On Mon, 11 May 2009 07:08:35 +0100
Michael Bell wrote:

snip
Yesterday evening I got the first attack of what felt like the same,
but it has gone this morning. What plants and their pollen are the
possible causes?


It's probably a tree pollen, but might be a fungus spore allergy
although that's usually something for the autumn.
If you disturbed some dust yesterday, you might get symptoms, but they
won't last. Pollen and spores can survive in dust for centuries.

R.