Exhaust gas is collected to the odor scrubber tower by an exhaust fan. When it is directed from the bottom to the top, a water pump pumps the water into the top of the odor scrubber tower, spraying downwards and generating water mist. The exhaust gas mixes with the water mist in the odor scrubber tower, in which the odor molecules and dust drops down into the water by the sprays. The purification filters remove the water and suspended particles in gas, and the odor gas as well, thus there is new and clean gas from the upper outlet of the tower in high-efficient purification.