Air purifier
From Wikipedia, the free encyclopedia
An air purifier is a device which aims to free air from contaminants. The popularity of air purifiers spur from the results from environment researches which claim that the air inside homes is dirtier than the air outside of homes. Air purifiers are particularly beneficial for allergy sufferers and asthmatics or those who wish to reduce second-hand smoke.
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[edit] Use of purifiers
Allergy-inducing culprits are known as allergens. Allergens can come in the form of dust or pollen as well as pet dander and mold spores. Hazardous smoke particles and airborne gases may also find their way into homes and bedrooms. Because of the significant amount of time most people spend indoors, many wish to ensure air purity.
[edit] Purifying techniques
Various techniques are used in air purifiers in the current market to accomplish indoor air purification. These techniques include mechanical filters, absorbents like charcoal, and electrostatic charges or ionizers. Additional setups include CaluTechgermicidal UV light and the emission of ions into the air to react with contaminants and making them harmless enough to breathe.
[edit] Consumer concerns
When selecting air purifiers, consumers are influenced by several factors, including visual appeal, noise level, and frequency of filter replacement. There are many different types of filters, some can be cleaned by water, by hand or by vacuuming while others need to be replaced within a few months or a few years.
The most popular sort of filters for air purifiers is the HEPA filter. The Department of Energy has rigid requirements manufacturers must pass to meet HEPA requirements. Products that say "HEPA-type" or "HEPA-like" may not meet these requirements. HEPA requirements necessitate being able to filter out 99.97% of pollutants in the air of 0.3 micrometres in size. While HEPA filters are extremely effective, they are also extremely expensive, and replacements can often cost nearly as much as the air purifier itself.[citation needed] For this reason, many air purifiers use both a HEPA filter and a less expensive "pre-filter" to reduce the frequency of HEPA filter replacement.
CADR, or Clean Air Delivery Rating, is a standardized indicator of how well a particular air purifier can function as compared to other air purifiers. The higher it is, the stronger the power of purification. CADRs are rated by AHAM, or the Association of Home Appliance Manufacturers, and are based on stringent requirements as produced by the association itself.
[edit] Air ionizers and ozone
As with all health-related appliances, there is some controversy surrounding the claims of certain companies, specifically involving ionic air purifiers. Particularly, some ionic air purifiers generate the pollutants ozone (an energetic allotrope of oxygen) and NOx. Either can be toxic in sufficient concentrations.
[edit] See also
[edit] External links
- AHAM Association of Home Appliance Manufacturers
- CADR.org Information on Clean Air Delivery Rate by AHAM
- DOE HEPA Filter Standards(pdf) HEPA filter specifications for DOE contractors
- EPA report on the effectiveness of ozone generators
- EPA report on indoor air quality
- DOE HEPA Filter Standards(pdf) HEPA filter specifications for DOE contractors
- Air Purifiers For You A comprehensive guide to various air purifier technologies, styles and brands