Always so bizarre to give my 9.5 lb chi a dose of benadryl that would put me out cold for hours and have her not even notice except it stops the sneezing.
A rub-down with a dampened microfiber cloth after being out might not be a bad idea.
I have heard of using raw local honey for pollen allergies in dogs, but have not tried it. When I get into a very bad spot, a tablespoon of raw local honey is my go-to. It will stop a reaction where nothing else will.
Quercetin/bromelain combo is something I like for humans and dogs.