Filtration - [Was: Culturable mold indoor~association w/moisture-related pro...]

[Guest guest]

Barb and others,

Yes, but that is only one reason HEPA and high MERV rated

filters cannot be depended on to solve contamination problems.

Not only for the ultrafine particles but even the ones they are

designed to capture.

1. No filter removes the contamination from its location. It can

only remove that portion of the contamination which is in the air. If

there is mold growing in the crawlspace or attic, for example, no

air filter in the bedroom can clean up the crawlspace or attic.

It's like having a cigar smoker in your house and trying to remove

all the smoke with an air filter. Can't be done because it just

keeps coming and coming. Like Timex watches which just keep

on ticking. Or the Energizer Bunny which keeps on going. Or

Doritos. We'll make more.

Filters may help to reduce, but they don't remove the cause of the

contamination. The cigar smoker has to be removed and then the

filter will help to gradually reduce the smoke.

2. It can only remove the contamination from air that actually

goes through the filter. Most air does not. It stays on the other

side of the room. Or in the other room, or attic, or crawlspace.

Behind the cabinets. Under the carpet.

3. A HEPA or high MERV filter only removes particles, not

chemicals or odors or molecules. These are hundreds of times

smaller than the pores in the filter. They go right through like sand

through screen wire. They have to. Because they are the same

approximate size as air molecules and the air must go through

the filter. If it can't then the particles can't be separated from the

air and captured on the filter. Different methods are needed for

molecules of chemicals and odors.

4. A HEPA or high MERV filter is limited, as Dr Thrasher clearly

stated, to particles 0.3 microns and larger. It used to be thought

that only a few percent were smaller than 0.3 microns. It is now

known, because there are instruments to measure smaller

particles, that 90% may be smaller! Those are the ultra fine

particles Dr Thrasher is discussing. They go deeper into the

lungs, tend to stay longer, and beginning acting like chemicals

rather than just particles.

5. A HEPA filter has a MERV rating of 17. As most of you know,

Jeff May recommends MERV 11 for air conditioners. The reason

he doesn't want a higher MERV rating is the higher the rating the

smaller the pores in the filter, restricting air flow. If you don't get

enough air flow air conditioners can freeze and motors can burn

out. MERV 11 is a good balance between particle removal and air

flow.

6. A HEPA filter has a very specific definition. It must capture

99.97% of particles at 0.3 microns. Smaller ones get through.

What's the 0.03% that isn't stopped? Can't be much, right? It

means that if 10,000 particles go through the HEPA filter 3 will

escape. Consider that typical air has 30,000 to 300,000 particles

in every cubic foot of air. That means 9 to 90 are not stopped by

the HEPA. Still, no big deal except many of you react at those

extremely low levels.

But that's not the whole story of exposure. If the filter is rated at

100 cubic feet of air per minute then 900 to 9,000 particles are

not stopped - every minute! Because there are 60 minutes in an

hour, that calculates to 54,000 to 540,000 each and every hour.

7. Finally, and here is the latest " kicker " on HEPA filters. The

HEPA filter is what goes inside a box with a motor. That box is a

HEPA " device " which contains the HEPA " filter. " The filter, not the

device, is rated at 99.97% at 0.3 microns. The device may or may

not perform at the same level as the filter itself, especially if the

filter doesn't fit tightly and correctly inside the box. Which most

don't.

An ANSI standard is being written to measure the effectiveness

of HEPA " devices. " Preliminary testing is showing that about 20%

of industrial grade HEPA devices fail. Many miserably. Almost

none of the industrial HEPA filtered vacuums pass. (Most home

units have not been tested but the ones that have are generally

not made as well as the industrial ones and perform worse).

Because of the high air resistance of the HEPA filter much of the

air finds an easier pathway around the edges, not going through

the filter at all. It isn't filtered at any level for any particle size!

Which means item " 2. " above should be changed to read, " It can

only remove the contamination from air that actually goes through

the device. Most air does not. It stays on the other side of the

room. And, of the air which does go through the device, much of

it doesn't go through the filter. "

So there are many reasons HEPA and high MERV filters don't

work for us much of the time.

Here's what does work, in order of decreasing effectiveness.

A. Identify the contamination, where it is located, and remove it.

You are no longer exposed because it is gone. If you can't

remove the source the exposure won't stop until you remove

yourself from it. That's why most on this group tell you to leave

the house.

B. If it can't be removed, isolate it. It is still present but it can't

become airborne, so you are not exposed. An example is painting

walls and ceilings. It covers the dust and dander so it can't get in

the air. Or, containment of the mold remediation work area with

plastic sheeting. Or, controlling air flow like Barb talks about with

her attic. Keeping the air moving from the living space into the

attic so it can't move from the attic back into the living space.

C. If none of the above are sufficient, or possible, try dilution by

ventilation. It mixes and some is removed. Like adding water to

coffee that is too strong. Make it weaker by dilution. The pollution

is still there and is still in the air. You are still exposed to it. But it

is now at lower levels, hopefully below your threshold of reactivity.

That's why it is less effective than removal or isolation. Also, it

works better for odors than for particles. Assuming the outside air

is clean, which is a real stretch nowadays. Just ask those living

along the Gulf coast!

D. Finally, the least effective method for both odors and particles

is filtration. For all the reasons stated above.

As an aside, some of you mentioned face masks. If you have an

N-100 mask you know how hard it is to breath. That's because an

N-100 is rated as a HEPA filter, which is MERV 17. The N-95 is

much easier to breath through but it is now only 95% rather than

99.97% effective.

What's the difference between 99.97% and 95%? Multiply the

HEPA ratings by 166 and the 540,000 particle leak now becomes

90,000,000. That's how much difference. Huge! And that's

through a properly functioning device or mask working at the

same level as the filter. Good luck!

But the main reason face masks are so lousy is because the

edges don't fit tightly on the face as you move, talk, and breath.

The air has an easier pathway around the edges much like in

HEPA devices. Workers must be fit-tested to verify the mask is

sealed to the face with no leakage. That requires a medical exam

stating they are healthy enough to handle strained breathing.

So, what many of you are experiencing about the limitations of air

filters are true, whether you know why or not. Afterall, the air and

the pollutants don't care what you know or think. And they don't

read the HEPA device instruction manuals and they certainly

don't care about the advertising claims. They behave according

to their physical and chemical properties.

Which is why it's important to know at least a little about them so

you can make better decisions and figure out what to do when

the " magic bullets " don't work.

Carl Grimes

Healthy Habitats LLC

-----

So even a high MERV filter for furnace or stand alone air cleaners, will not

catch these ultra fine particles and that is why one cannot depend on air

filters to solve contamination problem??

--- In , " Jack Thrasher, Ph.D. " <toxicologist1@...>

wrote:

>

> Sharon you are correct. I have emailed the authors for a copy of the

manuscript.

>

> We must remember the following fact: Mold colonies (also bacteria colonies)

shed particulates ranging from less than one micron to the size of spores and

hyphae fragments (2 or greater microns). The fine particulates (less than 1

micron) are up to 500 time more concentrated than are the spores. The fine

particulates contain the endotoxins (toxic metabolites) as well as the

allergenic proteins (enzymes, hemolysins, among just a few). I individuals in

this forum want copies of the papers that describe the fine particles, email me

and I will forward them to you.

>

>

> Jack-Dwayne: Thrasher, Ph.D.

> Toxicologist/Immunotoxicologist/Fetaltoxicologist

> www.drthrasher.org

> toxicologist1@...

> Off: 916-745-4703

> Cell: 575-937-1150

>

>

> L. Crawley, M.ED., LADC

> Trauma Specialist

> sandracrawley@...

> 916-745-4703 - Off

> 775-309-3994 - Cell

>

>

>

>

> This message and any attachments forwarded with it is to be considered

privileged and confidential. The forwarding or redistribution of this message

(and any attachments) without my prior written consent is strictly prohibited

and may violate privacy laws. Once the intended purpose of this message has been

served, please destroy the original message contents. If you have received this

message in error, please reply immediately to advise the sender of the

miscommunication and then delete the message and any copies you have printed.

Thank you in advance for your compliance.

>

>

>

>