Ultraviolet is the collectively of electromagnetic spectrum, from 0.01-0.40 micron wavelength (visible violet end of X-ray room)radiation, ultraviolet can not cause vision.

• UV Classification

UV wavelength of 100 ~ 400nm of the electromagnetic wave. It consists of: UVA and UVB and UVC. UV penetration of human skin is different. The shorter UV wavelengths, the greater the harm to human skin. Shortwave ultraviolet light can pass through the dermis, the wave can enter the dermis.

Ultraviolet spectrum

UVA: transmissive dermal tissue, leading to sagging skin, wrinkles, etc. consequences emerge. Also make skin dull dull, black skin. UVA year are equally violent, regardless of the season period.
UVB: will make the skin becomes dry, accelerated skin aging. After a long time the body by UVB radiation can cause skin melanocytes causing mutation, which is difficult to eliminate sun spots. But it can easily be blocked by clouds and other coverings, worse than the UVA penetration.
UVC: UVC basically been absorbed by the ozone layer before reaching the ground, has little influence on the human body.

• UV applications

Chemistry: paint curing, paint curing, lithography
Biology: Sterilization
Instrumental Analysis: ore, drugs, food analysis
Applications: human health exposure, kill pests, soot oxidation, light catalase (titanium dioxide)