Cu zeolite selective catalytic reduction catalysts and methods for exhaust gas treatment

An exhaust gas treatment system comprising:

• a combustion engine, and
• a selective catalytic reduction article downstream of the combustion engine;
• wherein:
• the exhaust gas treatment system does not have a diesel oxidation catalyst in fluid communication between the combustion engine and the selective catalytic reduction article,
• the exhaust gas treatment system does not have a catalyzed soot filter in fluid communication between the combustion engine and the selective catalytic reduction article,
• the selective catalytic reduction article has one or more washcoats comprising a copper containing small pore zeolite having a silica to alumina molar ratio ranging from 5 to less than 30,
• the copper containing small pore zeolite has an amount of copper ranging from 0.1 weight % CuO to 3 weight % CuO by total weight of the copper containing small pore zeolite, and
• the copper containing small pore zeolite has a molar ratio of copper to alumina ranging from 0.05 to 0.25.