With regard to breathing ozone, I probably take a less popular stance. I do agree that when you cross some threshold that it is too strong and will burn your lungs. However, I'm fine with holding my head over an ozonating cup of water and take in several whiffs. I feel like it boosts my immune system. However, I wouldn't do this with medical grade ozone, since that stuff is too strong.
When I first started breathing ozone, it was uncomfortable because I would cough some, but it is oxidizing all the crud built up over the years in my lungs (second hand smoke, smog, etc, etc). Once my lungs cleared out, I have no more such coughing or adverse reaction from breathing in moderate amounts of ozone. That's my take anyway.