Try the 3m disposable respirator - about £15, but works well on partical
and vapour, comfortable to wear and makes a good seal onto the face. The
air exhaust is in roughly nose position and angled down such that it will
not mist ordinary googles.

http://www.screwfix.com/app/sfd/cat/...38847&id=13038


Agreed. This is about the only one of the many I've tried that mostly avoids
this problem.