Pollen is a fine powder produced by certain plants when they reproduce. During the spring, summer, and fall seasons, it's released into the air and picked up by the wind, which brings it to other plants to fertilize them.Pollen is produced in the microsporangium (contained in the anther of an angiosperm flower, male cone of a coniferous plant, or male cone of other seed plants). Pollen grains come in a wide variety of shapes, sizes, and surface markings characteristic of the species.
The transfer of pollen grains to the female reproductive structure (pistil in angiosperms) is called pollination. This transfer can be mediated by the wind, in which case the plant is described as anemophilous (literally wind-loving). Inside of these pollen grains are proteins that commonly cause allergic reactions (such as sneezing, runny nose, and itchy eyes) when breathed in. The pollen that's most often responsible for causing allergies comes from grasses, trees, and weeds. Many people with asthma are allergic to pollen. When they breathe it in, it can trigger their asthma symptoms.
Allergy to pollen is called hay fever. Generally pollens that cause allergies are those of anemophilous, because the lightweight pollen grains are produced in great quantities for wind dispersal. Breathing air containing these pollen grains brings them into contact with the nasal passages.Anemophilous spring blooming plants such as oak, birch, hickory, pecan, and early summer grasses may also induce pollen allergies. Cultivated flowers are most often entomophilous and do not cause allergies.High pollen quantity leads to a reduction of these characteristics and stabilization of a population. Small quantity leads to their increase and destabilization of a population.
An allergy is an abnormal reaction to an ordinarily harmless substance called an allergen. When an allergen, such as pollen, is absorbed into the body of an allergic person, that person’s immune system views the allergen as an invader and a chain reaction is initiated. White blood cells of the immune system produce IgE antibodies. These antibodies attach themselves to special cells called mast cells, causing a release of potent chemicals such as histamine. These chemicals cause symptoms such as a runny nose, watery eyes, itching and sneezing.
An allergy to airborne particles most commonly leads to allergic rhinitis (symptoms in the eyes, nose, and throat). Hay fever is the term used for an allergic reaction to pollen. However, people may develop an allergic reaction to other particles in the indoor or outdoor environment that leads to symptoms virtually identical to hay fever.
Allergies are caused by an oversensitive immune system, leading to a misdirected immune response . The immune system normally protects the body against harmful substances such as bacteria and viruses. Allergy occurs when the immune system reacts to substances (allergens) that are generally harmless and in most people do not cause an immune response.
A few people develop allergies to other irritants in the environment, including smoke, fumes from industries or cleaning products, tobacco, powder (face powder, baby powder, and so on), laundry detergents, and other common substances.
When an allergen enters the body of a person with a sensitized immune system, it triggers antibody production. Histamine and other chemicals are released by body tissues as part of the immune response. This causes itching and swelling in affected tissues, mucus production, and in serious cases, hives and rashes , as well as other symptoms.
Symptoms vary in severity from person to person. Most environmental allergens contact the skin or eyes, or are inhaled. Therefore, most symptoms affect the skin, eyes, or the breathing passages.
Many disorders are associated with, triggered by, or worsened by allergies. These include eczema and asthma.
Allergies are relatively common. Heredity, environmental conditions, number and type of exposures can affect a predisposition to allergies. For reasons that are not fully clear to scientists, allergies are on the rise, particularly in so-called "Westernized" regions such as the United States and Europe.
There are a number of reasons that could explain the difference, including the time of day that the sample was taken; a change in temperature, wind conditions, humidity or precipitation; or differences in surrounding geography.
The time of day that aeroallergens are sampled can account for variances in the amount of pollen measured. Pollen concentrations are usually highest after the dew dries after sunrise to late morning. If one station samples at 8 a.m. and the other station samples at 2 p.m., there could be a significant difference in pollen concentration.
Weather conditions also affect pollen levels. The most variant factors influencing different pollen counts from approximately the same region are wind, humidity, and the proximity of the sampling equipment to pollen producing vegetation.
When the air is humid, such as during or after it rains, pollen becomes damp and heavy with moisture, keeping it still and on the ground. If one station samples right before a rain storm, and the other station samples just after it rains, there will probably be a significant difference in the concentration of pollen.
Another reason to account for the difference is the proximity of the sampling equipment to pollen producing vegetation. Samples taken from an urban area, where there is little vegetation, will most likely differ from samples taken from a rural area, where there is more vegetation.
The beginning and ending times of tree, grass and weed pollen seasons are very similar from year to year in the same location. Intensity differs every year based on the previous year's weather, current weather and other environmental factors.
Keep away from seasonal allergy:
You can't completely avoid seasonal allergens, but you can reduce your signs and symptoms and minimize your exposure with these simple reminders:
*Close doors and windows when pollen counts are high.
*Use air conditioning in your house and car. Air conditioning cleans, cools and dries the air.
*Stay indoors on dry, windy days. The best time to go outside is after a good rain, which helps clear pollen from the air.
*Use a dehumidifier to reduce indoor humidity.
*Use a high-efficiency particulate air (HEPA) filter in your bedroom and keep windows closed at night.
*Delegate lawn mowing, weed pulling and other gardening chores that stir up pollen and molds.
*Spring cleaning does wonders for clearing out the winter doldrums, but it's also good for reducing allergens.
*Use allergy-proof covers on mattresses, box springs and pillows.
*Wash sheets and blankets in water heated to at least 130 degrees Fahrenheite.
*Vacuum carpets weekly with a vacuum cleaner equipped with a small-particle or HEPA filter.
*Consider removing carpeting, especially where you sleep, if you're highly sensitive to dust mites.
*Think twice about letting your pet sleep on your bed or on your couch; pollen clings to pet fur.
In addition to using these self-care tips, you may want to talk to your doctor about allergy medications, such as nasal sprays, eyedrops or pills, to help control your signs and symptoms.
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