A vehicle includes a component coated with a pollutant reduction catalyst configured to remove pollutants from a flow of air over the component, a catalyst temperature sensor coupled to the component, a general temperature sensor, a vehicle speed sensor, and an active grille shutter (AGS) system having a plurality of movable grille shutters. A controller is configured to determine an efficiency of the pollutant reduction catalyst based on signals from the catalyst temperature sensor, the general temperature sensor, the vehicle speed sensor, and the AGS system.