Your exhale will last longer, but yes the sugar and yeast does work. How manny ppms you produce will be dependent on how active the yeast are.
If you really want to do a DYI co2 production chamber get you a 2 liter bottle, get a gallon of distilled or purified water, yeast packets, and sugar.
1L of water and a half cup of sugar, wait until the sugar fully dissolves, add the yeast package to the 2L bottle, shake the shit out of it and poke a small hole in the lid of the cap. Let it sit in the room.
Once the bottle seems to not be bubbling or foaming up anymore then sugar is most likely consumed, just pour out 80-90% of the liquid, fill back up with sugar and water and shake then set it in the room.
The yeast will continue to stay alive so theres no need to keep adding more everytime, u just need more sugar and water!