I just purchased a JET 1100 dust collector because it received high ratings from FWW.  I noted in FWW that the included dust bag was capable of filtering no smaller than 30 micron particle dust size.  The recommendation was a bag capable down to 1 micron size.  Then in this forum a reader mentioned Wynns Environmental cartridge filters “filter at 99.5% efficiency down to .02 microns.”  (Is it even possible to filter .02 micron dust out of the air?)  This leads me to two questions:  What is the particle size of dust produced by ANY power machine, including power sanding and are these particles as small as 1 micron or smaller?  Would FWW consider doing a test of dust collectors that are fitted with 1 micron filters exclusively and rate only those systems that are capable of moving enough air and filtering enough of the dust out to create a relatively healthful breathing environment?  I have worked wood for a long time and always knew that dust was a health hazard – and took whatever means I felt were effective to reduce the health hazard – but only in recent months have I noticed that “particle size” is specifically mentioned, including the fact that 1 micron sized dust can in fact get into your bloodstream.  It makes little difference what size the dust particles are; if current filtering systems are incapable of removing the ones that represent a serious health threat, I think we all need to know that and put aside any illusions that one brand is better than another.