Guide to Collecting a Dust or Particle Sample for Lab Analysis and Report InspectAPedia® -
How to collect indoor dust & debris from a surface to screen for problem or diagnostic particles of any kind
How to use collect settled samples to screen building dust for mold, fiberglass, insect fragments, dust mites, cockroaches, other particles
Questions & Answers about how to collect indoor dust samples for particle identification and indoor air quality investigation
This article describes a simple, inexpensive strategy for collecting a small number of settled dust samples in a building in order to screen for problem particles or to identify the contents of house dust.
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At MOLD TEST KITS for DIY MOLD TESTS we give six simple steps to use clear adhesive tape to collect a surface sample of dust, mold, or other materials in a building. This article explains how to choose a dust sampling location and when to collect samples.
Our page top photo shows a microscope photo of an interesting sample of dust from the basement of a one family home. Typical contents include skin cells and fabric fibers, occasional dust mite fecals. But (click to enlarge) this sample also detected a significant number of mold spores (amerospores) that were identified Penicillium or Aspergillus. Also see DUST ANALYSIS for FIBERGLASS.
First, should we be testing for problem particles at all?
Probably not: If your question is simply about mold identification, and you already see mold on indoor surfaces, NO mold testing is needed to just to confirm that mold is present in the building and that cleanup is needed. Sure, it might be just cosmetic mold (see Recognize Cosmetic Mold) but for small mold cleanup jobs testing is not normally appropriate.
Maybe yes: But if you need to identify the contents of dust, for example to help track down possible sources of building dust particles, or to screen for problem particles such as dust mite fecals, insect fragments, animal dander or hair, soot, fiberglass, etc., or if a large mold remediation project is planned, tests may be needed for project control - see When to identify mold?.
See MOLD EXPERT, WHEN TO HIRE for a discussion of when it is or is not appropriate, justified, and ethical to hire an environmental consultant to inspect, diagnose, and advise about mold or other contamination in a building.
More About our Page Top Dust Sample Lab Photo
Here is what our client told us about this tape sample of basement dust:
Tape sample of settled dust in a basement after
the basement was cleaned out - "this was a pretty musty basement - any cloth or paper left down there would be ruined in a short time. Sampled "before we go raising a cloud of dust in sweeping and vacuuming...40 years of dust...wife who lived in the house suffers from asthma"
It was possible that the mold reservoir - moldy basement contents - had already been removed from this basement, but the basement cleanup left lots of moldy dust on building surfaces. Additional cleaning would be appropriate. An asthma sufferer could be particularly troubled by high levels of moldy dust, or dust of almost any sort for that matter.
How to Collect Dust Samples or Particles from a Building Surface
As we explain in detail at MOLD TEST KITS for DIY MOLD TESTS, to collect and mail your own particle sample to a mold test lab,
all you need is clear tape and a plastic bag. Follow those instructions, then send your mold sample to a
competent laboratory to identify the particles you found
Where, When, & How to Collect Your Dust Samples
If you think that problem dust is being produced in a building, then the dust source is from some active condition.That means that if you clean off a test surface and wait a sufficient time, the problem particles should appear and be detectable in a surface dust sample.
An advantage of including a dust sample from a freshly-cleaned test surface is that you can avoid confusing old dust, dirt, or debris from a prior building condition with current building conditions.
If these considerations make sense for your situation, and in order to avoid collecting and processing an unnecessarily large and costly number of dust samples, try this procedure:
Collect a tape sample from a horizontal surface in the area where the dust seems worst.
Clean off that same horizontal surface thoroughly (if we were in court I'd have you sample the cleaned surface as a control, otherwise it's not necessary)
Wait a week and make a visual inspection - perhaps use a flashlight - to be sure there is dust now on the test surface (tips on using a flashlight to examine surfaces are at USING LIGHT TO FIND MOLD )
Collect a tape sample from that same surface in the same area
Send just those two samples to your chosen forensic lab for analysis and comparison
Finding Dust & Getting the Right Dust Sample
Our dust photographs below demonstrate that by shining a light along a surface rather than straight at-it dust shows up very well. The very thick dust in our photo (below left) may be too much to produce a good test as it may obscure particles when we prepare a slide for microscopic examination. That's why cleaning off a very dusty surface and following the procedure above for dust sample collection makes sense. But don't worry - in the lab we are experienced with all sorts of samples, including thick "dust bunnies".
Our photo at below right shows that in a dark room with a bright flashlight, airborne dust can be quite obvious. More is at USING LIGHT TO FIND MOLD .
Our photos below demonstrate further how a clean-looking indoor surface may be already rather dusty or even contain light-colored, hard-to-see mold.
How Many Dust Samples Do I Need to Collect?
Don't let anxiety make you waste money by collecting and processing more samples than are really needed.
If the building problem you are investigating involves only a single area, or if the building problem dust appears to be everywhere in the structure, then you may still be able to select a single representative room and surface for testing.
If you need to compare conditions in different building areas, then you will need to collect dust samples that represent each area individually.
If you are testing conditions inside of a mechanical system component such as an HVAC duct interior or air handler, it will need its own samples.
If it will help, you can send the lab multiple samples but ask that the lab to process only a smaller number of them, or even just one sample. Just pay for the smaller number of samples, and ask the lab to retain the others in reserve in case further inspection is needed, or in case some of the ones you think are most likely to be representative are not productive.
Notes
Warning for people at extra risk: if there is a significant amount of mold present, or if you have allergies, suffer from
asthma, have a compromised immune system, are elderly, or if infants or if others with those conditions or any other medical risk are in the building, do
not attempt to collect or disturb mold. Consult your physician in any case before proceeding.
Do you need an expert? This document describes a fast, low-cost, highly-effective procedure to collect and send a "bulk" or tape mold
sample to our mold testing laboratory. Sending a do-it-yourself mold test sample to a laboratory is not a substitute for consulting with or using the
services of a qualified professional to inspect your building. An expert is likely to find conditions most people would not recognize. But if you simply
want to know about mold which you see yourself, the procedure below is inexpensive, scientifically sound, and easily within the ability of a typical
home owner or tenant. See MOLD EXPERT, WHEN TO HIRE for help in deciding if you
need to bring in an expert to inspect or test your building for mold. See Mold Sampling Methods in the Indoor Environment for a discussion of the validity of various "home test kits" and
"toxic mold test kits" on the market.
What about hiring someone to just do an "air test" or "swab" or "culture" for mold: You can NOT rely on air
testing, settlement plates, swab testing, or culture plates to accurately and fully characterize the presence of mold in a building.
Such mold test kits are unreliable and are discussed at "Test Methods Critiqued" (link at left). While air testing and culture tests for mold can be useful tools, they are fundamentally inaccurate
in characterizing mold risk in a building. Thorough visual building inspection by an experienced building scientist who is also has expertise on mold, aerobiology, and mycology,
accompanied appropriate types testing of visible mold are key in any such investigation.
What Will the Forensic Lab Do With Your Dust or Particle Sample?
On receipt of your sample the lab will prepare one or more treated slides using your material samples. We will examine them for airborne bioaerosols, mold,
etc. and will perform identification using any of several low power stereoscopic and high-power light microscopes in our lab.
If the purpose of the dust analysis is to help track down its probable source in a building, the lab will identify the dominant particles in the sample including fiber type, color binder, or other particle type. See DUST ANALYSIS for FIBERGLASS for an example.
Our lab photo (left) shows fabric fibers, starch granules (upper center), and skin cells - common ingredients found in house dust.
Mold culturing for speciation, as well as other specialized particle identification techniques are available in our laboratory and can be special-ordered by telephone or email consultation. Usually culturing is inaccurate and unnecessary as only a small percentage of organisms, mold or otherwise, will grow in a specific culture media.
Genera/species or particle identifications are made based on experience, education, reference texts and keys, and by comparison with our very extensive library of known particle samples.
While certain problem particles (including molds) are well documented and may be identifiable some are not so we do not guarantee that we will identify all components found on the tape. There are thousands of particles that appear in building dust, including more than 80,000 mold species which have been identified and an estimated 1.4 million remaining to be identified.
However it's quite possible to
identify most problem building particles including the most common problematic mold species likely to be a concern in buildings.
Clients should also understand that there are multiple potential health hazards in buildings and that a client-selected remote-lab analyzed sample is absolutely not comprehensive. Other hazards may be present.
Ordinarily a written lab report will be provided within 24 hours of sample
receipt. In a few cases (lab closed for cleaning, holidays, complicated samples needing more analysis) we need more time to complete the analysis.
If we recognize a dangerous material we will also notify you immediately. Our report will include an identification of particles
and a statement about mold or other particle allergenicity or toxicity.
If you have questions about the best particle sample collection procedure for your situation, Contact Us by email.
Critique, contributions wanted: Contact Us to suggest corrections or additions to articles at this website, and if you wish, to receive online listing and credit as a contributor. Particular thanks are due to the many experts and also consumers who read and critique technical articles at InspectAPedia.com.
Additional technical contributors & reference sources for this article are listed below.
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Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
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
Allergen Tests in buildings advice about how to test, what to look for, in evaluating the level of dog, cat, or other animal allergens in a building
"IgG Food Allergy Testing by ELISA/EIA, What do they really tell us?" Sheryl B. Miller, MT (ASCP), PhD, Clinical Laboratory Director, Bastyr University Natural Health Clinic - ELISA testing accuracy: Here is an example of Miller's critique of ELISA
http://www.betterhealthusa.com/public/282.cfm - Townsend Letter for Doctors and Patients
The critique included in that article raises compelling questions about IgG testing assays, which prompts our interest in actually screening for the presence of high levels of particles that could carry allergens - dog dander or cat dander in the case at hand.
http://www.tldp.com/issue/174/IgG%20Food%20Allergy.html contains similar criticism in another venue but interestingly by the same author, Sheryl Miller. Sheryl Miller, MT (ASCP), PhD, is an Immunologist and Associate Professor of Basic and Medical Sciences at Bastyr University in Bothell, Washington. She is also the Laboratory Director of the Bastyr Natural Health Clinic Laboratory.
Allergens: Testing for the level of exposure to animal allergens is discussed at http://www.animalhealthchannel.com/animalallergy/diagnosis.shtml (lab animal exposure study is interesting because it involves a higher exposure level in some cases
Allergens: WebMD discusses allergy tests for humans at webmd.com/allergies/allergy-tests
Animal Allergens: Dog, Cat, and Other Animal Dander - Cleanup & Prevention Information for Asthmatics and regarding Indoor Air Quality.
Recognizing Allergens: What various indoor allergens look like - identification photos to help identify pollen, dust mites, animal dander, toxic or allergenic mold - Common Mold and other Allergens, Irritants, Remedies & Advice
Rodent control issues, including dander, fecal, and urine contamination of buildings and Building insulation are discussed at our
Fiberglass in buildings: hazards, testing, cleanup, prevention: references & products
For more information about fiberglass as an indoor air quality concern see:
Asbestos: How to find and recognize asbestos in buildings - visual inspection methods, list of common asbestos-containing materials (Asbestos is not fiberglass and vice versa).
BASEMENT MOLD includes examples of moldy fiberglass insulation found in basements
CRAWLSPACE MOLD includes additional examples of moldy fiberglass insulation found in
crawl spaces
Insulation Identification Photographs - Fiberglass insulation photos, yellow, pink, green, white fiberglass identification in building attics, walls, ducts, other locations
Lab Identification of Fiberglass photographs and text assist in laboratory identification of fiberglass fibers and fragments in air, dust, or material samples in the laboratory using forensic microscopic techniques.
Mold in Fiberglass building insulation, when, why, and how fiberglass becomes a reservoir of problem mold in buildings.
Fiberglass carcinogenicity: "Glass Wool Fibers Expert Panel Report, Part B - Recommendation for Listing Status for Glass Wool Fibers and Scientific Justification for the Recommendation", The Report on Carcinogens (RoC) expert panel for glass wool fibers exposures met at the Sheraton Chapel Hill Hotel, Chapel Hill, North Carolina on June 9-10, 2009, to peer review the draft background document on glass wool fibers exposures and make a recommendation for listing status in the 12th Edition of the RoC. The National Institute of Environmental Health Sciences is one of the National Institutes of Health within the U.S. Department of Health and Human Services. The National Toxicology Program is headquartered on the NIEHS campus in Research Triangle Park, NC. The National Institute of Environmental Health Sciences is one of the National Institutes of Health within the U.S. Department of Health and Human Services. The National Toxicology Program is headquartered on the NIEHS campus in Research Triangle Park, NC.
Following a discussion of the body of knowledge, the expert panel reviewed the RoC listing criteria and made its recommendation. The expert panel recommended by a vote of 8 yes/0 no that glass wool fibers, with the exception of special fibers of concern (characterized physically below), should not be classified either as known to be a human carcinogen or reasonably anticipated to be a human carcinogen. The expert panel also recommended by a vote of 7 yes/0 no/1 abstention, based on sufficient evidence of carcinogenicity in well-conducted animal inhalation studies, that special-purpose glass fibers with the physical characteristics as follows longer, thinner, less soluble fibers (for 1 example, > 15 μm length with a kdis of < 100 ng/cm2/h) are reasonably anticipated to be a human carcinogen for the listing status in the RoC. The major considerations discussed that led the panel to its recommendation include the observations of tumors in multiple species of animals (rats and hamsters). Both inhalation and intraperitoneal routes of exposure produced tumors, although inhalation was considered more relevant for humans.
Fiberglass insulation mold: occurrence of mold contamination in fiberglass insulation can be impossible to see with the naked eye, but can be significant
World Health Organization International Agency for Research on Cancer - IARC Monographs on the Evaluation of Carcinogenic Risks to Humans - VOL 81 Man-Made Vitreous Fibers, 2002, IARCPress, Lyon France, pi-ii-cover-isbn.qxd 06/12/02 14:15 Page i - World Health Organization, 1/21/1998. - Fiberglass insulation is an example of what IARC refers to as man made vitreous fiber - inorganic fibers made primarily from glass, rock, minerals, slag, and processed inorganic oxides. This article provides enormous detail about fiberglass and other vitreous fibers, and includes fiberglass exposure data.
http://monographs.iarc.fr/ENG/Monographs/vol81/mono81.pdf - the article (large PDF over 6MB)
http://monographs.iarc.fr/ENG/Monographs/vol81/mono81-6A.pdf - article details
http://monographs.iarc.fr/ENG/Monographs/vol81/mono81-6C.pdf - studies of cancer in experimental animals in re vitreous fibers such as fiberglass;
http://monographs.iarc.fr/ENG/Monographs/vol81/mono81-6E.pdf - summary of data reported & evaluation
http://monographs.iarc.fr/ENG/Monographs/vol81/mono81-6F.pdf for the article references
To search the IARC monographs on various environmental concerns and carcinogens, use http://monographs.iarc.fr/ENG/Monographs/PDFs/index.php
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)
Atlas of Indoor Mold, Online Clinical Mold Atlas, Toxins, Pathogens, Allergens and Other Indoor Particles - Medical Health Effects of Mold (separate online document)
Black Mold that is Harmless Photos of recognizable, usually harmless black mold on wood, bluestain, ceratocystis, ophistoma
Building Floods: quick steps after a building flood or plumbing leak can prevent costly mold contamination
Classes of Mold: what types of cosmetic, allergenic, or toxic mold are a problem? Can mold be cleaned-up successfully?
"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 Program for Certain Vegetable Crops," David B. Langston, Jr., Extension Plant Pathologist - Vegetables, University of Georgia (PDF document) original source: www.reeis.usda.gov/web/crisprojectpages/209797.html
"Disease Prevention in Home Vegetable Gardens,"
Patricia Donald,
Department of Plant Microbiology and Pathology,
Lewis Jett
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.
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