Working in conjunction with its carbon filter system, our air purifier pulls in unclean air from the rear, first passing through the carbon filter which removes airborne particles. This filter also acts to deodorize any unpleasant odors. Air then passes through the inner PCO cell, further filtering airborne contaminants. The anion emitters, now moved forward of the fan to the front panel, release trillions of negative ions into your home, attaching themselves to dust particles, and dropping them straight to the floor. This advanced function is ideal for eliminating dust, animal dander, and other harmful particles that float in the air. Left behind is fresh oxygen rich air. The sterilizer function turns on the units blue UV lamp. When you need to eliminate strong or offensive odors in your home, the Purifier/AWAY mode creates activated oxygen (ozone) based upon the square footage of your home. Perfect for eliminating tobacco smoke odors, cooking odors, chemical/cleaning agent odors, paint odors, etc. The activated oxygen will also clear pollution embedded in walls, ceilings, floors, carpets, furniture, clothing, countertops....all surfaces in your home. Use Purifier/AWAY mode (ozone function) when home is unoccupied on units built in timer. Ozone reverts back to oxygen after approx. 30 to 45 minutes. Return home to fresh, clean, oxygen rich air....provided only by the 4 advanced technologies of the Green Air Classic!! 2 year warranty.