Ultraviolet Germicidal Irradiation (UVGI)
Ultraviolet Germicidal Irradiation (UVGI) is a method that uses UVC light at sufficiently short wavelength to break down micro-organisms. It is used in a variety of applications, such as food purification, air purification and water purification. UVC has been a known mutagen at the cellular level for more than 100 years. The 1903 Nobel Prize for Medicine was awarded to Neils Finsen for his use of UV against tuberculosis. A common example of UVGI is the sterilization tank used in barbershops to disinfect combs and brushes.
UVGI utilises the short wavelength of UVC that is harmful to forms of life at the micro-organic level. It is effective in destroying the nucleic acids in these organisms so that their DNA is disrupted by the UVC radiation, which is a form of ionising radiation. This removes their reproductive capabilities and/or kills them.
The wavelength of UVC that causes this effect is rare on Earth as its atmosphere blocks it. Using a UVGI device in certain environments like circulating air or water systems creates a deadly effect, or purification, on micro-organisms such as pathogens, viruses and molds that are in these environments. Coupled with a filtration system, UVGI can remove harmful micro-organisms from these environments.
The application of UVGI to sterilization has been an accepted practice since the mid-20th century. It has been used primarily in medical sanitation and sterile work facilities. Increasingly it was employed to sterilize drinking and wastewater, as the holding facilities were enclosed and could be circulated to ensure a higher exposure to the UVC. In recent years UVGI has found renewed application in air sanitation.