[dreamcompiler]

> WARNING: Do not be in the room with any UV-C light for more than a few seconds.

This advice does not necessarily apply to far UVC (200-235 nm), which appears to be much safer for human skin and corneas than UVC outside this specific band. More research is needed before calling it "safe" but far UVC is almost certainly less hazardous than the rest of the UVC band.

Pay close attention to wavelength when purchasing UVC light sources.

https://en.wikipedia.org/wiki/Far-UVC

[genewitch]

254 doesn't make ozone but; yes, i explained the two i have used and researched. i have not researched far-UVC. it's still germicidal, i still wouldn't want to be in the room with it. I had to check what wavelength "common" UV lasers are, and i'm guessing 261nm or so. If you aim that at your skin, it feels hot real quick. Kinda feels, to me, like my entire life i've been told that all UV is bad, but UV-A blockers are snake oil, etc.

I'll keep my eye out for more research on far-uvc and the possibility of getting a bulb to test.

oh by the way, i must have sent back 2 dozen "185nm" UVC bulbs from a dozen "manufacturers" because they didn't produce ozone, because they were fraudulent listings of 253.7nm bulbs - so this is why i was trying to steer people away from amazon and ali, as it's real easy to get the wrong type if you're looking for ozone. I've only managed to acquire 4 bulbs total in the last 5 years that produced ozone, and i burnt out two before someone said "put a fan on it, those bulbs are designed to be inside an air exchanger!"

[vintermann]

Yes, this is a common dilemma in air sterilization. Far UV-C isn't as nasty for skin, but it produces ozone, and ozone is nasty and really bad for your respiratory health.

[genewitch]

> induced ozone levels of less than 10 ppb, and much less in moderately or well-ventilated rooms compliant with US far-UVC dose recommendations, and very much less in rooms compliant with international far-UVC dose standards.

https://pubmed.ncbi.nlm.nih.gov/38037431/

i'd never heard of ozone in far-uvc nor really far-uvc. For what it's worth, i don't think it matters. the "warning" median dose for Ozone is 1ppm, 100 times more than far-UVC puts out. the "danger" is 5ppm. For ref, Chlorine is 10ppm.

253.7nm does not produce any (or less than 1ppb, which i consider the same thing for my body), and 185nm produces a lot. My warning is specifically to people who want to or need to use the lamps and also think that google isn't very good.

supposition: we don't have the material or material science that is transparent enough between 185 and 254 nanometers to induce more ozone levels than 185nm does.