Embodiments disclosed herein include air-treatment mask systems having at least one controllable air-treatment device that is controlled responsive to one or more signals from at least one pollutant sensor, and related methods of operation and air-treatment masks. In an embodiment, an air-treatment mask system includes a wearable air-treatment mask having a mask body including a face-securing member, and at least one controllable air-treatment device supported by the mask body. The air-treatment device is configured to treat incoming air. The system includes at least one pollutant sensor configured to sense ambient air for a presence of at least one pollutant and output one or more signals responsive to the sensing. The system includes control electrical circuitry operably coupled to the air-treatment device and the pollutant sensor and configured to control operation of the controllable air-treatment device responsive to receiving the signal(s) from the pollutant sensor.