The spread of the coronavirus or COVID-19 (SARS-CoV-2 virus) has reached alarming rates that now affect many countries as of March 2020. There is something that can naturally defeat it which is more than welcomed. COVID-19 can be killed by the sun. To explain, the sun has various components of light that we can see and also don’t see. The light we see from the sun is visible light, but it has another component called UV (ultraviolet) light. These are forms of electromagnetic radiation that originate from the sun. Visible light contains photons, which help illuminate what we see in sunlight. UV is another component of sunlight, but it can be harmful to humans when there is too much exposure from the sun (e.g. sunburns, skin cancer). This is the reason for putting on UV blocking sunscreen during a summer’s day at the beach.
Viruses are not actual living organisms, but cells that thrive off other organisms. They are like parasites that require a host in order to reproduce. The virus is made of is made up of a DNA or RNA genome inside a protein shell called a capsid. Once they do replicate, they do so in large numbers that harm the host because they infect the host and drain them of their vitality. The virus uses the hosts metabolic process to further replicate and soon the virus takes over the host’s cells.
UV can also be useful in killing both viruses and bacteria. This is the reason the flu and other virus related diseases drop in numbers during the warmer seasons (remember, flu has a season that coincides with colder weather in temperate countries). More sun and warmer weather does not provide a friendly environment for viruses. While UV is known to be dangerous to humans since it is a source of cancer, it is likewise to viruses and bacteria as well.
According to Ian Lipkin, Director of Columbia University’s Center for Infection and Immunity (From National Geographic):
“UV light breaks down nucleic acid. It almost sterilizes surfaces. If you’re outside, it’s generally cleaner than inside simply because of that UV light.”
Scientists have known since the early 1900’s that UV can be used for germicidal purposes. Not just for microbes but it was also effective against viruses. UV can disrupt the structure of viruses. When exposed to UV light, the molecular bonds that hold the DNA together in a virus cell is destroyed. This is why in medical facilities and hospitals, devices called UV lamps are used for sterilization of instruments and surfaces.
UV emits high frequency, short wavelength signals between 400 nm (nanometers or billionth of a meter) and 100 nm. The shorter its wavelength in the nanometer range, the more energy it transfers, the more harmful it can be. The UV range is below X-Rays and Gamma Rays but above Visible Light in the electromagnetic spectrum. It also has much shorter wavelength than radio waves, but a much higher frequency.
There are three types of UV light:
- UVA (400–315 nm): Also called Black Light.
- UVB (315–280 nm): The range that affects cells.
- UVC (280–100 nm): These do not reach the Earth.
UV radiation is produced by high temperature bodies and surfaces. The sun, which has those characteristics, is the main UV source for Earth. Most of the harmful UV coming from the sun is absorbed by the ozone layer in the Earth’s atmosphere. The ozone is made up of oxygen atoms which form a protective layer against UV light. It does not prevent all UV from entering. Most of the UV that does hit the Earth’s terrestrial surface is in the form of UVA.
Today, the known uses for UV light include the following:
- Sterilization of instruments, surfaces and HVAC systems
- Germicidal purposes
- Drying materials like inks and coatings
- Water treatment and purification
- Cosmetic and aesthetic uses e.g. suntans
- Counterfeit detection
- Forensics investigation
There are devices that can create artificial UV light, not requiring the sun. These are UV lamps, often used for sterilization purposes in hospitals. The device consists of an electric discharge lamp which is set to the frequency between UVA and UVC. This element is housed in special glass or quartz for transmitting UV radiation between 300 to 400 nm. More specialized UV lamps used for sterilization can have even shorter wavelengths. The UV light is created by passing an electric current through vaporized mercury gas.
UV lamps actually have a commercial application which is not obvious to many people. It is used by suntan studios in their tanning beds for customers to get a deep tan look. UV lights are also used by forensic investigators at crime scenes. It can reveal among other things seminal fluid, saliva and urine stains. This is because certain elements fluoresce or become fluorescent i.e. “glow in the dark” when exposed to UV light. The electrons, when absorbing UV light, jump to a higher energy level. The absorbed energy is then emitted as visible light. It can also detect blood, though not through fluorescence. A UV light source causes the blood stains to absorb all light and appear black against a lighter background of cloth which reflects the UV light back.
When properly applied, it is safe for human use. The right amount of UV can darken the skin, but at the same time if there is too much exposure it can also destroy and affect skin cells. When applied in the right amount, that same effect can be applied to surfaces to kill viruses and microbes in areas that have extreme sanitary requirements.
Despite its known applications, there are no UV lamps that are being applied in public places for sterilization purposes. It can be rather expensive, and not practical at all. That is because the sun can do a better job in most cases, and it does not cost any money.
There are retail versions of UV lamps, but is it effective as a solution to prevent COVID-19?
Yes, it is being used widely in hospitals to disinfect rooms where patients have been treated as well as in certain quarantine facilities. However, it is not exactly necessary to place them everywhere. There is also no need for everyone to suddenly buy UV lamps. Hand sanitizers and germicides can be just as effective. They are definitely needed by hospitals or anywhere that treats patients of COVID-19. It helps to sterilize instruments and room surfaces along with further cleaning to make sure that everything follows strict requirements for health care.
It would be overkill, in terms of costs, to have germicidal lamps and UV sterilization used home purposes. If anyone is willing to buy it, that is fine but the costs of keeping them on 24 hours or so may not be practical. These lighting systems are more suitable where it is really needed.
UV lights will continue to aid in preventing the spread of viruses and microbes that cause diseases. However, everyone should remember the basics like washing hands, covering your mouth when coughing or nose when sneezing, avoid public places, get treatment if you are sick, using sanitizers and not rubbing your eyes unless your hands are clean. Unlike the common cold which has remedies and the flu which has a vaccine, there are plenty of things we still have to learn about COVID-19. According to most studies, since it is a virus, it should succumb to UV from long exposure to sunlight. Until we learn whether it is seasonal or will come as quickly as it arrived, there are preventive measures and the use of UV light will be helpful.