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What do you mean wrong wavelength? UVB is not technically ionizing, but breaks down DNA and cellular structures. UVC does this more effectively than UVB and, like welding light, can still damage your cornea even if you can’t perceive it. Far end of UVC is considered ionizing depending on the range definition used.
Read up. UV-C refers to a specific wavelength that tends to be absorbed by the surface layer.
The UV components that cause harm penetrate.
Corrected and expanded in place above. Too much multitasking tonight.
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Research ongoing which indicates otherwise.
Uh, dude I’ve had to take industrial safety
I’m gonna leave this here for anyone else but it’s not worth arguing with you: https://www.google.com/amp/s/amp.cancer.org/cancer/cancer-causes/radiation-exposure/uv-radiation.html
Cite your source if it’s against current scientific evidence
Paper about the efficacy of UVC disinfection:
UV-C ( 222nm ):
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Slightly different wavelength:
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UV-C covers all of 100-280nm; these are all specific wavelengths within the UV-C spectrum, not the typical UV-C light sources once encounters (which typically start with 257nm broadband disinfection lights, and then drilling down to niche light sources). Even those papers note that the typical UV-C sources are still dangerous to human tissue based on exposure times, and that these wavelengths were only “safe” in that a far shorter time of exposure produced the desired disinfecting results, and there is a significant disparity in effects on human tissue which would allow for setting safe exposure guidelines.
Whilst great for hospitals, this doesn’t translate well to our use. Between specialized light sources to get that specific range of wavelength in an adequate output, we’re still looking at time-based exposure whilst not overexposing people to start getting those effects.
Will we start seeing manufacturing of these more specialized UVC filters that do not output boardband within the typical marketplace? Probably. Are we there yet? That question is whether you’re willing to spend the money for medical equipment, or trust the light safety equipment from alibaba.
UVC light safety in the specific region talked about in these papers (200-220nm) still has safe exposure limits, which manuafacturers typically use IEC 62471:2006 as reference
(Also as an FYI, don’t spam replies; you can post all of that in a single message)
If we wanted to go this route at some point, some manner of shield would suffice. Running them as overhead lights would not be optimum, but local use might work with some thought. If the 222nm systems become cost effective, non contact sterilizations of whole machines at once would be a nice approach.
Like lots of other things - electric arcs for example - safe usage may require safety measures.
My point is that it’s not a super simple matter. And some seriously non-intuitive things are under development. I know a little about this stuff after the stink over the President’s comments about using light as a disinfectant. The system is under commercial development with Cedar Sinai Hospital. One of those papers discusses it I think. If not, Google will find it for those interested. Endo-tracheal insertion of a fiber optic device that emits UV light. Kills staph and fungi as I recall. As you note, care is required in that context to control the intensity and duration. It appears to kill pathogens significantly faster than healthy tissue. Kinda clever.
Can absolutely agree with you on this; I’m happy we could continue this discussion in a civil manner.
I used to work for a manufacturer of these disinfecting light systems and family is heavily invested in the tech (it’s why I have a lot of offhand knowledge about it).
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And now back to our regularly scheduled “All the machines are rusty” discussion… 
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Reflection? I’m not saying, just guessing. I think you might have to set up light and then clear the area.
Edit: I should have read to the end of the thread before posting. Many people are more informed than me.