Packed bed scrubbers are a major air pollution control device for hazardous waste incinerators. The contamination in packed bed scrubbers are removed by a gas absorption process that depends on intimate gas. These scrubbers are vessels filled with randomly oriented packing material such as saddles and ring. It is suitable for the removal of noxious gases in streams containing low or no particulate loading. It has high removal efficiency for gaseous and aerosol pollutants.