The activated charcoal is with including the carbon material outward appearance black, the internal crevice structure developed, is bigger than the surface area, adsorptive capacity strong kind of microcrystalline carbon. Is one kind of commonly used absorbent and the catalyst. Principle of work: Between activated charcoal use porous physical property as well as member mutual attraction principle, depends upon the air flow to take the medium, adsorbs in the air the noxious gas.

 Merit: The service life is long, purifies ability to be good continually. The easy to operate, may lay aside the place which directly most agglomerates to the pollution source and the contaminating material, the control pollution material proliferation. The environmental protection performance is remarkable, non-toxic, does not have the pollution.
 shortcoming: The passive purification adsorption, is weak to the long-distance range space air's contaminating material adsorptive capacity, the purification effect is relatively slow.