Context

• Union Minister of State for Science and Technology has said that Ultraviolet-C or UV-C Disinfection Technology will soon be installed in Parliament for the “mitigation of airborne transmission of SARS-COV-2’’.

What is UV?

• 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 380–700 nm.
• UV is divided into three bands: UV-C (100-280 nm), UV-B (280-315 nm) and UV-A (315-400 nm).
• UV-A and UV-B rays from the Sun are transmitted through our atmosphere and all UV-C is filtered by the ozone layer.
• UV-B rays can only reach the outer layer of our skin or epidermis and can cause sunburns and are also associated with skin cancer.
• UV-A rays 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-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.
• An in-vitro experiment conducted by Hiroshima University researchers showed that 99.7% of SARS-CoV-2 viral culture was killed when exposed to 222 nm UV-C irradiation at 0.1 mW/cm2 for 30-seconds.

Is it safe for humans?

• Researchers from the Indian Institute of Technology-Kanpur, noted that UV-C radiation could be harmful to the skin and eyes of the living beings, therefore the operator of the device must use spectacles with UV-C radiation protection.
• But few studies have shown that far-UVC light (207–222 nm) does not harm mammalian skin.
• Far-UVC 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,” Center for Radiological Research at Columbia.

https://indianexpress.com/article/explained/explained-what-is-uv-c-technology-and-how-does-it-work-on-coronavirus-7404573/

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