Abstract: A chilled beam with a bipolar ion generator located in the plenum. Conditioned air flows into the plenum through an air inlet. The plenum is pressurized by the primary air delivered from the HVAC system. The conditioned air exits the plenum through nozzles into a mixing chamber. The increased velocity of the conditioned air exiting through the nozzles induces return air through return an air inlet, past a heating/cooling coil, and into the mixing chamber. The conditioned air and the return air mix in the mixing chamber to create supply air that exits the chilled beam through supply air outlets. The electrodes of the bipolar ion generator are positioned at different locations in the plenum and are oriented in different directions to the direction of the conditioned air flowing into the plenum.