Ionic Pro Air Purifier Health Issues?

Hi, I was hoping that someone could tell me if using one of these things presents any health issues because of the ozone they produce. We have one a few years old and it does a good job with three cats we have in the house, but I overheard that there are potential health risks? I have it in the bedroom where the cats spend a lot of time. Are these things dangerous because we also have cildren? Thanks!