The reason for cleaning your air duct system is CLEAR! Dust and dirt continually accumulate on the inside surfaces of your ductwork. This environment provides the nutrients for molds, bacteria, allergens, and fungi to reproduce and grow. There are many other sources of indoor air pollution like pet dander, combustion sources, tobacco products, household cleaning products. Every time your system's fan goes on it forces this contaminated mixture into the air you breathe. Your indoor air quality is a major concern. In addition to cleaning the air you breathe, the buildup of household dust on furniture and on other contents is dramatically reduced. Clean ducts also increase the efficiency of your heating and cooling system, cutting utility costs and potential system breakdowns. The Environmental Protection Agency estimates that air inside your home can be up to 70 times more polluted than the outdoor environment. The EPA and American Medical Association agree that poor indoor air quality is a serious health hazard.