^^^ carbon filters are nice but not everyone has a fan powerful enough. Instead, i'd suggest looking into a standard hepa/ionizer air purifier. You can place it near the exhaust and it will clean most of the air. I can hardly smell my plants even if i put my face right into them... the day before i bought the purifier if you opened the room to my door (not the cab) it WREAKED of dank... within a day that problem was fixed. I have my air purifier place right in front of the exhaust so little air escaped without being filtered.