An air conditioner comprises a housing, a main fan, a heat exchanger, and a discharge generator. The housing is formed with an inlet, an outlet, a main airflow path. The inlet is provided for introducing outside air. The main airflow path extends from the inlet to the outlet. The main fan is disposed in the housing. The main fan is provided for generating a forced flow of the air through the main airflow path. The heat exchanger is disposed in the housing to heat and/or cool the air which flows through the main airflow path. The discharge generator has a casing, an emitter electrode, and an electrical insulator. The casing is formed with an intake, an outtake, and a second airflow path. The intake is provided for taking in the air into the casing. The outtake is communicated with the intake via the second airflow path within the casing in order to pass airflow through the casing. The electrical insulator is made of an electrical insulating material. The emitter electrode and the electrical insulator are disposed within the casing so as to form a discharge space. The emitter electrode is configured to apply high voltage to the discharge space. The emitter electrode has a circumferential surface. The circumferential surface is spaced from an inside surface of the casing by a clearance. The inside surface of the casing is opposed to the circumferential surface of the emitter electrode. The second airflow path is shaped to flow the airflow both through the clearance and the discharge space.
