Air Ion Counter

Almost all positive (“+”) natural ions during fair weather come from radioactivity. Natural negative ions usually come from radioactivity and evaporating water. Air ions cannot be produced without an energy source, such as heat or flame, radioactivity, frictional rubbing, electricity, evaporation (which is a heat process), etc. You can produce negative ions directly by rubbing cotton fabric (or your hair) against a plastic object, which will then briefly emit negative ions.