The ultraviolet rays are found to be present in solar radiation and are allowed to be incident on the earth. These solar radiations are comprised of nearly 8% of UV rays. These UV rays are of three types, namely UV-A, UV-B and UV-C which are harmful to the living organisms on earth. Of all the three, the UV-B and UV-C are highly dangerous that can cause various skin diseases like cancer.
The presence of the ozone layer in the atmosphere acts like a blanket that does not allow these harmful UV radiations to enter into the atmosphere of the earth. The majority of the UV-A is able to reach the earth's surface, but they are not able to cause much harm. So, out of this 8% of total UV radiations, a little amount of it is successful in reaching the surface of the earth.
