New research announced by a senior American official showed that sunlight is rapidly destroying the emerging corona virus, although the study has not been published yet and is still awaiting an independent evaluation.
Homeland Security Adviser to science and technology William Brian told reporters at the White House that government scientists have concluded that UV rays have a significant effect on the virus, adding to hope that the Covid-19 outbreak will decrease during the summer.
"The most noticeable observation we have so far has to do with the seemingly strong ability of sunlight to kill the virus either on rooftops or in the air," he said.
"We have noticed a similar effect with heat and humidity as well, as high temperature and humidity or both are generally less favorable to the virus," he added.
But the research has not yet been published for review, making it difficult for experts to comment on the accuracy of the methodology it adopted.
UV rays have long been known to have a sterile effect because rays destroy the genetic makeup of viruses and their ability to reproduce.
But the main question will be about the intensity and wavelength of the UV rays that were used in the test and whether they closely resemble natural sunlight during the summer.
Brian presented a summary of the most prominent test results at the National Center for Bio Defense and Countermeasures in Maryland.
It showed that the half-life of the virus (that is, the time it takes to halve its quantity) was 18 hours when the temperature was between 21 and 24 ° C at a humidity of 20 percent and on a non-porous surface, such as door handles and stainless steel.
But the half-life of the virus decreased to six hours, with humidity rising to 80 percent and just two minutes when adding sunlight.
In the air, the half-life of the virus was an hour when the temperature reached between 21 and 24 degrees Celsius with a humidity of 20 percent.
And this period decreased to only a minute and a half in the presence of sunlight.
Brian concluded that the summer-like atmosphere "creates an environment that may reduce transmission."
Nevertheless, he stressed that the decrease in the outbreak of the virus does not mean that it is completely eradicated, and consequently, the measures for social separation will be removed.
"Our saying that we feel that the summer will completely eliminate the virus and that people can ignore the instructions will be irresponsible."
Previous tests also showed that the virus was more active in cold and dry weather than in hot and humid weather. This may reflect the low incidence of outbreaks in southern countries that are still in the autumn and warm season.
For example, Australia recorded fewer than seven thousand confirmed infections and 77 deaths, which is much lower than that in countries in the northern hemisphere.
It is believed that this is due to the fact that the respiratory droplets remain in the atmosphere for a longer period in cold weather, and that viruses disintegrate faster on hotter surfaces, given that the protective lipid coating they cover dries faster.
