An air purifier is an appliance used for cleaning air indoors and they are used in homes, commercial buildings, industrial workplaces etc. The application of air purifiers is usually in places which tend to have unhealthy air due to pets, molds, pollutants, smoke or industrial work, hazardous materials etc. Air purifiers are also popular in homes of allergic people and asthmatics who wish to keep the air healthy in their homes. They are also popular due to the fact that the air inside homes is less healthy than the air outside.
Since people spend a significant amount of time indoors having an air purifier is healthy.
Allergic applications
Air purifiers are most popular for asthmatics and allergic people and they work by keeping allergens and triggers out of the air in homes. Allergens or triggers can be dust, pollen, mold spores, fungus, pet hair, smoke particles, airborne gases etc.
Functioning
Air purifiers employ various techniques for air purification like absorbents, ionizers, mechanical filters etc. Absorbents can be in the form of activated charcoal and ionizers can be in the form of electrostatic chargers. Some air purifiers have additional systems like germ killing UV light, ionizer for neutralizing contaminants.
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HEPA filters
HEPA is an acronym for High Efficiency Particulate Air. HEPA filters are very popular for air purifiers. Before being designated as HEPA, air purifiers must meet very stringent requirements as laid down by the Department of Energy. HEPA filters should remove at least 99.97 % of air borne particles of 0.3 micron size at 85 liters per minute rate. However HEPA filters are very expensive and replacing the filter in the purifier may cost as much as the purifier itself. Further HEPA filters cannot remove gases or odors from the air. For removing gases absorbent type of air purifiers are suitable.
Ozone
Some Ionic air purifiers produce ozone in the delivered air. Ozone can be dangerous at higher concentration, which is the cause of a controversy. However ionic air purifiers are associated with healthy air environments such as waterfalls, mountains etc, since these places have a negative ion concentration as in ionic air purifiers. An ionic air purifier in conjunction with an air filtration system is suited for most purposes.
What to look for
Customers usually look for aesthetic appeal, noise levels, size of the equipment, frequency of filter replacement, electricity consumption, air delivery rate etc. Most of the filters can be cleaned easily by vacuuming, by water or by hand. The filters may need replacement anywhere between months to a few years depending upon the type of air purifier.