That's a very good point that the article didn't make clear. I had assumed that the exhaust is filtered. Since the airline agents don't have an easy way to visu

That's a very good point that the article didn't make clear. I had assumed that the exhaust is filtered. Since the airline agents don't have an easy way to visually identify which masks do or don't filter the exhaust, it seems that the airline decided to ban all of the vented masks.