UV rays in full known as ultraviolet rays are classified into three types- UV A, UV B, UV C of which first two have effects of UV rays on skin. All three of them are derived from sun. Except UV C ray which is absorbed by the ozone layer, UV A and UV B rays are harmful for human skin. UV A causes photo aging by going deep inside our skin and in mid day, UV C is may cause cancer. UV B can get to the outer part of the skin which is called dermis and UV A can penetrate through and reach the second layer “Epidermis”.
Except these severe effects, the most common effect of sun ray is sun burn. Photo aging means “older” dry skin, tough feel, rude, inelastic and a pale color which is caused to chronic sun exposure. Due to cumulative sun exposure for a longer period, it may lead to skin tumor.
Tanning means pigments formation on the skin. The color of the skin is a result of melanin. Due to sun rays increased amount of melanin are produced which results pigmentation.
Sun burn is severe provocative reaction of our skin if we continue to stay on sunlight for a longer period of time. UV B rays damage DNA of keratinocytes which are main cells of our skin and lead to sunburn.
You can find more info on: http://www.medicineinanswers.com/effects-of-uv-rays-on-skin/
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