If you have chronic health problems, they may be related to the indoor air you are breathing. In numerous independent case studies as well as studies conducted by the EPA and OSHA, Sick Building Syndrome, has been traced to air ducts in the workplace and the home. Problems occur when the heating and cooling system in our homes and offices are not routinely and/or properly maintained. Some allergens commonly recirculated in air duct systems are bacteria, pollen, skin flakes, animal dander, decaying organic matter, fungi, hair, dust mites, viruses, textile fibers and residue from chemicals.