Dust collection, sampling & testing to screen for hazardous dust particles:

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.

We discuss when dust sample collection and testing is justified, proper sampling & collection methods, and what to expect from a dust analysis test.

Typical components of house dust are dominated by fabric fibers and skin cells, but using dust sampling (or less reliably, airborne particle sampling) we may find high levels of problem particles (mold, allergens, fiberglass) or low levels of particles that nevertheless indicate an indoor air quality problem (such as certain mold spore genera/species found in spore chains).

Building Dust Collection Methods: A Simple Approach

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.

[Click to enlarge any image]

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.

Should we be testing for problem dust articles 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 but for small mold cleanup jobs testing is not normally appropriate.

See COSMETIC MOLD, RECOGNIZE

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.

SeeMOLD TEST vs. PROBLEM DIAGNOSIS

See MOLD / ENVIRONMENTAL EXPERT, 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.

When, Where & How to Collect Dust Samples or Particles from a Building Surface

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:

1. Choose dust sampling area: you want to collect a tape sample from a horizontal surface in the area where the dust seems worst and where the dust or other particles are most likely to be representative of building conditions being investigated. Include a sample from an area where people spend the most time.
   
   For details about choosing to look for old or historical building dust versus recent post-cleaning project dust,
   
   See DUST SAMPLE TYPES.
2. 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)
3. 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
4. Collect a tape sample from that same surface in the same area.
   
   We explain in detail
   
   at TEST KIT for DUST, MOLD, PARTICLES: INSTRUCTIONS how to collect and mail your own particle sample to a mold test lab. all you need is clear tape (not satin, not frosted, not invisible tape) and a plastic bag.
   
   Follow those instructions, then send your mold sample to a competent laboratory to identify the particles you found.
   
   In short pull off a couple of inches of clean tape, fold over on end to make a handling tab, press the tape into the sample surface, then press the tape on the outside of a clean plastic freezer bag. |
5. Mail in the dust sample: Send just those two samples to your chosen forensic lab for analysis and comparison.
6. In the test kit instructions just cited above we include advice about using a sample control sheet to record information about each sample if you are collecting more than one. Or use
   
   this CHAIN OF CUSTODY FORM for ENVIRONMENTAL SAMPLES

How to Find Dust & Get the Right Dust Sample

Our dust photographs at left and 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". We'll be forced to pick off and throw away part of your sample in order to examine the remainder.

Our photo at below right shows that in a dark room with a bright flashlight, airborne dust can be quite obvious. More about how to use light & how to aim a flashlight to spot hard-to-see ddust or mold 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 TESTING METHOD VALIDITY 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.

Details about environmental & forensic test lab procedures are found

at TECHNICAL & LAB PROCEDURES

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2018-12-01 by (mod) -

Andrea

To protect reader trust in this website we do not sell any product or service.

However the article above describes a very effective and very inexpensive kit that you can assemble yourself using clear adhesive tape and a freezer type ziplock bag. You can collect representative dust samples that you didn't send to any forensic or environmental lab for analysis.

On 2018-11-30 by Andrea Ern

I want to purchase a dust testing kit for my home. I believe that there is some type of particulate in the ac system that is affecting the air quality

On 2018-05-02 by Gina

In the top picture of the article, what is the red strand located in the top right of the photo? I found similar looking particles throughout an office space and am unsure of exactly what it is and if it requires further testing

On 2018-03-04 by Rachel

What date was this article published?

On 2017-04-15 by (mod) -

Thanks for the nice comment, Carol. We also welcome questions & critique.

Daniel

On 2017-04-15 by Carol HI96734

Thank you for sharing your knowledge, Dan. I found reading about dust forensics surprisingly fascinating!

On 2016-12-05 by (mod) re: on a limited budget, getting help for indoor contaminants

Tracie,

The place to start with questions about envrionmental health and inspections/testing of your home is with your doctor. But certainly a person who is undergoing cancer treatment is at extra risk IF there are environmental contaminants in her home.

Homes cannot honestly "pass" or "fail" inspections as there is no agreed-on criteria for that label. Worse, it is too easy for people to charge plenty of money to take a few samples to toss over to a lab who tosses a report back to you.

What's needed is a thoughtful, thorough inspection of the building including its history, uses of chemicals, sewage backups, leaks, floods, etc., along with building materials and construction methods that make a hidden problem likely-enough that more invasive inspection or tests are justified.

"Black mold" is a "red herring". There are harmless "black" or dark colored molds in buildings on occasion. And there are hundreds of other potentially harmful mold genera/species found in buildings of just about every color.

So a supposed expert who is simply looking for "black mold" is not an expert.

It is easy to be preyed upon when one is both frightened and ill. Be careful.

You are welcome to contact me for limited pro-bono consulting via email using the page top or bottom CONTACT link.Try to keep focused on the specific question being asked as it's easy to drown in text.

On 2016-12-05 by Tracie Ann B - Bottom line, whatever "it" is in my air, it's making me very ill.

I've spent quite a while reading and re-reading all of the very valuable information you put together for consumers on this site. I have multiple questions, I did see your reply that you have retired from field work, however, I'm in a near 3 year battle with my home, trying to figure out what's happening inside.

My resources nearby are limited in RI, in fact, I reached out to a man in PA who inspects homes that others have "passed" and then he deems them as "sick homes". I am fighting cancer, 46, and trying to do this on my own. I am hoping to simply exchange some info with you, and hope you might be able to point me in the right direction. My home had black mold a little over 3 years ago, it was remediated and cleared of all mold.

However, it was deathly toxic for me & I had to live in a hotel for 4 1/2 months until it was safe for me to return. When I became severely ill again last Jan, I immediately thought perhaps some trace of the mold was back & paid slot of money to have the original IH to come back and retest, inside and out.

She gave it the all clear. I've paid multiple inspectors, vent and HVAC cleaners to come in and inspect. No one knows what to do. Tons of samples, but no one takes them.

One man said definitely organic, what's floating around here. When I asked him to provide greater detail, he said he had none. That for $400. Would you mind please exchanging emails with me so I may give you specifics?

Bottom line, whatever "it" is in my air, it's making me very ill. Already being immune suppressed with cancer, and having to spend 90%+ of my life in this house is becoming torture.

I gave hair samples to a dermatologist in Boston who monitors my cancer, and she told me I was imaging things and suggested I get a mental health therapist ( which deeply insulted me ). She wouldn't even look at these "dust" particles I collected with tape, attached to a ziplock bag, or the hair samples. That was four months ago. I'm facing a deadline given to me by my primary care physician... as of Sept 2016, I had 6 mos to figure this out or she would recommend that I move, given the damage it's doing to my health, my skin, even my hair is starting to fall out, yet all my medical blood work comes back normal ( as normal as it can ) etc..

I'm literally at the end of my rope, I've been on Disability for 8 years fighting cancer and I have debilitating fibromyalgia, have spent thousands, which I could not afford, to receive bad or just completely wrong advice and I suffer daily. I think it's insulation... that's why I'm hoping to run specifics by you.

Would you please get in touch with me, I may not have a lot but I will do anything to save my home and end this torture.

I don't know how else to reach you except thru this forum, so please forgive the long note. I don't even know if the site is secure but I'm going to leave an email I use infrequently, in hopes you will get in touch so you may be able to finally put me in touch with the right person or maybe even you can help. I'm terrible at asking for help, it's very hard for me, as I've been independent my entire adult life. However, there is nothing else I can do, I've tried to make well thought out decisions and now I'm looking at the possibility of losing my home because no one can tell me what's wrong. Losing my home because it's making me sick.

My home has been my safe haven since I had it built for myself in 1999. Now it's my worst nightmare.

This can't be a huge mystery, I just don't know why all these "experts" kept taking my $$, just to tell me they don't know what is floating around in my air, landing on all my furniture, floors, clothing, hair, skin, etc.

Friends can't even come to visit anymore because they get an itchy or burning rash within minutes of entering my home. Please help. I would be forever grateful for anything you can do to help me. - Tracie (Tracie.b1970@yahoo.com)

On 2016-03-21 by (mod) re: referrals to environmental testing services & labs

Thank you for your interest in my services, SS but I'm unable to serve you directly.
​​
After decades of field investigation and forensic lab work, I have retired from field work to concentrate full time on pure research, a little pro-bono work, and writing for InspectApedia.com, an online building and indoor environment diagnosis and repair encyclopedia. I do welcome questions and can sometimes offer help by email.

Building Inspector referrals:

Perhaps you can find a suitable expert by discussing your needs with some of the professionals listed in directories found at
https://inspectapedia.com/home_inspection/inspusa.htm

Environmental Test Lab referrals from Daniel Friedman​​
​​
For environmental or forensic investigative support and lab work, you can use any forensic lab provided you first check that their area of expertise matches your needs.

For strange particle analysis, building dust analysis, fiberglass particle screening, mold contaminant screening contact these expert forensic microscopists

Daniel Baxter (dbaxter@san.rr.com) or

Larry Wayne (lew@forensica.com)

For mold or general environmental dust samples also contact our backup

Susan Flappan
11020 W. 122nd St.
Overland Park KS 66213
913 322 2237. toll free number of 866 225 MOLD
http://moldetect.com/
sflappan@moldetect.com

EMS lab is a very large and competent network of labs offering a wide range of services
http://www.emlab.com

If you find it helpful, you are absolutely welcome to make PRINTED copies of any of our website articles that you find useful, and to give them away to others where you find that useful. We welcome questions or suggestions regarding the content found at our website.

InspectAPedia.com is an independent publisher of building, environmental, and forensic inspection, diagnosis, and repair information for the public - we have no business nor financial connection with any manufacturer or service provider discussed at our website.

We are dedicated to making our information as accurate, complete, useful, and unbiased as possible: we very much welcome critique, questions, or content suggestions for our web articles. Contributors, even if it's just a small correction, are cited, quoted, and linked-to from the appropriate additional web pages and articles - which benefits us both. Working together and exchanging information makes us better informed than any individual can be working alone.

A brief summary about InspectAPedia.com can be read at
https://inspectapedia.com/About_Us.htm

Respectfully,

On 2016-03-21 by SS

Can you analyze a sample of the dust in my house?

I really need to know what it is, then hopefully know where it is coming from. Thank you!

Question: part of our1970's building is being demolished & reconstructed without proper dust control. What should I do?

[Our university] is demolishing and reconstructing parts of our building build in built sometime in the 1970s. Half the building is being worked on while the other half has classrooms. In the past this has resulted in a considerable amount of dust, dirt and noise in the classrooms. What are or are there requirements for monitoring the air in the building. One time last semester, I was in that part of the building and had to breathe in the dust which actually smell like mold to me.

Reply:

A competent onsite inspection by an expert usually finds additional clues that help accurately diagnose a problem with site environmental hazards and dust control, and frankly, your question is so important, especially in the setting of a school, that I want to be careful to avoid a lot of hand-waving speculation. That said, here are some things to consider:

An expert inspection should have identified hazardous materials such as lead or asbestos-containing products that would in turn have required extra care in site management and dust control. Beyond that, in my experience, a competent contractor is expected to recognize when they are encountering a suspect material, stop work, and demand testing. If tests show that special methods are needed, work stops until those are in place and are being handled by the right expert.

In very general terms, your observation that dust is leaking from work area into occupied space is a red flag that deserves careful and quick response. Even non-toxic dusts, say just plaster dust, can be severe respiratory irritants.

There is also risk that the dust that is not being controlled from spread to occupied spaces is also contaminating the HVAC systems in the building, not to mention a question that is implied concerning possible hazards to the workers themselves

I'm not expert on state or federal regulations about monitoring at schools during construction or renovation work. My impression from the standards and codes I've read is that there are more guidelines than laws - until a known hazardous, regulated material is encountered and confirmed.

Unfortunately, on some projects I've encountered, a wish to avoid extra costs sometimes leads administrators to eschew looking or testing, just plowing ahead with the job using ordinary contractors - which might be OK if the contractor is able to recognize and willing to stop when trouble is suspected. But pressure on the contractor is also great to just keep at it.

You should check with your state to ask what regulations or guidelines pertain to construction work being performed on schools. For an example of such regulations, you can take a look at New York's Department of Education regulations for facilities planning. Those include "Section 155.2 Construction and remodeling of school district facilities" that specifies:

(a) All plans, specifications and work regarding the erection, enlargement, repair, replacement, maintenance or remodeling of occupied facilities of school districts and of boards of cooperative educational services shall comply with the Uniform Safety Standards for School Construction and Maintenance Projects as set forth in section 155.5 of this Part. Such uniform safety standards shall include but not be limited to: pre-construction testing and planning, exiting and ventilation, pre-construction notification, asbestos and lead protocols, control of dust, gases and fumes, protection from falling debris, and general safety and security.[1]

See Section 155.2 Construction and remodeling of school district facilities for details.[2]

In my OPINION, and summarizing,

You are describing a job that lacks proper dust control - placing occupants at a risk of respiratory illness and building indoor air quality complaints that could range from minor to serious.

It would be reasonable to

1. ask that proper dust control, barriers, negative air, whatever is required, be established immediately

2. ask that a qualified expert inspect the dust control measures AND collect some surface samples of settled dust for expert lab screening for the usual suspects: lead, asbestos, mold

Please do not suggest sending such samples to my lab - after our correspondence it would be inappropriate and a conflict of interest. For asbestos screening, you'd want a lab certified in NY for that purpose.

Question: indoor humidity problems

(July 26, 2012) kim said:

I have a 1954 lake house piecemealed together AT ground waterlevel, partly on clay, 80% indoor humidity, kinda like a cave inside. Partly inslab ducts now deteriorating, as is my health. What should i do? i've been researching for about 6 years now, you're the FIRST site i've seen talking about the problem!

Reply:

Kim,

That is a very very wet indoor home. You need to get an accurate determination of where that moisture is coming from (perhaps the in slab ducts) and fix that source as well as adding in-home dehumidification to get numbers down closer to 50% RH - else you're asking for mold problems.

As you've read, in-slab ducts can be the source of a variety of problems (I'm not sure how you went from our in-slab duct discussion to this page on dust sampling but you can search InspectApedia for in-slab ductwork.

Converting from in-slab air ducts can be costly if you have to fit the replacement ducts into or onto existing walls and ceilings. In some situations people surface mount and box in ducts as ceiling soffits; in others people go to a hybrid all or part hydronic (hot water) heat and eliminate all the ductwork - which of course is not going to work if your duct system is used for both heating and cooling.

Question: why do we have so much dust in our house?

12/5/2014 bruce bodnar said:

We have a 4 yr old home in sage creek winnipeg. We have the dark flooring and dark cupboards etc, 75% of the main floor is hardwood remainder carpeting. Since day 1 in this home my wife has had to vacuum(or mop) the floor and dust the cupboards at least twice weekly sometime 3 times.

There are only 2 of us in the home, seniors, clean in appearance . In the first year I had our furnace ducts cleaned 3 times, I personally inspected them and they are still very clean.

I use only the best furnace filters and change every 3 months, earlier if required. The dust I refer to is small particles and settles on top of every item in the home. Can you suggest what may be the cause. I would be much in your debt and my wife also of course.
Regards Bruce
bruceandg@shaw.ca

Reply:

Bruce

The most common house dust ingredients are fabric fibers and skin cells. But I can't guess about what comprises the dust in a building that I've not seen and know so little about. You might want to simply send a tape sample of dust to a forensic lab to ask them to identify the dominant particles by frequency.

Sometimes that will point to an apparent source such as damaged insulation in an AC duct or something else.

...

Continue reading at DUST SAMPLE TYPES or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• HOUSE DUST ANALYSIS
  • ALLERGENS in BUILDINGS
  • CARPET DUST IDENTIFICATION
  • AIRBORNE PARTICLE COUNT VARIATION CAUSES
  • AIRBORNE PARTICLE COUNT VARIATION EXTENT
  • CONCRETE DUST & ODORS
  • DUST ANALYSIS for FIBERGLASS
  • DUST, HVAC CONTAMINATION STUDY
  • DUST SAMPLE TYPES we distinguish between "old house dust" and "recent house dust" which in turn can aid in building indoor air quality investigation diagnosis
  • DUST SAMPLING PROCEDURE
  • TEST KIT for DUST, MOLD, PARTICLES: INSTRUCTIONS
  • FIBER & HAIR IDENTIFICATION
  • FIBERGLASS AIR DUCT MOLD TEST
  • FIBERGLASS PARTICLE CONTAMINATION TEST
  • HOUSE DUST CHEMICAL CONTAMINANTS
  • HOUSE DUST COMPONENTS
  • HOUSE DUST PARTICLE PHOTOS - a photo tour of what we found in dust from a London loft.
  • HVAC DUST CONTAMINATION STUDY - what do we find in dust in a heating or air conditioning system?
  • USES of AIRBORNE PARTICLE SAMPLING

Suggested citation for this web page

DUST SAMPLING PROCEDURE at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to BUILDING ENVIRONMENT

Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia

Or see

INDEX to RELATED ARTICLES: ARTICLE INDEX to BUILDING INDOOR AIR QUALITY IAQ

Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia

Or see

INDEX to RELATED ARTICLES: ARTICLE INDEX to MOLD CONTAMINATION & REMEDIATION

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