There's an approach called "displacement ventilation" that could help. The basic idea is if your contaminants are mostly warmer or more humid than room air then

There's an approach called "displacement ventilation" that could help. The basic idea is if your contaminants are mostly warmer or more humid than room air then convection will move them to the top of the room where they pool and can be removed efficiently. This is opposite of the mixing strategy in normal US HVAC and has some disadvantages but may work for you.