From the ABC 7 Weather team

Ragweed pollen in Washington D.C.

August 7, 2013 - 11:24 AM
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Ragweed typically makes its annual return to the D.C. area late August
and peaks in early September.

Ragweed is the highest cause of allergenic rhinitis in North America and will be making its annual visit to the D.C. area in the next couple of weeks. Thus far, pollen counts for Ragweed are relatively low.

Susan Kosisky, the Chief Microbiologist at the US Army Centralized Allergen Extract Lab stated in the latest pollen count, "The first week of August is when we usually start to see the first glimpses of ragweed season. By the second week in August, daily average totals are around 4 grains/cubic meter of air."

She did note, however, that the latter part of August through early September is usually the point when ragweed really begins to increase in the D.C. area. "In the month of August some 40% of our total annual ragweed pollen load is observed. The first week in September is usually the overall "peak week" for ragweed. In September, about 56% of the annual ragweed pollen load is recorded. We have not seen too much ragweed out there (maybe a grain or two to date)."

Ragweed plant

Ragweed, shown above, are annual or perennial herbs that range from small plants 3 feet tall up to 13 feet tall (Great Ragweed). 21 species of ragweed occur in North America, but most allergy problems are caused by just two species which account for more hay fever (bodies reaction to the pollen) than all other plants together. One single plant can release up to a billion pollen grains in a season. Not that I trust everything on wikipedia, but it stated that pollen grains have been recorded around 400 miles out at sea and up to 2 miles up in the atmosphere, so the pollen can travel exceptionally far.

How can you beat the pollen? Here are a few tips.

Stay indoors as much as possible during high pollen days (We will let you know when those days are!)

Keeps windows in your house and car shut as much as possible

Change clothes after being outdoors for a prolonged period of time

Shower before bed to wash off pollen

Equip your home with HEPA air filters

Remember to take your allergy medications (Claritin is my friend during the late summer and early fall!)

Wet conditions and humid air is usually good during ragweed season as it doesn't allow pollen to disperse in the atmosphere as much as it would if it were dry and windy. This could be a good thing for the next few weeks, but remember when the skies finally clear and drier air gets into the region later this month, you may want to keep the windows shut.

If you plan on traveling this fall, you may also want to take your allergy medications with you, as the ragweed season is longer the farther south you travel. Some species don't pollinate until the winter months in Florida. Ragweed is done after the first hard freeze, which after our record cool maximum yesterday may be sooner than we think!


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