Pollen and the Allergic Response

Everything you need to know about pollen and seasonal allergies

It only takes 20 ragweed pollen grains in a cubic meter of air to trigger an allergic reaction.

Millions of people suffer from seasonal allergies caused by pollen. But what is pollen and how does something so microscopic cause such miserable symptoms? Here is everything you need to know about pollen and the allergic response:

While pollen might make you miserable, it actually does have a purpose and that is to reproduce. These tiny, microscopic particles are part of the plant’s reproductive system and must be transferred to the appropriate parts of the flower in order to create viable seeds. Although some plants pollinate themselves, many rely on other means of transfer to carry their pollen to other plants for cross-pollination. In many cases animals, such as bees and other insects, carry pollen from one plant to another while they gather nectar for food. Other plants rely on wind or water for cross-pollination.

Pollen that relies on wind for cross-pollination is the kind of pollen weather reports measure when they create pollen counts for the public. Typically this count represents the amount of pollen in a cubic meter or air measured over a period of 24 hours. Since pollen counts tend to be highest early in the morning on warm, dry days and lowest on cool, wet days, pollen counts tend to give more accurate representations of actual allergen counts when taken over the course of an entire day.

Plants with showy, colorful flowers usually rely on insects for pollination rather than wind and therefore are not usually included in pollen counts. Wind-pollinated species such as oaks, ragweed, and grasses, spread pollen through air currents and are the types of pollen that produce allergic reactions for so many.

Different plants produce different kinds of pollen and symptoms vary as well. The chemical makeup of pollen determines whether it will cause allergic symptoms and the physical shape of the pollen can determine reactions as well. The biggest culprits in the US are weeds such as ragweed, lamb’s quarters, Russian thistle, English plantain, sagebrush, and redroot pigweed. Grasses also cause allergic reactions and the species that produce the most highly allergic pollen in North America include Kentucky bluegrass, Bermuda grass, Johnson grass, Timothy grass, sweet vernal grass, orchard grass, and redtop grass. Trees that produce the greatest allergens include ash, elm, oak, hickory, box elder, pecan, and mountain cedar.

Individuals suffering from seasonal pollen allergies constantly look for ways to alleviate their symptoms. Unfortunately, physical removal of plants does little good since pollen can travel hundreds of miles on wind currents. Some of these plants, like ragweed, can produce a million grains of pollen in one day and can travel hundreds of miles from its origin.

Unfortunately for allergy sufferers, it only takes 20 ragweed pollen grains in a cubic meter of air to trigger an allergic reaction. If you suffer from seasonal allergies, one of the most beneficial things you can do is keep your windows closed during high-pollen counts. Local weather stations will typically announce when various pollens are at their peak, so you know when to close things up and maybe stay inside. Remember that pollen is worst in the early morning hours; so waiting until later in the day to go out can help as well.