An air-sampling device called a Burkard spore trap is used to capture airborne pollen on a glass slide, which is stained with a dye and counted using a microscope.

During the grass pollen season, a slide is removed from the trap at the same time each day and counted twice. The first time all types of pollen on the slide is counted and the second time just the grass pollen (which has a distinctive shape) is counted. The daily pollen count is a report of both grass and all kinds of pollen (as grains per cubic metre of air) caught in the trap in the previous 24 hours.