A team of scientists has created new tools to better predict when certain trees release pollen that causes allergies. The work focuses on olive and oak trees, two of the biggest sources of pollen in southern Europe. The goal is to give people a heads-up before allergy season gets worse.
The research, led by S. Papadogiannaki from Aristotle University of Thessaloniki, uses past weather records and pollen data. Scientists studied several years of information to see how changes in temperature, sunlight, and rain affect pollen release.
These predictions can help doctors and public health experts warn people in advance. Many people, especially children, are sensitive to pollen, which can cause sneezing, itchy eyes, or asthma attacks.
In cities across Europe, nearly 4 in 10 people suffer from seasonal allergies. Climate change is making the problem worse by causing longer and stronger pollen seasons. That’s why researchers are racing to improve the way pollen seasons are tracked and predicted.
Scientists focus on olive and oak trees
Olive trees are common in the countryside around Thessaloniki. Oak trees grow in the nearby mountains. Both types of trees release large amounts of pollen into the air each year.
To understand how this pollen travels, scientists used special traps on a rooftop at Aristotle University. These traps have been collecting daily pollen samples since 1987. The team used the data from 2016 to 2022 to build their models.
The scientists looked at how much cold is needed in winter to prepare the trees for spring. They also studied how warm it has to be in spring for the trees to start flowering. These two events help set the beginning and end of the pollen season.
Different tools were tested. Some counted the number of cold hours during winter. Others added up warm days in spring. A few even used daylight hours to help fine-tune predictions. The most reliable method mixed winter cold with spring warmth. This combination helped make better guesses about when pollen would appear.
Local climate affects the timing of pollen seasons in Europe
In Thessaloniki, olive tree pollen usually begins in early April. It peaks by mid-May and lasts about 58 days. Oak tree pollen begins a bit earlier, around late March, and peaks near the end of April. The oak pollen season lasts about 55 days.
Researchers said their models predicted these timelines with good accuracy. However, some years were harder to predict, especially when the weather was unusual. In 2022, for example, olive trees released pollen for longer than expected. That year’s model didn’t fully capture the shift.
The study also showed that oak trees release more pollen than olive trees. One of the highest oak pollen years was 2016, with both an early start and a long season.
Compared to other Mediterranean cities like those in southern Spain, Thessaloniki had lower pollen counts. But the seasons lasted longer. This shows how pollen levels can vary based on location, even in similar climates.
Temperature and rainfall both play a big role in pollen timing. Warm winters can confuse trees, while a dry or cool spring can delay flowering. By using weather patterns to predict pollen activity, scientists now have a better way to help people prepare for allergy season.