[anessaiver]

Ionizers work through two mechanisms: 1. Charged particles stick together, forming larger clumps that eventually drop out of the air. 2. Charged particles can build up on the surface of airborne pathogens, sometimes directly disrupting membranes or lipid layers, and if there is enough of a buildup they can induce an electric current through the organism that can kill / inactivate it. One study on bipolar ionization showed antiviral efficiencies were 64.3, 89.1, and 97.4% with exposure times of 15, 30, and 45 min, respectively (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7094352/).

The advantage to ion generation based air purification systems is that they are able to actively operate in occupied spaces, not relying on air to get pumped out of a return duct and through a filter or UV system.

It's not possible for them to achieve an instantaneous elimination of airborne pathogens, but any significant percentage reduction can help to lower the total viral load that people in the room are being exposed to.

That being said, it's unlikely that what he's wearing around his neck will generate a sufficient quantity of ions to make much of a difference. It wouldn't be enough to fill the room, and the amount of time any such ions would have to act on a particle that comes close to him really isn't enough to have a large impact.