There are dangers ...and there are also benefits to things we cannot see.   I guess it just seems easier to talk about the dangers, though it shouldn't be.   But that seems to be how most of us are ...and when discussing something that is invisible, it's difficult to convince someone of the validity of it.   Many years ago, it was believed that the sun revolved around the earth, because that is how people saw it.   Now, I agree that learning the untruth about that was not nearly as painful as it would be to learn that carbon dioxide is invisible, yet can kill you.