Aerodynamic aerosol classifier
An aerodynamic aerosol classifier (AAC) is an embodiment of a measurement technique for classifying aerosol particles according to their aerodynamic diameters. The technique allows online size classification of particles without requiring them to be electrically charged, and advantageously allows selection of particles within a narrow range of aerodynamic diameters.
Source: Wikipedia — Aerodynamic aerosol classifier (CC BY-SA 4.0)