Most pollen counts are obtained using a volumetric device–a method by which number of pollen grains (or mold spores) are measured in a defined volume of air. At our office, we use a Rotorod system, which captures grains on a small rod that spins at a known rate at a defined interval. The pollen is transferred to a microscope slide, then grains are counted and categorized by our research coordinator (Andrea) as trees, grasses, or weeds. Although we are able to differentiate species based on pollen grain morphology (appearance under the microscope), we typically report the counts as a category rather than a species.
When grass season starts, the slide comes to life with beautiful oval grains that sometimes fill the entire microscopic field!
Pollen counts on other websites are typically made at other physical sites, i.e. Eugene, Portland, or Bend. We are currently the only pollen counting site in Southern Oregon. We make our counts available to news outlets (Channel 12 KDRV 6pm news) and tweet/post online (see front page of this site).
Kevin Parks MD