An apparatus and method of using electrical unit capable of improving air qualities in an indoor area. The electrical unit having an air circulator configured to generate an air stream, a cold plasma generator operably connected to a first and a second high voltage wires, the cold plasma generator configured to produce a high voltage between the first and second high voltage wires, a first electrode electrically connected to the first high voltage wire; and a second electrode electrically connected to the second high voltage wire; the first and second electrodes configured to generate a high voltage electric field in the air stream.