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Introduction of FAR UVC 222nm to kill COVID virus

              The world is having a long and constant battle against the infectious diseases and scientists are on the hunt of the new method that can kill the target pathogenic microbes without triggering new issues in human beings. The continued research at Center for Radiological Research at Columbia University Irving Medical Center (CUIMC) has a firm belief that using the light of specified wavelength and energy can provide a low-cost solution to eradicate indoor and outdoor viruses. The researchers researched low doses of far ultraviolet C (Far UVC) that can kill the viruses without causing any issues and damage to human skin. A new scientific report entitled as “Far-UVC Light: A New Tool to Control the Spread of Airborne-Mediated Microbial Diseases” suggested new methods of killing viruses by using them in schools, hospitals, offices, doctors’ clinics, aeroplanes, and public spaces. The solution provides power impact on the seasonal influenza epidemics. Considering their efforts and outcomes, we aim to propose a solution to COVID-19. Since the outbreak of novel COVID-19, researchers are working hard to find low cost and most effective solution to overcome the virus and to save humanity. Considering the use of UV light to kill the virus without inducing impact on human tissues can be breakthrough research. A direct approach can be defined to prevent transmission of COVID-19 in human beings and by using conventional UV light source can be cataract genic and carcinogenic. Research conducted by Welch et. al. (2018) shown that UVC light (207 - 222nm) effectively inactivates the viruses and have not to harm on exposure to human skin. Extending the research on Coronavirus, useful research outcomes can be extracted.  CERTX is the UV light source with effective controlling commands. Its working is based on excimer lamps that produce 222nm of light and it is capable to inactivate viruses and leaving them harmless. Our prime concern here is to discuss experimental setup and how CERTX is an alternative to prevent long-range surface infection due to coronavirus.

Balancing harms of action and inaction

Far- UVC is a bit harmful but still it’s worth it to implement. A little bit harms from Far-UVC light is better than much larger harms of COVID-19, as compared to the ecological damage that is going on because on worldwide lockdown which someone estimated to be about $10 million every minute which also include the future recession due to personal hardship and self-quarantines of the major population of every country.

If adding further, a person can get safe from UV light harms instead of harms of CVID-19. There are many ways to prevent our self from UV light like sun creams, appropriate clothing and use of eye wear can save us from effects of UV light than the semi-permanent lockdown and fast growing virus that is resulting into million and tons of deaths worldwide and cause sickness of large population and is increasing day by day. If handled intelligently, it can be managed to use UV in built environment, computer can highlight that where people where present and then turning on the UV light in those unoccupied areas, such a project can get ready at the start of next year 2021 and only with a little effort and purpose.

If this claim of safety about use of Far UVC is just partially true and not fully true, using Far UVC along with the physical protection like using eye wear and sun creams can cause acceptable amount of cancer or eye damage. At different level of granularity, the term almost safe Far UVC can get combine with management of intelligent. Like just suppose a lift that is just applied wit Far UVC every time when people leave it or the walls of Far UVC that separating from the people and can turn on and off automatically when a person walk through it. The advanced systems can even operate the optimum power of the Far UVC ( Roko et al , 2020).

Background of FAR UVC 222nm to kill COVID virus

Broad-spectrum of UVC light having a wavelength range of 200 to 400 mm can be effectively used for killing bacteria and viruses. Prolonged use of 254nm is hazardous for human being but it can kill be used in germicidal applications. Prolonged and overdose use of 254 nm can cause skin damage and eye damage which can potentially lead to skin cancer, photokeratitis, and skin ageing. New studies suggest the use of UVC 222 nm with different interactions. The mechanism is based on destroying the molecular bonds that hold DNA together. In routine usage, conventional UV light is used for decontamination of surgical equipment. In the broad spectrum, some wavelengths lead to human health hazards, cataracts, and skin cancer. Only a limited range of wavelength can kill the virus without causing damage to human skin. Research conducted by Brenner et al. (2017) provides solid evidence that UVC light effectively kills MRSA (Methicillin-resistant staphylococcus aureus) without harming human skin. The limited range of Far UVC light is unable to penetrate through the outer dead cell layer of the human body therefore less harm is expected. In another research conducted by Welch et al. (2008) killing aerosolized influenza virus in the air was observed by far UVC light (Welch, et al., 2018). Use of low doses of 222 nm far UVC light by a control group researcher killed flu virus H1N1 effectively. Researchers from all these experimental works concluded that use of Far UVC can efficiently inactive the viruses at a low dose of 2 mJ/cm² of 222 nm light. It can inactivate more than 95% of the H1N1 influenza virus. The researchers concluded that continues use of low dose rate UVC light for indoor public locations is a promising, low cost, safe and compatible technique to reduce the spread of diseases due to virus. 

Scaleup considerations of FAR UVC 222nm to kill COVID virus

Even a perfectly operating system fails worldwide if it is not scaled up and implemented throughout the world krypton Chloride (Kr-Cl) Examiner Lamps can help in generating Far UVC but if want to implement for longer term than Aluminum Nitride (AIN) Far UVC LEDs are much better option. For more longer term use, collimated Far UVC can be generated through lasers.it can be regarded as the important source of uncertainty, but further research and experiences are still required in this area (Tornberg, 2020).

Power considerations of FAR UVC 222nm to kill COVID virus:

Total of about 20J/m^2 energy of Far UVC is needed in order to kill about 99% of virus particles in air. In order to sterilize the whole virus aerosol which, have ability to travel from one person to the other, let’s say 5W/m^2 energy will be needed by the system in 4 second of total time period. The lower power system has advantage in this regard, as we know that people can get the infection from the air that was contaminated 0 minutes earlier. Kr-Cl Excimer Lamps can not benefit in order to get higher power in those wavelengths because the efficiency from power electricity is ~10% for Far UVC. But to get the higher conversion efficiency AIN Far UVC LEDs are better option to use.

Generality of FAR UVC 222nm to kill COVID virus

The most important privileged corner of using Far UVC is that this is regarded as the general weapon against this virus. Far UVC has the ability to kill or deactivate the bacteria, viruses and other pathogens MRSA, C-DIFF, influenza is all abled to killed by this technique or whatever pathogen will come on the way.

Methods of FAR UVC 222nm to kill COVID virus

The aim of the work is to indicate that 200 nm UV light is significant to kill the virus within tissues. The interaction of UVC light with human skin leads to a higher rate of absorption by proteins in the outer layer of skin and cause no damage. For this purpose, excimer lamps are the best alternatives that produce a spectrum of light and traces of higher and low wavelength. By contrast, far UVC light is generated by filtered excimer lamps with the emitted wavelength of 207 to 222 nm. The biophysical reason is that far UVC light shows strong absorbance by penetration through the outer skin layer. The earlier studies show that germicidal efficacy regarding UVC light and how irradiating the surface by UVC can provide a pathway to reduce transmission of the virus in human beings.  Considering the previous research outcomes, here, we propose a new solution to COVID-19 by having irradiation of UVC light. For the first time, we investigate how much UVC 222nm is efficient for COVID-19. Our goal is to provide a potentially safe and low-cost alternative to inactivate coronavirus. Our approach is to develop UV based sterilization by using UVC light to kill the virus without harming the tissues and cells. The process involves far UVC radiation that emits single UVC wavelength through the use of Krypton Bromine (Kr – Br) excimer lamp and used to provide 222 nm high intensity light. The excimer lamps are inexpensive, practical and appropriately intense. The intensity of UVC can be reduced relevant to the condition. The very short half value is measured for the 207 UV light in the biological material as it penetrates through the virus that is typically smaller than 1 um in size. The light is not capable to pass through the human stratum corneum (dead cells of our skin layer as (5- 20 um), individual cells of cytoplasm, and ocular cornea (500 um).

Far-UVC lamps of FAR UVC 222nm to kill COVID virus

Here we experimented by using three excimer lamps that have Kr-Cl gas mixture in it that reflects or emits at 222nm. The exit window of every lamp was covered with a filter usually known as bandpass filter that is designed to allow the passage of dominant emission wavelength which was also explained before. The center wavelength of about 222nm is present in between each bandpass filter (Omega Optical, Brattleboro, VT) a full width at half maximum (FWHM) of 25nm and enables >20% transmission at 222nm. A sensitivity range between 190 nm and 400 nm of A UV spectrometer (SPM-002-BT64, Photon Control, BC, Canada) was used to examine the 222 nm emission spectrum. A deuterium lamp standard with a NIST-traceable spectral irradiance (Newport Model 63945, Irvine, CA) was also used in this experiment for various purposes. An SM-70 Ozone Monitor (Aeroquip, Avondale, Auckland, New Zealand) evaluated the ozone from the lamps to be <0.005 ppm which was not enough level to give the effect of antimicrobial aerosolized viruses.

Far-UVC dosimetry of FAR UVC 222nm to kill COVID virus:

818-UV/DB low-power UV enhanced silicon photodetector with an 843-R optical power meter (Newport, Irvine, CA) was used to for the measurement of optical power. Some additional dosimetry in order to evaluate the uniformity of UV exposure was occurred through the use sensitive film of Far UVC as it was also described in previous work. There is another feature described here is, Tis film which has the high spatial resolution with the capabilities to resolve features to almost 818-UV/DB on the other hand the low power UV can increase the silicon photodetector with an optical power meter of about 843-R (Newport, Irvine, CA). and it also constitute of about ideal cosine response. Measurements were evaluated in between the experiment which allow the placement of sensors in the chamber system. In order to explain the curve of response calibrations a range of far-UVC exposures, from 3.6 µJ/cm2 up to 281.6 mJ/cm2 is used. Films were scanned as 48 bit RGB TIFF images at 150 dpi using an Epson Perfection V700 Photo flatbed scanner (Epson, Japan) and analyzed with radio chromic film analysis software (Mendez et al , 2014) in order to evaluate the total exposure in base of changes in measurement in optical density. Those measurements taken by the combination of both UV sensitive film and silicon detector were collaborated in order to get the total dose received by the particle that travel the exposure window of the chamber system. Te UV sensitive film indicated a power of approximately 120 µW/cm2 in the center third of the window and 70 µW/cm2 for the outer thirds. the irradiation chamber window yielded average doses of 1.3 mJ/cm2 and 0.8 mJ/cm2. Combining all the data will allow to evaluate the total dose 2.0 mJ/cm2 to a particle traversing the window in 20 seconds.

Figure : Schematic diagram of the custom UV irradiation chamber

Discussion of FAR UVC 222nm to kill COVID virus
With the use of single wavelength far UVC light, here is the development of an approach to UV bases sterilization which also generated by the filter exclaims, which deactivate the microorganisms selectively but does not cause the damage biologically that can be happen to mammalian cells or tissues (Buonanno, et al , 2013). This approach depend on the biophysical rules in which the far UVC light travel and hence deactivate the pathogen or the concerned microorganism that could be a virus or bacteria which of the size of micrometer dimension or even smaller but because of their strong absorbance in biological material, far UVC does not have the ability to pass even through the dead cell layer of human skin, not even the outermost layer of the eye tat is tear layer. In this paper we applied an approach to test the efficiency of 222nm far UVC light in order to deactivate the virus influenza A virus (H1N1) that travel with the help of aerosols in the top of chamber of aerosol UV irradiation, which produce the droplets of aerosol of size of almost same as the human cough and breathing generate. These aerosolized viruses that travel through the irradiation chamber were than exposed to emitting of UVC lamps that was placed in from of the window of the chamber.
As shown in the below figure is the deactivation of the influenza A virus (H1N1) through 222nm afr UVC light that is explained through the model of typical exponential disinfection with an inactivation cross-section of D95=1.6 mJ/cm2 (95% CI: 1.4–1.9). for instance, we have the comparison of almost similar experimental technique but here the use of conventional 254nm germicide UVC lamp is mentioned. Author found a D95 value of 1.1 mJ/cm2 (95% CI: 1.0–1.2) for H1N1 virus. It is also reported in some previous studies for the inactivation of bacteria, 222nm far UVC and 254NM of the broad-spectrum germicidal light are also used to compare in their capabilities for aerosolized inactivation of microorganism. Some other researches that compare the deactivation of viruses across the spectrum of UVC has shown some uncertainties but if talking general both regions or the areas of the spectrum are very useful in inactivation process of the microorganism although eh accurate cause of deactivation of bacteria viruses or oter microorganisms may vary in this regard  (Beck, et al , 2017). 

However as mentioned before that, based on biophysical considerations and opposite to human safety problems that is linked with the germicidal 254 nm broad spectrum UVC light, it can be say that far UVC light is not cytotoxic or very much dangerous to the human cells and tissues in vivo or in vitro 13-15

 

Figure : Quantification of the antiviral efcacy of 222-nm far-UVC light

If we confirm this case in some other situations, it can be illustrated tat the use of low powered far UVC light even in public places can be represented as safe and more useful way for limiting the transmission and spread of those microbial diseases that are airborne like influenza or Tb. It is known that the potential of using UV light for disinfecting the airborne pathogens are not new in use and this technique of using UV light to kill or deactivate the microorganisms was discovered almost 80 years ago. Airborne ultra violet germicidal irradiation (UVGI) can be used through conventional germicidal UVC light by applying on upper area of the room, avoiding the direct exposure to the occupied areas of the room. Talking about the advantages, a clear benefit of using UVC base approach other than the vaccination approach is that the UVC light is effective against almost all kinds of the microbes in air. For example, for different influenza strains appearance, variation in UVC inactivation efficiency is also certain. Sometimes they are more likely to be enlarged than previous. Just like that, a multi drug variants or the bacteria also appeared, its UVC deactivation efficiency is also unlikely to be change in great extent. In short, we have explained that with very low doses of far UVC light can inactivate the airborne viruses very efficiently (Beck et al , 2016).

Conclusion of FAR UVC 222nm to kill COVID virus
There still exist many causes that Far-UVC will nit work out, but there are still chances that it will work out and if it will it will give us a huge benefit. This is the reason that author is believing that this area should get the more attention t this crucial time period. The trials like scaleup and safety should start as early as possible more importantly if started parallel. The experts in relevant field has to give ideas in this regard like from UV physics, epidemiology and the researchers who study about etiology of the skin cancer. According to US government, this epidemic could possible last for about 18 months in a report they gave, so such plans like far UVC implementation could take months to carry out may be a component that is critical of the response later this year.