Watery eyes, runny noses and puffy faces will abound this year as a warm winter, human development and climate change converge to create a brutal allergy season that will likely get worse for years to come, according to experts.
Plants like ragweed are in pollen overdrive from very favorable weather, while stinging insects like yellow jackets and hornets are findings new homes farther north. More people are becoming susceptible to allergies over time as pollen seasons are getting longer.
This increases risks for people who are already sensitized and threatens those with respiratory problems. The spread of allergies can have tremendous economic consequences as patients with reactions fill clinics and emergency rooms and as afflicted workers stay home.
Allergy symptoms result from the body's immune system overreacting to a given substance, known as an allergen. The symptoms range from mild, such as itchy eyes and hives, to life-threatening when airways swell shut. These conditions already afflict 60 million people in the United States, according to the Asthma and Allergy Foundation of America, and annually cost $21 billion.
Though most allergies can be controlled and treated, public health officials have found that an increasing number of people are adversely reacting to pollen, dander, dust and insects. As the climate shifts, these allergens are expanding to new areas, and previously unexposed people are now reaching for antihistamines.
Ragweed is one of the most common allergen sources and has spread in part due to human activity. "There is a growing body of science showing warming temperatures and carbon dioxide levels cause increases in pollen from ragweed," said Miriam Rotkin-Ellman, a public health scientist at the Natural Resources Defense Council. The plant's pollen is most dangerous from when it flowers in midsummer until when it's killed by the first frost in the fall.
Other pollen sources, like trees, peak in the spring, while grass pollen peaks in the early summer. Warming temperatures have lengthened the risk period for these plants up to several weeks. "It means more misery for allergy sufferers because you're looking at a longer time for exposure to pollen," Rotkin-Ellman said. "All of these factors combine to create a really terrible allergy season."
A rising atmospheric carbon dioxide concentration is also important because it nourishes plants, and fast-growing pollen producers like ragweed are often the quickest to avail themselves of its increasing abundance.
The growing potency of weeds and mold
"When we look at weeds that are associated with pollen, those changes are having a disproportionate effect on their ability to grow and their ability to produce pollen," said Lewis Ziska, a plant physiologist with the U.S. Department of Agriculture's Agricultural Research Service. He noted that, geographically, these patterns change with latitude, with northern areas of the country showing the most drastic increases in environmental allergens.
Already, parts of the country have broken allergy records. In New Jersey, officials observed the highest pollen levels ever recorded in February this year. "I've never seen that in 25 years of my work in this area," said Leonard Bielory, an attending physician and allergist at the Robert Wood Johnson University Hospital and a professor at Rutgers University's Center for Environmental Prediction. "I told people before the year began that it's going to be a horrendous year."
Bielory co-authored a paper with Ziska last year in the Proceedings of the National Academy of Sciences documenting how the ragweed season has grown up to 27 days in parts of the country since 1995. "It's clear that just in New Jersey over the past 20 to 25 years, there's been an increase of five to seven days for pollen," he said.