An air cleaner has an electron generator that includes a pointed head, a collector element and an electric circuit included in the electron generator for generating a negative potential on the pointed head and a positive potential on the collector element. The pointed head is mounted at the free end of a cylinder of electrically non-conductive insulating material. The cylinder includes the electric circuit at the free end whereas its other end enters the collector element, which is cylindrical and is of electrically conductive material.