The ion chip has an ionizing structure in intimate electrical and physical contact with a conductor. The ionizing structure is either a carbon fiber layer or ionizing needles or both. The conductor may be a bare metal wire, a metal plate or a metal layer on a base insulation layer. A high voltage unipolar generator, usually negative, but possibly positive, supplies voltage to conductor and ionizing structure to generate ions. Guide strips confine, contain and protect the ionizing structure within a channel in which the ionizing structure is recessed. The metal layer can extend beyond the guide strips to provide electrostatic focussing power. Alternatively a distinct metal layer outside the channel and separated from the conductor and the ionizing structure by interruption blocks on the surface of the base insulation layer, is charged to greater voltage to provide greater focussing power. Typically the ion chip generates negative ions for air purification. It can also be used to generate positive ions or ozone.