Temporal variation of allergenic potential in urban parks during the vegetation period: a case study from Bratislava, Slovakia

Park greenery represents an oasis for urban residents; however, during the flowering period of trees that produce allergenic pollen grains, these areas threaten individuals suffering from seasonal allergic respiratory diseases. In this study, we evaluated the temporal distribution of the allergenic potential of three most important urban parks in Bratislava over the vegetation period, using a modification of the Urban Green Zone Allergenicity Index ( I UGZA ) and Individual-Specific Allergenic Potential Index ( I ISA ) designed as a running index — rI UGZA and rI ISA . We found that rI UGZA gives better information for park management and revitalization, since it considers the potential size of woody plants, while rI ISA , considering the actual size of the vegetation, provides more relevant information for pollen-allergy sufferers. Based on rI ISA , the allergenic potential was highest in May for the Grassalkovich Garden (formal baroque garden) and Janko Kráľ Park (English landscape park) and in April for the Medic Garden (repurposed baroque garden). We also found differences in the duration of the period of increased allergenic potential in these parks, ranging from 1 to 3 months. Based on the total annual sums of rI ISA , we found the highest allergenic potential in the Medic Garden and lowest in the Janko Kráľ Park. This variance is caused mainly by the different density of trees and percentage of allergenic species. The biggest contributors to the allergenic potential were Platanus , Acer and Tilia . Based on the information on temporal variation of the allergenic potential during the vegetation period provided by the running indices, it is possible to improve the planning of park revitalization based on the flowering period of allergenic species and provide better information to the pollen-allergy sufferers for minimizing the allergenic effect of urban green areas on their health during a particular month.