Far-UVC light safely kills airborne coronaviruses, study finds

Date:
June 24, 2020
Source:
Columbia University Irving Medical Center
Summary:
A type of ultraviolet light called far-UVC -- which is safe to
use around people -- kills more than 99.9 percent of airborne
coronaviruses, a new study has found.



FULL STORY ==========================================================================
More than 99.9% of seasonal coronaviruses present in airborne droplets
were killed when exposed to a particular wavelength of ultraviolet light
that is safe to use around humans, a new study at Columbia University
Irving Medical Center has found.


========================================================================== "Based on our results, continuous airborne disinfection with far-UVC
light at the current regulatory limit could greatly reduce the level
of airborne virus in indoor environments occupied by people," says the
study's lead author David Brenner, PhD, Higgins Professor of Radiation Biophysics at Columbia University Vagelos College of Physicians and
Surgeons and director of the Center for Radiological Research at Columbia University Irving Medical Center.

The research was published today in Scientific Reports.

Background Conventional germicidal UVC light (254 nm wavelength) can
be used to disinfect unoccupied spaces such as empty hospital rooms or
empty subway cars, but direct exposure to these conventional UV lamps is
not possible in occupied public spaces, as this could be a health hazard.

To continuously and safely disinfect occupied indoor areas, researchers
at Columbia University Irving Medical Center have been investigating
far-UVC light (222 nm wavelength). Far-UVC light cannot penetrate the
tear layer of the eye or the outer dead-cell layer of skin so it cannot
reach or damage living cells in the body.



==========================================================================
The researchers had previously shown that far-UVC light can safely kill airborne influenza viruses.

The new paper extends their research to seasonal coronaviruses, which
are structurally similar to the SARS-CoV-2 virus that causes COVID-19.

Study details In the study, the researchers used a misting device to
aerosolize two common coronaviruses. The aerosols containing coronavirus
were then flowed through the air in front of a far-UVC lamp. After
exposure to far-UVC light, the researchers tested to see how many of
the viruses were still alive.

The researchers found that more than 99.9% of the exposed virus had been
killed by a very low exposure to far-UVC light.



========================================================================== Based on their results, the researchers estimate that continuous
exposure to far-UVC light at the current regulatory limit would kill 90%
of airborne viruses in about 8 minutes, 95% in about 11 minutes, 99%
in about 16 minutes, and 99.9% in about 25 minutes.

Using far-UVC light in occupied indoor spaces The sensitivity of the coronaviruses to far-UVC light suggests that it may be feasible and safe
to use overhead far-UVC lamps in occupied indoor public places to markedly reduce the risk of person-to-person transmission of coronaviruses,
as well as other viruses such as influenza.

Ongoing studies in SARS-CoV-2 In a separate ongoing study, the
researchers are testing the efficacy of far- UVC light against airborne SARS-CoV-2. Preliminary data suggest that far-UVC light is just as
effective at killing SARS-CoV-2.

"Far-UVC light doesn't really discriminate between coronavirus types,
so we expected that it would kill SARS-CoV-2 in just the same way,"
Brenner says.

"Since SARS-CoV-2 is largely spread via droplets and aerosols that are
coughed and sneezed into the air it's important to have a tool that
can safely inactivate the virus while it's in the air, particularly
while people are around." Brenner continues, "Because it's safe to
use in occupied spaces like hospitals, buses, planes, trains, train
stations, schools, restaurants, offices, theaters, gyms, and anywhere
that people gather indoors, far-UVC light could be used in combination
with other measures, like wearing face masks and washing hands, to limit
the transmission of SARS-CoV-2 and other viruses." More information
The paper is titled, "Far-UVC light (222-nm) efficiently and safely
inactivates airborne coronaviruses." The other authors (all CUIMC)
are Manuela Buonnano, David Welch, and Igor Shuryak.

The study was funded by the Shostack Foundation and the NIH (grant R42- AI125006-03).

The authors declare that the Trustees of Columbia University in the City
of New York have a pending patent on the technology: "Apparatus, method
and system for selectively affecting and/or killing a virus." The authors declare no additional financial or other conflicts of interest.


========================================================================== Story Source: Materials provided by
Columbia_University_Irving_Medical_Center. Note: Content may be edited
for style and length.


========================================================================== Journal Reference:
1. Manuela Buonanno, David Welch, Igor Shuryak, David
J. Brenner. Far-UVC
light (222 nm) efficiently and safely inactivates airborne
human coronaviruses. Scientific Reports, 2020; 10 (1) DOI:
10.1038/s41598-020- 67211-2 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/06/200624172050.htm

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