How is pollen counting done?
A pollen sample is taken using an air-sampling device. These samplers collect particles from the air onto a transparent, sticky surface. The sample is then examined under a microscope, where the pollen grains are counted and identified. The result of this is the pollen count. Since pollen travels long distances through the air, this count is relevant to a large area, and a count from one sampling site is typically used as data for an entire city.