Ultraviolet light is a component of the electromagnetic spectrum that falls in the region between visible lights and X-Rays. This invisible radiation includes a wavelength of 100nm to 400nm. UV light can be further subdivided into four separate regions- Far UV, UVC, UVB, and UVA.
It includes a wavelength of 100nm to 280nm. Most natural UV radiation is generated by the sun and only three to 4% penetrate the atmosphere of the earth. But none of that is Ultraviolet C as this completely absorbed by the Ozone layer.
Harmful Effects Of Ultraviolet
UVC demonstrates significant germicidal properties because of the spectral sensitivity of DNA.
Its wavelengths reach us through artificial sources like LEDs or mercury lamps. But once these gets past the scattering length, it falls off exponentially. This means that the further away from the source less the exposure and as the absorption length of it in human skin is extremely short so that almost no radiation can reach the living cells and absorption occurs in the dead cell layers.
Rarely prolonged direct exposure to Ultra Violet C light causes temporary eye and skin damage such as cornea injury called “welder’s eye”.
Uses of Ultra Violet
It is emitted from a shortwave UV lamp which is made using a fluorescent lamb tube without coating, made fused quartz, since ordinary glass absorbs it.
It is mainly used as germicidal as evident by multiple types of researches. In the time when biological organisms are exposed to deep UV light in the range of 300nm, it is absorbed by DNA, RNA, and proteins.
Absorption by proteins can lead to the rupture of cell walls leading to the death of the organism. Absorption by DNA or RNA causes inactivation of DNA or RNA double helix strands through the formation of thymine dimers. If enough of these dimers are created in DNA, its replication process is disrupted, and the cell can’t replicate and can’t infect further.
Other uses of it are in Extreme ultraviolet lithography, photoionization, ultraviolet photoelectron spectroscopy, standard integrated circuit manufacture by photolithography, UV-ID, label tracking, barcodes, optical sensors, various instrumentation, protein analysis, DNA sequencing, drug discovery, etc.
UVC is also an investigating tool at the crime scene as it helps to locate and identify bodily fluids such as semen, blood, and saliva. Other applications include the authentication of various collectibles and art, detecting counterfeit currency, enhancing the contrast of ink, etc. Even when the artifacts are not tagged with UV sensitive dye it may have distinctive fluorescence under UV exposure.