The first day of spring was more like summer at Emory's Oxford College campus, 40 minutes east of Atlanta. It was the seventh straight day of highs above 80 degrees, breaking the March record for an unbroken stretch of such high heat in the Atlanta region.

Biology professor Eloise Carter and students in her field botany course returned to the lab from a trip to nearby Oxhouse Lake, sweaty and dusted in pollen. As the students laid out specimens of flowering plants they collected, Carter brought out her iPhone to show photos to another biologist in the department.

"It's pollen," she says, showing what looked like a sandy beach, but was actually tree pollen coating the surface of the water along the lake shore.

The count of 9,369 particles of pollen per cubic meter of air on Tuesday was 55 percent higher than the previous record, set in 1999. A mild winter, leading up to a hot spring, has blown back the clock, driving the blitz of allergens from trees that are pollinated by wind.

Instead of tree pollination extending as usual from February to May, "it's been telescoped down," Carter says. "It's pretty extreme."

Full story >>