The pollen, my friend, is blowin' in the wind

D.C. pollen count highest for early April in 12 years

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The single biggest complaint I've heard about this week's weather is neither the above-normal heat, nor the crowds of tourists ... It's allergies. The sudden burst of warmth and sun combined with the lack of rainfall over the past several days have sent trees that were snow-bound just weeks ago into a reproduction frenzy. Tree pollen has been the main culprit. (Grass, weed and mold pollen counts have been low; their peak pollen seasons are summer and fall.)

As of Tuesday, the local pollen count was off the charts at more than 4,000 grains per cubic meter. "Looking over the last 12 years of data we have not had recorded daily counts this high for the first week in April," according to the daily pollen report provided yesterday by the Department of Allergy and Immunology at Walter Reed Army Medical Center. Oak trees were by far the greatest contributor (more than 3,300 grains per cubic meter), with sycamore (263.58), birch (81.47) and other trees trailing behind. While the trees benefit from the onslaught of pollen, the respiratory tracts of allergy sufferers most certainly do not.

What are these tiny particles of pollen? And why are they blowing in the wind? It has to do with the birds and the bees -- literally.

Keep reading to learn more about pollen and why it causes allergies...

Pollination is the process by which flowering plants reproduce. It results in seeds and fruits that begin new generations of these species. Pollen grains from the male part of a plant are transferred via wind or pollinators (e.g., birds, bees, butterflies) to the female part of the new flower, or in some cases, the same flower. Once the pollen sticks, the now-fertilized plant produces one or more seeds encased in a "fruit." Without pollination, there would be no apples, grapes, oranges, plums, acorns, walnuts, rice, wheat or tomatoes (botanically, these are all considered fruits).

Like other trees, oak trees produce flowers, though they are small hanging flowers that do not look like the attractive landscape flowers we are used to seeing. Most trees rely on wind to carry their pollen. Since they do not need to attract pollinators, their flowers are not colorful or fragrant.

When pollen enters the respiratory tract of a person who is allergic to it, it is seen as an invader by his or her immune system. Thus the itchy eyes, scratchy throat and sneezes. In urban areas, the "invader" effect is enhanced when pollen interacts with air pollutants. As we speak, millions of tiny "invaders" are floating around us in the hot spring air. Comforting, no?

Just be thankful that we don't live in Knoxville, Tenn., which has been awarded the number one spot on this year's list of Spring Allergy Capitals compiled by the Asthma and Allergy Foundation of America (D.C. is ranked 43 out of 100), and that the chance of rain later today could mean temporary relief for allergy sufferers.

More resources:
Capital Weather Gang: D.C. area pollen, UV and air quality forecasts
Tree pollen kicks off Washington's allergy season
Web MD: Spring allergies
Allergy tips