The in-built APS characterizes the particle size distribution spectrum within the RASC.

<p>(A) Typical background particle spectrum before and after air wash. Note the 10-fold decrease in particle counts across all size ranges following the air wash. Total count from a typical five seconds of sampling. (B) Artificial dry release of fluorescent polystyrene latex (PSL) microspheres. The APS instrument groups all particles with an aerodynamic diameter less than 0.523 μm in the number bin on the far left of each chart. Note that the 1μm release (b) contained approximately ten times more particles in the release. Total count from ten seconds of sampling at the peak of particle concentration. (Inset) corresponding SEM images of the released particles.</p>