US scientists say coronavirus dies the fastest when it’s exposed to direct sunlight, though a study cited has not yet been made public and awaits external evaluation.
William Bryan, science and technology adviser to the Department of independent agency, told reporters at the White House on Thursday that government scientists found ultraviolet rays had a potent impact on the pathogen, offering hope its spread may ease over the summer.
“The virus dies quickest within the presence of direct sunlight,” Bryan said.
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“Our most striking observation up to now is that the powerful effect that solar light appears to own on killing the virus – both surfaces and within the air,” he added. “We’ve seen the same effect with both temperature and humidity additionally, where increasing the temperature and humidity or both is usually less favourable to the virus.”
It has long been known that actinic radiation includes a sterilising effect, because the radiation damages the virus’s genetic material and its ability to copy.
But coronavirus has also proven lethal in warm-weather places like Singapore, Malaysia, and Thailand, raising broader questions on the impact of environmental factors.
Bryan warned it might be “irresponsible” to mention the hotter summer months will eliminate the virus. But he said that point period would supply an “opportunity to urge ahead” of the pandemic.
The research cited by Bryan has not yet been released for review, making it difficult for independent experts to inquire into how robust its methodology was.
A key question are going to be what the intensity and wavelength of the UV light utilized in the experiment was, and whether this accurately mimics natural light conditions in summer.
Past studies haven’t found reliable evidence that warmer temperatures and therefore the higher humidity of spring and summer will help pack together the spread of the virus.
Bryan shared a slide summarising the foremost findings of an experiment dispensed at the National Biodefense Analysis and Countermeasures Center in Maryland.
On nonporous surfaces like stainless-steel, the new coronavirus takes 18 hours to lose half its strength during a dark, low-humidity environment, Bryan said.
In a high-humidity environment, that half-life dropped to 6 hours, and when the virus was exposed to high humidity and sunlight, the half-life dropped to 2 minutes, he said.
Researchers found the same effect with the coronavirus that was suspended within the air – simulating the coughing or sneezing that always spreads the disease. during a dark room, the virus maintained half its strength for an hour.
But when exposed to sunlight, it lost half its strength in 90 seconds, Bryan said.
Researchers also found that isopropanol was a more practical disinfectant than bleach, he added.