Hot and humid conditions have prompted allergenic ragweeds to bloom earlier than usual this year, researchers have warned.
Maximilian Bastl from the Pollen Service of the Medical University of Vienna told ORF that the combination of high temperatures and abundant rainfall in May and June created ideal conditions for ragweed growth.
“That’s why the plants are already quite advanced. Some are already flowering in and around Vienna,” he noted.
This could lead to an early peak in flowering, with some plants ready to bloom as early as July.
“We also anticipate that more pollen grains will be released, which could make this season particularly intense for allergy sufferers,” said Bastl.
Allergies caused by common ragweed (Ambrosia artemisiifolia) affect over 33 million people in Europe, according to a 2022 study by the Medical University. The study predicted that this number could double by 2060.
The pollen season is expected to persist throughout August and September, potentially remaining high into October.
When it comes to ragweed pollution, much depends on so-called “long-distance transport.”
“If we experience winds from the east or south-east, a significant amount of pollen is carried in from neighbouring countries, much more than we would normally see from the local bloom,” Bastl explained.
Allergy sufferers can take precautions by keeping an eye on the weather forecast. If winds from the east or south-east are predicted, exposure is likely to be higher. It’s also advisable to limit time spent outdoors.
Peak pollen levels are typically expected in the afternoon and evening, particularly due to long-distance transport. Wearing hats, sunglasses and masks can also offer some protection.