An air purifier is an electronic device that cleans the air and removes pollutants such as allergens, bacteria, and viruses. There are several types of air purifiers, but the most common type is the High Efficiency Particulate Air (HEPA) filter.

HEPA filters work by trapping tiny particles in a dense filter made of layers of fine mesh. To be considered a true HEPA filter, the device must capture 99.97% of particles larger than 0.3 microns in size. The filter removes contaminants such as pollen, pet dander, and dust from the air. Some air purifiers also use activated carbon filters or ultraviolet light technology to remove odors and kill viruses and bacteria.

Air purifiers work by drawing air through the unit and passing it through the filter. Once the pollutants are trapped in the filter, clean air is released back into the room. Most air purifiers are designed to be left on continuously to maintain clean air in the room.

Overall, air purifiers are an effective way to improve indoor air quality and reduce symptoms caused by allergies and respiratory conditions.

The table below illustrates how frequently the Karcher air purifier cleans the air.