Abstract: Baffle plate devices, exhaust gas aftertreatment apparatuses, and methods for controlling airflow in exhaust gas aftertreatment apparatuses are disclosed. In some examples, a baffle plate device is mounted within an outlet conduit via which the exhaust gas treated by an exhaust gas aftertreatment apparatus exits to the environment. The baffle plate device impacts the flow path of the treated exhaust gas within the outlet conduit to deflect a portion of the treated exhaust gas toward tips of sensors, which extend into the flow path toward the baffle plate device, in order to mitigate the impact of the recirculation region, improve the flow characteristics (e.g., rate, direction, and/or field) of the treated exhaust gas at the tips, and thereby improve the accuracy of the sensors. By improving sensor accuracy, the disclosed technology advantageously reduces false positives and improves engine performance and emissions compliance.