Ozone turns back into oxygen after 1-3 hrs after use. AIRBORNE COLD AND FLU VIRUSES ARE KILLED- by the blue light in the unit that is your UV STERILIZER. MAKE SURE TO USE THE OZONE FUNCTION ON THE UNIT IN UNOCCUPIED SPACES WITH NO HUMANS OR PETS AND RETURN 1-3 HOURS AFTER THE OZONE HAS TURNED OFF. The Breathe Fresh Air Purifier treats the air in your home or office by breaking down odor causing pollutants and dropping airborne particulate from your breathing space.The Breathe Fresh Air Purifier produces ozone and negatively charged ions, the same effective cleansing agents that natures uses to treat outdoor air. 1 The unit uses a needlepoint ionizer to drop dust, smoke and other harmful particles from the air we breathe. In our homes and offices there is a lack of negative ions and an abundance of positive ions. The buildings we spend most of our time in block out the natural occurring negative ions. The Air Purifier recreates the natural balance of positive to negative ions to significantly reduce airborne particulate. 2 The unit uses electricity to split oxygen O2 molecules into single o1 atoms, which attach loosely to other O2 molecules to become O3 (activated oxygen). This loosely attached oxygen atom is unstable and seeks to bond with chemical compounds and other odor causing pollutants in order to oxidize them. This unit makes ozone- to use the ozone function set the timer on the unit and leave your space- the ozone function must be used while no one is present-return 1-2 hours after the item turns off and the room will smell very fresh like after a lighting storm. While ozone is on it can smell like a mixture of bleach or chlorine while on that is a normal smell of it working and scrubbing the air- After the unit turns off wait 1-2 hours and the room will smell extremely fresh. You can tell the ozone function is on when the item is making noise like static electricity- that is normal. If you never want to use the ozone function you can remove ozone plate from the back of the unit and it will never produce ozone. The item "Air Purifier HEPA Breathe Fresh Air Cleaner Ozone Generator with timer Deluxe" is in sale since Tuesday, March 27, 2018. This item is in the category "Home & Garden\Home Improvement\Heating, Cooling & Air\Indoor Air Quality & Fans\Air Purifiers". The seller is "torontofalls211" and is located in Raleigh, North Carolina. This item can be shipped to United States, Canada, Australia, Japan, South Korea, Indonesia, Taiwan, South africa, Thailand, Hong Kong, Bahamas, Israel, Mexico, New Zealand, Philippines, Singapore, Saudi arabia, United arab emirates, Qatar, Kuwait, Bahrain, Malaysia, Brazil, Chile, Colombia, Costa rica, Panama, Trinidad and tobago, Guatemala, Honduras, Jamaica, Antigua and barbuda, Saint lucia, Barbados, Brunei darussalam, Bolivia, Ecuador, Jordan, Cambodia, Cayman islands, Sri lanka, Maldives, Nicaragua, Oman, Peru, Paraguay, Viet nam, Uruguay, Dominican republic, El salvador.