An intense field dielectric air filtration system includes a perimeter frame for wall or ceiling mounting at the inlet of a return air duct for an air conditioning apparatus. A door including a grille disposed thereon is mounted for movement on the frame between working and non-working positions for access to an air filter unit, a pre-filter unit and an intense field particle charging unit. Contacts on the filter unit and the field charging unit engage cooperating contacts on an enclosure mounted on the frame when the door is closed to supply electrical power. An interlock is provided to interrupt power when the door is moved to an open position or the grille is removed. A control system disposed in the enclosure includes user control features accessible when the door is in an open position. An alternate embodiment includes a support frame for positioning the filtration system in ductwork or the like other than a return air inlet.