Ah, the sweet smell of ragweed ... bane of every outdoor allergy sufferer's existence.
Come late summer and early fall, most of the air across the United States — especially from the Midwest to the East Coast — is teeming with ragweed pollen, causing as many as 30 percent of adults and 40 percent of children to suffer from allergic rhinitis, or "hay fever." Symptoms — sneezing, runny or stuffy nose, and itchy eyes, nose and throat — begin in mid-August when individual ragweed plants start releasing the billion or so pollen grains they will produce during the growing season and continue until the first frost mercifully kills the plants.
The potency of ragweed is due to the pollen grain's ability to travel long distances (it can be detected 400 miles out to sea) and that the weed can grow pretty much anywhere, including vacant lots and roadsides. Luckily (or not so, depending on your torture preference), high humidity levels cause the grains to clump together and become too heavy for long-distance air travel.
In 2005, the cost of treating allergic rhinitis in the United States was $11.2 billion — a number expected to rise with prescription costs, population growth and even climate change. According to research published in the Journal of Allergy and Clinical Immunology, higher temperatures and increased atmospheric carbon dioxide cause ragweed plants to grow more quickly, flower earlier and produce greater amounts of pollen.
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