Understanding Air Filtration Systems

How It Works

By better understanding the science of air filters you can get a better idea of how effective an air purifier can be to improving indoor air quality.


4-Stage Purification System

Fellowes® air purifiers feature a 4-Stage Purification that safely removes 99.97% of airborne pollutants as small as 0.3 microns from your air.

  1. Carbon Filter
  2. Sanitized® Technology
  3. True HEPA Filter
  4. PlasmaTRUE™ Technology

Air Purifiers PersonalWhy a carbon filter

Carbon filters are treated with oxygen which opens up millions of small pores in the carbon. Odors, gases and chemical fumes are literally absorbed into the carbon. Carbon filters are your first line of defense in air purity. A one pound activated carbon filter can have a surface area of over 60 acres.

solutioncenter_sanitized_smallWhy Sanitized® Technology

Fellowes® air purifier carbon filters are protected with Sanitized® Technology, which effectively reduces the development of bacteria, fungi, and dust mites on the carbon filter itself. This is important because, without this technology, microbes can settle on the filter and be re-circulated into the air.

SC_hepa_filterHow does a HEPA filter work?

HEPA stands for High Efficiency Particulate Arresting filters. The HEPA was originally used by the U.S. Atomic Energy Commission in the 1950s to remove small radioactive particles. HEPA filters are designed to capture very small air particles. The accordion shape of the filter increases the surface area, allowing it to capture considerably more particles. As air passes over the filters, the particles become trapped in the accordion maze of filter fibers. Dust, mold spores and pet dander are easily caught by the HEPA filter.

It is important to note the differences between a True HEPA Filter and a HEPA-type or HEPA-like Filter. In order to be rated as a True HEPA filter, a filter must pass the Dioctyl Phthalate Aerosol test and it must exceed a minimum efficiency of 99.97% at a particle size of 0.3 microns with less than a one inch drop of air pressure. HEPA-type and HEPA-like filters, while lower in cost, are much less efficient than True HEPA filters, especially at particle sizes less than 1 micron. Removing particles that are less than 1 micron in size is important as these particles can enter into the blood stream and contribute to illness and/or disease.

plasma truePlasmaTRUE™ Technology

Fellowes® Air Purifiers also feature the added benefit of PlasmaTRUE™ Technology, which creates an ionized field to help safely remove airborne pollutants. The energized particles released by this technology help to purify the filtered air without producing ozone or other harmful pollutants.