This doesn't answer your question - but in all seriousness you can smell it. Even the smallest amount of ozone has a very distinct smell you will recognize. If you stand in front of your air sanitizer and let the air pass over your face, you should be able to smell the ozone immediately.

If you haven't smelled it before - I would recommend going to a retail store that sells ozone-based air sanitizers. That should give you a whiff of the stuff for reference. You can also find it in [some] hospitals for air sanitization. I imagine once you smell it, you will realize you have smelled it before and maybe not realized it was ozone that you were smelling.