Air filter, air purifier, indoor air purifier: Which is actually which?

The different terms are often wildly mixed up. The bottom line is that air filters and air purifiers generally refer to devices that (should) ensure clean and healthy air. But are there differences? What are they? And which device can actually do what?


Air filter (air cleaner) and air purifier (air purifier)

Most often, the terms air filter and (indoor) air purifier are used interchangeably. But there are clear differences:

  • An air cleaner is a so-called filtering separator, i.e. a device that uses certain filters, such as a HEPA or activated carbon filter, to filter out pollutants, allergens, gases or aerosols from the air and collect them inside the device.
  • An (indoor) air purifier is not a classic filter, because it eliminates pollutants and pathogens with the help of UV-C light, ionization or the hazard-free photocatalysis with UV-A light. Depending on the device, by-products such as ozone and formaldehyde can be eliminated in the process or are actually not emitted at all.


Air Filter

(Indoor) Air Purifier

Hair, dust, fine dustfilterednot filtered
Pollutants, gases, odorsfiltered, accumulatingeliminated
Virusescan remain active in the filter for up to 7 dayseliminated
Bacteriafiltered bacteria can release toxic decay products (endotoxins) into the airbacteria + endotoxins are eliminated
Allergensremain active inside the filterrendered harmless
Filter changeCaution! filtered pollutants and pathogens may still be active inside the filterdepending on the device, no filter change is necessary
By-productspossible depending on devicepossible depending on device
TechnologyHEPA filter, activated carbon filterUV-C light, ionization, photocatalysis

AiroDoctor® Indoor Air Purifier with quadruple filters

Technology: Photocatalysis with UV-A LEDs + titanium dioxide (TiO2)

internationally patented & ISO certified


AiroDoctor - air filter or air purifier?

AiroDoctor is both, because it uses a dual technology: AiroDoctor is an indoor air purifier with an upstream filter system. Thus, it combines the advantages of both technologies. In the first filtering steps (including activated carbon and HEPA filters), infectious aerosols, pollutants, gases, odors, fine dust and allergens are filtered out of the air. In the final step, photocatalysis, the filtered-out pathogens and pollutants are neutralized, i.e. destroyed and rendered harmless, up to 99.9 % without leaving any residue with the help of reactive oxygen radicals. This process is absolutely safe, because no by-products such as ozone or formaldehyde are released.


Learn more about AiroDoctor's patented and certified photocatalysis technology here!