Really cool work from Aaron Collins (a.k.a. The Mask Nerd) and his team. They're also working on an open source condensation particle counter which can be used for quantitative fit testing (among other things).

If anyone wants to learn more about the nitty-gritty of the respirator prototyping process, there's a longer video in the description, and the projects are all available on OpenAeros' GitLab, where the hardware is licensed under CERN OHL-S v2, software under GPLv3+, and documentation under CC BY-SA 4.0.

They mention that in particular they're looking for artists/designers/industrial engineers to help with the aesthetics of the mask, so if that interests anyone you can reach out to them using the email in the description (or if you know someone who might fit the bill, share this video with them).