The sun emits Ultraviolet Radiation (UV) this UV radiation consists of 3 different forms, UVA, UVB and UVC rays.
UVA rays
UVA rays form the largest part (95%) of the ultraviolet radiation, they are not felt and penetrate deep into the skin. They are responsible for the long-term harmful effects, such as skin aging (wrinkles and spots) and skin cancer.
UVA rays also occur on cloudy days and go largely through clothing and through glass. So even if you’re in the car or in the office at the window, you’ll be dealing with UVA rays.
UVB rays
UVB rays are felt and give an effect in the short term. This radiation causes the redness (burning) of the skin. The UVB rays of the sun damage the outer layer of the skin and cause sunburn and skin cancer. UVB rays do not go through clothing and glass.
UVC rays
UVC rays are completely stopped by the atmosphere.

