No, masks don't create a dangerous atmosphere!
Channel: Jeremy Howard
Date: 28/06/2020

Some videos are incorrectly claiming that a mask causes you to breath an atmosphere of less than 19.5% oxygen (O2), which is considered the minimum safe level. In fact, masks reduce the level of oxygen you breathe by only around 0.1%. Watch this video to learn how this works, then share widely!

For more on the science of masks, go to http://Masks4All.co/facts .