Assessing allergenicity of urban parks: a case study from Aydin, Turkey

Allergenic pollens produced by some tree species in urban parks, a part of the urban flora, cause pollinosis, allergic rhinitis, allergic rhinoconjunctivitis, and asthma. The allergenic pollen levels of four urban parks in Aydin (Turkey) were determined using the Index of Urban Green Zones Allergenicity (I_UGZA). The potential allergenicity value (PAV) of each species and the crown volume of each individual belonging to the species were used in the index calculation. According to their PAV values, tree species were classified as nil (0), low (1–6), moderate (8–12), high (16–24), and very high (27–36) allergenicity. The Shannon Diversity Index (SHDI) was used to calculate the parks’ biodiversity levels. Canonical correspondence analysis, one of the ordination methods, was used to identify the species distribution among the four parks and reveal the relationship between the SHDI, number of species, tree density, and I_UGZA. The ratio of allergenic tree species in the four parks examined varied between 97.90 and 100%. The PAV of 9 tree species, including the genus Cupressus in the Cupressaceae family, was determined as very high, while the PAV of 20 tress species, including the genus Prunus, was revealed to be low. While the park with the lowest I_UGZA value (0.17) was Aytepe Recreation Area, the park with the highest I_UGZA value (0.52) was Pinarbasi Recreation Area. The lowest Shannon Diversity Index (SHDI) value (0.70) was detected in Aytepe Recreation Area, whereas the highest value (2.90) was determined in Nevzat Bicer Park. There was no correlation between the I_UGZA value and species count, tree density, and SHDI variables. Ismet Sezgin Park and Pinarbasi Recreation Area pose a risk to human health at any time of the year. The results, which focused on allergenic flora, should be used to design new parks and revitalize existing ones.