Oxidation reactions
Radicals generated from UV-A/B light can lead to breaks in
single-stranded DNA by forming hydroxyguanine and hydantoions from
pyrimidines. This reaction is pH sensitive. UV light may also cause the
formation of pyrimidine dimers in DNA. In addition, UV radiation has
many indirect effects through the generation of free radicals, therefore
the timescale upon which this mechanism acts to degrade DNA is hard to
conclude.