Ultraviolet (or UV) is electromagnetic radiation in the wavelength range of 4 to 400 nanometers, shorter wavelengths than that of visible light. The sun produces UV, which is commonly split into three bands: UVA,UVB, and UVC.
UVA is not absorbed by ozone. UVB is mostly absorbed by ozone, although some reaches the Earth. UVC is completely absorbed by ozone and normal oxygen.