An air purification system includes an internally hollow cylindrical casing made of a non-conducting material； an inner electrode arranged on an inner surface of the supporting member； an outer electrode arranged on an outer surface of the supporting member； a photocatalyst filter arranged on an outer surface of the outer electrode for purifying air inside a plasma generation zone； and a power source for supplying power of opposite polarities to each of the inner electrode and the outer electrode so as to generate plasma. The photocatalyst filter includes a filter element, and the filter element includes a porous titanium foil having a non-periodic spongy structure impregnated with anatase titanium dioxide particles as a photocatalyst.
