The hepa air cleaner and hepa air purifier was designed by the Atomic Energy Commission to remove radioactive particles from the air. HEPA air cleaners are also used extensively by Hospitals to remove bacteria attached viruses. Combined with other filtration media it is the most effective filtration system available, which does NOT PRODUCE HARMFUL OZONE. The American Lung Association and the EPA* have come out strongly against electronic air cleaners that produce OZONE.