Take in too much water, and you drown. Too much oxygen, you burn. Seriously, ozone at industrial strengths can be irritating, even toxic. In heavily polluted areas like the Los Angeles basin, there is more ozone than is desirable. No, ozone is our cleaning friend, at the levels that Nature intended.
Ozone is found in nature in all the best places.
Higher than average concentrations are found at the seashore, at waterfalls, in mountain forests. That sweet, bleachy smell you detect in the air after a thunderstorm is in fact, ozone. Yes, there is a physiological reason why people feel better at the beach, around waterfalls, and in the mountains. Ozone and ions are two large factors. Our goal in purifying indoor air is to recreate natural, outdoor conditions.