This is a common name for masks used to protect from dust, molds, filings, non-toxic fumes and vapors, and other particles.

Run a google search on "dust mask" and you will get many helpfull hits. This one is complete with pictures:

http://www.theairfilterstore.com/allergy/

For toxic gases and fumes, loose nose and mouth protection is not sufficient, in this case the all too familiar gas mask is called for.

Regards,

Alaa