[zootam]

A maker's implementation: https://www.youtube.com/watch?v=fzGrh2io9Ds&

Looks cool, not sure how well it works.

[mleonhard]

That mask uses UVA which doesn't kill germs. Only the horrifyingly dangerous UVC kills germs. Don't even think about making a DIY UVC device. You could blind yourself in seconds.

https://www.bbc.com/future/article/20200327-can-you-kill-cor...