Scientists want to know more about fighting COVID-19 spreads using UV lights. Nation/world

Located in the Seattle dining area dining room near the ceiling, Musa Firat recently set up a “killing zone.” This is where a band of invisible electromagnetic energy enters the air and is ready to disarm coronaviruses and other drifting dangerous pathogens, pointing up in small airborne particles.

Philat’s new system utilizes 100-year-old technology to prevent infections. Ultraviolet (also called energy UV, or GUV) energy waves are provided in adequate amounts to clear viruses, bacteria, and other microbes.

Studies have shown that bactericidal UV effectively inactivates measles, tuberculosis, an airborne microorganism that propagates SARS-CoV-1, and is a closely related species of the novel coronavirus. There is now growing concern that the coronavirus that causes COVID-19 can be easily transmitted via microscopic airborne particles called aerosols, and some researchers and physicians have identified We look forward to re-adopting technology that helps disinfect.

“I thought it was a great idea. I want customers to be safe,” said Firat, who runs a casual restaurant, Marlaina’s Mediterranean Kitchen, 20 minutes south of downtown Seattle.

Because the United States is working on ways to stop the spread of highly infectious viruses, UV can be used to decontaminate surfaces of public transport and hospitals with infectious splashes, and disinfect N95 masks for reuse. Is used for. But so far, providing continuous air disinfection using this technology is outside most mainstream policy-setting conversations about coronaviruses.

Experts attribute this to a combination of factors: misunderstandings about UV safety, lack of public awareness and technical know-how, concerns about the cost of introducing the technology, and the role of aerosols in the spread of coronaviruses. General resistance to.

Aerosols are tiny droplets that are emitted when someone exhales, talks, or coughs. Unlike large and heavy respiratory droplets that quickly drop to the ground, aerosols can remain in the air for long periods of time and travel indoors. When someone is infected by a virus in this way, the process is called “airborne transmission.”

It is already recognized that aerosols can spread coronaviruses during medical procedures. Therefore, healthcare professionals are advised to wear a mask (such as the N95 mask) that removes these small particles. Still, there is considerable debate about the potential spread of the virus via aerosols to other environments.

The problem of airborne transmission has gained new urgency, with significant consequences, when a group of 239 scientists recently called on the World Health Organization to take the threat of infectious aerosols more seriously. “

WHO officials admitted that more research was needed, but claimed that most infections did not occur this way.

As science continues to evolve, UV may emerge as an attractive defense against airborne infections, has a proven track record against pathogens, and reduces the risk of infectious aerosols accumulating in indoor environments such as schools and businesses. It can be deployed.

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There are two clues to the new UV disinfection system at the Marulina restaurant. There’s a subtle glow of blue light above the black grate on the drop ceiling, and a hand-chalked sign on the door to proudly inform the diner. “Coronavirus disinfection here!”

The system was installed when the restaurant was closed during the Washington blockade. This setup is known as “superstrate sterilizing UV” because the UV fixtures are mounted high and at an angle away from the person below.

A ceiling fan circulates the air, ultimately pushing suspended virus particles that have accumulated in the dining space from the grated drop ceiling into a horizontally positioned UV light that pushes them into the blasting area with radiant energy.

The inspiration and technical assistance to the owners of Marlaina came from customer Bruce Davidson, a pulmonary physician who was Philadelphia’s “tuberculous empire” in the mid-’90s. At that time, the United States was working on the development of new tuberculosis, including strains resistant to existing drugs.

“We had no drugs or vaccines, so preventing infections was the most important part,” recalled Davidson, who now lives outside Seattle. At that time, UV light turned out to be an important strategy, and Davidson believes it will help again. “Currently, it should be placed in most indoor public spaces.”

To demonstrate the concept, Davidson lit a cigar inside Marlaina, showing the smoke dancing upwards and gathering in a ceiling space with a UV fixture.

“If someone is unaware of the coronavirus and is talking without a mask and without eating, then most of those particles will be attracted to the killing zone where they will circulate and bounce off,” Davidson said. Said. “Statistically, the risk to others will be very low.”

Studies show that nearly 90% of airborne particles from the previous coronavirus (SARS-CoV-1) are inactivated in about 16 seconds when exposed to UV as intense as a restaurant ceiling. Other viruses, such as adenovirus, are more resistant and require higher UV doses.

“It’s not perfect, but it probably offers the best solution for direct air disinfection,” said David Sleeney, a faculty member at Johns Hopkins University and a long-time researcher on germicidal UV.

According to some studies, when used with proper ventilation, supraventricular GUVs are about 80% effective in expanding airborne tuberculosis. This is equivalent to changing the room air up to 24 times an hour.

However, widespread adoption of UV systems can be a daunting battle, Sleeney said. In the United States, scientists have turned their attention to powerful vaccines and drugs to combat infectious diseases, and in recent decades their interest in using UV for air disinfection has diminished.

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UV can be a powerful weapon against airborne viruses, but so far it can only be used to prevent infection. People can get sick from the large, heavy droplets that are expelled through coughing and sneezing. They inhale those droplets directly or touch a surface contaminated with them, and then their eyes, nose or mouth.

UV also does not prevent someone from being exposed to infectious aerosols that have just emerged from an infected person. And what researcher Richard Corsi called “the near field” remains fairly close to the body.

“In that scenario, we are inhaling a very concentrated cloud of small particles that we cannot see,” said Corsi, Dean of the Macy College of Engineering & Computer Science at Portland State University. “You are getting a fairly significant dose in your respiratory system.”

According to Corsi, face masks and social distances are still needed to block larger respiratory droplets and remove some of the aerosols in the short distance, even if there is UV light on the top of the building. But Corsi said there was enough evidence to show that coronavirus aerosols could hang in the air and spread throughout the room (“far field”), and it’s time to seriously consider its airborne spread. Stated.

One example of a long-distance transmission is documented in a study of Chinese restaurants. Some diners, sitting at a nearby table, never contacted the “index patient,” but were infected with the COVID-19 virus. Another piece of evidence came from the March 10 chorus practice at Mount Vernon, Washington. Members of the group then used hand sanitizers and took precautions to avoid hugs and handshakes, but most singers became infected with the coronavirus.

In a letter to the WHO, scientists pointed out that the MERS-causing coronavirus could spread through aerosols, “there are all reasons to expect the (COVID virus) to function similarly.” States.

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Germicidal UV utilizes a portion of the electromagnetic spectrum that includes short waves of radiant energy called UV-C. This wavelength is farther from the visible spectrum than other forms of UV light.

Think of it as giving the virus a deadly sunburn.

“Since it is not used in this country and Western Europe, there is little practical experience to show how effective it (in a pandemic) is,” said Johns Hopkins, Chair of the Lighting Engineering Institute. .. It recently released new guidance on GUVs.

Sliney recommends installing UVs in large ceiling stores, restaurants and grocery stores. “Similar to ceiling fans, it requires vertical air exchange, so it doesn’t just kill the air in the headspace of the room.”

Dr. Edward Nadell, a GUV professor at Harvard Medical School, said: “There is no doubt about the effectiveness of germicidal UV in killing small microbes and pathogens. If so, I think the big controversy is a misunderstanding about safety.”

Although low doses of germicidal UV can cause eye and skin damage, he says that proper risk can be avoided by following proper guidelines. Although international guidelines warn against direct human exposure to UV-C, the risk of skin cancer is considered negligible.

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Interested in UV climbing and worried about exaggerated claims about the effects of spoilers and viruses on the market, says Jim Murray, a professor of public health and disinfection at the University of New Hampshire.

Consumers should be wary of marketing claims about “UV wands” or special “portals” that people pass through that can ruffle quickly on the surface, he said, which probably inactivate the virus. It is not tuned correctly to do so and can be dangerous.

Marie believes that there is not a viable market for supper-room GUVs outside of healthcare facilities, but he does support technology installation in the most risky environments, such as meat-packing plants and nursing homes. I am.

“I intuitively have a horrific deadly record with the coronavirus, so he said we should do whatever we could at those places.

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The installation was relatively easy at the Marlaina restaurant.

The owner, Firat, bought four UV fixtures ($165 each), hired an electrician to install the fans, and bought a black grid plastic panel to enclose the ceiling space where the UV was installed.

Firat still encourages customers to wear masks and maintain social distance. But he said UV is part of the atmosphere.

“It’s more modern and clean, the reaction is great, absolutely great,” he said.

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(Kaiser Health News (KHN) is a national health policy news service. This is an editorial independent program of the Henry J. Kaiser Family Foundation, which is not affiliated with Kaiser Permanente.)

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(C) 2020 Kaiser Health News

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