In research on hundreds of patients over five years, the late Dr Igho Hart Kornblueh, from the University of Pennsylvania, found that negative ions have a sedative, healing and pain-relieving effect. He reported that patients recovered 57 per cent faster from surgery when exposed to negative ions, and treatment with negative ions provided relief from symptoms of hay fever for 63 per cent of patients. Conversely, positively ionised air (such as that from dirty, dry, hot winds and excessive indoor heating) produced headaches, nasal obstruction, dryness of the throat, dizziness and an itching nose. Dr Kornblueh also found that treatment with negative ions, at a level found in a natural setting, reduced the need for post-operative painkillers. Not only that, but getting your dose of negative ions increases efficiency.