From the ABC 7 Weather team

D.C. pollen count is high, but U.S. Army is on the allergy case

April 7, 2011 - 05:00 AM
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As the weather gets warmer, a virulent pollen swarm grows stronger in D.C. Fortunately, the U.S. Army is keeping track of it.

Pollen from sunflowers, morning glories, lilies, primroses and castor beans. (Dartmouth Electron Microscope Facility)

As the weather gets warmer, a virulent pollen swarm grows stronger in D.C. Plants are unleashing an invisible snowfall of reproductive cells that float into our orifices, making throats swell and locking grown men and women into into weepy sneezing fits like adorable kittens.

It won't help to run to the most concrete-shellacked regions of the city, like K Street or Rosslyn. Pollen can drift for hundreds of miles, sometimes aided by built-in air sacs. Hunkering indoors isn't much better if you have any windows cracked or a dog bounding in from the outdoors that will happily rub pollen all over you.

D.C. has had two spikes in pollen this year. The first was during those wonderful 70-degree days in February. Buds opened and anthers dried out and cracked, spreading pollen grains into the wind. The cool and drizzly March weather assured buds stayed tightly clenched. But with the recent warmth, the current pollen count in D.C. is “high,” meaning that most allergy sufferers are experiencing discomfort. (Like you needed to be told that over your Great Wall of torn-up Kleenex.)

Sources of pollen vary from city to city. During spring in D.C., it's the unassuming trees that make us suffer for the sake of their sex lives.

The elms standing majestically alongside the national monuments, the stately oak boughs of Georgetown and the dense forest growth that keeps Rock Creek Park cool in summer – all of them contribute to the vast pollen cloud enshrouding the city.

Who's to blame right now? Why, it's the rowdy bunch from the cedar/cypress/juniper family. These barky bastards are causing us to be “just inundated with tree pollen,” says Susan Kosisky, co-chief microbiologist at the U.S. Army Centralized Allergen Extract Lab at the Walter Reed Army Medical Center.

“People always say, 'Oh, the flowers are in bloom, the daffodils are out, my front lawn is loaded with dandelions,'” says Kosisky. “In actuality, those are insect-pollinated and their pollen is heavy and sticky and doesn’t get aerosolized. It’s the trees with inconspicuous flowers – small, greenish-brown flowers – that are releasing massive amounts of pollen into the atmosphere.”

So how much of a tree-pollen problem does D.C. have?

In April, Kosisky's lab started releasing D.C.-centric pollen guidelines in addition to the countrywide ranges used by the National Allergy Bureau. A “moderate” pollen count according to the NAB is 15 to 89 grains per cubic meter, a number arrived at by averaging the counts from a network of U.S. monitoring stations. (Follow your own city's pollen levels here.) But Kosisky and crew, after examining data collected by a roof-mounted volumetric sampler in Silver Spring, determined we were so thick with tree dust that a new definition of “very high” was needed.

Whereas NAB's "very high" means more than 1,500 grains per cubic meter, the count has to exceed 2028 grains to qualify as “very high” in our pollen-blasted neck of the woods. Conversely, a “very high” count for grass pollen in D.C. is more than 52 grains per cubic meter, while NAB's begins at a whopping 200 grains. You can thank the grassy prairie lands out West for skewing the national range.

These new D.C. ranges will help doctors determine how best to treat local allergy sufferers. After all, why use national averages to prescribe medication when they're out of whack with what's actually in the air? “Adjustments can be made in dosing so [patients] are not double-dosed,” Kosisky says.

So what plants should you punch as allergy season kicks into gear? Basically everything. April will see more trees pollinating, as well as dock, weeds and English plantain (those grassy stalks with brown coneheads that kids turn into weapons).

“April has something for everybody,” says Kosisky.

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