I would suggest that Reagan wasn't talking about pollen. If he had been, he wouldn't have qualified his comments about 'some trees'. He would have said all trees.
As for the pollen count, the inclusion of it in the daily index reporting doesn't make it pollution. It does make it bothersome for people with allergies, which is why they report it.
Thanks for the additional comments.
That's fine about Reagan. As I stated, I don't remember.
But - with all due respect, Google the simple question "Is pollen considered pollution?", and see what you get.
Pollen IS part of pollution, it's just not man-made.
And it's WAY more than "bothersome" for a lot of people.