How to divide the ultraviolet band?
Ultraviolet rays are electromagnetic waves with a wavelength smaller than visible light. Most of the ultraviolet rays on the earth’s surface come from the sun. Ultraviolet rays are referred to as UV. When the sun irradiates through the atmosphere, the rays that reach the earth’s surface are ultraviolet rays A and B due to the filtering effect of the atmosphere. UVA and UVB in our common sense. Ultraviolet rays have many advantages, but the disadvantages of ultraviolet rays are also extremely obvious. When the skin is exposed to excessive ultraviolet rays, it will damage the epidermal cells; activate tyrosinase, accelerate the synthesis of pigment, destroy the skin's moisturizing function, make the skin dry, and let the dermis The elastic fibers in the layer are damaged, causing fine lines to be produced. Under strong irradiation, it can also cause skin inflammation and burns. When there are abnormalities, it will become pigmented skin cancer.
Ultraviolet rays can be divided into three parts according to their wavelengths: A ultraviolet rays have a wavelength between 0.32--0.40 microns. The effect of A ultraviolet rays on us is that it can promote the synthesis of vitamin D, but excessive A ultraviolet rays can cause photo-condensation. , Inhibit immune system function, too little or lack of A ultraviolet radiation is easy to suffer from erythema and cataract; B ultraviolet wavelength is between 0.28 and 0.32 microns, the effect of B ultraviolet on us is manifested in making the skin red and reducing vitamin D in the short term Long-term acceptance may cause skin cancer, cataracts and suppress immune system function; C ultraviolet wavelength is between 0.01 and 0.28 microns; C ultraviolet rays are almost all absorbed by the ozone layer, which has little effect on us. The impact of ultraviolet rays on humans is mainly manifested in the combined effect of A ultraviolet rays and B ultraviolet rays.