Ions vs. Ozone
Both devices operate in a similar way. Ionisers use electrostatically charged plates to produce positively or negatively charged gas ions that particulate matter sticks to (in an effect similar to static electricity) in other words the ions generated connect themselves to dust particles, allergyns or other air born bacterias while passing through the air purifier.
Ozone generators are optimised to attract an extra oxygen ion to an O2 molecule, using either a corona discharge tube or UV light. At high concentrations, ozone can also be toxic to air-borne bacteria, and in many cases will destroy or kill these infectious organisms. Even the best ionisers will produce a small amount of ozone, and ozone generators will produce gaseous ions of molecules other than ozone, because air consists of more elements than oxygen.