You are over engineering this thing...

You have a room. In that room you have some stinky plants. You cut a passive vent in the bottom of your room (a hole) that lets fresh air in. Separately you have a filter attached to a fan attached to a duct which leads out of the room (through a separate hole near the ceiling). The fan pulls the air through the filter and then expels it out of the room via the duct. The filter cleans the air so that the air exiting the duct (outside of your room) is now odor free. Fresh air is drawn in through the hole near the floor due to negative pressure created by the fan. Here, I can diagram it if needed...

Filter > fan > duct out of hole near ceiling > filtered, odor-free air exits room

Room with odor
Room with odor
Room with odor

Hole near the floor > fresh air enters room