A microelectronic device capable of detecting multiple gas constituents in ambient air can be used to monitor air quality. The microelectronic air quality monitor includes a plurality of temperature-sensitive gas sensors tuned to detect different gas species. Each gas sensor is tuned by programming an adjacent heater. An insulating air pocket formed below the sensor helps to maintain the sensor at a desired temperature. A temperature sensor may also be integrated with each gas sensor to provide additional feedback control. The heater, temperature sensor, and gas sensors are in the form of patternable thin films integrated on a single microchip. The device can be incorporated into computer workstations, smart phones, clothing, or other wearable accessories to function as a personal air quality monitor that is smaller, more accurate, and less expensive than existing air quality sensors.