Climate change and the problem of airborne allergies: what do 20 years of tree pollen research tell us?
An analysis of two decades of pollen concentration measurements in Poland has shown that climate change is increasingly shaping the timing and duration of tree pollen seasons.
A research team from the University of Wrocław focused on five taxa that begin releasing pollen in the first quarter of the year: hazel, alder, willow, poplar and elm. This period is both critical for allergy sufferers and particularly sensitive to climate-related shifts.
The study has been published in the International Journal of Biometeorology: link to article.
Its lead author is doctoral student Szymon Tomczyk from the Department of Climatology and Atmospheric Protection at the University of Wrocław, in collaboration with prof. Małgorzata Werner (same department), dr hab. Małgorzata Malkiewicz from the UWr Institute of Geological Sciences, as well as other Polish researchers.
The aim of the study was to examine the spatial and temporal variability of pollen seasons in Poland and to assess the influence of meteorological conditions in the context of climate change between 2003 and 2022.
Why does this matter?
It is estimated that between 10% and 25% of Europeans now suffer from airborne allergies, with the figure rising to as much as 35% in urban areas. In Poland, allergic rhinitis may affect around one-third of the population. Higher pollen concentrations can trigger more severe symptoms, while sensitisation thresholds vary depending on plant species and individual susceptibility.
Understanding the relationship between weather and pollen concentration is key to predicting the course of pollen seasons. Temperature and sunshine determine plant growth and pollen production, humidity and rainfall affect its release, while wind drives atmospheric transport.
How was the research carried out?
Pollen concentration data were collected using Hirst-type traps in six cities: Szczecin, Poznań, Wrocław, Kraków, Rzeszów and Łódź. The device draws in air at a rate of 10 l/min, with pollen grains deposited onto a rotating drum covered with adhesive tape. Each week, the tape is transferred to a laboratory, where samples are prepared and examined under a microscope. Grains are counted to calculate daily pollen concentrations for the previous week.
What did the analysis reveal?
The findings are worrying: pollen seasons are starting earlier and lasting longer. The main drivers of this shift are mild winters and the rapid onset of spring. Pollen grains are appearing earlier than they did a decade or two ago – and this trend is observed across the whole of Poland.
For allergy sufferers, this means an earlier onset of symptoms.
Air temperature, sunshine and relative humidity were found to shape daily pollen concentrations, with climate change setting new long-term trends.
The study confirms the hypothesis that regional differences in the pace of climate change are reflected in the course of pollen seasons. Monitoring these processes will help improve preparedness for changing patterns in the intensity and duration of pollen seasons in Poland in the near future.
Complied by Katarzyna Górowicz-Maćkiewicz
Date of publication: 10.09.2025
Added by: EJK
