WHAT IS UV-C LIGHT?
UV-C light is one subdivided and categorized region of Ultraviolet (UV) light, which is a component of the electromagnetic spectrum that falls in the region between visible light and X-RAYs. This invisible radiation includes the wavelength range of 100 nm to 400 nm. UV light can be further subdivided and categorized into four separate regions:
UV-V (Far UV) (100 - 200 nm)
These wavelengths only propagate in a vacuum
UV-C (200 - 280 nm)
Useful for disinfection and sensing
UV-B (280 - 315 nm)
useful for curing, tanning and medical applications
UV-A (Near UV) (315 - 400 nm)
Useful for printing, curing, lithography, sensing and medical applications
BACKGROUND OF UV STERILIZATION
In 1879, after UV sterilization was discovered to be a useful technology for cleaning infectious spaces, more studies were done to determine the exact beneficial nature of UV Light. As such, since the 20th century, UV sterilization has been used to disinfect things like water and work surfaces.
With greater advancement in technology, today UV-C sanitizing has become much more accessible, portable and affordable. It is a proven technology that can aid cleaning and sanitizing.
HOW DOES UVC DISINFECTION WORK?
CELLS THAT CANNOT REPLICATE, CANNOT INFECT.
It is widely accepted that it is not necessary to kill pathogens with UV light, but rather just expose them to enough UV light to prevent the organism from replicating. The UV doses required to prevent replication are orders of magnitude lower than required to kill, making the cost of UV treatment to prevent infection commercially viable.
It has been scientifically proven that UV-C energy can be incorporated into sterilization technology to inactivate a wide range of pathogens (e.g. MRSA, C. diff, E. Coli and Pseudomonas). Studies have confirmed that UVC light can be effective for combating SARS-COV (source). However, additional studies are needed to determine and confirm the specific dose response required to inactivate COVID-19 on different surfaces and materials.
UV-C radiation naturally exists in the atmosphere. Through numerous studies it has been proven that UV-C exposure is unlikely to cause acute or long-term damage to human skin. However, aligned with most institutes including the EU healthy agency's recommendation, we should not expose direct UV-C energy to human skin and eyes (source).
“We’ve known for a century that UV light is extremely efficient at killing microbes, bacteria, and viruses"
(David Brenner, director of the Center for Radiological Research at Columbia University Irving Medical Center.)
"Ultraviolet light has been demonstrated to be capable of destroying viruses, bacteria and fungi in hundreds of laboratory studies"
(Kowalski WJ. (2009). Ultraviolet Germicidal Irradiation Handbook: UVGI for Air and Surface Disinfection.)
“In any case, UVC is strongly attenuated by chromophores in the upper epidermis (Young, 1997) and UVC-induced DNA damage in the dividing basal layer of human epidermis is not readily detected"
(Campbell et al, 1993; Chadwick et al, 1995)