A: Ductwork runs through attics, crawlspaces, basements, garages, and walls. Leaking return air ducts pull in dust and other indoor air pollutants and sends them to the central heating and cooling system. From there they sent to the living areas of your home. The Aeroseal air duct sealing system can reduce the amount of leakage by as much as 90%, reducing dust and other indoor air pollutants from the conditioned air in your home.