How are pollen counts done?
We use an air-sampling device called a Burkard spore trap to capture airborne pollen on a glass slide, where it can be stained with a dye and counted using a microscope. During the season, a slide is removed from the trap at the same time each day and counted twice. The first counts all types of pollen and the second just the grass pollen (which has a distinctive shape). Our daily pollen count is a report of grass/all kinds of pollen (as grains per cubic metre of air) caught in the trap in the previous 24 hours. Our pollen forecast is based on this count and on the weather forecast for the next 24-hr period.
