I decided to try wearing a simple single-use molded surgical mask when working with my router or table saw or when I produce a lot of wood dust while sanding. During my active practice as a surgeon, I operated for many years using the Aseptex brand masks manufactured by 3M, or Folio dress Mask from Hartmann.These masks are very inexpensive and comfortable and are available from several other manufacturers such Johnson and Johnson.  They cost approximately three cents apiece for a 50-count package at my local pharmacy.

For periodic woodworking, even the simplest single-use surgical mask offers excellent protection against the most minute wood dust particles which are far bigger than bacteria. These masks function for both inflow and outflow, providing 95% bacterial filtration efficiency.Although not affording biological protection, they permit simple mechanical air filtration.

This surgical mask are single-use, which means that it is of the utmost importance to discard each mask after wearing it once.When used in this way, I believe that a surgical mask offers better protection than a more expensive dedicated professional mask (having a special outflow valve and so forth).  

More sophisticated single-use masks come with a transparent screen to protect your eyes: these are especially useful for wood turning and are also very comfortable.