There is an urgent need for devices to eliminate viruses from the air in order to prevent outbreaks and spread of infectious diseases. Each year, infectious diseases cause millions of deaths around the world and many of the most common infectious pathogens are spread by droplets or aerosols caused by coughing, sneezing, speaking, singing etc. Spreading by air is an important transmission route for many pathogens including viruses. Virus particles are only nanometers in size, so they can remain suspended in the air long enough to be dispersed.

An air ioniser is a device that uses high voltage to ionize (electrically charge) air molecules. Negative ions (anions) are particles with one or more extra electrons. Positive ions, (cations) are particles with less electrons. Positive and negative ions both have been found to inactivate viruses
Particles of biological origin, such as viruses, bacteria, fungi, and pollen as well as their fragments that are present in air are referred to as bioaerosols. Bioaerosols can cause serious health hazards when they contaminate a human environment. The COVID19 virus, the avian flu and swine flu are natural examples illustrating the profound impacts of bioaerosols on public health.
Ionic air purifiers are used to break down viruses, bacteria, mold, odors and volatile organic compounds (VOCs) to sanitize air and surfaces. Negative air ionizers generate negative ions which electrically charge air molecules which pass electrons to airborne water molecules and other particles including viruses The device enables rapid removal of viruses and bacteria from air and prevents airborne transmission of diseases .
The moisture in the air tends to keep an extra electron on billions of oxygen molecules. Since negative particles attract positive particles these negatively charged oxygen molecules turn into the equivalent of miniature vacuum cleaners by attracting viruses, dust, smoke, pollen, mold spores, and other unwanted particles which have positive charges. When the negatively charged oxygen molecules attract positive particles, they form heavier clumps, which drop to the ground, leaving the air we breathe fresher and cleaner.
An ionizer was used for inactivation of virus and prevention of airborne transmitted influenza, a virus infection. The ionizer protected 100% of guinea pigs from infection. Moreover, the device effectively captured airborne transmitted calicivirus, rotavirus and influenza virus. Generation of negative ions has been shown to reduce transmission of Newcastle disease virus and several kind of bacteria in animal experiments.
The spread of infectious diseases in hospitals can be very serious. In many situations there is a need for a pathogen and particle free environment, e.g. in operation wards, environments for immunosuppressed patients as well as for patients with serious allergies. This makes it desirable to have a method for eliminating virus and other pathogens from air. The frequency of nosocomial infections in British hospitals prompted the National Health Service (NHS) to research the effectiveness of anions for air purification, they foind 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.
Normal speaking causes airborne virus transmission. Here is where the technology of a negative air ionizer may offer significant protection. It places an charge on bioaerosols including relatively large particles (like dust), smaller particles like bacteria and mold spores, and even tiny virus particles measuring as little as 0.052-0.140 micrometers. The charged particles fall to the floor, or are attracted to surfaces of grounded electronic devices (like computer screens), which can be wiped away during normal housecleaning. The air becomes more breathable and refreshing – and less hazardous to health.
The negative ions cluster around particles, increasing their mass until they become heavy enough to fall from the breathable air space. VOCs and odors are broken down on a molecular level to their most basic elements without the production of harmful byproducts. Mold, bacteria, and viruses are deactivated and rendered harmless with this air purification technology.
Negative air ions are highly effective in removing particulate matter from air. Airborne particles become charged as they attract charged ions from the ioniser by electrostatic attraction. The particles in turn are then attracted to any nearby earthed (grounded) conductors, either deliberate plates within an air cleaner or simply the nearest walls and ceilings.
The SARS epidemic fueled the desire for personal ionisers in East Asia, including Japan where many products have been specialized to contain negative ion generators, including refrigerators, air conditioners, air cleaners, and washing machines.