We all know UV light damages DNA, and since there is not much researches on how different visible lights affect on cell division, I can only further discuss based on following assumption:

UV light (left of light spectrum) is closer to blue light (middle of light spectrum)  comparing with red light (right of light spectrum), so based on energy levels, red is less destructive than blue on destroying nucleic acids and breaking apart germ DNA.

Based on this assumption, I would like to know on how the process of Sunburn generates free radicals within human body.

Does anyone have any suggestions?
Thanks, to everyone very much for any suggestions :>

Let's look at this again. My assumption is that anything within the UV range is dangerous AND the closer the wavelength is to x-ray, the more penetrating it is, and therefore more damaging. The formation of free-radicals occurs in plants, if I recall correctly, and they are prevented by certain pigment molecules like carotenoids - that's where photoprotection comes in.

Are you certain of this:

Referring to following statement, logic imply that Sunburn would lead to the generation of free radicals or other harmful reactive chemical species (e.g. singlet oxygen, or hydroxyl radical).

Do you have any suggestions?
Thanks, to everyone very much for any suggestions :>

If the energy of the UV photon were not transformed into heat, then it would lead to the generation of free radicals or other harmful reactive chemical species (e.g. singlet oxygen, or hydroxyl radical).
https://en.wikipedia.org/wiki/Photoprotection

Sunburn is a form of radiation burn that affects living tissue, such as skin, that results from an overexposure to ultraviolet (UV) radiation, commonly from the sun.
https://en.wikipedia.org/wiki/Sunburn

Unless you can provide a source for this, it's hard to confirm.

Some sources state that sunburns offer free-radical protection - the opposite of what you're proposing. The formation of free radicals occurs in *plants* because during photosynthesis, water is split into oxygen and protons (H+). This splitting of water and the exposure of oxygen is a gateway for free-radical formation. This is not the case in animals.