Sun tanning However, it operates not by inducing direct DNA damage, but by producing reactive oxygen species which damage DNA indirectly. UVA (see above) induces a cosmetic tan but little extra melanin protection against sun damage, sun burn, or cancer. Ultraviolet B (UVB) radiation is in the wavelength range 280 to 320 nm. Much of this band is blocked by the Earth's ozone layer, but some penetrates. UVB: A person's natural skin color affects their reaction to exposure to the sun. An individual's natural skin color can vary from a dark brown to a nearly colorless pigmentation, which may appear white .
Ultraviolet index numerical ranges, the recommendations for protection are as follows: When interpreting the UV Index and recommendations, be aware that: According to the U.S. Environmental Protection Agency, a helpful method to estimate the amount of UV radiation people are exposed to is by observing the length of their shadow. A taller shadow may mean a lower UV exposure while a shorter one could translate to exposure to higher levels of UV radiation. Ultraviolet index The ultraviolet index or UV Index is an international standard measurement of the strength of sunburn-producing ultraviolet (UV) radiation at a particular place and time. The scale