ObjectiveThe construction of urban green zone allergenicity index (I_UGZA) takes into account the unique biological characteristics and morphological characteristics of plants in green space. In order to make the index more widely used, this paper improves its research and discusses the practical application of the index. Application can provide theoretical basis for the management and maintenance of urban green space.

MethodBased on Gauss formula, the I_UGZA was analyzed and improved, and it was used to evaluate the allergenic potential of green space, and the allergenic potential of different regions was compared. The practical application of the index in estimating the allergenic potential of green space was explored. Spearman correlation analysis and principal component analysis (PCA) were used to analyze the correlation between I_UGZA and other parameters (surface area, number of plants, density, species richness and Shannon-Wiener index (H′)).

Result(1) The overall I_UGZA value of green space was 0.214 1, and the I'_UGZA value was 0.219 3. It had hypoallergenic potential, and the pollen of plants growing in the study area did not pose a high risk to patients with pollen allergy. However, when the study area was compared, the I_UGZA value of some areas was greater than 0.3, which had high allergenic potential. At the same time, allergic symptoms of allergenic people can be caused within 346 m range of allergenic plants. The I'_UGZA value at 1 000 m from the center of the field source approached 0, and there was almost no allergenicity. (2) There were many low allergenicity plants in green space, accounting for 65.7%. Highly allergenicity plants are Pinus tabuliformis, Quercus variabilis, Fraxinus pennsylvanica, Populus tomentosa, Ailanthus altissima, Betula platyphylla, Ulmus pumila, Juniperus chinensis and other plants, mainly belonging to Cupressaceae, Pinaceae, Salicaceae, Platanaceae, Leguminosae, Simaroubaceae, Ulmaceae, Betulaceae, and Fagaceae. (3) The results of principal component analysis (PCA) analysis were consistent with those of Spearman correlation analysis. There was a significant correlation between I_UGZA and species richness (P < 0.05), and the correlation with other parameters was not significant.

ConclusionThe improved index can reflect the allergenic potential from different locations in the green space and the allergenic effect on the surrounding environment. It is an effective tool for assessing the allergenic potential of urban green space and is used to quantify the formation of pollen emissions in the air in different regions of the green space; it can reflect the contribution of pollen produced by each plant in green space, and then identify plants with high allergenicity in urban green space; it can also be used as a tool to analyze the richness of plant species in green areas.