3 types of ultraviolet light

  1. UV-A: 315nm to 400nm
  2. UV-B: 280nm to 315nm
  3. UV-C: 200nm to 280nm

Only one has been proven safe and effective for killing bacteria:

UV-C is the type of ultraviolet light linked to the most benefits. UV-C is proven to work throughout the spectrum (200nm to 280nm); however, growing research shows that the 264nm wavelength variety of UV-C light is most effective at killing germs, viruses, and bacteria.