I've spent a lot of the last day and half trying to catching up on PM monitoring techniques for the microscope project. In this article - https://publiclab.org/wiki/silica-monitoring - there are a number of references to EPA monitoring techniques for different particles sizes. Beyond writing up an explanation of scanning electron microscopy and X-ray diffraction (which seems useful on its own), it might be useful to do a methodology review for how the EPA measures differently sized particles.
A brief overview of measurement techniques might be useful for providing context for what people will and won't be able to see. SEM pictures are detailed and very beautiful, and I think they give people a misleading view of what you can see with at the 5-10 um level. I've found that to be confusing when working with the Open Flexure microscope