The Impactor Inlet is an accessory for the Aerodynamic Particle Sizer® (APS® ) spectrometer. It combines a single-stage impactor with a filter to take a size-segregated sample. It then directs a small, representative sample of the initial test aerosol (diluted at 80 to 1) into the APS spectrometer for size-distribution measurement.

The inlet aerosol passes through a single-stage impactor (2.5 or 4.7 µm) and is collected with an afterfilter, which collects a sample for later mass or chemical analysis. The Model 3306 includes two inlet throats: one for standard applications; the other for pharmaceutical research. This impactor may be used with any style of APS spectrometer.