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Air purifiers comes in all kinds of sizes and shapes - using different cleaning
technologies such as HEPA, UVC, negative ions, etc.
You can choose from many brand names (Austin,
Bionaire, Honeywell, Sharper Image, Hunter, IonicPro, etc).
After reading this overview, you will understand the different
types of air purifier
available and you can then select one that is suitable for your home.
5 Types of Air Purifiers
The term "air purifier" and "air cleaner" are often use interchangeably. In general,
there are 5 different types (technologies) of air purifier. Each of them
works differently and has its pros and cons.
No single air purifier can eliminate all the air pollutants - different technologies are
used to remove different pollutants. For example, a HEPA filter is not able
to filter out air-borned viruses and a gas phased filter cannot remove pollens and dust.
Most modern (if not all) air purifiers are
the hybrid type, i.e. combining 2 or more of the technologies below in a single portable unit.
When choosing an air purifier for your home, always choose a one that
combines 2 or more cleaning technology - i.e. the hybrid type.
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 Mechanical (HEPA) Air Purifiers
draws air into the
unit and forces it through a 'filter media' to trap air-borned particles. The 3 types
filters generally used are: flat filters, pleated filters and
HEPA (High Efficiency Particulate Air Filters).
More info about HEPA air purifiers.
Electronic (Ionizers) Air Purifiers
uses an electrical field to trap particles. Air-borned particles are electrically
charged and deposited on the purifier's metal plates or on the floor. There are
3 types of electronic purifiers - "electrostatic precipitators", "charged media filters"
and "negative ionizers".
More info about electronic (negative ion) ionizers
Ozone Air Purifiers generates small quantities of
ozone into the air to reduce airborne pollutants.
Ozone (also known as "activated oxygen") is a powerful oxidation agent. It cleans the air
by oxidizing (i.e. destroying) the pollutant. However, high concentration of ozone is
a health concern and a possible lung irritant.
More info about ozone air purifiers
UV Air Purifiers uses a germicidal UV lamp to destroy
viruses and bacterias and render them harmless. As air is passed through the unit,
they are exposed th intense UV radiation which damages the DNA of thse microorganisms.
This action renders them harmless.
Many modern air purifiers incorporates a UV lamp in their units.
Read more about germicidial UV lamp purifier.
Gas Phase Filtration Purifiers
Mechanical (eg. HEPA) and electronic filters cannot remove gases and odors that are
typically 0.3 microns or smaller. Gas Phase filtration system usually uses
activated carbon - i.e.
charcoal that has been treated with oxygen to open up millions of tiny pores between
the carbon atoms. These filters then absorb gas molecules into these pores.
More info about activated carbon air purifiers
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Hybrid Air Purifiers
Hybrid air purifiers are those that use two (or more) different types of filter
technology. A common hybrid air purifier may combine an ion generator with a
mechanical filter (HEPA) in a self-contained portable unit.
Another popular hybrid purifier is the electrostatic media filter, which uses
electrostatic charge to attract airborne particles together with a HEPA system ... or
a UV system combined with a HEPA system.
Different manufacturers uses different combinations of available technologies to produce
an efficient (hybrid) purifier. Knowing these different technologies will help you make an informed
buying decision.
Air Purifier Summary
Mechanical and Electronic purifiers can efficiently remove air borned pollutants
(eg. pet dander, pollen, dust, etc). Electronic (negative ionizers have the additional
benefits of generating healthy negative ions.
However, they cannot kill viruses nor bacterias and are in-effective in removing voilatile
gases.
Germicidal UV air purifiers are very effective in rendering viruses, bacteria and other air-borne
microoorganism harmless by destroying their DNA. However, these type of purifiers do not
remove air-borne particles such as pet dander, pollen and dust.
Only Chemical (Gas) purifiers
can effectively remove gaseous contaminants and odors. The
active ingredients in these purifiers are usually 'activated carbons', and/or special sorbents
such as hydrogen sulfide and ammonia.
What about Ozone generators?
Although they can remove air-borne particles as well as some
gaseous contaminants, some is of the opinion that ozone poses a health risk to humans -
regardless of concentration. The FDA has set a safety limit of 0.05 ppm
(parts per million) for a 24 hr exposure of ozone. Reputable manufacturers of ozone purifiers
will adhere to that limit.
However, if you're not comfortable with ozone generators, then it's better you opt for
a combination of ionizers + UV or ionizers + HEPA systems.
There you have it. The various types of air purifiers and the different technologies used.
You should be able to make a well informed decision now.
If you need more help in choosing a suitable unit, see tips on
choosing air purifiers or see the recommended air purifier
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