In brief
Alder and hazel are in bloom but airborne pollen amounts may vary depending on the weather conditions. Pollen concentrations may rapidly increase during dry periods.
Good to know
Pre-seasonal symptoms are common at this time. Every year, some people who are highly sensitized to the Betulaceae pollen (hazel, alder, birch) report that they already have symptoms of allergy before the significant appearance of this pollen in the air. This phenomenon might be due to the early dispersal of fine allergenic particles, to a patient's anticipation effect or to the proximity of plants whose flowering is locally more advanced.
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