It's allergy season, and Chattanooga once again ranks in the top 10 for spring allergy capitals.

Once again, the Chattanooga metropolitan area ranks in the top 10, nationwide, in a miserable category.

The Scenic City is the U.S.'s sixth-worst "spring allergy capital," according to the Asthma and Allergy Foundation.

That's an improvement over last year, when the foundation ranked the Chattanooga area third nationwide based on pollen scores, the amount of allergy medications that residents use, and the number of board-certified allergists per patient.

The rankings were released right around the time Bradford pear trees were flowering here -- and releasing pollen that wreaks havoc on some allergy sufferers' sinuses. Tree pollen is common now, foundation spokeswoman Sanaz Eftekhari said. Grass pollen dominates during the summer, and weed pollen takes the fore in the fall.

But cutting down all the Bradford pear trees here wouldn't improve things, a Chattanooga tree expert says.

"There is no escape from the allergies," said Jon Nessle, an arborist who specializes in ornamental trees and serves as chairman of the city's Tree Advisory Commission.

Removing one species isn't a solution, Nessle said, because this area has such a wide variety of trees and plants that some other airborne irritant would likely take its place.

"You never know who's allergic to what," Nessle said, citing the high biodiversity here compared to other regions with a temperate climate. "Tennessee is very fortunate. There is only one other place in the world with the biodiversity of Eastern Tennessee ... in eastern China."

Chattanooga has removed city-owned Bradford pear trees because they break apart -- not because the trees aggravate some peoples' allergies, city Forester Gene Hyde said.

While cutting down trees isn't a solution, allergy sufferers can take matters into their own hands, Eftekhari said.

The foundation does its annual rankings in the largest 100 U.S. metropolitan areas partly to promote the idea that sufferers can take allergy medicines prophylactically, she said, "before you're coughing, sneezing and wheezing."

"We try to teach people to be proactive and go to their doctor and talk about it," Eftekhari said.

Contact staff writer Tim Omarzu at tomarzu@timesfreepress.com or 423-757-6651.