There’s only one type of UV that can reliably inactivate Covid-19 –
and it’s extremely dangerous.
Among the abundant “health” advice currently swarming around the internet, the idea that you can disinfect your skin, clothing or other objects with UV light has proved extremely popular. In Thailand, a college has reportedly even built a UV tunnel that students can walk through to disinfect themselves.
So lets learn more...
There are 3 types of UV:
UVA, UVB, UVC... and all may be damaging to the skin
Both UVA and UVB will damage the skin — but nothing is as damaging as UVC!
ultraviolet radiation can damage human DNA, causing health problems such as skin cancer or cataracts in the eyes.
We can look to previous coronaviruses, such as SARS and MERS, for insight. Studies on both SARS and MERS show that UV light could inactivate the viruses, so it’s not unreasonable to expect that it will have a similar effect on COVID-19.
THE VIRUS
Influenza virus spreads from person to person mainly through fine liquid droplets, or aerosols, that become airborne when people with flu cough, sneeze, or talk. The new study was designed to test if far-UVC light could efficiently kill aerosolized influenza virus in the air, in a setting similar to a public space.
In the study, aerosolized H1N1 virus—a common strain of flu virus—was released into a test chamber and exposed to very low doses of 222 nm far-UVC light. A control group of aerosolized virus was not exposed to the UVC light. The far-UVC light efficiently inactivated the flu viruses, with about the same efficiency as conventional germicidal UV light.
“If our results are confirmed in other settings, it follows that the use of overhead low-level far-UVC light in public locations would be a safe and efficient method for limiting the transmission and spread of airborne-mediated microbial diseases, such as influenza and tuberculosis,” Brenner said.
At a price of less than $1,000 per lamp—a cost that would surely decrease if the lamps were mass produced—far-UVC lights are relatively inexpensive. “And unlike flu vaccines, far-UVC is likely to be effective against all airborne microbes, even newly emerging strains,” Brenner added.
Warning: ultraviolet radiation (Particularly UVC) can damage human DNA, causing health problems such as skin cancer or cataracts in the eyes.
UVC is a relatively obscure part of the spectrum consists of a shorter, more energetic wavelength of light. UVC is particularly good at destroying genetic material – whether in humans or viral particles.
UNTRUE MYTH: sunshine will immediately kill it, as some reports on social media have claimed?
In short: no. Here’s why.
Dangerous rays
Sunlight contains three types of UV. First there is UVA, which makes up the vast majority of the ultraviolet radiation reaching the Earth’s surface. It’s capable of penetrating deep into the skin and is thought to be responsible for up to 80% of skin ageing, from wrinkles to age spots.
Next there’s UVB, which can damage the DNA in our skin, leading to sunburn and eventually skin cancer (recently scientists have discovered that UVA can also do this). Both are reasonably well known, and can be blocked out by most good sun creams.
Both UVA and UVB damage the skin — but nothing is as damaging as UVC (Credit: Getty Images)
There is also a third type: UVC. This relatively obscure part of the spectrum consists of a shorter, more energetic wavelength of light. It is particularly good at destroying genetic material – whether in humans or viral particles. Luckily, most of us are unlikely to have ever encountered any. That’s because it’s filtered out by ozone in the atmosphere long before it reaches our fragile skin.
Or that was the case, at least, until scientists discovered that they could harness UVC to kill microorganisms. Since the finding in 1878, artificially produced UVC has become a staple method of sterilisation – one used in hospitals, airplanes, offices, and factories every day. Crucially, it’s also fundamental to the process of sanitising drinking water; some parasites are resistant to chemical disinfectants such as chlorine, so it provides a failsafe.
Though there hasn’t been any research looking at how UVC affects Covid-19 specifically, studies have shown that it can be used against other coronaviruses, such as Sars. The radiation warps the structure of their genetic material and prevents the viral particles from making more copies of themselves.
As a result, a concentrated form of UVC is now on the front line in the fight against Covid-19. In China, whole buses are being lit up by the ghostly blue light each night, while squat, UVC-emitting robots have been cleaning floors in hospitals. Banks have even been using the light to disinfect their money.
This study was published online today in Scientific Reports.
Scientists have known for decades that broad-spectrum germicidal UV light, which has wavelengths between 200 and 400 nanometers (nm), is highly effective at killing bacteria and viruses by destroying the molecular bonds that hold their DNA together. This conventional UV light is routinely used to decontaminate surgical equipment.
“Unfortunately, conventional germicidal UV light is also a human health hazard and can lead to skin cancer and cataracts, which prevents its use in public spaces,” said study leader David J. Brenner, PhD, the Higgins Professor of Radiation Biophysics at the Vagelos College of Physicians and Surgeons and director of the Center for Radiological Research at Columbia.
About the study
The study is titled “Far-UVC light: A new tool to control the spread of airborne-mediated microbial diseases.” The other contributors are David Welch, Manuela Buonanno, Veljko Grilj, Igor Shuryak, Connor Crickmore, Alan Bigelow, Gerhard Randers-Pehrson, and Gary Johnson (all at CUIMC).
The study was supported by grants from the Shostack Foundation and the National Institutes of Health (1R41AI125006-01).
The authors declare that they have no financial or other conflicts of interest.
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FDA GUIDELINES AND NASA OZONE WATCH (https://ozonewatch.gsfc.nasa.gov/facts/SH.html)
The Occupational Safety and Health Administration (OSHA) requires that workers not be exposed to an average concentration of more than 0.10 ppm for 8 hours.
Ozone protects life on Earth from the Sun's ultraviolet (UV) radiation.
At ground level, high concentrations of ozone are toxic to people and plants. ... exposure to ozone levels of greater than 70 parts per billion for 8 hours or longer is unhealthy.
More on masks...
THE MASK : MedHealth.Tech Notes on the Mask called "N95"
The 'N95' designation means that when subjected to careful testing, the respirator blocks at least 95 percent of very small (0.3 micron) test particles. If properly fitted, the filtration capabilities of N95 respirators exceed those of face masks. However, even a properly fitted N95 respirator does not completely eliminate the risk of illness or death.
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