Tree pollen with allergenic potential in cities triggers nasal, skin, eye, and asthmatic allergic reactions in humans. Pollen is one of the most common allergy-causing inhaled substances. Tree species composition, cultivar selection and the proximity of certain trees to humans can influence allergic responses. Data from 53 cities or states from various parts of the world were used to assess the magnitude and differences in an allergy index (AI) among the sampled locations and among land uses within cities. Index values for species ranged from one (most allergy-free species) to 10 (highest allergy potential). The average index score among the cities and states was 6.3, with values ranging from 4.2 (Halifax, Nova Scotia) to 8.3 (Austin, Texas). On average, forest/open space areas had a slightly higher average index score (6.4) than commercial/industrial/transportation (6.2) and residential areas (6.1). About 2/3 of the analyzed cities had higher index scores in forest/open space than in residential areas. Forest/open space areas contributed over 40 percent of total leaf area and may influence allergenicity in cities. Cities developed within areas with naturally occurring Pinaceae (pine, spruce, fir, cedar, Douglas fir, larch) forests and/or have more Pinaceae species tended to have the lowest pollen index scores. Most leaf area tended to come from trees in index class 8. While pollen production is essential for natural regeneration and potential seed/food production, limiting tree species with high allergenic potential in areas near people can help reduce tree-related allergies. Through better understanding and quantification of urban forest allergenicity, managers can create sustainable local-scale landscapes that limit pollen exposure to humans, but also provide numerous ecosystem services and values to residents.

在城市中具有致敏潜力的树花粉会引发人类的鼻、皮肤、眼睛和哮喘过敏反应。花粉是最常见的引起过敏的吸入物质之一。树种组成、品种选择和某些树木与人类的接近程度会影响过敏反应。来自世界各地的 53 个城市或州的数据被用于评估样本位置之间和城市内土地利用之间的过敏指数 (AI) 的大小和差异。物种的指数值范围从 1（大多数无过敏物种）到 10（最高过敏潜力）。城市和州的平均指数得分为 6.3，其值范围从 4.2（新斯科舍省哈利法克斯）到 8.3（德克萨斯州奥斯汀）。平均而言，森林/开放空间区域的平均指数得分略高（6. 4）商业/工业/交通（6.2）和住宅区（6.1）。大约 2/3 的被分析城市在森林/开放空间的指数得分高于住宅区。森林/空地面积占总叶面积的 40% 以上，可能会影响城市的过敏性。在拥有天然松科（松树、云杉、冷杉、雪松、花旗松、落叶松）森林和/或拥有更多松科物种的地区内开发的城市往往具有最低的花粉指数分数。大多数叶面积往往来自指数等级 8 的树木。虽然花粉生产对于自然再生和潜在的种子/食物生产至关重要，但在靠近人的地区限制具有高过敏潜力的树种有助于减少与树木相关的过敏。通过更好地了解和量化城市森林致敏性，