A system may include an air treatment assembly configured to deliver treated air to an enclosed space within a vehicle, at least one upstream sensor upstream from the air treatment assembly, and at least one downstream sensor downstream from the air treatment assembly. The upstream sensor(s) and the downstream sensor(s) are configured to detect at least one attribute of air, such as air pressure. An air treatment monitoring system is in communication with the sensors. The air treatment monitoring system receives one or more sensor signals from the sensors, and calculates an attribute differential (such as a pressure differential) based on the one or more signals.