Ultraviolet-C Technology – UPSC Prelims

Ultraviolet(UV) Light:
  • Ultraviolet(UV) is a type of light or radiation naturally emitted by the Sun. It covers a wavelength range of 100-400 nm. The human visible light ranges from 380 to 700 nm.
  • Types of UV light: There are three types of UV radiation that are classified according to their wavelength:
    • UV-A (315-400 nm): It has a long wavelength, which accounts for approximately 95% of the UV radiation reaching the Earth’s surface. It can penetrate the middle layer of your skin or the dermis and can cause aging of skin cells and indirect damage to cells’ DNA.
    • UV-B (280-315 nm): It has a medium wavelength. It is biologically active but cannot penetrate beyond the outer skin layers. It can cause sunburn and is also associated with skin cancer.
    • UV-C (100-280 nm): It has a short wavelength and is most harmful. However, it is completely filtered by the ozone layer and does not reach the Earth’s surface. But the UV-C radiation from man-made sources has been known to cause skin burns and eye injuries.
Can UV-C kill Coronavirus?
  • UV-C radiation (wavelength around 254 nm) has been used for decades to disinfect the air in hospitals, laboratories, and also in water treatment.
  • A paper published in June 2020 in Scientific Reports noted that UV-C radiation can destroy the outer protein coating of the SARS-Coronavirus.
  • Moreover, few studies have shown that far-UVC light does not harm human skin. This is because UV-C light has a very limited range and cannot penetrate through the outer dead-cell layer of human skin or the tear layer in the eye, so it’s not a human health hazard.
  • But because viruses and bacteria are much smaller than human cells, far-UVC light can reach their DNA and kill them.