Electrostatic air filtration is another name for the electrostatic precipitator (ESP).
Ionic Breeze wss one very popular “ionic” air purifier using ESP filtration technology, Freidrich C90b was another.
Neither of these air cleaners survived the ozone shake out, but they still serve as leading examples of the electrostatic type air cleaner.
ESPs generally do NOT have HEPA filters, they impart a charge to incoming
particulate, causing it to stick to an oppositely charged metal grid.
ESPs are efficient cleaning devices that offer less restriction to air flow than HEPA filters.
They can remove fine particulates to .01 micron when properly maintained.
Electro-static filtration is common in industrial particulate emissions applications.
Its adaptation to residential air cleaning has a few problems.
An ESP charges the air in it with a very powerful electric field, creating ionized particles.
Oppositely charged metal collector plates, often made of stainless steel, attract and collect most of the particles in the air stream.
ESP air cleaners run at high voltages.
”I was working in the lab late one night,
The electrically charged nature of this group raises several issues in my mind: these suggest theme lyrics from the 1962 pop hit “Monster Mash” by Bobby “Boris” Pickett.
Some plate precipitators, such as the once popular Ionic Breeze, are completely filterless.
Others, like the Friedrich C90 series, will have a pre-filter and a post filter with some carbon.
The first ESP filtration issue is: as dirt accumulates, the efficiency of the unit dramatically declines, the dirt electrically insulates the collector plate.
Then newly charged particles don’t stick, re-entering the room, sticking to hair, carpet, furniture, clothes and lungs.
The efficiency of electrostatic air filtration can drop 20% in the first few days after plate cleaning.
Seems he was troubled by just one thing”
If the collection plates are left unwashed, the dirt may stick to the metal so that heavy scrubbing is needed to clean them. Other parts inside the air cleaner may also get gummed up.
I gave my son a Honeywell 60001, which uses ESP filtration, collecting particles on a honeycomb grid.
If not rigorously cleaned it bypasses.
He ran the 60001 for three years in a dirty apartment, THEN we cleaned it.
The entire interior of the Honeywell electrostatic was coated with black soot.
Some consumer ESP’s are offered with special soak-off cleaners, which soak the plate overnight, to loosen the tightly bound particulates.
When some models with electro-static air filtration get dirty, they begin to arc across the plates, making a sharp crackling pop.
This was a common problem with the Friedrich unit.
Popping can be a very frequent and annoying reminder that cleaning has been neglected.
This is not loud like HEPA units, but many owners complain.
Among Sharper Image Ionic Breeze’s few credits is the fact that it doesn’t pop, making only a minor hum.
Electronic air filtration removes only particles, having no effect on gas phase VOC pollutants.
As my readers know, I consider this a fatal flaw.
ESPs are rarely used by the scientific or medical communities where clean air is critical.
The party had just begun!
Many common electronic products including copy machines, televisions, and hair dryers, produce trace levels of ozone. ESPs can produce substantial ozone.
There are government safety standards for ozone in other settings.
50 parts-per-billion (ppb)concentration (equals .050 parts per million)is the established limit for indoor medical devices.
CARB (California Air Resources Board) has excluded a list of air cleaners which exceed .050 parts per million.
Most ESP air filtration units crowd or exceed the 50 ppb medical device/CARB air cleaner limit.
In a Consumer Reports two-inch (from device output) ozone test in the open lab, the Surround Air XJ-2000 produced the most ozone, 319 ppb, followed by the IonizAir P4620 at 168 ppb,
the Ionic Breeze at 48 ppb, the Ionic Pro CL-369 at 33 ppb and
the Brookstone Pure-Ion at 26 ppb.
In the three-feet open lab test, the Brookstone emitted the least ozone of the ionizers at 2 ppb, and the IonizAir producing the most at 28 ppb.
Ozone is a strong oxidizing agent: when we take anti-oxidant vitamins to protect our health, why add unnecessary oxidants to our air?
I do not accept the idea that low levels of ozone can safely be added to the list of toxins and oxidants we already breathe.
Some electronic air filtration air purifiers, including Ionic Breeze, but not Friedrich, charge particles positively and collector plates negatively.
Positive ions were implicated in the original ion research as the bad guys.
Negative ions were the source of claimed health benefits before the feds banned such claims.
I have seen no tests, but it seems to me like dirty ESP ionic air purifiers might be dumping positive ions. Another minus.
To get a jolt from my electrodes”
I am concerned that the strong electrical fields used to charge the particles in ESP air filters may be more harmful to health than competing technologies.
Of course, my 120 volt AC purifiers, clocks, and fans are kept far away from my head while I sleep.
I run the purifiers on high until bedtime, then use the remote to downshift, turning the unit down during the night.
ESP air purifiers are not cheap, and with so many good products available, I don’t give electro-static air filtration systems top ratings.
Air Purifiers at Amazon.com.
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