Abstract: An air filtration system includable in and for HVAC equipment includes one or more intense field dielectric filter units and a field charging unit retained in a support structure or cabinet by a removable door which includes control circuitry and contactors engageable with corresponding contact members on a filter unit and the field charging unit for supplying high voltage DC potential to the respective units. Each filter unit includes a filter core comprising a stacked array of filter elements formed of dielectric sheets interconnected by elongated spaced apart ribs forming flow passages. The field charging unit and the filter units are removable from the support or cabinet for cleaning or replacement by opening or removing the door. An interlock switch and a field shorting mechanism are actuated during servicing or replacement of the system components.