In 1877 the English scientist Thomas P. Blunt and Arthur Downes observed that microorganisms stopped reproducing when irradiated with direct sunlight. It was later discovered that UV-C light destroys nucleic acids and disrupts the DNA and RNA of microorganisms causing structural changes and rendering them incapable of replicating and other vital functions, or in effect, killing the organism. The process of killing pathogens with UV-C light is often referred to as Ultraviolet Germicidal Irradiation (UVGI).

UV-C disinfection is an established and reliable technology. Since the mid-20th century UVGI has been used in disinfecting water, air, pharmaceutical products and surfaces against all manner of human pathogens. All bacteria and viruses tested to date (including coronaviruses) respond to UV-C disinfection. Some organisms are more susceptible to UV-C light than others, but all respond when the appropriate dosage is applied.

Studies have shown that the dose required for disinfection for bacteria typically varies between 2 and 25 mJ/cm2 (with a few resilient strains requiring doses up to a 100 mJ/cm2). Slightly higher values are required in general for viruses, typically between 10 and 100 mJ/cm2 (and for adenovirus, more towards the 100-200 mJ/cm2 range). Studies are ongoing regarding COVID-19 (SARS-COV-2), but many in the coronavirus family requires a dose between 6 and 30 mJ/cm2 on average.