Air purifiers: how they work

In short: Air purifiers remove pollutants, allergens, and odours from room air by passing it through filters or treating it with other methods. They can be especially useful for allergy sufferers or in heavily trafficked areas.

In more detail: Effectiveness depends heavily on the filter technology and the room size the device is designed for.

In detail

• HEPA filters: Highly effective particle filters reliably capture even the finest particles like particulate matter, pollen, and some bacteria.
• Activated carbon filters: These filters bind odours and gaseous pollutants that mechanical filters cannot capture.
• Ionisers: Some devices electrically charge particles so they settle on surfaces, but can produce some unwanted ozone in doing so.
• Consider room size: A device designed for too small a room fails to effectively circulate and clean the air.
• Filter replacement: Filters must be regularly replaced or cleaned, as they otherwise lose effectiveness and can themselves become a source of germs.
• No miracle fix: Air purifiers replace neither regular ventilation nor removing the pollutant source itself.
• Operating noise: Powerful devices can be clearly audible on high settings, which is worth considering for bedroom use (klimaanlage-und-ventilator-funktionsweise, richtig-lueften-und-schimmel-vermeiden).