Why use UV-C light?

Ultraviolet (UV) light is a component of the electromagnetic spectrum that falls in the region between visible light and X-Rays.

Most natural UV light is generated by the sun with about ten percent of sunlight being UV and only about three to four percent penetrating the atmosphere to reach the ground. Of the UV radiation that reaches the earth, 95 percent is UVA and five percent is UVB.

No measurable UV-C from the sun reaches the earth’s surface. Because of the spectral sensitivity of DNA, only the UV-C region demonstrates significant germicidal properties.

The Electromagnetic Spectrum

• Ultraviolet (UV) is a form of electromagnetic radiation
• It’s wavelength is shorter than visible light but longer than X-rays
• It constitutes about 10% of the electromagnetic radiation output of the sun
• UV-A: Black light, used in bank note forgery detection
• UV-B: Causes sunburn and cancer
• UV-C: Filtered by the ozone layer. Germicidal version sterilises surfaces

Notes

• UV-A: 370 - 400nm Black light, used in bank note forgery detection
• UV-B: 280 - 315nm Causes sun burn and premature ageing
• UV-C: 245nm Germicidal, deconstructs microorganisms DNA, stopping reproduction

History of UV-C

Niels Ryberg Finsen

• 1878 - First used to kill microorganisms that caused indoor air quality problems.
• 1903 - Danish-Faroese physician and scientist, Niels Ryberg Finsen employed UV rays to treat diseases, receiving the Nobel Prize for Medicine in 1903.
• 1910 - UV light used to disinfect drinking water in Marseille, France.
• 1930's - First commercial UV-C germicidal lamps manufactured by Westinghouse in the United States.
• 1940's - UV-C used to sterilise air in hospitals, kitchens and food processing plants.
• 1950's - UV-C incorporated into air conditioning equipment.
• 1990's - Over 6000 water treatment plants use UV-C to disinfect water.
• 2020 - Violegen launches a range of high performance sterilisers to a provide low cost, chemical free solution to reduce COVID-19 infection rates.