Pollen Forecasters See Serious Sneezing Ahead
Danielle Rozniatoski hopes this spring won't be as cruel as the last one. The 18-year-old education major at Cabrini College in Radnor, Pa., has allergies so severe that she attends college close to where she grew up. When the pollen kicks in, she can take refuge in her parents' air-conditioned house in Philadelphia. After last year, she says, when her allergies caused her to miss a dozen days of high school, "I'm really kind of nervous about how bad I'm going to be once spring comes."
She, along with 36 million other Americans who suffer from seasonal allergies, may have good reason to worry. The burgeoning field of pollen forecasting has found hints of sniffly times ahead, for this spring and many springs to come. Such forecasting is still a "baby science," explains allergist Linda Ford, past chair of the National Allergy Bureau. But aerobiologists are working to figure out the complex interplay of weather, pollen biology, and allergies.
One pollen research company has already gone out on a limb with a prediction for this year. More than 80 percent of allergy sufferers in the United States will face a sneezing season just as severe as last year's, says Surveillance Data. Pollen was fairly high last year, according to the company, which posts pollen levels on its Web site at pollen.com. And this year's winter temperatures, which influence bud growth, were similar to last year's across much of the country. Only a handful of states, including Texas and Louisiana, are expected to have lower pollen counts.
Local forecast. Still, the factors controlling pollen levels vary so much from day to day and place to place that right now, most scientists hesitate to make seasonal predictions. Pollen production "really depends upon local weather," says Ira Finegold, chief of allergy at St. Luke's-Roosevelt Hospital in New York. While a cold snap at the right time can stunt pollen growth, a moist, mild period feeds it. A heavy downpour can cleanse the air of pollen, while dry gusts disseminate the dust.
But in Europe, scientists who have been working with 30 years of pollen data are finding hints of an unsettling trend. "They're seeing earlier timing and more abundant pollen," says Christine Rogers, a researcher at the Harvard School of Public Health. A warming world may be to blame. Higher temperatures during the summer, Rogers says, could allow plants to allocate more resources to pollen production for the following spring.
Another factor may add to the misery in years to come, say some researchers: rising levels of carbon dioxide--the same gas believed to be driving global warming. "CO2 makes everything grow--it doesn't just make all the good things grow; it also makes all the things you don't want to have around grow," says weed ecologist Lewis H. Ziska. In a study released last summer, he and colleagues at the U.S. Department of Agriculture showed that carbon dioxide directly increased ragweed pollen production in the lab. At the rate carbon dioxide is being emitted, Ziska's team projects that pollen counts could triple in 50 years.
Yet the best predictions may still be your own. "The plants can tell better than forecasting," says Rogers. If you know which kind of tree makes you sneeze and wheeze, take a close look at it next time you're outside. See if tiny bouquets of petal-less flowers have begun to dangle from the buds, she says. "That means it's almost time."
This story appears in the March 12, 2001 print edition of U.S. News & World Report.