The main source of ultraviolet light in nature is the sun, which absorbs ozone from the atmosphere with ultraviolet light with a wavelength of 290nm meters.

Artificial UVC light source has a variety of gas arcs (such as low-pressure mercury arc, high-pressure mercury arc), ultraviolet light has a chemical effect to make the photo negatives light-sensitizing, fluorescent effect, fluorescent lamps, various fluorescent lamps and agricultural black lights used to kill insects are used to stimulate the glow of fluorescent substances.

Ultraviolet light is defined according to physical spectroscopy, and light is electromagnetic waves, all 40nm-400nm wavelengths of electromagnetic waves are uniformly called ultraviolet light, because the wavelength is too short, the human eye is difficult to see, so there is no difference between man-made and daylight ultraviolet light. This is like synthetic amino acids and amino acids in organisms are exactly the same (the same molecular structure).

Ultraviolet light has a chemical effect to make the photographic negatives sense light, and the black light used to kill insects also glows with ultraviolet light. Ultraviolet rays can sterilize, disinfect, treat skin diseases, etc. General disinfection cupboards are integrated with ultraviolet light and high temperature disinfection. At the same time ultraviolet radiation on human skin will increase melanin, so some friends who want to blacken their skin will use ultraviolet light to irradiate the skin, which is the same effect as sunbathing, but to control the time, time transition will increase the incidence of skin cancer.