Far UVC- To The Rescue form Covid-19

Among the three types of UV radiation, UVC is by far the most energetic - having a higher frequency (shorter wavelength) and the most damaging. Because of the higher energy, they react with ozone high in our atmosphere and don't reach the ground at all. This article tries to explore how this lethality of the UVC can be redirected to our fight against SARS COV2 aka the novel Corona Virus which causes COVID19.

Updated: Apr 24, 2020 15:36 IST

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Hari Aditya

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Tags: India Corona

UVC a Beam to Rescue from Covid-19

The sun emits three types of UV radiation: UVA, UVB, and UVC. The three types of I-JV radiation are defined by wavelength/frequency intensity each. The higher the temperature, the greater the energy, and the radiation which is unhealthy. Let's look at what World Health Organisation has to tell regarding the vulnerability to UV radiation.

'Erythema,' the common skin reddening called sunburn, is the most documented acute result of prolonged UV exposure. UVA rays, which compensate for 95 percent of radiation entering the surface of the planet, induce lines, "heat spots," and other forms of premature aging. My, less obvious physiological consequence is a thickening of the skin's outermost layers. Medium-wavelength I-JVB is very biologically active but cannot penetrate beyond the superficial skin layers. It is responsible for delayed tanning and burning; in addition to these short-term effects, it enhances skin aging and significantly promotes the development of skin cancers such as non-melanoma skin cancers, malignant melanoma.

Any high school student should probably be aware of the adverse consequences of ultraviolet light and that during a solar eclipse one will not be staring at the sky. The sun releases enormous quantities of energy in the form of heat and light since there is no communicating medium between earth and air, the energy enters humans in the form of radiation at various electromagnetic (EM) spectrum wavelengths.

The ozone layer blocks much of the Solar UVB. This is calculated by the WHO that up to 20 percent of cataracts may be triggered by overexposure of UVB rays and thus should be prevented. UVB exposure often tends to reduce the immune system's efficacy. We should not worry though, seeing the frightening results of UV radiation in our body. Only prolonged exposure or acute high doses such as unprotected viewing of a solar eclipse pose a significant risk; on the contrary, a minimum amount of dose is essential for the synthesis of a type of Vitamin (vitamin D3) in our body.

UVC is a Saviour

UVC is by far the most energetic of the three forms of UV radiation listed-with a higher frequency (shorter wavelength), and the most harmful. Owing to the higher energy they react high in our atmosphere with ozone and do not touch the earth at all. This article tries to explore how this lethality of the UVC can be redirected to our fight against SARS COV2 aka the novel Corona Virus which causes COVID19. Ultraviolet light kills microbes by a completely different mechanism from the way the drugs kill them, so ultraviolet light is just as capable of killing a drug-resistant microbe as any other microbe.

Currently, the practical usage of ultraviolet light for airborne disinfection is by no means recent and was first demonstrated about 80 years ago. Ultraviolet radiation kills the DNA and breaks cells. The light initiates a reaction between two molecules of thymine, one of the bases that make up the DNA, the DNA can repair this, but a prolonged enough exposure can override the repair mechanism making the DNA impaired. If the damage is moderate, cancer will result, if it is extensive apoptosis will result- the programmed cell death.

However, because of the safety risks, as described above, the use of UVC as a germicide in public spaces is severely limited. The new kid in the corner-'The far UVC 'Far-UVC light has a shorter duration, higher frequency, higher energy than UV-C, resolving this extreme restriction of UV, which allows its impact on microorganisms distinct from normal germicidal UVs.

Far UVC needs to be chemically produced because none of those that exist naturally reach the ozone layer. We have the requisite equipment in the spectrum to generate this kind of radiation.

A study by David Welch et.al from Colombia University in paper details how the spectrum, of far UVC, can be used to effectively counter microbial growth with zero harm to the human tissue. 

Far UVC light having a wavelength of 222 nanometers and a comparatively low dose of 2 milli Joules/ Cm3  is shown to inactivate all aerosolized SARS-COV-2. 

The coolest thing about this particular spectrum of ultraviolet light (207–222 nm) is that it efficiently inactivates the virus without any harm to exposed human cells. 

This particular wavelength cannot penetrate the outer layer of the skin, even the thickness of the tear layer on the outer surface of the eye is larger than the ability of far UVC light to penetrate; neither of which contains living cells. 

Viruses are typical of micron or smaller dimensions, far-UVC light can still effectively penetrate and inactivate them by messing with their RNA mechanisms as discussed above. 
This study has been reported by Nature Magazine.

This ability of the far UVC light makes it the most potent candidate in using in Public spaces where the virus can possibly linger around and spread. 
Airports, Railway stations, Bus Stands, Schools, Theatre halls can be potentially and safely be irradiated without causing cellular damage to humans which hazards inherent with conventional germicidal UV lamps. 

This is a powerful, yet inexpensive approach for the prevention of airborne viral infections and has the potential to revolutionize public health. 
India is also geared towards using Ultraviolet light in its fight against COVID19.