Downdraft systems have a suction unit (fan) mounted below the cooking surface and a vent pipe going outside. When the fan is on, the suction pulls the air containing the smoke and odors down and pushes them out the exhaust vent.

a downdraft is air that goes down-the air gets colder and it sinks

It depends. It is an updraft in most tornadoes, but in some tornadoes there is a downdraft at the center much like that in the eye of a hurricane.

downdraft

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