Ultra-violet ray radiation

Economic growth in developing countries were increasingly improved. Many buildings are now beginning to be built to improve the facilities and infrastructure such as roads, buildings, and so on. For that many people are absorbed in the field of building work. We know that working in the field of building sometimes are out of the room or out door are often exposed to ultraviolet rays from sunlight.
Harmful component of sunlight is the light "ultraviolet" light that is invisible to the earth that only UV-A and UV-B. Ultra-violet ray radiation is electromagnetic radiation of shorter wavelength with visible light, but longer than X-rays is small. UV-A or could be called suntan makes brown skin, while UV-B or Sunburn makes the skin red and even become sore.
UV radiation can be divided into:

1. Near UV (380-200 nm wavelength)
2. Vacuum UV (200-10 nm)

When considering the influence of UV radiation on human health and the environment, visibility is often subdivided wave:
1. UV-A (380-315 nm), which is also called the "wave length" or "BlackLight"
2. UV-B (315-280 nm), which is also called "Medium Wave" (Medium Wave)
3. UV-C (280-10 nm), also called "Short Wave" (Short Wave).