How UV Works
Ultraviolet light has been used as a disinfection method for over 50 years. There are numerous scientific research supporting the effectiveness of ultraviolet light in killing various types of viruses and bacteria.
An article published in April 2020 in IEEE Spectrum has shown that the UV light kills 99.9% of the new coronavirus that causes COVID-19 in just 30 seconds.
A 2014 study in the American Journal of Infection Control found that UV light killed 100 percent of several types of bacteria commonly found on surfaces after just five seconds. According to the researchers, a UVC device is a reasonable alternative to using chemicals to disinfect surfaces.
The effectiveness of UV depends on the length of time a microorganism is exposed to UV, the intensity and wavelength of the UV radiation. The most effective wavelength for destroying the DNA of microorganisms is 265 nm as shown below. The majority of the research in this area has shown a UV light with 2-4 mJ per cm square can kill most germs.
Boeing's Self-Cleaning Bathroom Would Nuke Germs with UV Rays
Narrow Range of UV Safely Kills Drug-Resistant Bacteria
Here are further readings on the proof of UV-C technology:
Using the Power of Light: Preventing the Airborne Spread of Coronavirus and Influenza Virus
As Coronavirus Looms, Mask Shortage Gives Rise to Promising Approach
https://www.nytimes.com/2020/03/20/health/coronavirus-masks-reuse.html
Inactivation of the coronavirus that induces severe acute respiratory syndrome, SARS-CoV
What the structure of the coronavirus can tell us
https://www.washingtonpost.com/graphics/2020/health/coronavirus-sars-cov-2-structure/
What America can learn from China’s use of robots and telemedicine to combat the coronavirus