Acetic acid odor while testing CO2 sensor; can it be easily removed, is there a better way?
You could use a less volatile acid, like oxalic. But I think the reaction with NaHCO3 probably gives off a mist as the reaction bubbles, and that might be why the odor is so strong.

How about using seltzer water (or Perrier? or Diet Coke!) as the source of CO2? I estimate that the pressure of CO2 is about 45 psi in the unopened bottle, and if you attach a balloon to a freshly opened bottle and let it outgas slowly, the balloon will fill up and be essentially pure CO2. If a latex balloon is unsuitable or too hard to handle, a mylar balloon ($1 at the Dollar Store) will work just as well. The gas will be saturated with water vapor.