Birch trees release more pollen this year
Sweden's birch trees are beginning to bloom, spelling misery for many hay fever sufferers. This year is set to be the worst in a while, warn biologists.
High levels of birch pollen have been recorded in several places across the country.
"It looks like we'll have more pollen this year than the last few years," says Pia Östensson, biologist at the Natural History Museum in Stockholm.
The area around the large central lake Mälaren, which runs from Örebro out to the Stockholm archipelago and the Baltic Sea, is among the worst affected.
High levels of birch pollen have been recorded not only in the capital but in Eskilstuna and Norrköping. Down south, Malmö, Jönköping and Nässjö also have high readings.
Higher temperatures have caused the birch trees to release their pollen, says Pia Östensson.
The warm weather has not yet reached north of Stockholm, but Östensson says southerly winds could bring some of the pollen there during the week.
The birch trees blossom for three weeks on average. At that point, oak trees usually go into bloom.
"A lot of people who are allergic to birch tree pollen are also sensitivte to oak pollen, but they might not have realised that as the two trees bloom almost at the same time," says Pia Östensson.