I found this video fascinating, and I have probably shared it before. When I hear people say that they want to add ions to air, I assume that this is a bad idea because ions are reactive chemicals. It is the equivalent of putting bleach into the air. According to the video, there are many ions in the air already, but compared to the total number of molecules, the number is not significant. The video also demonstrates that salt lamps don't really produce negative ions like they claim that they do.