Thanks for all the replies so far. I agree that there has been some very useful info on this thread.

I took a look at the items in the two recent posts (by Am_Fear_Liath_More and Armageddon Aviator). They're both interesting pieces of gear - seems like either one would be ideal for dealing with smoke from fires, or the kind of dust pollution that happened in 9/11 on the streets of Manhattan. The British version of the personal hood appears to be (somewhat) fire resistant, whereas the Draeger item seems to offer breathing protection - but not heat protection. I could be wrong about that, though.

I'm taking a look at the various suggestions on this thread. I will definitely add some kind of breathing protection to my emergency gear.

cheers,
Pete2