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Lundgren, Linnea, and Jeff Wald. "Allergy Basics." 02 May 2006. HowStuffWorks.com. <http://health.howstuffworks.com/how-allergies-work.htm> 17 May 2008.
by Linnea Lundgren and Jeff Wald, MD
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Allergic Rhinitis: Weed Pollen
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Allergic Rhinitis: Weed Pollen
Summer is half over by the time grass pollens are finished doing their job. That's when weed pollens, which have waited patiently, spring forth. Those pesky plants that, along with cockroaches, will inherit the earth someday are ready to take over pollen production from midsummer to mid-fall. This section looks at the ways that weed pollens can cause allergy havoc for millions of Americans.
Hay Fever? |
When it comes to weed allergies, ragweed is the star. Its pollen is one of the most potent. Only a few ragweed pollen grains are needed to produce hay fever, which is bad news considering that one ragweed plant can produce one billion pollen grains in a season. This demon plant knows no boundaries and in some places can grow 12 feet or higher. Ragweed pollens love to book one-way tickets out of town: Ragweed pollen has been found 400 miles out to sea and two miles up in space.
While there are few places to hide, ragweed isn't fond of areas in upper New England or the southern tip of Florida. The West Coast has western ragweed, which is not as bad as giant ragweed but still causes allergies. While the Rocky Mountain states don't have ragweed, they do have other weed pollens.
Other Types of Weeds
Some weeds are prolific pollinators. Take dock weed for example, which comes in several varieties -- bitter, green, white, and yellow; it pollinates from April all the way to December.
Other weeds to watch out for include aster, cattail, clover, dandelion, fireweed, mugwort, nettle, pigweed, California poppy, rabbit brush, sagebrush, and Russian thistle. Along with the nuisance weeds, some crop weeds, such as alfalfa, hemp, hops, sweet clover, and sunflower, produce pollens, too.
Monitoring Weed Pollen
Allergists and meteorologists help you stay on top of pollen allergies by constantly assessing and reporting on the amount of pollen in the atmosphere. During pollen season, these experts take daily pollen counts, which measure the number of pollen grains in one cubic meter of air during a 24-hour period. Pollen is collected with a plastic rod or similar object that is covered in a greasy, sticky substance. The rod rotates or spins continuously, collecting pollen specimens that are then examined under a microscope and counted. Local wind currents, rainfall, and humidity sometimes limit the accuracy of the readings.
Many newspapers list local pollen counts on the weather page and some newscasts announce pollen counts during the weather report. Always remember that the pollen count you hear on the news is 24 to 48 hours old and counts can change quickly depending on weather conditions. Pollen counts are worse on clear, windy days and generally improve on rainy days or after the first light frost. Make note of the weather conditions the day prior (when the pollen count was taken) before drawing any conclusions about present-day pollen conditions.
Where to Find Pollen Counts
If you don't see the pollen count in the paper or on television, you can get pollen counts by going to the following site(s) on the Internet:
- National Allergy Bureau of the American Academy of Allergy, Asthma, and Immunology at www.aaaai.org
- The Asthma and Allergy Foundation of America: www.aafa.org
While flower pollens don't disperse in the wind as easily as other pollens, they can cause problems in an enclosed environment. If you must give flowers, choose those with a few prominent stamens, such as lilies. (Stamens are the flower's male reproductive organs that produce pollen.) Then, before offering the flower, perform surgery by carefully removing the stamens. If such "castration" is too much for you, try giving a card instead. Orchids are another good choice. They don't readily release pollens and are generally well tolerated. They are the symbol for the Asthma and Allergy Foundation of America. |
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Please copy/paste the following text to properly cite this How Stuff Works article:
Lundgren, Linnea, and Jeff Wald. "Allergy Basics." 02 May 2006. HowStuffWorks.com. <http://health.howstuffworks.com/how-allergies-work.htm> 17 May 2008.
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