Your skimmer draws no air? How do you get the bubbles?
I think any smoke in the room will eventully enter the water as dissolved solids. However, it's probably to a very very minor degree unless youre exhaling directly into the venturi. Is it possible to open a window while they smoke to help it clear a bit? Afterall, you don't want your room to smell like an old pool hall regardless if you have a tank or not!