The Washington Post

Tree pollen spikes to “very high” levels

Walter Reed Army Medical Center reports tree pollen has reached its highest level yet this year, climbing to 2302 grains per cubic meter. Thankfully, today’s rain showers should knock it back down a bit.

While “very high”, today’s levels are well off last year’s tree pollen peak, when the count soared to an eye-reddening, nose stuffing 4174 on April 6.

Dr. Susan Kosisky, co-chief of Walter Reed’s Allergen Extract Lab, says last year’s amped up count resulted from an abrupt transition from cool, damp weather to a stretch of warm, dry weather.

“There was a long period when things were kept a bay, but then everything blew,” she said. “The oaks just went sky high.”

This year, the tree pollen counts have been more up and down due to the topsy turvy nature of the weather, with wet and dry days alternating .

“The tree pollen is being expended, but at intervals,” Kosisky said.

If you’ve noticed your tree pollen allergies getting worse over the years, you’re not imagining things. Kosisky said there’s been a slight upward trend in tree pollen levels during the 13 years of observations. She suspects it may be related to urban tree planting programs (sometimes referred to as canopy initiatives).

“There are huge initiatives for tree planting,” she said. “These increase the pollen load over a period of time.”

Jason is the Washington Post’s weather editor and Capital Weather Gang's chief meteorologist. He earned a master's degree in atmospheric science, and spent 10 years as a climate change science analyst for the U.S. government. He holds the Digital Seal of Approval from the National Weather Association.


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