Devices, system, and methods generate expiratory flow-based pulmonary function data by processing a digital audio file of sound of a subject's forced expiratory maneuver. A mobile device configured to generate expiratory flow-based pulmonary function data includes a microphone, a processor, and a data storage device. The microphone is operable to convert sound of the subject's forced expiratory maneuver into a digital data file. The processor is operatively coupled with the microphone. The data storage device is operatively coupled with the processor and stores instructions that, when executed by the processor, cause the processor to process the digital data file to generate expiratory flow-based pulmonary function data for assessing pulmonary function of the subject. The sound of the subject's forced expiratory maneuver can be converted into the digital data file without contact between the subject's mouth and the mobile device.
