Albonair’s selective catalytic reduction (SCR) system achieves optimum NOx emissions reduction by using a urea dosing system to adjust the reducing agent diesel exhaust fluid (DEF) droplet size depending on exhaust conditions. The dosing system enables fine spraying of the agent (to a Sauter mean diameter of less than 10 µm) into the exhaust tract so the DEF vaporizes within a few centimeters into the pipe. A compact, integrated design allows use with different vehicle types. The system consists of a housing with SCR catalysts; injection nozzle; temperature and NOx sensor; and a urea tank with level and temperature sensor, dosing unit, and aftertreatment control unit. System mass is 1.6 kg (3.5 lb). The compact nozzle can be positioned without difficulty in thermal hot areas of the exhaust system because no moving parts or sensors are fixed at the injection point.