Which UV Light is most effective against COVID-19?

Baggage is found to be one of the common causes of the spread of infection at public places like railway stations, airports, hotels, etc. In association with Vehant Technologies, a Noida-based tech firm, an R&D centre based in Hyderabad has developed a UV based baggage disinfection tunnel named “KritiScan UV Baggage Disinfection System” to provide 360-degree coverage to disinfect any luggage within less time. It can also be installed at bus terminals, commercial buildings, and metro stations for quick baggage disinfection to fight against COVID-19 infection. 


Now the question is – Which UV Light is most infective? 

UVA and UVB lights were also used to kill the SARS-CoV2 virus, but they were not found to be most effective. This way, the UV-C radiation has been proven to be most effective as disinfection is entirely chemical-free and dry. It quickly kills the genetic material of the virus when it is released on the infected baggage surface. 


Why is UVA or UVB light not used for disinfection? 

UVA radiation has been found to be less harmful than UVB, but it is also around 1000 times less powerful to kill SARS viruses than UVB and UVC. It can also increase the risk of developing skin cancer and skin ageing. 


On the other side, UVB radiation has been found to be quite useful to inactivate various SARS viruses, but it is not much powerful against COVID-19. It is also more harmful than UVC to humans as it can be absorbed deeply into the eye and skin. It can also develop cataracts and skin cancer and also leads to DNA damage.


Are all UVC radiating lamps the same?

No, UVC lamps emit different UV-C radiation in different wavelengths, i.e. 222nm or 254 nm, or even further. You may see infrared and visible radiation emitted from some lamps. These wavelengths may also affect the lamp’s efficacy when it comes to inactivating a virus and pose a health hazard to the user. Some lights release several wavelengths. So, it is essential to test the lamp to find out how much wavelengths are emitted. It is found that 222nm of wavelength may be less harmful to the DNA, eyes, and skin than 254nm. But there is still a lack of long-term records. 


What types of lamps can emit UV-C Radiation? 


  • Far-UVC Lamp or Excimer Lamp – It has around 220 nm of peak emission. 
  • Low-pressure mercury lamp – It is the most widely-used type of light which has been used for a long time to emit UVC radiation. It emits UVC at 254nm. This type of lamp can also emit other wavelengths. 
  • Pulsed xenon lamps – These lamps emit a mild pulse of infrared and visible UV light at a broad spectrum. It has been filtered and used in various hospitals to disinfect surfaces in treatment rooms and operation theaters. These are widely used when no one is there. 
  • LEDs – Light-emitting diodes or LEDs are very prevalent and produce the most common UV radiation at a very narrow wavelength. The peak wavelengths of the most widely used UV LEDs are 265 nm, 280 nm, and 273 nm. LEDs have no mercury. Hence, they are better than low-pressure mercury. But they are also less effective against germs because of high directionality and small surface area. 


Are UV-C lamps effective against COVID-19? 

UV-C radiation has been proven effective in non-porous surfaces, air and water. It has been used widely for decades to control the spread of TB bacteria. Hence, these are also known as germicidal lamps. It is found that UVC radiation can inactivate the outer protein shell of SARS-CoV, which is different from the existing SARS-CoV-2. 


But it ultimately inactivates the virus. It may also work against the novel Coronavirus that causes COVID-19. It is widely used to disinfect the air in air ducts. It can safely use UVC radiation while preventing direct exposure to eyes and skin. In addition, installing UVC in a baggage scanner can also avoid any human contact as it is completely covered from both sides.