Do You Know Your Ultra Violet ABC's?
What is UV Light?
Most people have heard of UV light. Most of us know that UV light can damage our skin in the form of sunburns (or beautiful tans for the lucky ones!). Sure, UV light comes from the sun, but how is that different from the UV generated by bulbs in disinfecting devices like the Blue Box UV and other industrial disinfection units?
First we have to break down the different wavelengths of the ultra violet (UV) spectrum. 
UVA 320-400
95% of all UV light on the earth is UV-A. It is the longest wavelength of the three types of UV light. Because of it’s long wavelength UV-A has a much easier job slipping through the earth’s atmosphere and penetrating to the surface of our planet. These longer UVA rays can penetrate the middle layer of your skin (the dermis), and is responsible for the immediate effects of a tan or sunburn.
UVB 280-320
UVB is the medium-wavelength is mostly filtered out by the earth’s atmosphere but some UVB still manages to sneak it’s way in. Because of it’s longer wavelength, it cannot penetrate beyond the outermost layer of your skin. That doesn’t mean that it isn’t dangerous! UVB is still responsible for delayed tanning and burning as well as promoting the development of skin cancer.
UVC 200-280
This is the most damaging type of UV radiation. Luckily our atmosphere completely filters this wavelength and it is unable to reach the earth’s surface. Scientists have been able to synthesize this frequency with UVC bulbs for it's germicidal effects since the 1930s.
UVC light destroys harmful bacteria and viruses by altering the structure and the molecular bonds of their DNA. When viruses and bacteria are exposed to UVC, they are vibrated at an incredibly high frequency. Vital parts of the microbes cannot withstand being shaken so violently, so they break down and no longer function.
When their DNA/RNA is damaged, the microbe is no longer able to reproduce. It's as if their blueprint for world domination went through a paper shredder. The organism dies off and leaves no offspring. A microbe that is unable to reproduce poses no harm as it cannot spread or infect any other living cells.