Seems like we still need to be be pushing for further regulatory changes. I saw a report from Kevin’s lab that the limit for is 478 mJ/cm^2 per 8-hour day, and that ~5 minutes of light at around 100mJ/cm^2 kills ~99% of (bacterial) pathogens, whereas ~5 minutes at closer to 10mJ/cm^2 kills ~90% of (bacterial) pathogens, which means we would need a higher limit. Alternatively, the current limits seem to show that AlN LEDs at 210nm would be allowed to be much stronger than 222nm, (around double?) which seems like a good reason to try to work on improving them, rather than pushing for 222nm LEDs—or pushing for KrBr Excimer lamps at 208nm, though I understand they have other problems and aren’t commercially viable at present.
(Also, why is UVA is considered so much safer for eyes than far-UVC? It seems from basic skimming that it causes long-term retinal damage...)
That’s the old limit; it was changed last year. See e.g. this figure from Blatchley et al.
Seems like we still need to be be pushing for further regulatory changes. I saw a report from Kevin’s lab that the limit for is 478 mJ/cm^2 per 8-hour day, and that ~5 minutes of light at around 100mJ/cm^2 kills ~99% of (bacterial) pathogens, whereas ~5 minutes at closer to 10mJ/cm^2 kills ~90% of (bacterial) pathogens, which means we would need a higher limit. Alternatively, the current limits seem to show that AlN LEDs at 210nm would be allowed to be much stronger than 222nm, (around double?) which seems like a good reason to try to work on improving them, rather than pushing for 222nm LEDs—or pushing for KrBr Excimer lamps at 208nm, though I understand they have other problems and aren’t commercially viable at present.
(Also, why is UVA is considered so much safer for eyes than far-UVC? It seems from basic skimming that it causes long-term retinal damage...)