Development of performance test system for virtual impactor of respirable dust

This work introduces a polydisperse aerosol testing system for respirable dust virtual impactor evaluation for the first time, and characterizes its performance. The aerosol in the dust chamber diluted and mixed completely, its diameter distribution follows a lognormal distribution. Although the aerosol concentration increased from top to bottom in the chamber, the particle distribution in the same measurement plane was relatively uniform. The sample flow rate of the test system is stable, and the change of temperature on the flow rate is negligible. The most common virtual impactor with the operating point flow rate of 4 L/min was selected as the subject, and its separation performance, flow variation and load characteristics were evaluated by this test system. The results show that the cutoff diameter deviation is − 2.8% and the maximum deviation from the BMRC curve is − 4.85%. The deviation in the cut-off diameter was more likely to be caused by the minor flow rate than that of a major flow rate. With an increase in the loading time and dust concentration, the virtual impactor was overloaded, which required maintenance according to its actual usage.