Ultraviolet light is classified UVA, UVB, UVC wave. Every wave band plays a different role in our daily life. In this article I will introduce more detail about these three different ultraviolet light.
UVA wave length band
Wave length between 320~400nm called long wave black spot effect ultraviolet ray. It has a very strong penetration power to penetrate transparent glass and plastic. Sunlight contains long wave ultraviolet that 98% can penetrate ozone sphere and atmosphere to the surface of the land. UVA can directly penetrate into epidermis of skin destroying the elastic plastic and collagen fiber, so the skin color will become deeper. 360nm wave length UVA ray is according with the reaction curve of phototaxis of insecta. 300-420 nm wave length UVA ultraviolet rays can penetrate to the Special colored glass tubes which cut off the visible light. It only radiates nearly UV light in a 365nm center. 300-420nm wave length can use to be currency detector, and Ore appraisal, stage decoration lamp.
UVB wave length band
Wave length between 275 to 320nm is also called middle wave erythemal effects ultraviolet ray which wave have middle penetration power. The shorter part of wave will be absorbed by the transparent windows. The most of the middle UV ray in the light are absorbed by ozone sphere, only 2% of the middle wave UV ray are reach to the surface of the earth, the UV light will be strong on the summer and afternoon. UVB UV ray have erythemal effect to human body and facilitate syntheses of the Vitamin D and metabolism of mineral substance. But it will cause the skin tanning after a long term irradiation, and lead to red swollen and skin peeling. The Lamps for plant growing are made by using the special purple glass and the fluorescent powder which the peak near of 300nm.
UVC wave length band
UVC wave band wave length between 200 to 275nm it also called shorter wave sterilization UV ray, its penetration power is weaker, and it difficulty to penetrate to the most of the transparent glass and plastic. The shorter wave UV in sun light ray is almost absorbed by ozone sphere. The short wave UV ray has a great harm to the human body, it can burn skin during the short time irradiation, and it also will cause the skin cancer under the long tern and high power irradiation. The emitted from the ultraviolet germicidal lamp is the UVC shorter wave UV ray.