a. Distribution of total symptom scores for each study day during the period 1 June–12 July in Malmö 2009. Each box plot is composed of 3 horizontal lines displaying the 25th, 50th, 75 th and 90th percentiles. The dots represent outliers. b. Sum of pollen counts and precipitation, day by day during the same period. The horizontal line denotes 80 pollen grains per cubic metre, the suggested lower limit for “high grass pollen concentration”. Pollen counts are expressed as square roots of the actual numbers.