The Danger
Particles that are
less than 2 microns in size will enter and remain in the lung
linings and mucus membranes (Common
Particles Sizes in Microns).
These particles can contain, mold, fungus, bacteria, pollen, dust
mites, dust mite feces and other airborne respirable allergens. These
are the particles you need to remove from your air.
The Big Lie
There
are those that would have you believe that a washable type electrostatic
air filter will protect you from these harmful particles. They
don't...never did. In fact most electrostatic air filters are less
then 10% effective in capturing dangerous respirable particles.
The Numbers Game
Well it
would be pretty hard to sell any of these washable electrostatic air
filters if they advertised a whopping 10% efficiency rating. Instead
sellers of washable electrostatic filters advertise the results of a
test that measures an air filters ability to capture large
particles.
This test "the
average
synthetic dust weight arrestance test" has only one use, it
gives the people selling the washable electrostatic air filter a
high number to hype.
Here's
how the tests work
Average
Synthetic Dust Weight Arrestance Test
This test
measures a filters ability to remove large particles. Most large
particles are to heavy to stay suspended in the air and soon fall to
the ground. Small particles are the ones which have the
greatest potential to aggravate allergies.
An air cleaner is mounted in a clean
test duct. A highly efficient filter is carefully weighed and
mounted downstream from it, and then a measured quantity of
synthetic dust is released into the duct. The downstream filter
captures particles that get through the air filter.
That filter is weighed
again, and the pre- and post-test weights are compared to establish
a rating.
Atmospheric Dust
Spot Test
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This test
accurately represents an air filters ability to capture fine respirable
allergens.
An air filter is mounted in a clean test
duct, with highly efficient filters mounted upstream and downstream from
it. Outdoor air is then introduced into the duct. The upstream filter
catches a sample of airborne particles before they reach the air filter,
providing a bench mark for later comparison with the downstream filter.
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