An Environmental Control System includes sensors, an air purification subsystem, and a controller in communication with the sensors and air purification subsystem. The sensors detect contaminants in outside air supplied through engine and APU bleeds or other air sources including ground supplies and electric compressors, contaminants in recirculated air, particulates in outside air, carbon dioxide in recirculated air, temperature in an environment, and pressure in an environment. These sensed parameters are compared against thresholds. Based on the comparisons, changes to the outside air and/or recirculated air are made.