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		Unfortunately for hayfever sufferers, pollen is a natural pollutant of the air.	Key Points Pollen carries male DNA to the female part of a plant. Plants release pollen twice a day, early in the morning and late in the afternoon. Many more pollen grains are released than are needed. Also in BBC Weather Allergies Coping with Hayfever bbc.co.uk Links BBC Health - Allergies External Web Links The British Allergy Foundation Disclaimer The BBC is not responsible for the content of external websites.

	Pollen is essential in the reproduction of plants as it carries the male DNA to the female part of the flower. ...grains have evolved to stay in the air longer. Many plants, including various trees and grasses, use the wind to carry that pollen. The wind is not altogether the most reliable form of transport, so to ensure the pollen reaches its destination, many more pollen grains are released than are needed, and in time the grains have evolved to stay in the air longer. The wind is very important in determining the amount of pollen in the air. Plants release pollen twice a day, early in the morning and late in the afternoon, but the wind can mix pollen back into the air at almost any time. If the winds have been light for a while, the pollen will have had nothing to make it airborne. Once the winds pick up, a bad day for hayfever sufferers is on the cards. A blustery wind may help in dispersing the pollen, but it will also carry it further. ...the count can depend heavily on the wind direction. As pollen is carried by the wind, the count can depend heavily on the wind direction. The prevailing winds in the UK are westerly and this air will be virtually pollen free, having come from the Atlantic. As the wind travels across the land it picks up pollen all the time, so generally the west coast has a lower pollen count than the east coast. When the winds are easterly, the pollen count lowers in the east as you might expect, but pine pollen has been detected on the coast, presumably from Norway. This shows just how far pollen can travel. The pollen count in the Midlands has very little dependency on the direction the winds are coming from. Being in the centre of England, winds from all directions bring pollen and the counts are often the highest in the UK. One June the count in Derby was 1024. To gauge how high this is, 150 is considered very high.

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Pollen and Wind