[Mod edit: post moved from separate topic to here. (TR)]
Germicidal UV Light Fixtures run at 30 to 40 watts and emit high energy UV light which as a side effect, creates ozone. Both the UV light and the ozone will kill germs. However, the UV light intensity and the ozone are harmful to pets and humans. These light fixtures come with a remote control to allow starting them and controlling them from outside the room where they are placed. They are capable of disinfecting an entire room. They run for just 15 minutes, typically, and that is enough time. It is important to understand that the room and indoor area where they were run, must be ventilated for an hour, a whole hour, to dissipate the generated ozone, which is harmful to human and pet health. Opening a window to ventilate seems to negate the use by letting in outside air, but perhaps not, if run on a sunny day.
Germicidal UV Lights have suddenly started showing up online in quantity since the COVID pandemic has progressed. They are normally used in hospital, restaurant and other commercial buildings and are not typical for home use, because of the health issues and care that must be taken to run them and ventilate afterwards.
Will a home run germicidal UV light help combat COVID? No. COVID contact and spread will more likely be encountered in public spaces, not in the home. If such a light is run in a public commercial building, it is the responsibility of that business or facility maintenance to properly run the light and ventilate the space afterwards. We can hope to trust them to use the lights responsibly.
Small wand UV light fixtures run at a lower wattage and emit lower intensity UV light and may be used for short applications in the home. Such wands typically are used to disinfect computer keyboards, shoes, door knobs and kitchen/bathroom areas, - places with high touch frequency. They should not be used to disinfect skin.
NEVER look directly at a UV light source!
