Energy propagated in the form of electromagnetic waves or particles (photons), which can be reflected, imaged ordispersion, this energy andCommunication processIt is called light radiation.
It is generally believed that the wavelength is 10nm~1mm, or the frequency is 3´1016Hz~3´1011Hz.
Hazards of light radiation
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ray radiation
RecentPhotobiologyResearch shows that light radiation is closely related to human health, whether it isultraviolet、visible light、infrared lightUnder appropriate irradiation, it can have a positive impact on human physiology.However, when the exposure is insufficient or excessive, the impact of light radiation can either be ignored or there is potential harm.
1、 UV hazard
Ultraviolet radiationMeansWavelength rangeThe light radiation at 100nm - 400nm is generally called UVC at 100nm - 280nm and UVC at 280nm - 315nmUVB315 nm - 400 nmUVA。The ultraviolet radiation of 100nm - 200nm isAtmospheric absorptionIt has no effect on human beings and is called vacuum ultraviolet. Therefore, the main impact on human beings is 200nm - 400nm ultraviolet radiation.
becauseultraviolet raysThe wavelength of is the smallest, the energy is the highest, and the ultraviolet radiation is the most harmful light radiation, so it has always beenPhotobiologyThe main objects of concern.In 1801, ultraviolet light was introduced by JW. Ritter found that in 1877, people first observed the effect of ultraviolet radiation onLife systemDownes and Blunt reported the inactivation of bacteria.The second milestone was in 1928, when Gates found that different wavelengths of radiationrelative efficiency(i.e. fatalAction spectrum）Parallel tonucleic acidBaseOfabsorption spectrum。
As far as we know, the beneficial effects of ultraviolet light on human body are very few (such as promoting the production of ultraviolet light in human skinvitamin D）However, ultraviolet rays can cause a lot of harm.The harm of ultraviolet rays to eyes mainly includes: light inducedkeratitis, Photoinducedconjunctivitis、cataractEtc.The main hazards of ultraviolet rays to face skin are: erythema（Short term effects）、Skin cancer（Long term effects）。
As time goes by, it means that the brown substanceretinal pigmentepithelial cellsThe accumulation ofretinaIt is more vulnerable to damage caused by long-term light.Research shows that blue light is particularly harmful to people with the above retinal spot problems due to heredity, nutrition, environment, habits, age and other factors.Although the wavelength is shorterUVAandUVBBy cornea andLensHowever, research has found that the ultraviolet to blue light radiation can cause such harm.
3、 Visible and infrared hazards
electromagnetic waveThe wavelength range of the visible part is about 380nm to 780nm, and various wavelengths within this range can be distinguished by the color sense of the eyes.Blue and purple belong to shortwave, red belongs tolong wave, yellow and green are in the middle of the visible wavelength range, which is also the most sensitive area of the human eye.visible lightThe most important effect of theLight energy conversionElectric energy orNerve impulseThe process ofPhotochemical reactionnamelyphotophysicsAndPhotoisomerization。Vision is the most important perceptual function of human beingsExternal informationEighty to ninety percent of them come from vision. Visible light enables us to feel, understand, and remember the world, so that we can maintain our orientation.The light radiation hazards of visible and infrared parts mainly include burnsErythema effect, cataract, etc.
In addition, the light radiation of high intensity light source can also cause damage to human body. For example, direct vision laser can cause macular burn, which will cause unrecoverable vision loss. This damage is physiological and often cannot be repaired.[1]
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It can last from a few seconds to tens of seconds, and can burn people, animals and objects.For example, 20000 tonsequivalentNuclear bombExplosion and lighting lasts for about 2.4 seconds, which can make equipment and buildings fire or meltburn、Blindness。 All light blocking objects can weaken its effect.White and light colored objects have better protection effect.
