Adjective: ultraviolet (UV) - having or employing wavelengths shorter than light
but longer than X-rays; lying outside the visible spectrum at its violet end; "ultraviolet
radiation"; "an ultraviolet lamp"
Ultraviolet germicidal irradiation (UVGI) is a disinfection method that uses short
wavelength ultraviolet (UV) light to destroy bacteria. It is used in a variety
of applications, such as food, air and water purification. UV has been a known mutagen*
at the cellular level for more than a hundred years. The 1903 Nobel Prize for Medicine
was awarded to Niels Finsen for his use of UV against tuberculosis. Application
of UV irradiation to purify water was a technique invented by Ashok Gadgil.
UVGI utilises short-wavelength ultraviolet radiation (UV-C) that is harmful to microorganisms.
It is effective in destroying the nucleic acids in these organisms so that their
DNA is disrupted by the UV radiation. This removes their reproductive capabilities
and kills them.
The wavelength of UV that causes this effect is rare on Earth as the atmosphere blocks
it. Using a UVGI device in certain environments has a destructive effect on micro-organisms
such as pathogens, viruses and mould that exist in these environments. Sometimes
coupled with a filtration system, UVGI can remove harmful micro-organisms from those
environments.
The application of UVGI in disinfection 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
UV. In recent years UVGI has found renewed application in air sanitization. The
most recently available hand held products are proven to kill most germs found on
kitchen work surfaces. It’s interesting to note that kitchen work surfaces are
often have more bacteria than lavatory seats!
* A mutagen (Latin, literally origin of change) is a physical or chemical agent that
changes the genetic material, usually DNA, of an organism and thus increases the
frequency of mutations above the natural background level.
