Birch pollen season has begun early this year and people with allergies may suffer more severe symptoms than usual, according to AirAllergy, Sciensano's national aerobiological monitoring network.
Alder and hazel pollen season have just ended but people with allergies are still at risk of developing symptoms due to the arrival of birch pollen.
Allergies affect one in ten people in Belgium, and birch trees are the most allergy-inducing trees in the country, according to Sciensano. In addition, symptoms are often intensified and prolonged by other trees that produce similar pollen such as alder and hazel. The successive high peaks of each pollen-producer mean that "cross-reactions" are likely around this time of year.
Birch season is relatively early this year, with 104 grains of birch pollen per cubic metre of air measured in Brussels on Tuesday.
"We expect daily concentrations to rise further over the coming days, especially if the weather conditions are optimal," explained scientific associate Nicolas Bruffaerts. "When the critical threshold of 80 grains of birch pollen per cubic metre of air is exceeded, most allergy sufferers develop symptoms."
'Long and intense'
Global warming has affected the reproductive cycle of trees, which has prompted an earlier pollen season this year. However, the season is not expected to end any earlier than usual. Exposure to airborne pollen will therefore last longer, making for a "long and intense" allergy season.
Sciensano recommends that people with allergies avoid outdoor activities, wear sunglasses and dry laundry inside rather than outside. People are also advised to rinse their noses regularly and wash their hair before going to sleep.
Typical allergy symptoms should not cause alarm, but individuals should pay attention to fever and body aches as they may signal viral infection.
