We have trash. What I like about the construction of this improvised gas mask is that you need a very minimal amount of materials to make it work. What I will say on a very serious note is that I have no idea how effectively this things may or may not be. It is only offering fresh oxygen through a tiny hole in the two liter cap. In a physically taxing situation I do not know how this thing would hold up.
That said, the skill is still a great one. The author makes it very simple and offers a solution when one is not in sight. What would you be able to pull off with a mask like this one? Of the answer to that question I am not sure. Still, it would be better than not having one.