> Additional comment by poster:
>
> It would be very interesting to see the effects of large doses of
> negative air ions in the setting of an old age home.
I heard about a study where a negative ion generator was used in an office building, and absenteeism due to respiratory infections went down. But I got this information off a web page pitching negative ion generators, and they didn't cite a source, so it remains what my father calls "science by word of mouth".
I really want to get a negative ion generator, but I don't know which kind to buy, as any one I've found could actually work or not work at all and I wouldn't be able to tell. If anyone has a recommendation, please let me know.
I was amused by this:
http://www.wellnessenergy.com/air15b.html
which is a device you wear in your pocket that supposedly kills bacteria and knocks out other airborne particles in your immediate vicinity. They have an abstract from UCLA showing some experimental proof that it works.