Activated carbon is again used as a filter medium during air
filtration. The micropores of the activated carbon can trap
larger molecules like dust and pollen, but it also captures
smaller molecules such as odorous gases. When the air is pushed
(or pulled) through a bed of activated carbon, the main foulants
found in that air stream are captured and allow just the filtered
or clean air, to pass through to the final destination.
Due to the organic nature of the foulants being captured in air
filtration systems, all forms of activated carbon (other than
powdered) can be cleaned through a process known as carbon
reactivation and reused. This reduces waste and overall running
costs of large air filtration systems.