A method and device for cleaning air. The air to be cleaned is directed as a continuous flow in succession through a) a first zone wherein the air is treated with ozone and possibly also water, ammonia or other aerosol growth promoters； b) a second zone wherein the air is subjected to ultraviolet light； c) a third zone wherein the air is maintained for a sufficient time to allow aerosol growth； d) a fourth zone where particles in the air are given an electrical charge； e) a fifth zone wherein the air is passed through an electrostatic filter； and f) a sixth zone wherein the air flows over a catalyst to break down residual ozone.
