A particulateair filteris a device composed offibrous, orporousmaterials which removes solidparticulatessuch asdust,pollen,mold, andbacteriafrom theair. Filters containing anadsorbentorcatalystsuch ascharcoal(carbon) may also removeodorsand gaseous pollutants such asvolatile organic compoundsorozone.Air filters are used in applications whereair qualityis important, notably in buildingventilationsystems and in engines.