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New Far-UVC light: A new tool to control the spread of airborne-mediated microbial diseases
https://www.nature.com/articles/s41598-018-21058-w
Airborne-mediated microbial diseases such as influenza and tuberculosis represent major public health challenges. A direct approach to prevent airborne transmission is inactivation of airborne pathogens, and the airborne antimicrobial potential of UVC ultraviolet light has long been established; however, its widespread use in public settings is limited because conventional UVC light sources are both carcinogenic and cataractogenic. By contrast, we have previously shown that 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.
"Science is the belief in the ignorance of the experts" – Richard Feynman
New Interesting...
It looks like 222 nm UV has been used disinfect things going back to 2008 or earlier.

But note:

1) The wavelength range is rather small (only a 15 nm wavelength window). Outside it, one risks burns and ozone generation and all the bad aspects of ozone and UV.

2) 2 mJ/cm^2 - how much is that? Standard AM1.5 sunlight is about 1000W/m^2 or 100 mW/cm^2 total. A J is 1 W*s.

The peak AM1.5 spectrum is about 2 W/m^2/nm^-1 x 15 nm or about 30 W/m^2 peak over a 15 nm passband. Or 3 mW/cm^2. Or for 1 second, 3 mJ/cm^2. So, the far-UVC light necessary is about 1.5x the peak solar intensity. So, it's quite a bit of light (in a small wavelength band), but not a huge amount. But, given the amount of viruses going into and out of a real room, the light would have to be on quite frequently.

3) The testing setup was a chamber that was 6.3 cm (2.5") deep and had an aluminum back wall to reflect more of the incident light. Real rooms aren't quite so ideal, of course. More light will be required in real situations.

No silver bullet. But interesting.

Thanks.

Cheers,
Scott.
New kid just started a job in a import food warehouse (chilled)
they irradiate the incoming food per regs
Not sure what they use or frequencies but he claims it makes his fillings hurt.
more work to be done for sure.
"Science is the belief in the ignorance of the experts" – Richard Feynman
Expand Edited by boxley April 23, 2020, 11:51:25 PM EDT
New Thanks for ackshul Physics on this. (Calculation moots consternation, mass cacophony/pipe-dreams:-)
New Been used for ages.
There's a shrine in Kyoto next to a spring. There are ladles for drinking the water and they're sterilized by UV light. Or they were when I was there 20 years ago.

Wade.
     Far-UVC light: A new tool to control the spread of airborne-mediated microbial diseases - (boxley) - (4)
         Interesting... - (Another Scott) - (2)
             kid just started a job in a import food warehouse (chilled) - (boxley)
             Thanks for ackshul Physics on this. (Calculation moots consternation, mass cacophony/pipe-dreams:-) -NT - (Ashton)
         Been used for ages. - (static)

Do not meddle in the affairs of dragons, for you are crunchy and good with ketchup.
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