Pollen grains are sampled from the air and the total number of pollen grains, per cubic metre of air, are calculated as well as the number of grass pollen grains that are present within the sample. Grass pollen grains are typically a trigger for hay fever and the number of grass pollen grains present in the sample is correlated to a reading of LOW, MODERATE, HIGH and EXTREME for that day. For example, if 120 pollen grains are observed (per cubic metre of air) and 20 of those are grass pollen grains, then the count will
be represented as 20/120, and the reading for the day will be MODERATE. Based on what has been observed, as well as weather conditions, the university forecasts the grass pollen level for the next day.
