In brief

The alder and hazel pollen season is in full swing.

The current weather conditions are optimal for airborne pollen dispersal. On Thursday, 268 grains/m³ were measured in the air in Brussels. The concentrations might fluctuate depending on the meteorological conditions.

Ash and poplar trees are also blooming.

Alder + Hazel

Latest measure: 
Thursday, 25 February, 2021
20202021Mean 2011 - 202007 Jan14 Jan21 Jan28 Jan04 Feb11 Feb18 Feb25 Feb04 Mar11 Mar18 Mar25 Mar01 Apr0200400600800100012001400grains / m³

Good to know

  • 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.


  • Because of cross-allergy between the various Betulaceae species ( alder, hazel, birch and hornbeam), people sensitized to birch pollen may suffer from allergy symptoms when hazel and alder pollen counts are high !