Mechanical Filters – Mechanical filters force air through filtering screen trapping particles that include pollen, pet dander and dust mites. The most well-known type of mechanical filter is a HEPA (High Efficiency Particulate Air) filter which must be able to capture at least 90% of all particles that are 0.3 microns in diameter or larger.
Electronic Filters – Electronic Filters use electrical charges to attract and trap allergens and irritants which are collected in a collecting plate.
Gas Phase Filters – Gas Phase Filters remove odors and gases such as cooking gas, paint fumes and perfume.
Thermodynamic Sterilization – Thermodynamic Sterilization (TSS) refers to air sterilization via a ceramic cone with microcapillaries that are heated to 200 degrees C (393 degrees F). This destroys (incinerates) 99% of bacteria, viruses, dust mite allergens, mold and fungus spores.
UV Germicidal Irradiation (UVGI) – UVGI sterilizes air that passes through a UV layer through forced air killing bacteria.
What to Consider – Many Air Purifiers have a HEPA filter which need to be replaced annually. Most portable models have an annual operating cost of from $150 to $200 which included filter replacement and electricity. Carbon filters need to be replaced every 3 months.
Most room Air Purifiers have a fan that sucks the air in for filtration. Those without a fan run quieter but usually do not work as efficiently.
Look for an Air Purifier with a Service Indicator which alerts if the air cleaner is clogged or working inefficiently. This will indicate if the unit needs to be cleaned or have the filter replaced.
Another important feature is a Programmable Timer which allows the Air Purifier to run for a set number of hours before a room will be used. It also shuts off automatically.
A carrying handle is also useful to transport the unit from room to room.
Speed selection is also a very important feature of aaner. It allows for a lower speed when sleeping or working and requiring quiet and a higher speed in prime allergy season.
If a unit includes an ionizer which attracts particles, it is very important to ensure that the unit does not emit ozone which is a lung irritant. This information should be included either in the operations manual or on the side of the box.
A Remote Control is also a very useful factor will allow the unit to be controlled from across the room.
In some room models, a dirt sensor will automatically adjust the fan speed to the level of dust and dirt in the air.
A Washable pre-filter which collects large particles is also advisable as it is reusable and can cut down the overall operational costs.
Volatile Organic Compounds (VOCs) result from paints, adhesives and other organic pollutants. Some portable Air Purifiers claim to filter all organic compounds but according to the Environmental Protection Agency these types of filters are usually only for specific environmental gases.