Tree pollen allergy risks and changes across scenarios in urban green spaces in Brussels, Belgium

Urban green spaces may improve human health and well-being. However, also emit allergenic pollen these trigger asthma, allergic disease, respiratory infections. How allergy risks in be modified by environmental change is still not widely understood. This study analyzed tree inventory data of 18 urban (5940 trees; 278 taxa; 93 ha) the Brussels Capital Region, Belgium. We investigated present risk (AR) changes AR driven species composition, potential season duration. was estimated calculating allergenicity index I UGZA (range 0–1, 1 worst) for situation 13 scenarios. The average 0.08 (SD 0.05; range 0.002–0.17). increased 11–27% scenarios, 44% duration scenario. Preventive removal birch, hazel alder reduced 13%. 99–111% combined scenarios with without preventive main taxa. These findings indicate that could considerably rise when ongoing lead to a combination longer seasons, allergen potency, sensitization one or more species. cannot sufficiently counter caused other are amplified change, highlighting importance careful selection space policy planning.