In brief

The very first alder and hazel pollens were collected irregularly in the air.

However, the pollen season 2021 has not yet started.

Alder + Hazel

Latest measure: 
Sunday, 17 January, 2021
20202021Mean 2011 - 202007 Jan14 Jan21 Jan28 Jan04 Feb11 Feb18 Feb25 Feb04 Mar11 Mar18 Mar25 Mar01 Apr050100150200250300350grains / m³

Good to know

  • Each year some individuals highly sensitized to Betulaceae pollen (hazel, alder, birch) report early symptoms of allergy before the pollination period. This phenomenon has been described in literature and according to some authors, it should be due to the presence in the air of very small sized allergenic particles from these plants.


  • Typical allergy symptoms such as runny nose, cough or shortness of breath (in case of asthma) can easily be mistaken for a cold, flu or coronavirus infection. However, fever and body aches should be given special attention as they might be caused by viral infection. It is recommended to call your general practitioner in case of doubt.