The birch tree is the tree that causes hay fever in the most people in the Netherlands. Birch pollen is a strong allergen and responsible for severe symptoms in an estimated one million Dutch people. In this article you will learn when the birch pollen season starts, when the peak occurs and how best to prepare.
In brief: the birch pollen season runs from late March to early May. The peak falls around mid-April and lasts two to three weeks. The Veluwe, Drenthe and Het Gooi experience the highest concentrations.
When does the birch pollen season start?
The birch pollen season in the Netherlands typically begins in late March. The first birch pollen is detected once temperatures rise sufficiently and birch trees start to bloom. In mild winters this can be as early as mid-March; in a cold spring the start shifts to early April.
When is the birch pollen peak?
The peak of the birch pollen season generally falls in April. Around mid-April, pollen concentrations usually reach their highest point. The exact timing depends on the weather: warm, dry and windy days lead to higher concentrations in the air, while rain temporarily washes pollen out of the air.
The peak period lasts on average two to three weeks. During those weeks, the pollen concentration can rise to thousands of pollen grains per cubic metre of air -- enough to cause significant symptoms even in people with a mild allergy.
Late March
First birch pollen appears. Mild symptoms in the most sensitive individuals.
Mid-April -- peak
Highest concentrations. Severe symptoms for most birch pollen allergy sufferers.
Early May
Concentrations decline. Most birch trees have finished flowering by mid-May.
How long does the birch pollen season last?
The full birch pollen season lasts approximately four to six weeks: from late March to early May. After the peak in April, concentrations gradually decrease. By mid-May most birch trees have finished flowering and birch pollen largely disappears from the air.
Regional differences in the Netherlands
The Veluwe, Drenthe and Het Gooi experience higher birch pollen levels due to the large number of birch trees in these regions. In the coastal provinces (Zeeland, South Holland, North Holland) the concentration is generally lower because the sea breeze dilutes pollen in the air. Cities warm up faster than rural areas, which means flowering in urban areas sometimes begins earlier.
Symptoms from birch pollen
Birch pollen causes the well-known hay fever symptoms in sensitive individuals: sneezing, runny nose, blocked nose, itchy and watery eyes, and fatigue. In addition, birch pollen is a common cause of cross-allergy: approximately 50--70% of birch pollen allergy sufferers also react to raw apple, hazelnut, carrot and other foods.
Watch out for cross-allergy: do you experience a tingling or itching sensation in your mouth after eating raw apple, hazelnut or carrot? This could be a cross-allergy with birch pollen -- read more about it.
Tips to prepare
Start medication early
Begin taking antihistamines or nasal spray 1--2 weeks before the season so the medication is already working when pollen appears.
Check the pollen map
Monitor the live pollen map for daily concentrations in your region.
Plan around the weather
Schedule outdoor activities on days with rain or low pollen pressure. The highest concentrations occur on warm, dry mornings.
Keep pollen outside
Close windows and doors on high-pollen days. Wash your hair and clothes after a day outdoors and do not dry laundry outside.
After birch pollen: the grass pollen season
As soon as the birch pollen season ends in May, the grass pollen season begins. Grass pollen causes symptoms in approximately two million Dutch people and peaks from late May through July. For many hay fever sufferers, it is therefore a continuous season from March through August.