The shorter bands of UVC, as well as even more-energetic UV radiation produced by the Sun, are absorbed by oxygen and generate the ozone in the ozone layer when single oxygen atoms produced by UV photolysis of dioxygen react with more dioxygen. The ozone layer is especially important in blocking most UVB and the remaining part of UVC not already blocked by ordinary oxygen in air.
the shorter bands of uvc as well as even more-energetic uv radiation produced by the sun are absorbed by oxygen and generate the ozone in the ozone layer when single oxygen atoms produced by uv photolysis of dioxygen react with more dioxygen the ozone layer is especially important in blocking most uvb and the remaining part of uvc not already blocked by ordinary oxygen in air