An air ionizing module and method for generating ions of one and opposite polarities within a flowing stream of air or other gas includes a thin-filament electrode mounted within the flowing stream in regions thereof of maximum flow velocity. The thin-filament electrode is mounted in a multi-sided polygonal configuration to receive high ionizing voltage of alternating one and opposite polarities to form an intense stream of ions toward an electrically-isolated reference electrode positioned upstream of the filament electrode. Another reference electrode positioned within the flowing stream downstream of the filament electrode receives a bias voltage of selected polarity to control the quantities of generated ions of positive and negative polarities in an outlet stream of the ions and flowing gas.