Negative Ions in the air are supposed to be good for a person's mood, they increase the flow of oxygen to the brain which tickles the happy places. Some winds produce negative ions and so does a shower head, a finding I find very difficult to believe.
Positive Ions in the air are not so good for a person's mood. Computers produce
positive ions which certainly explains the vitriol in social media, and I'm
pretty damned certain that Spring Frosts and visits to town produce positive ions.