What is Pollen and which ones cause allergies?

Posted by Christine Handler-Kralits on

Each spring, summer, and fall, tiny pollen grains are released from trees, weeds, and grasses. Some of these pollens enters human noses and throats and in some people it triggers a type of seasonal allergic rhinitis called pollen allergy, commonly known as hay fever.

Pollen Allergies

The type of allergens in the pollen is the main factor that determines whether the pollen is likely to cause hay fever. Most allergenic pollens are small, light, and dry so it can be carried by wind sometimes for very long distances. For example, Ragweed pollen has been collected 400 miles out at sea and 2 miles high in the air. Also, these allergenic pollen plants usually produce large quantities of pollen, like Ragweed which can generate a million grains of pollen a day.

Among North American plants, weeds are the most prolific producers of allergenic pollen with Ragweed being the major culprit. In addition, grasses and trees are important sources of allergenic pollen. Although more than 1,000 species of grass grow in North America, only a few produce highly allergenic pollen.

Some Allergenic Pollen Grasses:

  • Timothy Grass
  • Kentucky Bluegrass
  • Johnson Grass
  • Bermuda Grass
  • Redtop Grass
  • Orchard Grass
  • Sweet Vernal Grass


Some Allergenic Pollen Trees

  • Oak
  • Ash
  • Elm
  • Hickory
  • Pecan
  • Box Elder
  • Mountain Cedar


These are ways to reduce exposure to offending allergenic pollens:

  • Remain indoors with windows during times of high pollen counts like in the morning and during sunny, windy days
  • Wear a face mask to filer pollen out of the air and keeping if from reaching reaching nasal passages and throat when you go outside
  • Take a vacation during the height of pollinating periods, like on an ocean cruise.

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