Catalytic filters are a type of air pollution control technology that combines the principles of catalysis and filtration to remove harmful pollutants from exhaust gases. These filters typically consist of a catalyst-coated ceramic substrate that promotes chemical reactions to convert pollutants into less harmful substances, such as converting nitrogen oxides (NOx) into nitrogen and oxygen. Catalytic filters are used primarily in industries with high emissions of pollutants, such as power plants, chemical plants, and automotive manufacturing facilities. They are also being increasingly used in diesel engines to reduce emissions of particulate matter and NOx. Overall, catalytic filters offer a cost-effective and efficient method for reducing air pollution and improving air quality.