Carbon comes in three kinds- dust, coconut shell or granulated. The latter is the most expensive A. Granular activated carbon This substance is used in many larger air cleaners. While it may be effective for the removal of gases and odors that are drawn through the unit, it often significantly reduces the airflow of the air cleaner, which means that not enough air is being cleaned by the unit. Zeolite is a mineral. Since it is less expensive than activated carbon, many manufacturers like to mix it in with activated carbon to lower their production costs.
Some manufacturers claim that zeolite is efficient for the control ammonia.
This assertion lacks scientific foundation. Potassium permanganate has the capacity to remove specific gases such as formaldehyde. This technology relies on a fiber pad to be impregnated with carbon dust. Due to glue used in binding the carbon dust to the fibers and the small amounts of activated carbon used, the effectiveness of this type of activated carbon filters is very limited. There is also a great deal of variability in terms of noise.