Achoo: Bless you! Longer Ragweed Season May Worsen Hay Fever

Written by Lisa Hayden on . Posted in Learn

Itchy, swollen eyes and stuffy nose – it’s August and high season for hay fever, when some of my worst allergens are floating around in the air. (Perhaps my allergic response accounts for my recent general spaciness? Or not!)

Anyhow, media accounts this spring proclaimed it to be one of the worst allergy seasons ever, though some skeptical allergy sufferers say they have heard this before. But recent scientific studies are corroborating the inflamed noses and sinuses many are experiencing.

A study released earlier this year found that that allergy season for a common irritant, ragweed pollen, is getting longer in North America, possibly leading to worse allergic reactions among more people.

Ragweed season generally runs from August until October or the first frost in most parts of the U.S., and this allergy is commonly known as “hay fever.” An estimated 17.7 million American adults and 7.2 million children were diagnosed with hay fever (also called allergic rhinitis) in the past 12 months, according to the Centers for Disease Control.

Upper or northern latitudes are warming faster than lower ones as greenhouse gases accumulate in the atmosphere, and with this change, research shows the growing season for some plants that produce allergens has gotten longer – also extending the sneezing, wheezing and sniffling. So, as Scientific American reported, the ragweed pollen season in Minneapolis has gotten 16 days longer since 1995 while LaCrosse, Wisc. has added 13 days to its season.

Another study by the National Wildlife Federation, Extreme Allergies and Global Warming, found that ragweed plants growing in today’s carbon dioxide levels are likely produce about twice as much pollen as they would have 100 years ago. Ragweed that grows faster for a longer season equals bigger plants with more pollen and a higher allergenic content per plant, according to the report.

This sounds like monster ragweed! Check out this photo of “giant ragweed.”

Another study of blood test results used to confirm allergies, Allergies Across America by Quest Diagnostics, found that during a four-year period, sensitization to common ragweed grew 15 percent nationally while mold grew 12 percent compared a 5.8 percent increase in sensitivity to other allergens combined.

Meanwhile the number of Americans with asthma, a respiratory condition that makes it hard to breathe, rose slightly over the previous four years to about 8.2 percent (or 25 million) Americans in a 2009 survey, according to the Centers for Disease Control and Prevention.

Though acknowledging that causes of asthma are complex and should be further studied, Australian researchers have hypothesized that an increase in carbon pollution and globally warming temperatures may be contributing to a global rise in asthma.

So, what can you do to ease your suffering?

You can try to remove ragweed from your yard. Two different-looking plants cause ragweed: giant ragweed (Ambrosia trifida) and common ragweed (Ambrosia artemisiifolia).

But, it’s tough to completely escape: ragweed often grows along road sides and its pollen has been measured 400 miles out to sea. So you can also minimize your outdoor activities when the pollen count is highest (usually between 10 a.m. and 3 p.m.).

Especially with the recent record hot weather in many parts of the country, asthma sufferers should try to avoid the things that trigger their attacks, such as humid air, smoke or exhaust, and exposure to pets, mold or other specific substances to which they are sensitive. While we all want to get outside to enjoy summer, remember to stay safe and hydrated in the heat when air quality can be poor.

And keep that tissue box within reach!

Lisa Hayden is a feature writer and blogger for The Nature Conservancy

Photo by Flickr user Carolina Biological Supply Company (Microscopic view of ragweed pollen spore) Used under a Creative Commons license.

Inset photo by: Flickr user gmayfield10 (Close up image of bloom of Ambrosia trifida or Giant Ragweed, in the James Woodworth Prairie Preserve) Used under a Creative Commons license.

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