The air filter on the intake eliminates odors, but the odor that escapes into the exhaust under the intake is so slight that even without the filter the smells aren't noticeable. I have a separate 8 in. blower exhaust for my lights which are sealed in tubes. The intake for this comes from the cool night air from an separate intake I installed on the roof above the room. This is the exhaust blowing into the central intake. The negative air pressure in the room is actually created by another 8 in. blower exhaust into the attic, which then escapes freely outside. It will be better if I post some pics, I don't really feel like this is explaining things. But I had to go to all of this trouble to beat the summer heat here in Arizona.