How is OZONE emitted from portable air purifiers? Is it from the IONIZER that come on some?

UV does emit ozone, UVC does not by the way.

There are 3 ways to make ozone. Carona discharge, UV, or needle point ionization. Negative ions are great, no side effects. Ozone is great if you have pets and foul smells, as long as you don’t overdo it. The ozone will oxidize the junk in the air and then create extra oxygen, always a good thing. What brand of air purifier do you have? Maybe I can give a better answer.