Dvorin is a full-time allergist, but he’s also a part-time, volunteer detective. Consulting a homely rooftop machine atop his Center City office building, he’s the one who figures out the region’s daily pollen counts. And in recent years, they have taken on a fresh importance.
As they do every spring, the region’s trees are dispersing their microscopic pollen grains to sow the seeds for the next generation. In the process, however, they are tormenting some of Dvorin’s patients and perhaps a million other local allergy sufferers.
But something is different these days, say allergy experts, and evidently it’s tied to the warming of the last few decades.
These annual reproductive extravaganzas are lasting longer, said Dvorin, who has been the region’s official volunteer pollen counter for the National Allergy Bureau for 25 years.
“That’s definitely a trend,” said Dvorin, founder of the Asthma Center, which has several offices on both sides of the Delaware River.
Historically, the tree season has started in March, picked up steam in April, and ended in June. Now the timetable appears to be moving up, and a secondary tree season is showing up in the fall, he said.
Last year, Dvorin’s data detected several September days with significant levels of tree pollen. Those levels were negligible from 1998 through 2000.
The pollen trends track neatly with climate trends during the last two decades – higher temperatures and longer growing seasons.
“We’re seeing changes in the wind,” said Leonard Bielory, a Rutgers University researcher, allergist, and veteran pollen counter.