and Your Home", U.S. Environmental Protection Agency US EPA - includes basic advice for building owners, occupants, and mold cleanup operations. See http://www.epa.gov/mold/moldguide.htm
"Disease Prevention in Home Vegetable Gardens,"
Department of Plant Microbiology and Pathology,
Department of Horticulture, University of Missouri Extension - extension.missouri.edu/publications/DisplayPub.aspx?P=G6202
Fifth Kingdom, Bryce Kendrick, ISBN13: 9781585100224, is available from the InspectAPedia online bookstore - we recommend the CD-ROM version of this book. This 3rd/edition is a compact but comprehensive encyclopedia of all things mycological. Every aspect of the fungi, from aflatoxin to zppspores, with an accessible blend of verve and wit. The 24 chapters are filled with up-to-date information of classification, yeast, lichens, spore dispersal, allergies, ecology, genetics, plant pathology, predatory fungi, biological control, mutualistic symbioses with animals and plants, fungi as food, food spoilage and mycotoxins.
Ozone Warnings - Use of Ozone as a "mold" remedy is ineffective and may be dangerous.
Rot concerns in buildings-some building mold such as Meruliporia incrassata "Poria" risks serious rot and hidden structural damage
US EPA: Una Breva Guia a Moho - Hongo [Copy on file as /sickhouse/EPA_Moho_Guia_sp.pdf - en Espanol
OTHER IAQ ISSUES: How To Find and Address Other Indoor Air or Indoor Environment Contaminants Besides Mold
Mold or allergens may not be the only or even the main indoor environmental contaminant. Don't let media attention to mold
cause so much enviro-scare fear that other, possibly more urgent hazards go un-addressed.
Rodents, Mice, Squirrel Control - I find high levels of mouse and rodent dander, fecal dust, and urine-contaminated dust in some buildings,
and high levels of these materials in building insulation in those locations. If you have a mouse problem, particularly if mice and their waste (fecals or urine) are contaminating
the building HVAC or building insulation, may need both steps to clean up or remove infected materials and steps to stop an ongoing
rodent problem. If squirrels are a problem, the cleanup needs to include closing off entry openings into the building. Get some
help from a licensed pest control expert.