Sunlight destroys coronavirus quickly, say US scientists

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Winston

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Note that half-life figures are quoted. The mainstream media is implying that it's a total kill-off.

APRIL 24, 2020
Sunlight destroys coronavirus quickly, say US scientists


The new coronavirus is quickly destroyed by sunlight, according to new research announced by a senior US official on Thursday, though the study has not yet been made public and awaits external evaluation.

William Bryan, science and technology advisor to the Department of Homeland Security secretary, told reporters at the White House that government scientists had found ultraviolet rays had a potent impact on the pathogen, offering hope that its spread may ease over the summer.

"Our most striking observation to date is the powerful effect that solar light appears to have on killing the virus, both surfaces and in the air," he said.

Bryan shared a slide summarizing major findings of the experiment that was carried out at the National Biodefense Analysis and Countermeasures Center in Maryland.

It showed that the virus's half-life—the time taken for it to reduce to half its amount—was 18 hours when the temperature was 70 to 75 degrees Fahrenheit (21 to 24 degrees Celsius) with 20 percent humidity on a non-porous surface.

This includes things like door handles and stainless steel.

But the half-life dropped to six hours when humidity rose to 80 percent—and to just two minutes when sunlight was added to the equation.

When the virus was aerosolized—meaning suspended in the air—the half-life was one hour when the temperature was 70 to 75 degrees with 20 percent humidity.

In the presence of sunlight, this dropped to just one and a half minutes.

Bryan concluded that summer-like conditions "will create an environment (where) transmission can be decreased."

He added, though, that reduced spread did not mean the pathogen would be eliminated entirely and social distancing guidelines cannot be fully lifted.

"It would be irresponsible for us to say that we feel that the summer is just going to totally kill the virus and then if it's a free-for-all and that people ignore those guides," he said.

Previous work has also agreed that the virus fares better in cold and dry weather than it does in hot and humid conditions, and the lower rate of spread in southern hemisphere countries where it is early fall and still warm bear this out.

Australia, for example, has had just under 7,000 confirmed cases and 77 deaths—well below many northern hemisphere nations.

The reasons are thought to include that respiratory droplets remain airborne for longer in colder weather, and that viruses degrade more quickly on hotter surfaces, because a protective layer of fat that envelops them dries out faster.

US health authorities believe that even if COVID-19 cases slow over summer, the rate of infection is likely to increase again in fall and winter, in line with other seasonal viruses like the flu.
 

Funkworks

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Ok but UV sterilization has been known for longer than most of us have been alive (https://en.wikipedia.org/wiki/Ultraviolet_germicidal_irradiation).

So I suppose it's reassuring that this particular pathogen is similar in its sensitivity to UV's, but yeah, UV's screw every other organic (carbon-based bio-) molecule, so resistance would have been a lot more surprising.
 
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