Oh man, you gotta get a new office. There’s nothing worse than realizing that even if you can’t smell that spud, you’re breating in the contents of someone’s intestines.
Altering the ventilation may not be feasable, especially if the bathroom wasn’t properly ventilated to begin with. Adding shit (uh…) to the HVAC system may or may not work and it may throw off the balancing for the building, which could turn it into a huge money-hole.