A fuel cell includes a membrane electrode assembly, a fuel storage reservoir, an air supply unit, a temperature regulator, and a particulates blocking device. The particulates blocking device includes an multi-layer air filtering unit communicated with the air supply unit for blocking unwanted particulates from the air supplied by the air supply unit. The air filtering unit includes a particle filter layer having a plurality of porous gratings formed thereon for allowing molecules which are smaller than a size of the gratings to pass therethrough, and a molecular filler layer having a plurality of filler grains chemically bound together for absorbing a predetermined kinds of molecules so as to block the molecules from entering into the membrane electrode assembly.