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Artificial summer: far ultraviolet against coronavirus

Authors: Alexey Turchin, Roko Mizhich

Roko Mizhich - author of the idea Roko Vasilisk, Alexey Turchin - futurologist, author of the book “The structure of the global catastrophe” and “Futurology. 21st century: immortality or global catastrophe ”(with me). Source

Status: there are many different uncertainties, but the idea has certain evidence and high potential returns. But here we offer to discuss it.

Tl; dr: We need to urgently study the placement of special Far-UVC lamps safe for humans throughout our artificial environment in order to “kill” viruses while they are in the air, thereby significantly reducing the spread of covid-19.

Based on: www.nature.com/articles/s41598-018-21058-w

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One of the most promising and forgotten ideas to combat the spread of Covid-19 is the use of widespread ultraviolet radiation in our artificial environment (trains, offices, hospitals, etc.). Ultraviolet light is already being used as a disinfectant worldwide; it is the acronym UVGI - "Ultraviolet Bactericidal Irradiation." Energetic photons of ultraviolet light destroy chemical bonds in DNA and kill / inactivate both viruses and bacteria.

Ultraviolet light on the earth exists in the range from 200 to 400 nm. Light above 400 nm - blue visible light. Light below 200 nm is called "vacuum ultraviolet radiation" because it is strongly absorbed by oxygen in ordinary air and therefore cannot exist, except in a vacuum or some other non-air medium. In the range of 200-400 nm we have types of UV: UVA, UVB and UVC, and the short-wavelength edge of the UVC band we have "Far-UVC"; it has a wavelength of from about 200 nm to 220 nm.

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Security Considerations


People are also vulnerable to ultraviolet radiation. It causes skin cancer and serious eye damage.

However, recent studies show that the Far-UVC band is actually safe for human skin because it cannot penetrate a thin layer of dead skin cells on the surface of our skin.

This means that it would be possible to provide long-term protection against coronaviruses and other pathogenic microorganisms by constantly illuminating our artificial environment with far-UV light. If Far-UVC light is truly safe for humans, Far-UVC can be turned on continuously and can destroy or deactivate viral particles before they can spread from person to person.

Why has this not been reviewed by the relevant authorities? Far-UVC appears in the WHO literature review , but is currently not being applied, as there is little evidence to support safety and effectiveness.

There is some uncertainty as to whether ozone generation will be in this band (200–220 nm). Ozone is harmful to health. However, the 200-220 nm band does not appear to be a strong ozone producer. In addition, UV degradation of surfaces can occur from chronic exposure to UV radiation.

Balancing the harm of action and inaction


Even if Far-UVC is somewhat harmful, it can still be used. The small damage from Far-UVC light can be much less serious than the large damage from covid-19, or from the economic damage caused by universal self-isolation, which, according to one author, is approximately $ 10 million per minute, plus a lot of personal difficulties. which will be triggered by the upcoming recession.

In addition, it is easier to protect a person from ultraviolet radiation than a virus. Sunscreens, clothing, and UV protection goggles can be less dangerous than semi-permanent isolation of the population or an exponentially growing flash of covid-19, which leads to millions or tens of millions of de facto victims.
Ultraviolet radiation in an artificial environment can even be controlled intellectually - computer vision can determine the location of people and include ultraviolet radiation only in places where there are no people. Such a project, at best, will be ready by the beginning of 2021.

If Far-UVC's safety statements are not completely true, a combination of Far-UVC with physical skin and eye protection, such as glasses, may still present acceptable risks of cancer and eye damage. In the longer term, this “almost safe” Far-UVC can be combined with intelligent control at various levels of detail; imagine an elevator that Far-UVC shines brightly every time people leave it, or “walls” of Far-UVC pillars of light separating people who automatically shut off for a moment when a person passes through them. Ultimately, the system can even adjust the power of Far-UVC using AI.

Epidemiological considerations


Even the ideal Far-UVC solution, which is harmless to humans, 100% deadly for Covid-19 particles and easily scaled, may not be enough to reduce R0 to exactly 0. But the key question is whether it can lower R0 below 1, and also whether it allows you to continue most of the economic activity.

So far, we do not know the real effectiveness and safety of the constant use of Far-UVC. A simple preliminary experiment that could be done: put the virus samples in boxes with mice - possibly in aerosol form - and treat some cells with Far-UVC, leaving the other cells alone, and see if the level of infection in the treated cells.

Scaling issues


Even a perfect system is useless if it cannot be scaled and implemented around the world. Krypton chloride excimers can be sources of Far-UVC, but modern Far-UVC LEDs with aluminum nitride (AlN) are the best solution in the long run. In the longer term, lasers can produce collimated Far-UV. Further research and expert feedback on the most effective source of Far-UVC is needed.

Energy considerations


The amount of Far-UVC energy needed to kill 99% of viral particles is estimated at about 20 J / m2. With a power of, say, 5 W / m2, the system will take 4 seconds to basically sterilize the viral aerosol, which can be transmitted from person to person. However, a low-energy system will still have some advantages, as we know that people can get infected with air that was infected 30 minutes earlier. Higher power at these wavelengths can be difficult to achieve with excimer Kr-Cl lamps, since their efficiency is ~ 10%. AlN Far-UVC LEDs are likely to have much higher conversion efficiency .

Versatility


One of Far-UVC's greatest benefits is that it will be a very common weapon against pathogens. Far-UVC kills / deactivates bacteria, viruses and other pathogens. MRSA, C-DIFF, flu, etc. is LL killed by UVC, as is the case in the next problematic pathogen.

Summary


There are many different reasons why the ubiquitous spread of Far-UVC lighting may not work, but if it does, it can have huge advantages. For this reason, the authors believe that at this critical moment he should pay more attention. Trials of scalability, safety and efficiency should be carried out as quickly as possible, preferably in parallel. More importantly, the idea requires more attention from experts in relevant fields - ultraviolet physics, epidemiology and people who study the etiology of skin cancer. At the time of writing, there are reports thatwhich is estimated by the U.S. government that the epidemic could last up to 18 months), so a plan like Far-UVC, which could take months to implement, can still be an important component of the response at the end of this year.

Application. Other ways to use ultraviolet radiation to control coronavirus


One explanation for the seasonality of influenza and other infections is that solar UV kills viruses. However, people spend a lot of time indoors even in summer, especially during self-isolation. Most of our infections occur indoors: at home, in transport and in the workplace. Ultraviolet radiation from the Sun could be part of the explanation for lower cases of coronavirus in southern countries.

If we replace bulbs everywhere with light sources that, in addition to usually light, also emit ultraviolet light with a certain wavelength, we will kill most of the viruses in the air and clean the fomites (virus particles on surfaces). Thus, we will create an “artificial summer" everywhere and lower the coronavirus R0 below 1.

The main obstacles are the duration of exposure and possible harm to people. Recently, in Moscow, 20 children had eye burns after a school teacher forgot to turn off the UV cleaner in the classroom.

Besides the idea of ​​using the relatively safe range of Far-UVC, there are several other ideas for preventing damage to the eyes and skin of a person with ultraviolet light :

1) Intelligently controlled ultraviolet light. Ultraviolet light turns on at the maximum level when there are no people in the room. We already have motion detectors for lighting, but here they will work the other way around. Motion detection light sources can also direct light in directions where there is no movement, so there are no people. On videoYou can see UV light sources with motion detectors on sale.
Or, for example, the light intensity can be temporarily increased after the sound of sneezing. But this will make the whole system more complex, and its large-scale implementation will take more time.

2) Not "too strong" sources of UV radiation , which produce the intensity of the level of UV radiation of the Sun at ground level and act mainly on fomites. As you know, people can live at least 1 hour of sunlight without severe damage (on the beaches). We could use this estimate as a guideline for calibrating UV sources.

3) Strong ultraviolet light + gloves. Everyone will wear gloves, masks and glasses on the street. In this case, no area of ​​the skin will be exposed to ultraviolet light (and viruses). Wearing personal protective equipment will be effective in any case. Women in the East wear full-dress clothes, and they are fine.

4) A wearable UV headlamp will direct ultraviolet light in the opposite direction to human eyes, but will illuminate everything that it inhales or touches, as well as the hands. The light will be the strongest near the human face (but not affect the face), and will attack the droplets and dust that a person is about to breathe. However, this light will be scattered at a distance of 1-2 meters to a safer level. UV headlamps and flashlights already exist and are soldbut may not be strong enough for disinfection. This will be especially effective if Far UVC wearable light sources are used, but other UV ranges can be tried if the skin is protected. In addition, narrow UV sources can be used to sterilize disposable masks and respirators, which will allow them to be reused.

5) UV flashlight that emits ultraviolet radiation in a wide beam. It can be used by cleaners as an additional step when cleaning surfaces.

Pros of UV Light


  1. Easier, easier, cheaper and faster to build than other solutions.
  2. Less harm to people, as ultraviolet light can be directed and not always turned on.
  3. Test implementation (Minimal viable product, in terms of startup) for more advanced implementations.
  4. Mobile can be used in several places.

Minuses:

  1. Less effective than always-on UV ceiling lamps.
  2. Requires additional time / effort in addition to normal cleaning procedures.

Artificial light now exists almost everywhere modern people live: at home, in any store, in cars and even on the streets. All we need is to replace part of the electric lamps. A large number of lamps can be produced within 0.5-1 years, and a smaller one for critical places, such as elevators, even in a shorter time.

However, there is the problem of actually testing the technology until it is approved by the FDA as safe and effective. It is technically difficult to produce deep ultraviolet (220 nm) LEDs.

A good start will be the installation of ultraviolet lamps in places of short-term use by people, where nevertheless there is a high risk of infection: elevators, shops, toilets.
It is much more convenient to wear light protection than virus protection, and after several months of blocking the idea of ​​returning to an almost normal life, but with sunscreen and / or gloves, will be quite pleasant.

References:

Welch, D., Buonanno, M., Grilj, V. et al. Far-UVC light: A new tool to control the spread of airborne-mediated microbial diseases . Sci Rep 8, 2752 (2018). doi.org/10.1038/s41598-018-21058-w
Narita K, Asano K, Morimoto Y, Igarashi T, Nakane A (2018) Chronic irradiation with 222-nm UVC light induces neither DNA damage nor epidermal lesions in mouse skin, even at high doses . PLOS ONE 13 (7): e0201259. doi.org 10.1371 / journal.pone.0201259

Willie Taylor, Emily Camilleri, D. Levi Craft, George Korza, Maria Rocha Granados, Jaliyah Peterson, Renata Szczpaniak, Sandra K. Weller, Ralf Moeller, Thierry Douki, Wendy WK Mok, Peter Setlow DNA damage Kills Bacterial Spores and Cells Exposed to 222 nm UV Radiation
Applied and Environmental Microbiology Feb 2020, AEM.03039-19; DOI: 10.1128 / AEM.03039-19
Colorado company uses UV lighting technology to kill 99.9 percent of bacteria and viruses . Fox Denver 7 Macrh 2020

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