I’m looking at getting the Delta 50-760 Dust Collector with the 1 micron bag.  From a measurement perspective I know what 1 micron means, but from a practical standpoint and putting that in relative terms I’m at a loss.  I’m having a hard time putting that size into some relative perspective. 

What kinds of particles are 1micron in size?  Is that smaller than drywall dust produced when sanding at 100grit sandpaper?  Can I use this filter to suck up drywall mess after I’ve sanded? 
Also, when cutting something on a TS, is there a percentage of particles that will be at 1micron or below?  Is there a certain percentage of particles below this size (but large enough to do damage) that are present in ambient air?

thanks!

T.