Pollen and Grain Dust -

Each spring, summer, and fall, tiny particles are released from
trees, weeds, and grasses. Known as pollen, these tiny particles
catch a ride on the prevailing winds, and end up in your nose and
throat, causing a sort of rhinitis commonly known as hay fever.

Pollen is probably the most widespread cause of seasonal allergies -
so common, in fact, that many newscasts regularly give a pollen
count. Pollen sufferers in farming communities commonly feel the
same effects from grain dust which can be quite a problem during
harvest time.

People who are sensitive to pollen often develop problems with dust
mite extracts which leaves them experiencing allergic reactions
year-round.

Fir Pollen

Birch Pollen