System Integration of an Optimally Designed Virtual Impactor with a QCM Sensor as a One-Stop PM_2.5 Classification and Detection Platform

Excessive exposure to airborne particulate matter (PM), especially PM_2.5 particles, adversely affects human health. Conventional PM_2.5 detection instruments based on light scattering are generally bulky, expensive, and easily affected by particle size and composition. Here, we report a low-cost and compact one-stop PM_2.5 detection platform by integrating a three-dimensional (3D) printed virtual impactor with a QCM sensor. To reduce eddy and airflow impact on the side wall and improve the VI lifetime, a computational fluid dynamics simulation is used to optimize the VI structure. Results show that when the included angle between the minor flow channel and the inner side of the major flow channel is 40-45° and the included angle between the inlet channel and the outside wall of the major flow channel is 125°, the VI has a relatively small particle loss, eddy, and good collection efficiency. Finally, the system detection performance is experimentally evaluated with a sensitivity of 0.08 Hz/min per μg/m³, showing a comparable performance with the commercial instrument.