RE: Re: IEC Article on Carpet Dust Sampling

[Guest guest]

I have a case where a client states that an area is too dusty. I am considering

collecting a surface sample to determine the composition of the dust and compare

it to the rank order of the ingredients given below. Also I will be doing

particle testing etc.

Can someone suggest a method to collect the surface dust and a good laboratory

to do the analysis.

Thanks

Bob

Re: IEC Article on Carpet Dust Sampling

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.

>

>

>

[Guest guest]

Try this lag out. They are very helpful.

http://www.mvainc.com

Re: IEC Article on Carpet Dust Sampling

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.

>

>

>

[Guest guest]

If possible do a bulk sample of the dust. Use a teflon cassette and

high-flow vacuum pump and collect enough dust to indicate a build-up on the

cassette. The flowrate of the pump is not important. Just make sure that

the pump is strong enough to draw the dust off of the surfaces sampled.

Also, the length of the sample is not important. Again, the amount of dust

collection is what is important. The lab will weigh the sample.

I would suggest sending the samples to P & K Microbiology in Cherry Hill, NJ.

Their address is 1936 Olney Avenue, Cherry Hill, NJ 08003. Their phone

number is .

Request dust characterization analysis.

Adam J. Pratt

Project Manager

BEM Systems, Inc.

100 Passaic Avenue

Chatham, NJ 07928

x144

apratt@...

Re: IEC Article on Carpet Dust Sampling

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.

>

>

>

[Guest guest]

A lot of microbiology labs do this sort of analysis--typically called forensic micro-screen.

RE: Re: IEC Article on Carpet Dust SamplingIf possible do a bulk sample of the dust. Use a teflon cassette andhigh-flow vacuum pump and collect enough dust to indicate a build-up on thecassette. The flowrate of the pump is not important. Just make sure thatthe pump is strong enough to draw the dust off of the surfaces sampled.Also, the length of the sample is not important. Again, the amount of dustcollection is what is important. The lab will weigh the sample.I would suggest sending the samples to P & K Microbiology in Cherry Hill, NJ.Their address is 1936 Olney Avenue, Cherry Hill, NJ 08003. Their phonenumber is .Request dust characterization analysis.Adam J. PrattProject ManagerBEM Systems, Inc.100 Passaic AvenueChatham, NJ 07928 x144apratt@...-----Original Message-----From: , Sent: Monday, August 09, 2004 11:01 AMTo: iequality Subject: RE: Re: IEC Article on Carpet Dust SamplingI have a case where a client states that an area is too dusty. I amconsidering collecting a surface sample to determine the composition of thedust and compare it to the rank order of the ingredients given below. AlsoI will be doing particle testing etc.Can someone suggest a method to collect the surface dust and a goodlaboratory to do the analysis.ThanksBob -----Original Message-----From: Gerber Sent: Friday, July 30, 2004 1:17 PMTo: iequality Subject: Re: IEC Article on Carpet Dust SamplingDear 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. 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