Industry Review
Not All Air Purifiers are Created Equal
With our very high standards in mind, we did some research.
Here's what we found:
60% of brands we reviewed use technology we do not recommend.
See Safety First below.
We eliminated other brands because they use a plastic casing which can
off-gas and irritate the chemically sensitive individual.
We found other brands to be unsuitable because of insufficient
capacity to remove pollutants from indoor air.
Safety First
The best air purifiers are safe for the human body's delicate, intricate systems.
Of the 75 brands in our air purifier review, we found that over 50% were ionizers
or ozone producers. Both types produce ozone in varying amounts, and therefore
are not recommended by The Clean Air Coach. Others use an
electrostatic process to charge and 'trap' particles. These
also can produce some ozone, and the negative charge on
the particles can be problematic. (For further information
see Air Purifier Technologies.)
If an air purifier is advertised as being "silent", it is probably one of the above types
which we do not recommend. In filtration technology a fan is needed to draw the air across the filters.
If you see "no filters needed", then you know the equipment is either
putting something into the air (such as with ionizers and
ozone producers mentioned above); or electrostatic plates
are charging and attracting particles to itself.
Effectiveness
The best air purifiers are not only safe, they are effective
and efficient in removing a broad spectrum of pollutants.
The size, type and positioning of filters are crucial.
They must have the capacity to significantly trap specific pollutants
over an extended period of time.
Since both airborne chemicals
and particles aggravate, and in some cases, may even trigger
allergies and asthma, it is vital that an air cleaner for
respiratory conditions provides filtration for both.
The best filtration for particles including biological contaminants
(dust, pollen, pet dander, mold, bacteria, viruses) is true,
medical grade HEPA which traps 99.97%
of particles 0.3 microns in diameter; and smaller and larger particles with even
greater efficiency. This is the type of filtration used for medical and scientific clean rooms.
For airborne chemicals and gases the best filtration medium is activated carbon.
In order to meet our strict criteria, the granular
activated carbon bed must be deep enough to allow for effective dwell time. This again narrows the
field considerably. Many air purifiers on the market have only a few token ounces of carbon;
some simply have carbon sprayed on a foam pad.
Construction
The next feature in our air purifier review is the housing
of each unit. Plastic casing is unsuitable, since it could
off-gas and therefore aggravate, rather than alleviate,
the effects of poor air quality. This again disqualified
several brands.
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