EXPLANATION OF THE POLLEN COUNT

Pollen is a small, spherical shaped grain that is produced by plants and is necessary for plant fertilization. Each plant has its own pollinating season that tends to be fairly constant from year to year. In this region, trees generally pollinate from around the first of March through May, grass from the first of March until killing frost, ragweed in the fall, and marigold during the late summer. The actual amount of pollen in the air at any given time depends on the weather conditions, as well as total amount of pollen produced.

Pollen is measured using Durham pollen samplers. Pollen is collected on a microscope slide that has been smeared with a light coating of white petroleum jelly or silicone grease. The slide is exposed for 24 hours and then returned to the laboratory where it is stained with a few drops of Calberia's staining solution. The pollen on the slide is read with a microscope on low power (10X). Five (5) scans across the stained area are counted, and the pollen count is computed as the number of grains of pollen per centimeter. The following descriptive words are used along with the actual pollen count:

0 to 5 Pollen Grains/cm	Slight
6 to 15 Pollen Grains/cm	Moderate
16 to 25 Pollen Grains/cm	Heavy
Greater than 25 Pollen Grains/cm	Extremely Heavy

In addition to this website, a daily recorded update of the Pollen Count (during the pollen season) can be obtained by calling (615) 340-0488.