Abstract: In an air ionizing apparatus of a type utilizing a sheath gas not containing water (hydrogen) or impurities to sheathe corona electrodes, sufficient amount of ions are generated to fully eliminate static electricity from the interior of a production environment such as a clean room and to prevent the impurities from depositing on the corona electrodes. The tips of corona electrodes 21a and 21b are positioned inwardly of the tips of sheath gas nozzles 4a and 4b, respectively, by a certain distance. The distance is so determined that for a sheath gas containing no negative gaseous molecules, electrons emitted by corona discharge can reach air existing outside the sheath gas nozzle 4b and that for a sheath gas containing the negative gaseous molecules, negative ions emitted by corona discharge can rapidly disperse into the air outside the sheath gas nozzle 4b without remaining in the interior of the nozzle 4b.

Abstract: A method and apparatus for eliminating electric charges in a clean room is disclosed involving removing fine and superfine grains from air in the clean room, and generating ions in the thus purified air inside the room.