Ultraviolet radiation is part of the sun's rays that reach the earth. About ten percent of it. A distinction is made between UVA, UVB and UVC radiation. The latter is the radiation with the highest energy but the least relevant for us, since it is largely filtered by the atmosphere and the oxygen in the air. UVB rays are short-wave and only penetrate the upper layers of the skin. It is they who cause sunburn.
The ozone layer filters most of these rays, but some still gets through. UVB rays accelerate skin aging and can cause skin cancer.
The long-wave UVA rays penetrate into the deeper layers of our skin. They are responsible for tanning and also cause our skin to age. For a long time it was believed that they had no negative effects. However, recent studies suggest that they also have a major influence on whether we develop skin cancer.
