I second it is dangerous for your health and high levels are bad for plants. I read this while making a tesla coil, which also produces ozone.
I read you should not operate a Tesla coil in a confined area and you should never breathe in ozone for more than a few minutes a day. Even low levels.
Of course a Tesla coil is a little different. I've never looked into to a store bought ozone generator.
I also never looked into very much, I just read the warnings and took their word for it. So I could be wrong, wouldn't be the first time.