In article ,
Hugh Newbury wrote:

Does rain/drizzle reduce pollen levels? It must take some pollen out of
the air, but what happens to it then? Just sits on the ground and waits
for sunshine to dry it out? Or what?

Yes. It then gets attacked by the ferocious bacteria that are
hiding in the soil, waiting to pounce or poor, innocent pollen
grains.

More seriously, airborne pollen is generated by relevant plants
(trees and grasses, mostly), and drops out very slowly and is
taken out quite fast by rain. The process continues. Pollen,
unlike seeds, does not remain viable in the soil, but its
structure seems to be really quite durable and so it is used
in archaeological invegigations of historical ecosystems.


Regards,
Nick Maclaren.