Re: IEC Article on Carpet Dust Sampling

[Guest guest]

I have always had mixed feelings about carpet dust sampling. To me, it equates to sampling a furnace filter. AS with filters, aren't all carpets loaded with mold spores anyway ?

The age of the carpet must be a big variable in this equation too. If I sample the dust from 6 months old carpet as opposed to 10 year old carpet, wouldn't I find a lot more spores in the older carpet and does this really indicate the existence of a mold source elsewhere in the building or does it just tell me that this carpet has been collecting dust spores for a longer period of time ?

What about the effectiveness of the vacuum used to clean the carpet ? Wouldn't that skew the results ?

On one hand, I find the idea of analyzing carpet dust very attractive because, in a way, it contains the entire "history" of the building since the carpet was installed but I wouldn't be sure how to interpret the lab results. What guidelines do you follow to interpret the test results ? Can the numbers be compared to anything ?

I'd like the understand this carpet dust theory better.

e

Indoor Environmental Testing Inc.

IEC Article on Carpet Dust Sampling

The July 2004 issue of Indoor Environment Connections has an interesting article titled, Sampling Carpet Dust for Microbials.The authors appear to have almost inadvertently focused in on carpet dust sampling as a tool to evaluate the "cleanliness" vs. "uncleanliness" of carpet. And if one is to use carpet dust assessment for this very narrow, myopic purpose, then what the authors have said is all quite true; with the possible exception that they did not include a time factor into their equation.But, IEQ investigators use carpet dust sampling for a purpose larger than just determining if the carpet needs to be cleaned. It is my experience that many investigators collect carpet dust and analyze the mold constituents in carpet dust as a way to indicate something beyond the carpet itself. Carpet dust is very useful as an indicator of the possible existence of a mold source elsewhere in the building, and for this purpose, the content of mold per sample weight is far, far, far more important than determining loading of mold per unit surface area. Yet, the true beauty of dust sampling is one can calculate both the surface area loading and the concentration per weight at the same time! So you can use the data for two totally separate purposes: to determine if the carpet (or given surface) is being maintained or cleaned adequately AND you can pick up on abnormal rates of mold accumulation relative the rate of accumulation of the other constituents in the dust, thus indicating the possible presence of a source nearby.I think this is obvious. Any one care to pick up on this topic or have comments to my opinion that the authors chose a narrow, almost misdirected focus for their article? GerberFAIR USE NOTICE:This site contains copyrighted material the use of which has not always been specifically authorized by the copyright owner. We are making such material available in our efforts to advance understanding of environmental, political, human rights, economic, democracy, scientific, and social justice issues, etc. We believe this constitutes a 'fair use' of any such copyrighted material as provided for in section 107 of the US Copyright Law. In accordance with Title 17 U.S.C. Section 107, the material on this site is distributed without profit to those who have expressed a prior interest in receiving the included information for research and educational purposes. For more information go to: http://www.law.cornell.edu/uscode/17/107.shtml. If you wish to use copyrighted material from this site for purposes of your own that go beyond 'fair use', you must obtain permission from the copyright owner.

[Guest guest]

Actually,

there was an old paper (~6 years, exact reference escapes me) that described

the different spore composition found in carpets of “problem” and “nonproblem”

buildings. Might be worth a look

if I can dig it up…

That said,

I don’t place too much faith in carpet dust sampling. It is far too erratic for my tastes—depending on how much

suction is applied and the type of carpet sampled, results will vary

dramatically. It can be

interesting to build an historical profile of the building air, but I would never

use it as a determiner of clearance due to the variance. If I need the history, I tend to pull

up a corner of the carpet and scoop the dust I invariably find there into a bag

for bulk analysis, which is slightly more accurate. The use of dust as an historical profile is fraught with

peril, because all mold spores do not necessarily end up in the carpet—some of

the smaller spores, particularly A/P, can remain aloft almost indefinitely,

which means that settled dust is typically skewed toward larger (and therefore

heavier) spores with higher settling rates.

A. Walsh MS, CIE

-----Original

Message-----

From: e

Sent: Thursday, July 29, 2004 8:31

PM

To: iequality

Subject: Re: IEC

Article on Carpet Dust Sampling

I have always had mixed feelings about carpet dust sampling. To

me, it equates to sampling a furnace filter. AS with filters, aren't all

carpets loaded with mold spores anyway ?

The age of the carpet must be a big variable in this equation too.

If I sample the dust from 6 months old carpet as opposed to 10 year old carpet,

wouldn't I find a lot more spores in the older carpet and does this really

indicate the existence of a mold source elsewhere in the building or does it

just tell me that this carpet has been collecting dust spores for a longer

period of time ?

What about the effectiveness of the vacuum used to clean the

carpet ? Wouldn't that skew the results ?

On one hand, I find the idea of analyzing carpet dust very

attractive because, in a way, it contains the entire " history " of the

building since the carpet was installed but I wouldn't be sure how to interpret

the lab results. What guidelines do you follow to interpret the test results ?

Can the numbers be compared to anything ?

I'd like the understand this carpet dust theory better.

e

Indoor Environmental Testing Inc.

[Guest guest]

for the " old paper " on this topic, see:

M. Hodgson, , R. (1999) " Prevalence of fungi in carpet dust

samples " , in Bioaerosols, Fungi and Mycotoxins: Health Effects,

Assessment, Prevention and Control, E. Johanning (ed.), Eastern New

York Occupational and Environmental Health Center, Albany, New York

regards,

Wane

<><><><><><><><><><><><>

Wane A. Baker, P.E., CIH, RPIH

Director, Air Quality Services

" Bad air gets you down "

MICHAELS ENGINEERING INC.

811 Monitor Street, Suite 100

PO Box 2377

La Crosse, Wisconsin 54602

Phone , ext. 484

Cell

Fax

mailto:wab@...

On the web at: http://www.michaelsengineering.com

" To love what you do and feel that it matters - how could anything be

more fun? "

- Graham

> Actually, there was an old paper (~6 years, exact reference escapes

me) that

> described the different spore composition found in carpets

of " problem " and

> " nonproblem " buildings. Might be worth a look if I can dig it up…

>

[Guest guest]

Dear e, Please allow me to elaborate.

The following does not apply to determining if a surface is clean or

dirty. It only applies to determining if the dust on a surface is a

normal type of dust. That is, examining the dust to indicate a

possible abnormality in the environment.

The theory is that the carpet, or any other horizontal surface for

that matter, is accumulating DUST, and regardless of how thick the

dust, what is most interesting is that the components in the dust

should accumulate at roughly predictable ratios. Such that we

should be able to DEFINE " normal dust " in terms of the RATIOS at

which the constituent ingredients are distributed. This is similar

to the way drinking water is defined. I mean, it does not matter

how much water you have when trying to determine if the water is OK

to drink, but it does matter the ratios or ppm of the various

ingredients in the water.

Whether the horizontal surface has 1 month's worth or 1 year's worth

of dust, the DUST is made up of many ingredients, present at

predictable ratios:

Rank Order Distribution by weight

1. Minerals,

2. Synthetics,

3. Paper fiber (commercial), dryer lint (residential)

4. Hairs,

5. Skin cells,

6. Arthropod frags and frass,

7. Mold spores,

8. Pollen grains,

As time goes on, a surface will accumulate more of each, but always

in roughly the same ratios. Cleaning typically reduces each

category equally, still maintaining roughly the same ratios. What

we are trying to determine are the ratios at which these ingredients

should be present with respect to one another, under normal

conditions. Keping in mind " normal conditions " is sort of an

average term that factors in how building are typically cleaned,

used and located. Obviously there are wide variables, and hence a

range is set for " normal " . But all this is true for air sampling as

well.

Let's say for the sake of argument, that under " normal "

environmental conditions, we expect the common ingredients in DUST

to follow the rank order shown above. Then, on one of your

projects, you find a house in which the DUST analysis places mold in

rank order position 3.

WOW! You can then say that it appears mold is accumulating at a

RELATIVE RATE faster than it should be. You can say the dust is

abnormal dust, without a care in the world for how much dust is

present. Just like we could say bottled water with 0.05% crude oil

is not normal for bottled water. It still might be safe to drink if

you only drink a little bit, but it would be a quantifiable

abnormality. WOW! You could say that something is causing the mold

component of the dust to be out of balance, i.e. maybe a source is

nearby. Could be a moldy fruit basket or the mother lode of mold in

a kitchen wall cavity. It may or may not be a big deal, but still a

quantifiable abnormality.

You see, when analyzed this way, it really does not matter HOW MUCH

dust is present, only the relative rate at which MOLD component is

accumulating compared to the OTHER COMPONENTS in the dust. And, if

you further do a surface loading calculation it is entirely possible

to then say, " The carpet does not need cleaning, but the composure

of the dust indicates an abnormality which should be investigated. "

This is what indicator tools are all about. They are not supposed

to be definitive.

One big problem with constituent ratios is that the ratio of the

mineral constituent (the heaviest) can vary greatly depending on

things like whether your house is near a gravel road. Norms need to

be established for different ambient environments. But, to

circumvent such variables, some published literature on this subject

chooses to only examine the relative rates at which the various mold

genera accumulate in dust with respect to one another. This can be

useful in categorizing the mold constituent per se as normal versus

abnormal, without a care in the world for how much mold is present

relative to all other components. For example: In this method, the

mold category might still be in rank order position 7 (i.e. normal)

but the various types of mold within the category might be out of

whack. See Air Quality Sciences 20/20 Rule for a brief introduction

into how this could work. (www.aerias.org)

Carpet may not be the best surface from which to collect your dust

sample. But carpet is the most used surface in dust studies from

Europe to Scandinavia to the USA. And therefore, is the most

practical dust sink to cross-reference with other studies.

And lastly, if the only thing you are trying to determine is whether

the carpet needs to be cleaned, NONE of the above applies, and most

evaluative methods would cost more than simply opting to have the

carpet cleaned. K.I.S.S. – just clean the carpet, it probably needs

it anyway, especially in the elevator. That is why I believe the

only thing worth discussing on the topic of dust assessment is how

to use dust as an indicator that something in the environment may be

out of whack.

Gerber

> I have always had mixed feelings about carpet dust sampling. To

me, it equates to sampling a furnace filter. AS with filters, aren't

all carpets loaded with mold spores anyway ?

>

> The age of the carpet must be a big variable in this equation too.

If I sample the dust from 6 months old carpet as opposed to 10 year

old carpet, wouldn't I find a lot more spores in the older carpet

and does this really indicate the existence of a mold source

elsewhere in the building or does it just tell me that this carpet

has been collecting dust spores for a longer period of time ?

>

> What about the effectiveness of the vacuum used to clean the

carpet ? Wouldn't that skew the results ?

>

> On one hand, I find the idea of analyzing carpet dust very

attractive because, in a way, it contains the entire " history " of

the building since the carpet was installed but I wouldn't be sure

how to interpret the lab results. What guidelines do you follow to

interpret the test results ? Can the numbers be compared to

anything ?

>

> I'd like the understand this carpet dust theory better.

>

> e

> Indoor Environmental Testing Inc.

>

> IEC Article on Carpet Dust Sampling

>

>

> The July 2004 issue of Indoor Environment Connections has an

> interesting article titled, Sampling Carpet Dust for Microbials.

>

> The authors appear to have almost inadvertently focused in on

carpet

> dust sampling as a tool to evaluate the " cleanliness "

> vs. " uncleanliness " of carpet. And if one is to use carpet dust

> assessment for this very narrow, myopic purpose, then what the

> authors have said is all quite true; with the possible

exception

> that they did not include a time factor into their equation.

>

> But, IEQ investigators use carpet dust sampling for a purpose

larger

> than just determining if the carpet needs to be cleaned. It is

my

> experience that many investigators collect carpet dust and

analyze

> the mold constituents in carpet dust as a way to indicate

something

> beyond the carpet itself. Carpet dust is very useful as an

> indicator of the possible existence of a mold source elsewhere

in

> the building, and for this purpose, the content of mold per

sample

> weight is far, far, far more important than determining loading

of

> mold per unit surface area.

>

> Yet, the true beauty of dust sampling is one can calculate both

the

> surface area loading and the concentration per weight at the

same

> time! So you can use the data for two totally separate

purposes: to

> determine if the carpet (or given surface) is being maintained

or

> cleaned adequately AND you can pick up on abnormal rates of mold

> accumulation relative the rate of accumulation of the other

> constituents in the dust, thus indicating the possible presence

of a

> source nearby.

>

> I think this is obvious. Any one care to pick up on this topic

or

> have comments to my opinion that the authors chose a narrow,

almost

> misdirected focus for their article?

>

> Gerber

>

>

>

>

> FAIR USE NOTICE:

>

> This site contains copyrighted material the use of which has not

always been specifically authorized by the copyright owner. We are

making such material available in our efforts to advance

understanding of environmental, political, human rights, economic,

democracy, scientific, and social justice issues, etc. We believe

this constitutes a 'fair use' of any such copyrighted material as

provided for in section 107 of the US Copyright Law. In accordance

with Title 17 U.S.C. Section 107, the material on this site is

distributed without profit to those who have expressed a prior

interest in receiving the included information for research and

educational purposes. For more information go to:

http://www.law.cornell.edu/uscode/17/107.shtml. If you wish to use

copyrighted material from this site for purposes of your own that go

beyond 'fair use', you must obtain permission from the copyright

owner.

>

>

>