> An inhalation valve does less to protect other people, because the expelled air still has to go somewhere, and will just blow out of the sides of the mask. It could theoretically go through the mask material if it was thin enough, but there’s probably too much pressure inside and it’ll burst out the sides
No, an inhalation valve makes 0.0% difference here. Here's a simple mental exercise to understand better. Imagine two people side by side. They are wearing identical masks, except one has an inhalation valve. They breathe in, pause, breathe out. In your mind, freeze the frame at the pause between breathing in and breathing out. At that moment, what's the difference between the two? Nothing. Now watch them breathe out. What's the difference? Still nothing.
No, an inhalation valve makes 0.0% difference here. Here's a simple mental exercise to understand better. Imagine two people side by side. They are wearing identical masks, except one has an inhalation valve. They breathe in, pause, breathe out. In your mind, freeze the frame at the pause between breathing in and breathing out. At that moment, what's the difference between the two? Nothing. Now watch them breathe out. What's the difference? Still nothing.