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Is 222nm UVC light efficient and safe?

Time: 2020-05-01

Recent research has proved that a part of ultraviolet light, which is 222nm UVC light, is safe for humans.

Generally, ultraviolet light is considered hazardous to human health because of its penetration properties into the human skin, and consistent exposure of ultraviolet light can even cause cancer.

However, the research found that 222nm UVC light has a very restricted scope and cannot pierce through the outer layer of human skin or the tear apart the layer in the eye. 

UVC harm

Does it mean we can take 222nm UVC light as the disinfection partner? Let's take a deeper look.

The research on 222nm UVC light

On March 29, an important result was published online in Photochemistry & Photobiology, titled “ Long-term effects of 222nm ultraviolet radiation C sterilizing lamps on mice susceptible to ultraviolet radiation”.

This is a joint research between Kobe University and Ushio Ins. and has provided the first proof in the world that direct and repeated illumination of the powerful sterilizer 222nm UVC  light will not cause skin cancer and is also safe for human eyes and skin.

222nm UVC light

The research team exposed the mice to different ultraviolet lights in different groups, one group was exposed to a 222nm UVC light, and the other group was exposed to UVB light (280-315nm).


After a period of observation, reasearch team found that the mice exposed to UVB developed skin cancer and showed adverse reactions, but the mice in the 222nm UVC light did not develop skin cancer at all.

222nm UVC research


The reasearch team also investigated the effects on their eyes, and no abnormalities were found even under the microscope.


Therefore, they believed that 222nm UVC light has efficient powerful in killing microorganisms, like viruses & bacteria, but without harming human health risks due to the level of skin penetration .

Can 222nm UVC light kill viruses?

Scientists have known for decades that traditional germicidal UVC light having wavelength around 254 nm can be utilized to sterilize and disinfect empty spaces such as empty rooms or empty subway cars, but these conventional ultraviolet light cannot be used in the crowded places as it is a health hazard.


To overcome this problem, scientists have started studying the 222nm UVC light.


A new study at the Center for Radiological Research at Columbia University Irving Medical Center shows that continuous low doses of 222nm UVC light can successfully kill the airborne flu viruses whitout harming human body.

222nm UVC research process


222nm UVC light has a very limited reach and it cannot enter the human skin or the eye. But they are known to be fatal for the microorganisms like viruses, bacteria, etc.


Because these organisms are much tiny than the human cells, far-UVC light penetrates their DNA and demolishes them. It firstly stops their reproduction and multiplication property, then stops them from functioning.


It is an efficient method to disinfect the environment and inactivate the germs because most of the viruses and bacterium travel through the air.

New discovery of 222nm UVC light

The sensitivity of the microorganisms to 222nm UVC light recommends that it might be achievable and safe to be used in crowded indoor public places.


In this way, a place full of crowd can be disinfected and sterilized without harming humans as well as the risk of transmission of a virus can be reduced in a crowded place. 

It sounds excited with 222nm UVC light and a wide range of possible applications can be realized.

People even imagined that 222nm UVC light can be a replacement for the typical liquid hand sanitizers which are installed at public places like restaurants, subways, schools, toilets, etc. Equipment exhibiting rays of 222nm UVC light can sanitize and possibly disinfect human body parts.

Applications of 222nm UVC light

Why not put 222nm UVC light into operation?

The idea of producing 222nm UVC light at the public and domestic level is good and it can really help in overcoming certain types of diseases that can be transmitted through the environment or human contact.


This will certainly reduce the amount of budget spent on health industries because it will decrease the number of people being affected.


But this is not very easy to implement.


There are a lot of complications involved in fully implementing and utilizing this technology for common. Few of them are listed below:


· 222nm UVC LED has no clinical trial data


Whenever a new medicine or a vaccine is formed, it is firstly tested on other living things that have many features in common with human beings.


There are few animals that are identified by chemists and they are suitable for testing the new vaccinations.

Testing process of 222nm UVC LED


For example, most of the vaccines are firstly tested on the mouse. If the first level of the mission is successful, then they are tested on the family of the monkeys. There are many rounds of analytical testing before actually using them for humans. Once they pass all the clinical tests, they are provided in the market for human beings.


Up till now, the scientist has their research only to prove that 222nm UVC light is not harmful to mice. They need to actually test these radiations on different animals to have a soundproof of no harm to human life.


In the other hand, scientists have presented another theory that there might be long-lasting effects on human health if the exposure of 222nm UVC light is kept for a longer period of time. A repetitive round of tests on mice, which was exposed to 222nm UVC light, is proved to be hazardous for its health.


Scientists are in a continuous effort to build up the data and the effects, even they are minimal, which can be possibly caused by 222nm UVC light.


· 222nm UVC LED has no scale effect


Due to immature technology, LED chip with 222nm UVC light is still in the stage of small-batch production. There are many challenges in the production of 222nm UVC LED:

High cost of 222nm UVC LED


(1) Costly Raw Materials

In small-scale production, raw materials are purchased in small quantities and these materials can be provided to small producers at higher prices.


(2) By-product waste

In small-scale production, it is impossible use by-products as economically as in large-scale production. The by-products of small producers will generally go waste.


(3) Lack of Standard goods

In small-scale production, the quality of goods is not standardized or up to requirement. It is difficult to sell because of the low standard and inferior quality of the goods.


(4) Lack of Research

Small-scale industries have limited means at their disposal. They cannot spend too much on research in the field of science and technology. In this way, small-scale industries have become an obstacle in the way of technological research and industrial development.


· 222nm UVC LED has a higher Cost


One of the major hurdle in the production of 222nm UVC LED is the cost. Though this is a one-time charge for the equipment, but it is relatively very higher than the conventional LEDs.


Even the 250nm and 270nm UVC LED chips are expensive. Further consider the small-scale production,  the cost of production per unit increases because there is a high cost of labour, a very little scope for division of labour and lesser use of machinery. 

Therefore, the cost of 222nm UVC LED will be too high to be accepted by ordinary consumers.


All in all, from the eyes of a business man, 222nm UVC is just a good vision and still has a long way to go. 


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