Air purifiers are an excellent tool for eliminating indoor odors and reducing allergens. Simply put, an air filter captures pollutants and expels clean air, much like a tree absorbs carbon dioxide and releases oxygen. However, just like trees, the types of filters are legion. Carbon prefilters capture hair and some odors; volatile organic compound (VOC) filters trap odors and airborne pathogens; and HEPA filters reduce indoor allergens such as dust and pollen. However, air filters are only the tip of the purification iceberg. Some air purifiers use ionizers and UV light, but you may not know what these technologies actually do. This article will give you simplified explanations and warn you about the potential dangers of both. We do not want to scare you away from air purifiers that use ionizers and UV lights, but we do want you to understand the risks and be careful when you use them. Many of the air purifiers that we reviewed include an optional ionizer. In fact, some of our favorite purifiers use ionizers to increase the cleaning power.

But what does this technology do? Without confusing you with too much chemistry, oxygen is a neutral element that loves to change its charge. An ionizer uses an electromagnetic charge to add or remove electrons from oxygen atoms, making the oxygen particles either positively or negatively charged as they leave the ionizer. Ionized particles are far more common in the upper atmosphere, and the air we breathe tends to combine oxygen molecules with several other elements. In theory, after the oxygen passes through the air filter, it detaches from other particles and looks for a new particle to bond with. The ionizer gives the outgoing air an electromagnetic charge so that it will bond with other particles more easily. Then, when the charged ion passes through the air filter a second time, it is easier to capture. The potential danger with this is that humans don't usually breathe ionized air, and many studies show that electromagnetically charged particles can damage lungs. Also, if an oxygen molecule bonds with two others, it becomes O3, or ozone.

Ozone can irritate airways and exacerbate breathing-related problems. The best way to use an ionizer is with an operation scheduler or timer. This way, you can run your air purifier and ionizer while you are out of the house. Then, the charged particles will bond with other compounds without damaging your lungs. However, if you are sensitive to ozone, you should avoid ionizers entirely. When an air purifier uses a UV light, it promises to eliminate airborne pathogens. Many point to the UV light hospitals use to purify equipment. In theory, ultraviolet rays will kill the microorganisms passing through your air filter. However, this type of purification cleans as much air as your television. Most UV light cleaners are ozone free and will not damage lungs, but they also will not actually kill the pathogens. Air purifiers zip air through the filters and out the vents, creating air circulation in a room. Hospital UV lights are effective in killing particles by reducing or eliminating airflow.

Also, air purifier manufacturers do not usually explain what kind of UV technology they used, and some of these technologies produce high volumes of ozone. Ozone is not an effective or safe way to eliminate airborne pathogens. Since UV lights are not effective purification methods and could generate ozone, it is best to avoid air filters with this technology, or turn it off. Air purifiers are an excellent tool in the fight against indoor allergens and pathogens. nanotechnology air purifierHowever, you should pay close attention to the technology the air filter uses. ionic air purifier as seen on tvClean air is not worth damaged lungs.do air purifiers help sleep apneaJ Occup Environ Hyg. 2006 Oct;3(10):536-46.Kujundzic E1, Matalkah F, Howard CJ, Hernandez M, Miller SL.

Author information1Department of Civil, Environmental and Architectural Engineering, University of Colorado at Boulder, Boulder, Colorado 80309-0427, USA. shelly.miller@colorado.eduAbstractIn-room air cleaners (ACs) and upper-room air ultraviolet germicidal irradiation (UVGI) are engineering control technologies that can help reduce the concentrations of airborne bacteria and fungal spores in the indoor environment. This study investigated six different types of ACs and quantified their ability to remove and/or inactivate airborne bacteria and fungal spores. Four of the air cleaners incorporated UV lamp(s) into their flow path. In addition, the efficacy of combining ACs with upper-room air UVGI was investigated. With the ventilation system providing zero or six air changes per hour, the air cleaners were tested separately or with the upper-room air UVGI system in operation in an 87-m3 test room. Active bacteria cells and fungal spores were aerosolized into the room such that their numbers and physiologic state were comparable both with and without air cleaning and upper-room air UVGI.

In addition, the disinfection performance of a UV-C lamp internal to one of the ACs was evaluated by estimating the percentage of airborne bacteria cells and fungal spores captured on the air filter medium surface that were inactivated with UV exposure. Average airborne microbial clean air delivery rates (CADRm) varied between 26-981 m3 hr-1 depending on the AC, and between 1480-2370 m3 hr-1, when using air cleaners in combination with upper-room air UVGI. Culturing, direct microscopy, and optical particle counting revealed similar CADRm. The ACs performed similarly when challenged with three different microorganisms. Testing two of the ACs showed that no additional air cleaning was provided with the operation of an internal UV-C lamp; the internal UV-C lamps, however, inactivated 75% of fungal spores and 97% of bacteria cells captured in the air filter medium within 60 min.PMID: 16908454 DOI: 10.1080/15459620600909799 [PubMed - indexed for MEDLINE] Publication TypesComparative StudyEvaluation StudiesResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, P.H.S.MeSH TermsAerosolsAir IonizationAir Pollution, Indoor/analysisAspergillus/physiologyDisinfection/instrumentationDisinfection/methodsDisinfection/standardsEquipment and Supplies/microbiologyEquipment and Supplies/standardsInfection Control/instrumentationInfection Control/methodsInfection Control/standardsMicrococcus luteus/radiation effectsMycobacterium/radiation effectsSpores, Bacterial/radiation effects*Spores, Fungal/radiation effects*Ultraviolet Rays*Ventilation/instrumentationVentilation/methods*Ventilation/standardsSubstancesAerosolsFull Text SourcesTaylor & FrancisIngenta plcOther Literature SourcesCOS Scholar Universe