at the main hospital here they have a large UV/ozone machine that makes a popping sound like a large flashbulb twice a second or so. I don't think it's a robot.

As an aside, where can i reliably get any real UV-C + Ozone bulb these days? I had 3, i gave one away and two broke during the pandemic, and all i have been able to find in the past year and a half is UV-C that doesn't produce ozone, but instead that weird "too much sunlight" smell - anti-septic smelling but it doesn't murder pathogens like ozone does.