The UV-C wavelength (253.7 nm) is invisible to the eye, the blue light that one sees represents only 5% of the total output of the lamps. So unlike the dark or flickering lamp above your desk or in the conference room, the visible light emitted from a UV-C lamp is NOT a good indicator of its performance. UV lamps will continue to emit the blue light long after the UV-C output has decreased, even by more than 50%!
How Ultraviolet Purification Works – H2O Distributors
Indigo-Clean Lighting
How to tell if UV-C LEDs work
What is the Difference Between UV-A and UV-C?
What is UV-C Disinfection Lighting: The Basics
UV-C Lamp Meter from UV Resources Ends Replacement Uncertainty for Building Engineers - UV Resources
Myth or Fact: UV Lamps Edition, 2017-08-28, ACHRNEWS
Bright Future of Deep-Ultraviolet Photonics: Emerging UVC Chip-Scale Light-Source Technology Platforms, Benchmarking, Challenges, and Outlook for UV Disinfection
Could a novel UV light device inactivate SARS-CoV-2 on surfaces?
XP360 UV-C Replacement Bulb - Purafide
Pandemic Created New Markets for UV-C
UVC Light for Home - LightSources