A Sharp FU-888SV Plasmacluster air purifier. The same air purifier, cover removed. An air purifier is a device which removes contaminants from the air in a room. Pressure swing adsorbers or other adsorption techniques are typically used for this. Dust, pollen, pet dander, mold spores, and dust mite feces can act as allergens, triggering allergies in sensitive people. Smoke particles and volatile organic compounds (VOCs) can pose a risk to health. Exposure to various components such as VOCs increases the likelihood of experiencing symptoms of sick building syndrome.[1] Air purifiers are becoming increasingly capable of capturing a greater number of bacterial, virus, and DNA damaging particulates. Several different processes of varying effectiveness can be used to purify air. Other aspects of air cleaners are hazardous gaseous by-products, noise level, frequency of filter replacement, electrical consumption, and visual appeal. Ozone production is typical for air ionizing purifiers.

Although high concentration of ozone is dangerous, most air ionizers produce low amounts (<0.05> ppm). The noise level of a purifier can be obtained through a customer service department and is usually reported in decibels (dB). The noise levels for most purifiers are low compared to many other home appliances.[] Frequency of filter replacement and electrical consumption are the major operation costs for any purifier. There are many types of filters; some can be cleaned by water, by hand or by vacuum cleaner, while others need to be replaced every few months or years. In the United States, some purifiers are certified as Energy Star and are energy efficient. HEPA technology is used in portable air purifiers as it removes common airborne allergens. The US Department of Energy has requirements manufacturers must pass to meet HEPA requirements. The HEPA specification requires removal of at least 99.97% of 0.3 micrometers airborne pollutants. Products that claim to be "HEPA-type", "HEPA-like", or "99% HEPA" do not satisfy these requirements and may not have been tested in independent laboratories.

Air purifiers may be rated on: CADR(Clean Air Delivery Rate); air changes per hour; the clean air delivery rate, which determines how well air has been purified; and the cost of the replacement filters. Two other important factors to consider are the length that the filters are expected to last (measured in months or years) and the noise produced (measured in decibels) by the various settings that the purifier runs on. This information is available from most manufacturers. As with other health-related appliances, there is controversy surrounding the claims of certain companies, especially involving ionic air purifiers. Many air purifiers generate some ozone, an energetic allotrope of three oxygen atoms, and in the presence of humidity, small amounts of NOx. Because of the nature of the ionization process, ionic air purifiers tend to generate the most ozone.[] This is a serious concern, because ozone is a criteria air pollutant regulated by health-related US federal and state standards.

In a controlled experiment, in many cases, ozone concentrations were well in excess of public and/or industrial safety levels established by US Environmental Protection Agency, particularly in poorly ventilated rooms.laser air purifier Ozone can damage the lungs, causing chest pain, coughing, shortness of breath and throat irritation. air purifier in open roomIt can also worsen chronic respiratory diseases such as asthma and compromise the ability of the body to fight respiratory infections—even in healthy people. carburetor cleaner air intakePeople who have asthma and allergy are most prone to the adverse effects of high levels of ozone.[17] For example, increasing ozone concentrations to unsafe levels can increase the risk of asthma attacks.

Due to the below average performance and potential health risks, Consumer Reports has advised against using ozone producing air purifiers.[18] IQAir, the educational partner of the American Lung Association, has been a leading industry voice against ozone-producing air cleaning technology. Ozone generators used for shock treatments (unoccupied rooms) which are needed by smoke, mold, and odor remediation contractors as well as crime scene cleanup companies to oxidize and permanently remove smoke, mold, and odor damage are considered a valuable and effective tool when used correctly for commercial and industrial purposes. However, there is a growing body of evidence that these machines can produce undesirable by-products. In September 2007, the California Air Resources Board announced a ban of indoor air cleaning devices which produce ozone above a legal limit. This law, which took effect in 2010, requires testing and certification of all types of indoor air cleaning devices to verify that they do not emit excessive ozone.

^ a b c ^ Photocatalysis: Considerations for IAQ-Sensitive Engineering Designs, David J Branson, P.E.., Engineered Systems, April 2006 ^ [1], Formaldehyde Test Report: Genesis Air Populated Catalyst Panel RTI Report Number: A03230901 May 2009 ^ [2], Office VOC Mixture Test Report: Genesis Air Populated Catalyst Panel RTI Report Number: A03230902, May 2009 ^ The Application of Ultraviolet Germicidal Technology in HVAC Systems, Michael J. Taylor, Product Manager, Carrier Corporation, Syracuse, NY ^ Ozone Generators: air cleaners intentionally designed to generate ozone Duck Hunter is the interactive target game that's fun, fast and safe! Simply switch on the rechargeable duck and gently toss him in the air. He flaps his wings and flies in a circle or in a straight line. Then get ready... aim... and fire! The blaster shoots a harmless beam of infrared light. Two hits stop the wings momentarily — and a third hit means this duck is out of luck! Everything you need to keep your life running smoothly.