Estimating the allergenic potential of urban green spaces: A case-study in Granada, Spain

a b s t r a c t A new quantitative index for estimating the allergenicity of tree species in urban green spaces takes into account allergenic potential, pollination strategies, duration of the pollination period, tree size and number of individuals per species as intrinsic parameters depending on the tree species concerned. Other factors analysed included the surface area occupied by each tree, with a view to calculating the overall percentage coverage of each allergenic species. The index is expressed as a ratio, thus enabling the design of an urban green space to be compared with a hypothetical space of similar characteristics and maximum allergenicity: the value to be obtained would thus lie between IUGZA = 0, for spaces with no allergenicity at all and IUGZA = 1 for spaces with maximum allergenicity. The expression of allergenicity by an abstract number facilitates comparisons and the index can be applied to green spaces sharing similar characteristics. A case study of Garcia Lorca Park, Granada, Spain, assessed the practical application of the index in a real-life situation. It was found that a 44.13% of the park' total surface area was occupied by species with moderate to elevated allergenic potential. Other key factor influencing the index is the presence of species whose pollen is classified as a major local allergen. The index may also be used as a management tool for evaluating certain aspects which may need to be modified in order to minimise their allergenic impact, including the presence of single-species stands, hedges, and tree screens, and the