Pollen Allergen
Pollen information:
Pollen grains are microscopic or small reproductive structures produced in the anthers, or male elements, of seed bearing plants. They are dispersed mainly by air, water or animals.
Plants with colorful flowers are generally insect pollinated or entemophilous and do not get airborne in large numbers, or at all. Plants, such as trees, shrubs and weeds, that depend on the wind for pollination are called anemophilous and generally do not produce large colorful fragrant flowers.
Our Company is concerned with airborne pollen that produce allergens causing health problems such as allergies and asthma. Examples of important aeroallergens are oak, birch, maple and ragweed. We do, however, observe some pollen from insect pollinated plants or trees on our samples, but they are usually in low numbers and do not play an important role in allergic reactions.
When pollen from anemophilous plants become airborne they can be carried for long distances. The chemical makeup of pollen is the basic factor that determines whether it is likely to cause an allergic reaction. The size of the particles can also influence the kind of reaction that may occur. Large pollen grains do not tend to travel deep into the lungs or alveoli and therefore more often cause allergic reactions and not asthma. If particles or fragments, which tend to be smaller, become airborne and end up deep in the lungs they can cause an asthmatic reaction. Pine trees, for example, tend to produce large amounts of pollen but their chemical makeup is such that it rarely causes allergic reactions.
Weeds can produce copious amounts of pollen in the air and ragweed is the major culprit, but others such as sagebrush, pigweed, English plantain and Russian Thistle can also be significant allergens.
Grasses and trees are also important sources of allergenic pollen. Only a few species of the grass family are considered highly allergenic. Some of the most prevalent trees that produce allergic reactions include oak, ash, elm, hickory, pecan, box elder, the birch family and mountain cedar (found in some parts of the United States). Other tree pollen can cause allergic reactions. Allergies and sensitization are unique to the individual.
Plants such as roses and tulips are unlikely to cause allergies in humans unless they are sensitized through prolonged close contact. Most people do not have enough direct contact with pollen grains of flowering plants to become sensitized.
Pollen allergies are seasonal in nature. The tree-pollinating season can vary drastically from year to year. This depends on the type of winter, spring and weather conditions during pollination. Seasons can vary by as much as a month from year to year for certain trees, and daily fluctuations in temperature, rain and sun can also affect the amount of pollen released on a daily basis. Ragweed occurs during the summer and is less affected by winter and spring temperatures. During the pollination period the fluctuation in temperature, rain and sun affect the daily pollen grain concentrations as well as the start and end dates of the season.
Pollen reports are a measure of how much pollen is in the air. They often give a measure of the total concentration of pollen with little indication of the types of pollen found or the portion that is made up of allergenic species. A more meaningful and informative report is one that includes a breakdown of specific types of pollen that may cause allergic reactions and their relative concentrations. Using these reports asthma and allergy sufferers may be able to identify their own unique sensitivities and thus monitor the levels of allergens in the air that are relevant to them.
Copyright (c) 2000 Aerobiology Research Laboratories, All Rights Reserved
Contact info@aerobiology.ca for more information