The Ultraviolet Germicidal Irradiation (UV-C) wavelength is an invaluable tool for room decontamination.
However, some facility managers may hesitate to leverage these benefits for their application due to a concern about ozone. While the Ultraviolet spectrum contains four separate wavelengths—UV-A, B, C and Vacuum UV—each operates at different energy levels and only one is capable of producing ozone (Vacuum UV).
As you’ll note in the graphic below, Vacuum UV operates in the 100-200nm range, where it is capable of producing ozone. UV-C, conversely, reaches its optimal germicidal strength near 253.7nm. Because ozone may only be produced below 200nm, at 253.7nm (rounded to 254nm), the germicidal wavelength does not generate ozone.
In addition to the stronger 254nm wavelength that does not produce ozone, UV-C lamps offer another layer of ozone protection.
Most germicidal lamps, including those from UV Resources, are produced with doped quartz glass, which blocks the transmission of the 185nm ozone-producing wavelength. The doped quartz glass allows the 253.7nm radiation to pass through, but it blocks the 185nm wavelength from escaping. Therefore, germicidal lamps with doped glass CANNOT produce ozone.
WHAT IS OZONE?
Ozone is present in low concentrations throughout the earth's atmosphere. Some researchers say that this chemical is “good up high, but bad down low.” Without the ozone layer protecting our Earth’s stratosphere, for example, the Sun's ultraviolet radiation would make life on Earth uninhabitable. At street level, however, a high concentration of ozone is toxic to plants and animals. In humans, ozone can irritate nasal passages, cause nausea and extended exposure can lead to lung inflammation.
Ozone, also called Vacuum Ultraviolet (UV-V), is a gas molecule that contains three (3) oxygen atoms – and as such, it has a destabilizing effect on oxygen in the air (leading to its irritation and danger to humans). A UV lamp “tuned” to 185nm can create ozone from oxygen (O2) by disrupting the O2 molecule and splitting it into two oxygen atoms. These two oxygen atoms attempt to attach to other oxygen molecule (O2). It is the attachment of this third oxygen atom that creates ozone (O3).
Ironically, UV light in the 240-315nm wavelength will break this third oxygen atom attachment above and convert it back to oxygen. The peak ozone destruction occurs at the 254nm wavelength. So, a UV-C lamp at the 253.7nm wavelength will actually destroy ozone!
FAR UV - THE FUTURE!
UV Gear are always on the case for the next development in UV applications. Right now we are very excited about the prospects for Far UV. This is the next step in UV-C Germicidal product development. A lighting source with all of the Virus-killing power of 254nm but without the dangers to skin and eyes. The product is already here but is yet to attain FDA and MHRA (The Medicines and Healthcare products Regulatory Agency) approval. When approved, this will radically alter and improve our fight against viral infection. Some day, you will see Far UV lighting in use everywhere.
"far-UVC light (207–222 nm) efficiently inactivates bacteria without harm to exposed mammalian skin. This is because, due to its strong absorbance in biological materials, far-UVC light cannot penetrate even the outer (non living) layers of human skin or eye; however, because bacteria and viruses are of micrometer or smaller dimensions, far-UVC can penetrate and inactivate them."
UV Gear Germicidal lamps are built ready to accept this new technology so that you can upgrade your sterilisation lamp from UV-C to Far UV with the quick change of a bulb. Register here to keep updated on this fascinating new technology.