Main source of airborne pollen varies by month.People with seasonal allergies know that some months can be tougher than others. An unprecedented 15-year study conducted in the New York City New York City: see New York, city. New York City City (pop., 2000: 8,008,278), southeastern New York, at the mouth of the Hudson River. The largest city in the U.S. area charts how air concentrations of different types of pollen vary throughout an average year. Ragweed ragweed, any plant of the genus Ambrosia, coarse, weedy herbs belonging to the family Asteraceae (aster family), most of which are native to America. They have inconspicuous greenish flowers and soft subdivided leaves. pollen, the most significant cause of allergy, is airborne mainly during August and September, report researchers at the University of Medicine and Dentistry dentistry, treatment and care of the teeth and associated oral structures. Dentistry is mainly concerned with tooth decay, disease of the supporting structures, such as the gums, and faulty positioning of the teeth. of New Jersey-New Jersey Medical School in Newark. By contrast, tree pollen is most abundant during May and is nearly absent from the air after the end of June. Grass-pollen concentrations peak in June and rise again, albeit to a lesser extent, in September. Contrary to what some people with allergies might think, pollen abundance has decreased--at least in the New York City area--over the past decade. The new data might help some people avoid unnecessary outdoor exposure at times when their allergies are most likely to be active, Leonard Bielory and his colleagues say in the May Annals an·nals pl.n. 1. A chronological record of the events of successive years. 2. A descriptive account or record; a history: "the short and simple annals of the poor" of Allergy, Asthma and Immunology immunology, branch of medicine that studies the response of organisms to foreign substances, e.g., viruses, bacteria, and bacterial toxins (see immunity). Immunologists study the tissues and organs of the immune system (bone marrow, spleen, tonsils, thymus, lymphatic . They note that seasonal pollen patterns are likely to differ from one region of the country to the next.--B.H. |
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