Clive Begg and colleagues at the University of Leeds showed that air ionisers (which emit negative ions) could comprehensively disinfect hospital wards, reducing infection to zero. The staff at St. James Hospital in Leeds were astonished and so impressed that they asked the researchers to leave the equipment with them after the year-long trial was completed.

The researchers first thought that the negative ions collided with airborne bacteria and viruses, giving them a negative charge and causing them to fall out of the air. Apparently not quite. Electronics company Sharp had previously shown that both the positive and negative ions produced by their air conditioning systems inactivated viruses, including flu viruses.

See also Garlic zaps MRSA in the section on Complementary Medicine.