Most ventilation-system-attached or free-hanging Farm Shop Air Cleaners/Purifiers are able to filter out welding fumes, grinding dust, diesel smoke, paint overspray, and other nuisance or potentially dangerous airborne dusts, mists, and vapors. Because no air is exhausted outside but rather filtered by the unit, heat is kept inside for winter comfort. They are motor-driven with multi-stage filtration systems and clean/purify the air at the rate of up to 3,000 cfm.