An air cleaning system has a field charger comprising a plurality of bars comprising a conductive inner core and a non-conductive overmold, and a plurality of pins attached to the bars and extending out of the non-conductive overmold. The conductive inner core is molded over the plurality of pins, conductively connecting the pins, and the non-conductive overmold is molded over the conductive inner core. A method of manufacturing the field charger includes placing a plurality of metal pins in a mold, placing contact points in the mold, molding a conductive resin over at least a portion of the plurality of pins and contact points, molding an insulating resin over the inner core, plurality of pins, and contact points, wherein at least a portion of the pins and contact points extend from the non-conductive overmold, and mounting an earthplate to the conductive overmold.