Every year local television stations report the daily pollen count. Depending on where you live, (the information on this site is for Maryland) pollen counting starts in March and lasts until after the first frost in October.
WHY COUNT POLLEN? Besides physicians and researchers, people with allergies are also interested in the count. Whether you are allergic to grass, trees, or weeds, the count will alert you to which particular pollens are out there waiting to make you miserable.
HOW IS THE POLLEN COUNT DONE? Pollen counting is very scientific and should be done by Certified Pollen Counters with an approved Pollen Station. For a station to be approved it has to be a certain height, somewhere between 12 and 15 feet off the ground. The location is also very important. It should be in an open area. If the station is placed in an area that has several pine trees you would end up with a large number of pine pollen, which of course, would not be a true reading. Basically, every morning between 6 a.m. and 8 a.m., a small plastic, lubricated rod is placed in a machine called a rotorod. The rotorod is preset to spin at certain intervals at a specific speed for a period of 24 hours. While spinning, pollen grains will stick to the rod. Then the "counter" will stain the rod, look at it under a microscope and manually count each pollen that he/she sees.
HOW ARE POLLENS IDENTIFIED? By their size, shape, color, and texture. Some pollens have pores and some have furrows. As you will see in the following pictures there are many differences in pollens.
TREES:
1.Alder 
2.Beech 
3.Elm 
4.Oak 
5.Pine 
6.Walnut 
7.Linden 
8.Hickory 
9.Hackberry 
10.Birch 
WEEDS:
1.Giant Ragweed 
2.False Ragweed 
3.Dock 
4.Pigweed 
5.Queen Anne's lace 
6.Plantain 
7.Woodrush 
8.Sagebrush 
GRASSES:
1.Cattail 
2. Grass 
3.Orchard 
4.Timothy 
5.Bermuda 
