UV radiation can be divided into three areas according to the band? What are the effects?

In order to facilitate the research and application, we will be in accordance with the short wavelength ultraviolet radiation is divided into three zones, UVA (UV-A, 315-400nm) and ultraviolet B (UV-B, 280-315nm) ultraviolet (UV-C, 100-280nm).

When the sun passes through the earth's atmosphere, short wave ultraviolet light will be blocked, only the medium and long ultraviolet rays to reach the earth's surface. In recent years, with the periodicity of sunspot outbreaks, human activities such as modern industrial and aerospace technology development to the atmospheric ozone layer destruction and pollution, the sun reaches more and more ultraviolet radiation of the earth's surface, has become one of the main topics of human health.

Ultraviolet radiation penetrates into the skin deep, where the presence of melanin is oxidized to form melanin, making the skin black. If UV radiation continues to shine, the resulting melanin will form pigmentation, which is known as the pigmentation effect. According to the research, the effective band of the pigmentation is UV-A band, and its peak value is near 365nm. Ultraviolet radiation UV-A can treat skin tinea, herpes and other diseases.

In the strong ultraviolet radiation, the skin will produce a variety of chemical media, and the release of diffusion into the dermis, causing local vascular expansion, specifically for the skin erythema. Medical research found that, with the formation of different forms of erythema, ultraviolet radiation caused by erythema disappeared slowly. Although the mechanism of the scientists on the erythema effect is not completely clear, but the main effect on the formation of ultraviolet erythema wavelength has a unified understanding, which is near 310nm, that is to say, erythema should be UV-B ultraviolet radiation effect.

Vitamin D is synthesized in the human body by the absorption of ultraviolet radiation, which is very effective in the prevention and treatment of rickets and osteoporosis. This is often said that the health effects. The absorption wavelength of 280nm was 220-320nm, and the highest efficiency was near the. As doctors often recommend that parents in winter with newborn in a certain amount of outdoor activities in the sun, so to promote the baby baby son bone development is very favorable. In addition, the clinical use of UV light irradiation of the body, in order to achieve the purpose of health effects of health care. These are typical examples of the use of UV health effects.

A certain amount of UVC has a great destructive effect on microorganisms, which can kill Escherichia coli, Shigella, typhoid bacteria, Staphylococcus, Bacillus tuberculosis, Bacillus subtilis and cereal mold. The ability of UV radiation varies with wavelength, the peak value of sterilization is about 254nm, that is to say, the effect of ultraviolet radiation on the wavelength of 254nm is the best. The sterilization effect of ultraviolet radiation has been widely used in the medical and health care and food industry. The most common is the sterilization of the air and medical products.