Air ioniser

An air ioniser (or negative ion generator or "Chizhevsky's chandelier") is a device that uses high voltage to ionise (electrically charge) air molecules. Negative ions, or anions, are particles with one or more extra electrons, conferring a net negative charge to the particle. Cations are positive ions missing one or more electrons, resulting in a net positive charge. Most commercial air purifiers are designed to generate negative ions. Another type of air ioniser is the electrostatic discharge (ESD) ioniser (balanced ion generator) used to neutralise static charge. In 2002, Cecil Alfred 'Coppy' Laws was credited with being the inventor of the domestic air ioniser in an obituary in The Independent newspaper.

Air ionisers have been used to eliminate the occurrence of air-borne bacterial infections and to reduce static electricity buildup in electronics.

Air ionisers are used in air purifiers to remove particles from air. Airborne particles are attracted to the electrode in an effect similar to static electricity. These ions are de-ionised by seeking earthed conductors, such as walls and ceilings. To increase the efficiency of this process, some commercial products provide such surfaces within the device. The frequency of nosocomial infections in British hospitals prompted the National Health Service (NHS) to research the effectiveness of anions for air purification, finding that repeated airborne acinetobacter infections in a ward were eliminated by the installation of a negative air ioniser—the infection rate fell to zero, an unexpected result. Positive and negative ions produced by air conditioning systems have also been found by a manufacturer to inactivate viruses including influenza.

The SARS epidemic fueled the desire for personal ionisers in East Asia, including Japan (where many products have been specialised to contain negative ion generators, including toothbrushes, refrigerators, air conditioners, air cleaners, and washing machines). There are no specific standards for these devices.

...
Wikipedia