Understanding Air Purifiers

"body">cleaner for your home.
Purchasing an air purifier can be confusing, andOzone Air Purifiers
you do get an awful lot ofinformation thrown atOzone is created in nature by everything from
you when you visit the different manufacturingwaterfalls to thunderstorms,and is responsible for
websites,don't you? How can you tell what's what,that fresh, clear smell after a heavy rain or storm
and why do we need air filters anyway?haspassed. It's nature's way of cleaning the air.
And how do air purifiers work? Is the air reallyOzone air purifiers essentiallydo the same thing
that bad? Haven't we beenbreathing the same airindoors by artificially mimicking the natural process
for thousands of years?thatcreates ozone.
Yes and no. First of all, we've been breathing theOzone molecules exist in the air all around us, and
same air for thousands ofyears, but we live in awill react with anyparticles they come into contact
symbiotic relationship with the plants around us -with, but are very unstable and tend to existin
thatis, we rely on each other to survive. Wesmall quantities for short periods of time.
breathe oxygen to live, and give offcarbonOzone air purifiers work by using electricity to
dioxide. Plants exchange carbon dioxide forgenerate more ozonemolecules, which have one
oxygen, effectivelymore oxygen (O3) than we normally have in the
"exchanging" the air in a healthy relationship withair (O2)around us. Since ozone is highly unstable,
us. This makes plants thefirst primitive air purifiersone of the oxygen atoms is alwaysinclined to
on earth, and explains why scientists arebreak away and find another molecule to bond to.
soconcerned about the ecological balance on earthThis process causesa chemical reaction which
and the need for the survival ofrain forests anddestroys odors and germs in the air and then
plants - they ensure our own survival as well byconvertswhat is left of the molecules into
preservingoxygen in our atmosphere.harmless oxygen and CO2.
Nature cleans the air in other ways as well -There is some confusion between ozone air
ozone (positively chargedoxygen molecules) iscleaners and ionic air cleaners,but there are some
generated by waterfalls and thunderstorms.differences. With an ozone air purifier, the ozone
Ozone alsocleans impurities and particulates fromthat isreleased into the air will be unstable and
the air naturally.cause a reaction that will alter anddestroy certain
The Industrial Revolution and Air Qualitygerms, viruses, bacteria and molds. It does not,
The industrial revolution made great strides inhowever, have acollection plate where dirt or
everything but air quality.grime collects.
In fact, pollution such as emissions fromIonic Air Cleaners
automobiles, smog and pollution fromeverydayAn ionic air cleaner also uses electrical charges to
chemicals like cleaning fluids, carpeting and paintsalter oxygen atoms inthe air, like an ozone air
enter the airevery day. In industrial settings, aircleaner. But unlike an ozone cleaner, an ionic
purifiers clean the air before it isreleased into theaircleaner will rid the air your breathe of dust and
atmosphere in order to meet governmentpollen as well.
requirements.Ionic air cleaners negatively charge the air
Today's homes are also more energy efficientparticles in a room, which willcause a magnetic
and cost effective, but to getthere they haveattraction to occur. The positively charged
become much more "closed in." When they areparticles in theair, such as dust, pollen and pet
this sealed up,indoor pollutants are shut in so thatdander, will naturally be attracted to theseand
today's homes are actually two to fivetimesthey will "cling" to each other, creating a sort of
more polluted than outdoor levels! Obviously, airmagnetic bond. Particlesthat form into bonds like
purifiers are essentialto improving indoor air qualitythis become too heavy to remain suspended in
to combat the effects of this stale,recirculated air.the airand fall to the ground, where you will no
Beginning in the 1980's, medical practitioners beganlonger be able to breathe them intoyour system.
to take note of thedirect link between poor airVacuuming and regular dusting can get rid of
indoor air quality and the increased incidencethese particles. In today'sionic cleaners, there are
ofconditions such as asthma, allergies andalso fans that move the room air over
recurring colds and upper respiratoryinfections.negativelycharged metal collection plates that the
The development of a variety of improved,positively charged particulates willstick to. These
scaled-down air filtrationsystems for in-home usecan be regularly cleaned by simply wiping them
soon emerged.with a softcloth.
How the Main Types of Air Purifiers WorkElectrostatic Precipitators
One of the most commonly used type of airThe original electrostatic precipitators were huge
purifier is also one of the firstdeveloped, and ismonsters used to controlpollution emissions from
used in most hospitals and clean rooms. This isindustrial plants. The waste by-products of a
the HEPAfilter.plantwere sent through large chambers that were
HEPA Filterscharged by electrodes that acted asenormous
During the Manhattan Project in the 1940's, thecollection plates to attract the oppositely charged
Arthur D. Little firmdeveloped the first HEPAwaste products
filters in order to filter out very small particlesthat(such as dust, lead, sulfur, fly ash and other
had become contaminated by nuclear radiation inhazardous chemicals) from thematerials passing
atomic bomb testing areas.through, filtering out all harmful materials.
It was during this initial development that thePeriodically,the precipitators would be "tapped" so
HEPA standards were set at 0.3microns, whichthat these materials could be dumped fromthe
could effectively capture condensed radioactivechambers into disposal units.
iodine.Home electrostatic precipitators also work on the
The filters at that time were called "absolutetheory of using a negativecharge and a positive
filters," and not called HEPAcharge to collect and retain particulates, however,
(High Efficiency Particulate Air) until the filtersthecharge takes place within the air purifier itself
were marketed in the 1950's.rather than in huge chambers,and the dust and
Today these filters are used by hospitals, surgicalparticulates are captured on metal filters that can
wards, biopharmaceuticalresearch labs, microbe removedand cleaned or replaced, getting rid of
circuitry labs, and the aerospace industry forthe need for a separate collectionchamber for the
theirexceptional ability to control dust andparticulates.
particulates.Electrostatic Filters
HEPAs remove 99.97% of particles of 0.3With electrostatic filters, a small static charge is
microns or larger. For even moreintense filtration,created that attractsairborne particles as they go
there is an ULPA, or Ultra-HEPA filter, which filtersthrough a filter, capturing even thoseparticulates
outwhich are too small too be captured by the
99.99% of contaminants pass through the filter.relatively loose weaveof the filter itself. Because
Obviously, something has to draw the air throughof the looser weave, the air flow in
the filter, and with HEPAfilters this is a motorizedanelectrostatic filter is very good, but the filtration
fan. This can make them noisy, which makesis very effective becauseof the electrostatic
them anannoyance to some people. A HEPA filtercharge.
will need to be replaced every 12-18months,These filters do have to be carefully maintained
depending upon how it is used and the interiorand cleaned at leastmonthly, and should be
environment of your home.replaced every year for peak effectiveness. As
For instance, if you have pets, especially cats orthefilters do become dirtier, the air flow will
dogs that shed a lot, you mayneed to change itbecome less efficient.
more frequently because of the dander. If thereFinally, there are systems that combine two or
are smokers inthe house you will also need tomore types of air purificationsystem. While these
change your air filter more frequently toare usually more expensive, they can be worth
ensureproper filtration.the price ifyou are looking for the best possible
However, for overall performance, nothing filterscombination of features. For instance, anair purifier
out or eliminates moreparticulates than a HEPAthat will kill viruses and bacteria like an ozone air
filter, so it is a matter of balancing cost,purifier, butwill also effectively filter out dust and
soundpreference and convenience against yourdander with a HEPA filter.
relative needs when choosing the rightmodel of air