Hi Terri - Mine stand-alone unit has filters which I regularly clean & replace. The ones on the furnace, my husband replaces twice as often as required. Both are charcoal & HEPA - not ionic. Our friends have a HEPA plus ionizing systems, located at the furnace & venting through the furnace outlet - this is supposed to reduce the ozone in the air. But it requires monthly maintenance, which sounds like a pain to me.
My concern with the "personal" purifiers is that you are blowing the ozone right in your face, and even low doses can accumulate. If yours is a room-sized unit situated away from your bed & body, chances that your are receiving much ozone from it is probably pretty small. But worthwhile checking.
Sue