Rising allergenic risk in cities: a progressive pollen calendar analysis in response to climate change in Central Europe

Abstract Climate change is affecting the timing and intensity of pollen seasons for allergenic plant species. This creates a growing need to monitor pollen season trends and update tools for allergy management. In this study, we analysed pollen season characteristics – onset, end, duration, and intensity (seasonal pollen integral and peak pollen concentration) – over a 20-year period (2002–2023) in five cities across Slovakia and the Czech Republic. By comparing two timeframes (2002–2012 and 2013–2023), we constructed progressive pollen calendars to visualise the shifts over time. We identified regional differences, including an earlier start to woody plant pollen seasons in Slovak cities, contrasted with a delayed onset in Czech cities. We also observed an intensification of the Ambrosia pollen season in Slovakia, while its intensity remained stable or declined in the Czech Republic. The most consistent trends included earlier and extended pollen seasons for Alnus and Cupressaceae and a reduced intensity of the Artemisia pollen season. These findings highlight the importance of localised pollen monitoring and the need to regularly update pollen calendars, providing valuable tools for urban healthcare planning and public awareness of climate-driven allergenic risks.