Indoor Air Quality &Toxic Mold & Toxic Gas Testing Methods Compared InspectAPedia® -
What to do about toxic or allergenic mold in buildings
Mold Testing Methods & Validity Comparisons
Air tests for mold., Surface, tape, & bulk tests for mold -which tests are really useful?
Why mold Culture tests are not reliable to screen buildings for mold
Why mold sniffing dogs, infra red, thermography, MVOC detection, & moisture detection are useful tools but unreliable as mold detection methods
Mold lab procedure articles
Indoor air and toxic mold investigation report guidelines
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This document lists and compares classes of mold, air, gas, test methods used in indoor air quality investigation
methodology in searching for possible causes of respiratory illness, asthma, immune system disorders, rashes, skin disease, psychological and neurological
disorders, eye infections, or other symptoms which may have a physiological and environmental component.
Methods of inspection and testing building air quality for toxic mold,
allergen or other sick house investigations, mold lab testing services, information on mold, mildew, moisture, pollen, dust mite, & environmental
testing for home buyers, home owners, consultants, as well as a service to provide on-site field investigations and expert mold laboratory testing, and
mold identification services are offered.
Links here organize the indoor air quality methods portion of our environmental website and take the reader
either directly to an in-depth article or to the collection of such articles addressing a particular environmental or IAQ topic.
Air sampling equipment includes some useful, expensive tools, but if used alone, air sampling is not reliable for characterization of building
conditions. In short, a "negative" (no mold problem detected) result is not reliable because the level of airborne particles in indoor air varies by several orders of magnitude from minute to minute in a building. Waving a notebook, turning on or off a fan, opening a door, even walking across carpeting can completely change the level of airborne particles.
A mold inspector who relies only on tests and who omits thorough visual inspection, history taking, occupant interviews,etc. is not making a reliable mold-assessment of a building.
This photo shows some sampling devices we used in comparing the effectiveness of vacuuming a couch to test
thick upholstered furnishings for mold contamination.
We collected comparison samples using different
collecting devices as well as by using adhesive tape, for laboratory analysis.
Vacuuming furniture to
test for mold contamination may be useful for general qualitative assessment when an expert has
examined the building and its content.
Vacuuming building insulation may be the most reliable non-quantitative approach to detecting mold-contaminated fiberglass insulation.
Quantitative analysis of such samples is questionable.
Tape to collect mold or other surface sampling methods provide useful, inexpensive tools which, combined with careful visual inspection,
are reliable and inexpensive for characterization of building conditions. Particles collected are very useful for genera and often mold species
identification.
Bulk & Tape Samples: Tape lift from mold-covered surfaces; scrapes onto microscope slide and other methods also used by do-it-yourselfers and by experts
Wall Check type vacuum pump and canister permits "sampling" of mold and allergens in wall, ceiling, and floor
cavities but our direct field testing indicates that this method is highly unreliable. Working with Louis Relle, a Louisiana mold remediation expert on a New Orleans building which was to be demolished we
collected wall-check samples from every suspect building cavity. When the building interior surfaces were demolished we then performed a visual
inspection and collected bulk surface samples using tape.
The wall check samples were completely unable to detect large and significant mold contamination in the cavities of this
building. We postulate that even with mechanical agitation (banging on the wall during wall check sampling) the flow rate of the sampling method does not move enough air to reliably pick up surface contamination unless
the mold genera/species happens to be at a particularly high state of active sporulation. The tool remains in the professional's arsenal, to be used with discretion.
Vacuum samples of carpeting, drapes, furniture, clothing permits testing for mold contamination. We use this method for screening of areas where mold is not visible, and in clearance testing.
Cultures, Swabs, "Home Test Kits" Mold Testing Protocols
Only about 10% of all molds will grow on any culture medium whatsoever, and there are literally hundreds of culture media mycologists have developed to try to coax mold to grow in the laboratory.
90% wrong to start: So the moment you open your "mold culture test kit" you're roughly 90% wrong in whatever conclusion you and your kit are going to reach. (We're exaggerating slightly because not all of the 1.5 million mold species will grow indoors in buildings anyway).
The mold that likes the culture media and grows on it may not be the mold that is a problem in the building anyway - it may just be a nice marriage between what fell onto the plate and the chemistry of the mold growth media.
The rate that particles fall out of the air has no reliable correlation to how many of them are in a building or where they're coming from.
So where's the mold? The most troubling thing about this and some other mold test kits, when used by someone who's not an expert, is that even if the mold test kit indicates the presence of a problem mold, and even if the kit "got it right" in a particular case (that is, the mold it detected is actually the main problem in the building), we don't know where the problem is nor how big it is nor what to do about it.
Mold Sniffing Dogs as a Building Screen for Mold
Mold sniffing dogs are unreliable, though fun. For details, see INEFFECTIVE MOLD PRODUCTS for an explanation of why mold sniffing dogs make poor mold detectives and why it's not good for them anyway.
There's no doubt that a dog can be trained to smell mold. What is the dog smelling? MVOCs.
Not all molds generate MVOCs, and even molds that do generate MVOC's don't do so all the time. If the humidity, temperature, light, and other factors don't cause a particular MVOC-generating mold to release this gas, you're not going to detect it on the day of the inspection and test. Just later. Even if we detect MVOCs, is that the problem mold in the building?
Beagles are short as dogs go - and are not good at sniffing out MVOC's that telltale a mold problem high in a building wall or in a ceiling.
Beagles are cute, though.
Infrared, Thermography, & MVOC Testing as a Building Screen for Mold
These good tools form a part of the arsenal of building investigation tools for many uses and problems, but they are unreliable as a building screen for mold.
IR and Thermography detect temperature differences, not mold. In short, IR, or thermography, which are wonderful and fun tools to use, only detect temperature differences. If your building has a mold problem in a wall or ceiling due to a leak that occurred a long time ago, the cavity may now be quite dry. The mold is happily growing along on ambient moisture, but the IR won't detect a thing.
IR and thermography are good at seeing leaky windows and doors, though. At one of our investigations a "mold killing" company had charged our client a few thousand dollars to "spray biocide into the moldy walls". Our acquaintance who owns the company was excited with his new IR camera and used it as a "mold detector" - now this is a smart thing to do if you're looking for what building cavities have just gotten wet due to a leak.
But in this case what he detected was cool spaces around windows and doors - which is where he sprayed his biocide and "mold killer". When we cut open those walls we found absolutely no indication that there had ever been mold present, nor leaks, nor anything but lower temperatures. The mold problem (there was one) was in a completely different area of the home.
IR and thermography are great tools in the hands of an expert. They're not a mold detector.
Sampling for Mold Volatile Organic Compounds - MVOCs and other Mold-Related Gases in buildings
Not all molds generate MVOCs, and even molds that do generate MVOC's don't do so all the time. If the humidity, temperature, light, and other factors don't cause a particular MVOC-generating mold to release this gas, you're not going to detect it on the day of the inspection and test. Just later. Where's the mold smell or musty odor problem source? Even if we detect MVOCs, is that the problem mold in the building? If we don't detect MVOC's does that promise there is no problem mold? No.
Production of toxins and microbial volatile organic compounds (MVOCs) by fungi in an environmental sample is dependent upon many factors, such as the substrate on which mold is growing, relative humidity and temperature in the moldy environment; the relative importance of each of these factors in toxin production is poorly understood.
Our Indoor Gas Sampling Plan for Residential buildings describes gas testing
procedures, instruments, detection limits, and it lists some of the toxic (or other) indoor gases for which we can test, depending on the building complaint and building conditions.
Good Mold Testing Laboratory and Microscope Procedures
TECHNICAL PROCEDURES describes proper mold testing laboratory procedures,
and sample processing not by a "supervised" technician but by a qualified expert are critical in making sense of field samples.
Competent, trained, experienced aerobiologists, mycologists, and
microbiologists can identify sample contents with good accuracy.
Depending on the experience of the laboratory, it is also possible to interpret the
meaning of the sample for the building and its occupants.
Laboratory professionals who have also performed the field inspection can often offer useful interpretations of even low levels of certain particles or classes of particles found in indoor air or surface dust. For example, if a field test for mold detects certain fungi not usually found on indoor surfaces, those molds may not themselves be a likely health hazard to building occupants, but they may be common water-indicators that suggest that further investigation of the building is in order to look for the presence other, more problematic molds that the initial investigation failed to detect.
Indoor Air / Toxic Mold Investigation Reports
MOLD INVESTIGATION REPORTS provides a document outlining what to look for in a toxic mold field
investigation report or mold test laboratory report. we have been troubled that some very costly "mold investigators"
simply collect a few air, culture, or swab samples, toss them over to a mold testing lab, and give their clients the lab
report.
A valid and useful mold investigation needs to include a detailed visual inspection to identify problem sources,
the presence and extent of a mold or other problem reservoir, and then it needs to provide the supporting lab work to
justify what may be a costly cleanup (i.e. let's not spend a lot cleaning up "cosmetic" mold). The end product of the investigation
needs to include the following
Where are the problem mold or other reservoirs in the building?
What is the extent of cleanup needed? Exactly where are the problems actually located?
What do lab results indicate about toxicity, allergenicity, medical implications of potential exposure, and the need for expert cleaning services?
What needs to be changed or fixed on the building to prevent a recurrence of the original problem?
What to do About Mold - Here are the Key References
Mold Information Center: What to do about mold in buildings, when and how to inspect and clean up mold - detailed in-depth articles, well
organized, researched. Taking a broad approach involves a site and building examination for probable sources of moisture, bioaerosols, other allergens, as well as dangerous conditions such as obviously blocked
chimneys. This group of links outlines what to do about mold, when to hire a professional, and how to look for mold in buildings.
Mold Action Guide: an easy step-by-step outline of what to do about mold, how to including
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.
Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.
Mark Cramer Inspection Services Mark Cramer, Tampa Florida, Mr. Cramer is a past president of ASHI, the American Society of Home Inspectors and is a Florida home inspector and home inspection educator. (727) 595-4211 mark@BestTampaInspector.com (review comments 3/09)
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
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.
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.
Ozone Warnings - Use of Ozone as a "mold"
remedy is ineffective and may be dangerous.
Pet control - if you can't say goodbye to your bird, cat, dog, guinea pig, hamster, tropical fish, then limit the
areas they occupy and limit the airflow from that area to sleeping or other areas of the building, use allergenic
bedding, eliminate wall-to-wall carpeting, improve housecleaning including use of a HEPA-rated vacuum cleaner. For more details
see our article Dog, Cat, and Other Animal Dander - Information for Asthmatics and Indoor Air Quality
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.
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