Activated carbon filters are a type of air filter that use activated carbon to remove impurities from the air. Activated carbon is a highly porous material that is treated with oxygen to open up millions of tiny pores between the carbon atoms, creating a large surface area for adsorption.

When air passes through an activated carbon filter, the impurities in the air are attracted to the surface of the carbon and become trapped in the tiny pores. This process is called adsorption, which is different from absorption in that the impurities are not absorbed into the carbon but rather adhere to its surface.

Activated carbon filters are effective at removing a wide range of impurities from the air, including volatile organic compounds (VOCs), odors, and chemicals. They are often used in combination with other types of air filters, such as HEPA filters, to provide comprehensive air cleaning.