> 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.