A multifunctional wall flow filter and a system having same performing removal of noxious compounds comprising nitrogen oxides, volatile organic compounds and carbon monoxide and particulate matter from exhaust gas of a compression ignition engine by performing in series the steps of (a) adding an amount of SCR reductant in form of droplets of an aqueous urea solution to the exhaust gas; (b) introducing the exhaust gas admixed with the droplets of the aqueous urea solution into inlet channels of a wall flow filter and oxidizing the volatile organic compounds and carbon monoxide to carbon dioxide and water and nitrogen monoxide to nitrogen dioxide in presence of an oxidation catalyst arranged on permeable porous partition walls at inlet side of the wall flow filter, the oxidation catalyst active in; (c) subsequently evaporating and decomposing the droplets of the aqueous urea solution in the exhaust gas from step (b) to ammonia; (d) passing the exhaust gas containing the ammonia through the permeable porous pa
