CoVID-19 has paralyzed the world by infecting more than 4 million people and causing upwards of 300,000 deaths [1]. It has also devasted the global economy as the governments around the world had to enforce lockdowns to limit the spread of the virus. However, after almost 3 months of lockdown, conversations have started shifting towards reopening the countries and people returning back to work.
Proper sanitation in public spaces will play a vital role to ensure the safety of the people. Sterilization of high traffic areas like public transport will have a pivotal role in the safety of the population. In China, robots and drones are being used to spray disinfectant in public spaces. Airlines have been using fogging as a sanitation technique to keep their airplanes clean. But there is another option that can help in this and it is proven.
UV Light is an effective disinfectant that has been used for decades in hospitals and operating theatres around the world. The Global UV Disinfectant Equipment is valued at $1.1 billion in 2018 and projected to grow to $3.4 billion by 2026 [2]. Although strong UV Light cannot be used on the human body, it can help prevent the spread of the Coronavirus. With technological breakthroughs, UV Light may play a key role in returning to normal in the world with a looming COVID-19 threat.
What is UV Light?
Ultraviolet light is a type of electromagnetic radiation that makes black-light posters glow and is responsible for summer tans — and sunburns. However, too much exposure to UV radiation is damaging to living tissue.
Ultra-violet (UV) is a form of electromagnetic radiation with wavelength [3] from 10nm to 400nm, shorter than visible light but longer than X-Rays. Thus, UV rays are not visible to the human eye [4]. UV radiation is present in sunlight and constitutes about 10% of the total electro-magnetic radiation output of the sun. The amount of UV light produced by the sun means that the earth would not be able to sustain life on dry land if most of the light was not filtered out by the atmosphere.
UV radiation is also produced by electric arcs and specialized lights such as mercury-vapor lamps, tanning lamps, and black lights. Although, long-wavelength ultraviolet is not considered as ionizing radiation because its photons lack the energy to ionize atoms. Short-wave ultraviolet light damages DNA and sterilizes surfaces with which it comes in contact with it. For humans, suntan and sunburn are familiar effects of exposure of the skin to UV light, along with an increased risk of skin cancer.
More energetic, shorter-wavelength “extreme” UV below 121nm ionizes air so strongly that it is absorbed before it reaches the ground.
According to the U.S. Navy’s “Ultraviolet Radiation Guide,” UV is generally divided into the following categories:
· UVA or near UV (315-400nm)
· UVB or middle UV (280-315nm)
· UVC or far UV (180-280nm)
· The guide goes on to state, “Radiations with wavelengths from 10 nm to 180 nm are sometimes referred to as vacuum or extreme UV." These wavelengths are blocked by air, and they only propagate in a vacuum.
The sun produces all three types of UV Radiation but UVC does not reach the earth’s surface as explained above. UVC sits in the germicidal disinfecting range.
UV Light was first used to disinfect surfaces in 1877. In 1910, UV Light was first used to disinfect water and air in 1935. For more than 100 years, UVC is been known to be very good at killing micro-bacteria and viruses both.
However, UVC can be very harmful to humans. It can burn the skin or damage the retina of the human eye. The WHO has issued guidelines against the use of UV Lamps [5] to disinfect a human body. UVC being a health hazard can only be used if people are not around.
How does it work?
The UVC light interferes and destroys the DNA and RNA of the bacteria or viruses and other microbes. It forms new chemical bonds in the DNA of the microbes and these new chemical bonds prevent those microbes from replicating. UVC light has proven itself in effectively and efficiently disinfecting many surfaces. For many decades it has been used to disinfect drinking water, wastewater, air, pharmaceutical products, and surfaces against a whole suite of human pathogens.
However, there are some things that limit its effectiveness, like; if there is dirt on the surface, then that dirt impacts the amount of UVC Light can get to the microbes. So, it works best if the surfaces are cleaned first and then exposed to the UVC light. If a telephone is kept on the bed, then the area below the telephone on the bed will not be sterilized by the UVC light when it is zapped.
UVC Light has been used to combat other coronaviruses like MERS and SARS and has also been used against Ebola. It has proven effective against the previous coronavirus family and due to the structural similarities of all the viruses in the coronavirus family, experts say it will be effective against the current coronavirus – SARS CoV2 or CoVID-19.
Currently, UVC Light is being used in the healthcare industry to disinfect their operation theaters, rooms etc. The area that needs to be sterilized, is first cleaned to take away all the dirt, things cleared away so that all the surfaces are exposed. Then the UVC Light Robot is brought into the room. The room is vacated of all human presence. The UVC Light Robot then zaps the room, spreading UVC Light in all directions to sterilize the room or operation theatre. It is very important to note that UVC light cannot be used in the presence of human beings. (as seen in Video above.) Hospitals in the USA that have used this UVC Light disinfecting robot, have dropped its hospital-acquired infection rate [6] by 50-70%.
Advantages of UVC
The UVC Light is mobile. It just requires electricity and a set of bulbs to disinfect the area. So this can be taken to the various temporary CoVID-19 treatment centres being created as well.
It is faster and less labor-intensive than cleaning by hand. Because of it being faster, the room turnaround time is reduced.
Also, the need to clean with powerful chemicals is reduced. One can use bland soaps to clean the surfaces and then rely on UVC to sterilize the surfaces. Harmful chemicals must be left visibly wet on the surfaces for several minutes before they can be wiped down. These chemicals are to be used on only hard non-porous surfaces and to be used only in well-ventilated areas. Also, several studies have suggested that cleaning staff can leave out areas while cleaning the room. Almost 50% of the high touch surfaces are left out by the cleaning staff (Image 3). In Italy recently, it was noticed that the hospitals were agents of transmission of CoVID-19. With UVC Light all these surfaces are attended to.
How UVC is fighting CoVID-19?
UVC light can be a powerful tool in the fight against CoVID-19. It is already being used as a disinfectant to reduce the spread of CoVID-19. China is using UV Light to disinfect entire buses and Chinese banks are using UVC on currency notes to disinfect them (as seen in Image 4).
Pittsburg International Airport became the first airport to use UVC Light Robot to disinfect all public areas of the building. There are special UVC Light Disinfecting apparatus for aircraft that have articulating arms that move over the seats to disinfect all areas you would normally touch (Image 5).
Since the spread of the pandemic of CoVID-19, the demand for these UVC Robots has shot through the roof. All countries that were hit hard by this pandemic, were putting these robots in use for the fight against coronavirus.
The CDC and International Ultraviolet Association are looking into how they can use UV Light as a disinfectant for PPE’s, to be able to increase the extending life of the PPE’s in times of shortage like this. N95 Masks have been found to be safe for use after being blasted by UVC Light Disinfectant [7].
UVC Light is being used successfully to disinfectant phones and the product is available in the retail market. In today’s world, the cell phone can be the largest carrier of infections.
UVC Light can also be used by hotels to sterilize the hotel rooms. The room can be cleaned by the housekeeping staff and then use the UVC Light to sterilize the surfaces of the room before the guest uses it again. Like hospitals, this can help reduce the spread the infection among guests and staff.
Far-UVC light – The Future
As we have read above, the UVC Light can only be used in the absence of human beings in the room. With the technological breakthroughs, researchers are experimenting with a shorter wavelength of UVC which can be safer to exposure but still effective against micro-organisms, this is called the Far-UVC Light.
With a wavelength of 222nm, studies have shown that it is effective against microbes but does not penetrate the skin or damage the eyes thus safe for use in the presence of human beings. This light was developed to tackle influenza and are currently studying the effect of it will have on the CoVID-19 virus.
Far-UVC lights are currently under testing but the initial result looks promising. If this technology is successful, then Far-UVC lamps can be permanent fixtures along with normal lighting luminaires in high-risk spread areas like hospitals and airports.
Hotel rooms can also have this fixture that can be used to sterilize the room while the guest is still in it. Buses, Planes, Trains, Gyms, Subways, Restaurants, Nursing Homes, Grocery Stores, Offices, Schools and Universities can all benefit from this technology.
This is how UV Light can help stop the spread of CoVID-19.
You can download the document to share with your team and colleagues.
Prepared by
Faircon Uno - MEP Engineering and Lighting Consultants
E303/304 Remi Bizcourt, Off Veera Desai Road,
Andheri W, Mumbai 400053, India
Sources:
· Centre for Systems Science and Engineering (CSSE) at Johns Hopkins University (JHU).
· Allied Market Research.
· Wikipedia : https://en.wikipedia.org/wiki/Ultraviolet
· CNBC research on the use of UV Light to kill the coronavirus.
[1] Source: Centre for Systems Science and Engineering (CSSE) at Johns Hopkins University (JHU) as on 05/16/2020 [2] Source: Allied Market Research [3] nm – nano meters, this unit is generally used to measure the Electro-magnetic spectrum. 109 nm = 1 m [4] The lower wavelength limit of the human vision is conventionally considered at 400nm. [5] The guideline issued by the World Health Organization (WHO) states, ‘UV Lamps should not be used to sterilize hands or any other areas of the skin as UV radiation can cause skin irritation.’ This was issued in the recent in light of the question, ‘can UV light kill the coronavirus.’ [6] Hospital-Acquired Infections (HAIs) – These are infections acquired by the patient in the hospital during/after being treated for an illness they primarily were admitted into for. [7] As per UVC Light Robot manufacturer – Xenex Disinfectant Services, UVC Light Robot has successfully passed 3M’s fit and filtration tests when used on N95 masks.