Dan Arnold works for UV Technology, a company that provides disinfection equipment to hospitals, pharmaceutical companies and food manufacturers across the UK.
As the global new coronavirus crisis gradually heats up, whether ultraviolet rays can kill new coronavirus has also become a hot topic. Recently, Arnold received some unusual consultations. Many people asked: Can ultraviolet rays kill new coronavirus?
Arnold claims that only one type of UV can kill the new coronavirus, but the process is very dangerous and poses a serious threat to human health.
Someone asked why we don't install a UV lamp at the supermarket entrance? Customers stand under the UV lamp for a few seconds and then enter again to play the role of sterilization. I do not support such a proposal.
In the overwhelming "health advice" of the Internet, the idea of using ultraviolet rays to disinfect skin, clothes or other objects has proven to be very popular.
A university in Thailand even built a UV channel through which students could disinfect.
So, is it a good way to kill new coronavirus with ultraviolet light? It is reported on social media that the new coronavirus hates sunlight, and sunlight will kill it immediately. Is this true? Simply put, this view is wrong.
Dangerous UV
Sunlight contains 3 kinds of ultraviolet rays. The first is long-wave ultraviolet rays (UVA), which is the most radiation of the sun's rays reaching the surface of the earth. It can penetrate deep into the skin and is considered to be the 80% cause of skin aging. .
The second type is medium-wave ultraviolet (UVB), which can damage DNA in human skin, cause sunburn, and eventually form skin cancer.
Long-wave and medium-wave UV are known to be harmful to the human body, and most good-quality sunscreens are resistant to both.
The third is short-wave ultraviolet (UVC), which is a relatively obscure part of the spectrum. It is composed of shorter, more energetic light wavelengths. It is particularly good at destroying genetic material, whether it is humans or virus particles.
Fortunately, most of us are unlikely to be exposed to short-wave UV, because short-wave UV is filtered by the Earth's atmospheric ozone layer before it reaches human skin.
The fact is that at least scientists have found that the use of short-wave UV can kill certain microorganisms. Since the discovery of short-wave UV in 1878, artificially produced short-wave UV has become a major method of disinfection and is used in daily life in hospitals, aircraft, offices and factories Disinfection facilities.
It is essential that short-wave UV can be used for the disinfection of drinking water. Some parasites are resistant to chemical disinfectants such as chlorine, so the use of short-wave UV sterilization is more significant.
Although there has not been any specific research on how short-wave ultraviolet rays affect new coronavirus, studies have shown that it can be used to treat other coronavirus, such as the SARS virus.
Ultraviolet radiation distorts the structure of their genetic material and prevents viral particles from replicating.
Therefore, some countries now use high-dose short-wave ultraviolet rays to sterilize the new coronavirus. Some public transportation vehicles are exposed to blue short-wave ultraviolet rays. Robots emitting short-wave ultraviolet rays are responsible for cleaning the ground in hospitals. Banks have been using short-wave ultraviolet lamps to disinfect coins for many years. .
At the same time, sellers of UV equipment suppliers are also setting new records. Some suppliers have increased their output in order to meet orders. Arnold said that UV technology has now been applied to all disinfection equipment.
An important warning!
Arnold said: "Short-wave UV is really annoying. People should not touch it. If they are exposed to medium-wave UV for several hours before they get sunburned, short-wave UV can only burn the human body in a few seconds.
If your eyes are exposed to the sun, do you know the feeling of staring at the sun? It can cause serious eye damage in just a few seconds. "
In order to use short-wave UV safely, people usually need to receive professional training to properly operate related equipment.
Can sunlight kill new coronavirus?
Do medium-wave and long-wave UV have germicidal effects? If it has a short-wave UV-like effect, does it mean that people can sterilize substances containing viruses in the sun?
The simple answer is: it is possible, but people cannot rely on this method. In developing countries, sunlight is already a popular method for disinfecting water. The World Health Organization (WHO) even recommends using sunlight to disinfect water.
The technique involves pouring water into a transparent glass or plastic bottle and then exposing it to sunlight for 6 hours. The method is considered effective.
Because the long-wave ultraviolet rays in the sun react with dissolved oxygen to produce unstable molecules, such as hydrogen peroxide, the active ingredients of many household disinfectants can destroy pathogens.
Sunlight does not react with water and can still be used to disinfect the surface of objects. Its duration may be longer than you think. The problem is that we don't know how long it will last because scientists working on the new coronavirus are still in their early stages.
Studies of SARS (a close relative of the new coronavirus) found that exposing the virus to long-wave UV for 15 minutes had no effect on its infectivity. However, researchers did not expose the SARS virus to mid-wave UV. As we all know, Medium-wave UV damages genetic material even more.
Instead, other viruses may provide some important clues, such as the flu.
When scientists analyzed the records of hospitalization in Brazil, they found that the number of flu cases suddenly increased during the wildfire season. It is speculated that the forest fire caused more smoke, which reduced the ultraviolet concentration in the sun.
Another study showed that the longer the influenza virus particles are exposed to the sun, the higher the concentration and the less likely they are to remain infectious. The study looked at influenza virus particles suspended in the air, rather than adhering to the surface of the object.
The above research shows that the use of sunlight to disinfect the surface of objects is not obvious. First of all, it is not clear how long it takes ultraviolet radiation to inactivate the new coronavirus, and no one knows what dose is needed.
Even if they do, the amount of UV rays in the sun varies with different times of day, weather, season, and location of people's latitudes, so this is not a reliable method of effective sterilization.
In the end, it is self-evident that using any kind of ultraviolet light to disinfect human skin will cause damage and increase the risk of skin cancer.
Once the virus enters the body, no amount of ultraviolet light will have any effect on whether you are infected.
Special Report: Fighting The New Coronavirus
