Packed bed scrubbers are air pollution control devices used to remove contaminants from industrial exhaust gases. They consist of a vertical column filled with packing material, which increases the surface area for gas-liquid contact. As the polluted gas flows upward through the packed bed, it comes into contact with a liquid, usually water or a chemical solution, that absorbs or reacts with the pollutants. These scrubbers are effective for removing various pollutants, including volatile organic compounds (VOCs) and particulate matter. The design allows for efficient mass transfer, making them suitable for applications in industries such as chemical manufacturing and power generation.