Does UV light can kill the new coronavirus? Is it true that reports on social media say that the neo-coronavirus hates sunlight and that sunlight will kill it immediately? Simply put, the idea is wrong.
According to the BBC Future section, Dan Arnold, who works for UV Technologies, a company that supplies disinfection equipment to hospitals, pharmaceutical companies and food manufacturers across the U.K. As the global crisis of the new coronavirus heats up and whether UV can kill the new coronavirus becomes a hot topic of debate, Arnold has received some unusual inquiries recently, with many People ask: Can UV light kill the new coronavirus?
According to Arnold, there is only one type of UV light that can kill the new coronavirus, but the process is very dangerous and poses a serious threat to human health. Someone once asked why we don't install a UV lamp at the entrance of the supermarket. Customers would stand under the UV lamp for a few seconds and then go back in to sterilize and disinfect. I don't support such a proposal.
The idea of using UV light to disinfect skin, clothing or other objects has proven to be very popular among the "health advice" that is all over the Internet. One university in Thailand has even reportedly built a UV channel through which students can disinfect themselves.
So, is using UV light to kill the new coronavirus a good way to go? Is it true that reports on social media say that the neo-coronavirus hates sunlight and that sunlight will kill it immediately? Simply put, the idea is wrong.
Sunlight contains 3 types of ultraviolet rays, the first is long-wave ultraviolet (UVA), which is the vast majority of radiation from the sun's rays reaching the earth's surface and is able to penetrate deep into the skin, and is believed to be responsible for 80% of skin aging, causing wrinkles and age spots.
The second is medium-wave ultraviolet (UVB), which damages DNA in human skin, causing sunburn and eventually skin cancer. Long-wave UVB and medium-wave UVB are known to be harmful to the human body, and most good quality sunscreens can protect against both.
|The UV light destory DNA|
The third is short-wave ultraviolet (UVC), a relatively fuzzy part of the spectrum made up of shorter, more energetic wavelengths of light that are particularly good at destroying genetic material - both human and viral particles. Fortunately, most of us are unlikely to be exposed to short-wave UVC because it is filtered by the Earth's atmospheric ozone layer long before it reaches human skin.
That's just the way it is, and at least scientists have found that the use of short-wave UV can kill certain microorganisms, and since its discovery in 1878, man-made short-wave UV has become a major method of disinfection used in hospitals, airplanes, offices and factories in routine disinfection facilities. Crucially, short-wave UVC can be used to disinfect drinking water. Some parasites are resistant to chemical disinfectants such as chlorine, so the germicidal effect of using short-wave UVC is somewhat more significant.
Although there has not been any specific research to date on how short-wave UVC affects new coronaviruses, studies have shown that it can be used to treat other coronaviruses, such as the SARS virus. UV radiation distorts the structure of their genetic material and prevents virus particles from replicating.
As a result, some countries are now using high doses of short-wave UVC to sterilize new coronaviruses, some bus vehicles have blue short-wave UVC radiation inside, robots that emit short-wave UVC are responsible for sweeping floors in hospitals, and banks have been using short-wave UVC lamps to sterilize coins for years.
Meanwhile, suppliers of UV equipment are now seeing record sales from their latest vendors, with some increasing production to meet orders, and Arnold says UV technology is now used in all disinfection equipment.
Arnold said: "Short-wave UV is really nasty and people shouldn't be exposed to it. If it takes hours to get sunburned by medium-wave UV, it only takes a few seconds for short-wave UV to sunburn the body, and if your eyes are exposed to the sun, you know that feeling of staring into the sun? It only takes a few seconds to cause serious damage to your eyes."
In order to use short-wave UV safely, people usually need to receive professional training to properly operate the relevant equipment.
Do medium-wave and long-wave UVC have a germicidal effect? If it has a similar effect to short-wave UV, does that mean that people can sterilize substances containing viruses by placing them in sunlight?
The simple answer is that it is possible, but one cannot rely on that method. Sunlight is already a popular method of disinfecting water in developing countries, and the World Health Organization (WHO) even recommends using sunlight to disinfect water. This technique involves pouring water into a clear glass or plastic bottle and then exposing it to sunlight for six hours, a method that is considered effective. Because long-wave ultraviolet light from sunlight reacts with dissolved oxygen to produce unstable molecules, such as hydrogen peroxide, the active ingredient in many household disinfectants that can destroy pathogens.
Sunlight does not react with water and can still be used to disinfect surfaces, which may last longer than you think. The problem is that we don't know exactly how long it will last because scientists are still in the early stages of studying the new coronavirus. Studies of SARS (a close relative of the new coronavirus) have found that exposing the virus to long-wave UV for 15 minutes had little effect on its viral infectivity, yet researchers did not expose the SARS virus to medium-wave UV, which is known to cause more damage to genetic material.
Instead, other viruses may provide some important clues, such as influenza. When scientists analyzed hospitalization records in Brazil, they found a sudden increase in flu cases during the wildfire-burning season, presumably due to forest fires producing more smoke, which reduces the concentration of UV light in sunlight.
Another study showed that the longer influenza virus particles are exposed to sunlight, the higher the concentration and the less likely they are to remain infectious. The study looked at influenza virus particles suspended in the air, not attached to the surface of an object.
The above study shows that the use of sunlight to disinfect the surface of an object is not effective. First, it is not clear how long UV exposure is needed to inactivate the new coronavirus, and no one knows how large a dose is needed. Even if they did, the dose of UV light from sunlight varies with the time of day, the weather, the season, and the latitudinal location where people live, so it is not a reliable method for effective sterilization.
Ultimately, it is a truism that using any kind of UV light to disinfect human skin can cause damage and increase the risk of skin cancer. Once a virus enters the body, no amount of UV light will have any effect on whether you get an infection or not.