A permanently installed wall cavity and filtration system provides molded base dry block members that install along the base of a wall between the floor and a bottom edge of drywall, gypsum board or other conventional interior wall construction material. The base block members have connection ports at opposite ends that communicate with an interior airflow channel on an inner facing side of the block members. The air flow channel communicates with the wall interior. A forced flow of dry air is directed through one of the ports, thereby allowing the forced dry air to circulate into the interior wall cavities in order to remove moisture and dampness. The damp, contaminated air can also be pulled out through any one of the connection ports by vacuum force, and filtered to avoid contamination of the surrounding interior living environment.