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.
I know what Ozone smells like (I remember the old laser printers that were also effective ozone emitters), but trust a sensor more than my ability to smell low levels of Ozone.
My air purifier is built into the furnace ductwork so it's already pretty diluted air by the time it comes out of a duct.
> My air purifier is built into the furnace ductwork
That's neat! Do you know if the ozone is produced before or after it reaches the blowing mechanism? I ask because if it is produced before, like right after the air intake, that's a really great setup for keeping your ductwork mold and mildew free. I've wanted to buy such a system but keep holding out for things to get cheaper... in the meantime, I use an ecoquest "FreshAir" model sitting on top of the fridge.
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.