Selectively sorting aerosol droplets in exhaled human breath based on a mass-size parameter

A selective-sorting system for aerosol droplets in human breath includes a mouthpiece to receive a flow of human breath, and a flow path coupled to the mouthpiece. This flow path includes one or more bends that cause the flow of human breath to change direction, which causes aerosol droplets in the flow having different mass-sizes to change direction at different rates. Moreover, the flow path is shaped so that droplets that change direction at different rates are directed to different destinations. The system also includes a collection path, which is coupled to the flow path so that aerosol droplets meeting a specific mass-size criterion are directed into the collection path. A condenser tube is located in the collection path, wherein the condenser tube includes a cooling mechanism that cools the condenser tube to facilitate condensing aerosol droplets to sides of the condenser tube for subsequent collection.