Allergenic risk assessment of urban parks: Towards a standard index

Allergenicity indices are a powerful tool to assess the health hazard posed by urban parks to pollen allergic subjects. Nonetheless, only few indices have been developed and applied to urban vegetation in the last decade, and they were never compared nor standardised over the same dataset. To address this issue, in this paper the two best-known allergenicity indices, the Urban Green Zones Allergenicity Index (IUGZA) and the Specific Allergenicity Index (SAI), have been calculated for the same park (the Botanical Garden of Bologna), collecting vegetation data through both systematic sampling and arboreal census. The results obtained with the two data collection methods were comparable for both indices, indicating systematic sampling as a reliable approximation of the total census. Besides, the allergenic risk resulted moderate to high according to SAI, and very low according to IUGZA. Since SAI does not consider the total volume of the vegetation, it was deemed less reliable than IUGZA in evaluating the allergenicity of an enclosed green space. •SAI and IUGZA provide different estimations of the allergenic potential of a park.•IUGZA tends to be more reliable than SAI when applied to enclosed green spaces.•Systematic sampling can replace complete census in calculating allergenicity indices.•Systematic sampling can misidentify the main allergenic species of the park.