Yes NOx isn't good for you. Either version medical or non-medical for short periods won't hurt you really. If you sit there with a non-medical blowing right in your face for a 1/2 hour each day, in my opinion you will be healthier. That's just my opinion. We had one on about 18 hours a day at times when my wife had cancer the first time. That and drinking ozonated water from it cured her cancer. 16 tumors. That's why I say any ozone is better than no ozone & I don't put down people who use medical grade generators. Again, that's just my opinion. I'm sure Dr. Pressman and others will argue that, but they are the ones selling medical grade generators too. Some people have problems breathing medical grade ozone too. I can breath medical grade ozone in amounts that would make just about everyone cough for an hour. That's only because I've been doing it for years. So always let the body be the guide in all alternative treatments. "First do know harm."