An exhaust aftertreatment system includes a housing including at least one exhaust aftertreatment component. The housing defines a body portion and an outlet portion terminating in an outlet opening. The outlet portion decreases in diameter from the body portion toward the outlet opening. A sampling tube is positioned within the outlet portion and extends between opposing sides of an inner wall of the outlet portion, with the sampling tube having a plurality of openings facing the body portion. A NOx sensor is positioned in fluid communication with an interior of the sampling tube.