Summer is ending, you’re heading into fall. But you’re still sneezing and sniffling all day and into the night. What’s going on?
Ragweed is one of the most potent producers of an allergic reaction than any other plant in the world. It is the number one cause of hay fever symptoms and seasonal allergy symptoms and is the most common cause for allergic rhinitis. This plant can produce billions of pollen grains that float into the atmosphere and find their way into the nose of allergy sufferers. Their pollen alone can travel many miles due in part to their lightweight texture. Although the ragweed plant can only survive for one season, the fact that they produce so much pollen and their pollen can travel so far makes eradication of this plant impossible.
If you are allergic to any form of pollen you are
probably allergic to ragweed. Nearly 10 to 30% of Americans suffer from these
allergies each year. From August until the first freeze, allergy sufferers
respond with symptoms such as watery nose and eyes, sneezing, coughing and
congestion. But it is not the flower itself that creates these annoying
symptoms for us allergy sufferers; it is our bodies that make that happen.
When we breathe in pollen or other allergens, our
bodies see this pollen as a harmful invader. Once these pollens enter our
bodies our immune system attacks this harmless substance, also known as
allergens, and calls upon a substance called immunoglobulin E (IgE) to fight
the invaders. Everyone has these IgE antibodies, but a person with allergies
has a very large amount of these defenders.
Once these defenders take their stance they activate
special cells in our bodies called mast cells. When a mast cell is activated,
it then releases an assortment of chemicals into our bodies and this includes
the chemical known as histamine. Histamine is the irritating chemical that
causes itching, swelling and fluid leaking from cells
Ragweed pollen concentration fluctuation
Longer Pollen Season
The figure below shows how the length of ragweed pollen season changed at 10 locations in the central United States and Canada between 1995 and 2011. Red circles represent a longer pollen season; blue circles represent a shorter season. Larger circles indicate larger changes.
Since 1995, ragweed pollen season has grown longer at eight of the 10
locations studied (see Figure 1).
The increase in ragweed season length becomes more
pronounced from south to north. Ragweed season increased by 24 days in Fargo,
North Dakota, and 26 days in Saskatoon, Saskatchewan (see Figure 1). This trend
is consistent with many other observations showing that climate is changing more
rapidly at higher latitudes.
The trends in Figure 1 are strongly related to
changes in the length of the frost-free season and the timing of the first fall
frost. Northern areas have seen fall frosts happening later than they used to,
with the delay in first frost closely matching the increase in pollen season.
Meanwhile, some southern stations have experienced only a modest change in
frost-free season length since 1995.