Make an ioniser
`The principle of ion generation is fiendishly simple. The electrical charge on an object is greatest at the sharpest point (that’s why electrostatic generators favour big curvy domes for charge retention), so if a high negative voltage is applied to a sharp needle then the charge at the tip is so high that ions are literally thrown off and then repelled by the negative field on the needle. This results in a physical draught and a slight hissing noise. In a very dark room you will also see a faint purple corona glow on the needle tips.
Most technical wisdom suggests that while negative ions make you feel good, positive ions can cause headaches and nausea. This is why a negative ion generator can improve the perceived atmosphere in an office that has an unaturally high positive ion balance.
But enough of the quackery… Here’s the data.’
