Your air duct network acts as the homes respiratory system.

Breathe Fresh Air 
Heating, ventilation, and air conditioning (HVAC) systems have been shown to act as a collection source for a variety of contaminants that have the potential to affect health, such as mold, fungi, bacteria, and very small particles of dust. The removal of such contaminants from the HVAC system and home should be considered as one component in an overall plan to improve indoor air quality.

Sanitizing your home’s air duct system after a thorough cleaning will help in preventing allergic reactions caused by microorganisms.  Sanitizing not only controls microbial growth within your air ducts, but also eliminates unpleasant odors that are the result of this growth.