Ultra-violet radiation

The ultra-violet radiation can be divided into two types – ultra-violet A and ultra-violet B. The main difference between them depends on the energy of radiation and the depth of penetration into derma. The ultra-violet B radiation possesses higher energy and results in burning the skin. So the first sun protected means had to block this type of radiation and due to that it was considered the most dangerous one. Firstly the burned skin is braking out into bubbles, then shredding away. It results in harmful damages in DNA.
We have another situation with ultra-violet A, which is considered to be very useful because it causes sun tanning, but doesn’t have too much energy to burn the skin. Now it is known it is the ultra-violet A that can penetrate derma and damage biological molecules. People, who don’t know about such an effect, can lie in the sun for a long time not being afraid of over burning the skin. Thus, we can make a conclusion that both ultra-violet A and ultra-violet B have the same harmful effect on the skin. They are absorbed by biological molecules and resulted in the occurrence of free radicals. There is a chemical reaction between the molecules. For example, ultra-violet A, penetrating into the skin, can turn collagen into free radicals. As a result, collagen tissues are connected with each other, forming the formations of nonelectric collagen, so to say, and the skin becomes wrinkled and uneven. The wrinkles may appear long far ahead before your skin starts to age due to natural factors. In addition, DNA can change its composition: two parts of molecules of DNA, having become the radicals, may introduce some chaos in the genetic code of cell. From these damaged cells the cancer can be developed. That is why, people started to evaluate the sun protector means, which had special marks about the so called sun protector factor. However, it appeared to be an unreliable protector. For example, if normally your skin begins to turn red during 20 minutes, then due to the sun protector means it becomes red in 200 minutes. As you know, the rudeness of skin occurs thanks to ultra-violet B radiation, then sun protector factor shows only the effectively of ultra-violet B protector. Nowadays sun protector means industry try to indicate ultra-violet A degree of protection on the box. And people get used to applying these means for protection their skin and receive the necessary tan hoping for the best.