But, do these mister units actually do anything useful against an aerosol dispersed disease? It feels from here behind the TV set its performative hygiene theatre, and does nothing of substance. Because of mosquito control they have the devices, and they can fog bleach, or TCE or something (that would be terrible)
Or, are "fomites" still a real concern?
UV was said to be used to "sterilise" aircraft interiors. I would probably ask the same question: does it do anything useful?
Here is a review of some studies that mention cases linked to fomites: (scroll down)
https://ncceh.ca/documents/evidence-review/fomites-and-covid...
In each case, the link is pretty tenuous. Each of these events could be explained (much more parsimoniously, imo) by respiratory droplets in the air.
So it could be therefore argued that in the absence of other (more preferred) options, fogging is a decent last resort to try to combat stagnant COVID aerosol because it will weigh down and/or disperse and/or dilute stagnant areas of COVID.
Of course it is well understood by now that the preferred means to combat COVID is high levels of ventilation (open windows) and filtration (HEPA filters). But this is not always possible to achieve in an ideal manner either due to building construction (sealed windows etc.) or climate (cold weather, windy days etc.). So it is quite possible that using fogging as a "plan B" should not be entirely disregarded.
(Disclaimer: I am not a scientist, the above is a simplified summary of my understanding based on what I've read from reputable scientists)