Design of a virtual impactor aimed at inertial classification of bioaerosols

The virtual impactor, a microfluidic air chip for particulate matter classification, is of great significance in identifying the compositional characteristics of particulate matter and has high application value in fields such as the study of the transmission mechanism of respiratory pathogens and the tracing of allergenic pollen. In this paper, based on aerodynamic theory and with the aid of COMSOL numerical simulation, a virtual impactor with a cutoff diameter of 2.5 μm was designed. The impacts of parameters such as the inlet flow rate (Q), pressure, width of the minor flow channel (L), width of the main flow channel (S), and split ratio (r) on its performance were thoroughly analyzed. Finally, polystyrene microspheres with particle sizes of 1 μm, 2 μm, and 5 μm were used to simulate bioaerosols for experimental verification. The experimental results demonstrate that this chip has an excellent sorting effect.