What is UVC?
Ultraviolet refers to invisible light spanning a range of wavelengths between about 100 to 400nm. UVC (deep ultraviolet) light does not exist in nature on Earth from the sun, because its wavelength ranging from about 100 to 280nm cannot reach the Earth due to filtering effects of the protective ozone layer.
Main Feature of UV Sterilization
There are several methods for sterilization such as heat and chemicals. UV sterilization is one of the methods which uses UV irradiated light. It has features not found in other sterilization methods and is used in many applications.
| Pros | Cons |
|---|---|
| ・Since no chemicals are used, no need to wipe off or remove ・Effective against chlorine-resistant micro-organisms that are not sterilized by chlorine ・Does not produce UV-resistant bacteria |
・Hazardous to the human body and organisms (acute/chronic UV damage) ・Damage to plastic materials such as synthetic resin ・Cannot sterilize places where the light does not reach or places in shadow |
Sunlight also contains UVC, but most of them are absorbed by the ozone layer before reaching the earth's surface. UV-C light artificially with lamps allows us to utilize the same cleaning powers of UV-C from the sun.
The longer the light is irradiated, the more the total light intensity,
and therefore the bactericidal effect increases. On the other hand, if the irradiation time is short, a more powerful level of UV light will be needed to achieve sufficient sterilization.
Principle of UV Sterilization
Germs multiply by replicating the genetic material found in the nucleus of living cells, thus leading to infections and onset. DNA and RNA possess the genetic material necessary for proliferation. The UVC range of light can change and rearrange the "strands" constituting the helical structure of DNA/RNA.
UV sterilization becomes possible by "inactivating" DNA/RNA
Effectiveness of UV sterilization
UV sterilization can achieve a reliable bactericidal effect simply by irradiating UV rays. It can also sterilize pathogenic micro-organisms that cause infectious diseases and health problems in the human body. Many universities, research institutes, and commercial companies have used and trust UV sterilization for decades maintain cleanliness of food, water, and air.