The UVA light is also known as blacklight, causes specific materials to “fluoresce” or radiate visible light in total darkness. This means when you ut anything under UVA light, the material will glow. Bodily fluids such as saliva, semen and vaginal fluid will fluoresce and can be detected under blacklight. That is traditionally used in depicting crime scene investigations.
Since certain bodily fluids can transmit certain sickness-causing bacteria and viruses, a blacklight can detect potentially threatening bodily fluids. However, the blacklights are not seen as a detecter that specifically illuminates bacteria and viruses – it only illuminates fluorescent bodily fluids that can potentially contain said bacteria and viruses. There is no specific way of knowing if the fluids contain bacteria and viruses using a black light.
If you want to use a UV lamp to detect bacteria without any chemicals, it is not possible. UV light is used to kill micro-organisms but will not visualize them. To visualize bacteria, you have to stain them with a fluorescent dye first.
Blacklight is not able to isolate and distinguish the virus specifically, “Coronavirus is a microscopic virus that can’t be visualized unless you use advanced electron microscopy. A blacklight should not be seen as a method to detect Coronavirus. It can be used to demonstrate germs how germs can spread if you put something on your hands that does glow like laundry detergent or dye.
To summarize: A blacklight cannot identify bacteria at home. All it will do is show your traces of bodily fluids. But You can use UVC light, which is a germicidal effect and sanitize your spaces effectively. UVC light effectively deactivates the DNA of bacteria, viruses and other pathogens by destroying their ability to multiply and cause diseases. You might not be able to see the bacteria, but you can be assured of it getting deactivated by UVC light.