In brief

Birch trees are currently in full bloom.

On Thursday, 109 birch pollen grains per m³ of air were measured in Brussels.

Airborne pollen amounts may vary depending on weather conditions. During dry and sunny spells, concentration can be high.

People allergic to birch pollen should remain cautious and follow the treatment prescribed by their doctor.

Ash, hornbeam, poplar and willow are also in flower.


Latest measure: 
Thursday, 15 April, 2021
20202021Mean 2011 - 2020threshold value11 Mar18 Mar25 Mar01 Apr08 Apr15 Apr22 Apr29 Apr06 May13 May0500100015002000250030003500grains / m³

Alder + Hazel

Latest measure: 
Thursday, 1 April, 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.
  • The standardized pollen detection technique allows retrospective measurement of the levels from samples taken the day before. Samples are analyzed manually during the working days by optical microscopy.
  • There is a cross-allergy between birch pollen and certain fruits such as apples, hazelnuts, kiwis. Consumption of these raw fruits can lead to food allergy problems in people sensitised to birch pollen.
  • Follow us too on Twitter @AirAllergy !