Carbon filtering is a method of filtering that uses a bed of activated carbon to remove contaminants and impurities, using chemical adsorption. Each particle/granule of carbon provides a large surface area/pore structure, allowing contaminants the maximum possible exposure to the active sites within the filter media. One pound of activated carbon contains a surface area of approximately 100 acres. Activated carbon works via a process called adsorption, whereby pollutant molecules in the air to be treated are trapped inside the pore structure of the carbon substrate. Carbon filtering is commonly used for air purification. Active charcoal carbon filters are most effective at removing chlorine, formaldehyde and other volatile organic compounds (VOCs)