Airborne pollen assemblage depends on the land cover of the area surrounding the volumetric trap and the flow of air masses. In urban contexts, the amount of airborne pollen is the result of the contribution of both local green areas and extra-urban vegetation, in addition to wind direction and speed. The present study focused on the combined effects of land cover and wind on the airborne pollen recorded in Florence over a 5-year period, in order to identify the area from where most of the pollen comes to the city. The study revealed that Cupressaceae, Olea and Quercus pollen display a positive correlation among their pollen concentrations and the geographical distribution of their sources. The overall influence of maximum wind speed is greater than the number of calm wind days. The latter is appreciable only for the pollen of Cupressaceae and Olea , whose trees are located in the proximity of the urban area, in the southern part of the city. The results showed that the land cover configuration strongly influences the airborne pollen captured by volumetric traps; despite the prevalent wind directions, the vegetation of the reliefs surrounding the city can be considered as the greatest area of pollen contribution.

中文翻译：

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南欧城市地区记录的土地覆盖和风对空气中花粉的贡献

空气中的花粉组合取决于体积捕集器周围区域的土地覆盖和气团的流动。在城市环境中，除了风向和风速之外，空气中的花粉量是当地绿地和城外植被共同作用的结果。本研究的重点是土地覆盖和风对佛罗伦萨 5 年间记录的空气传播花粉的综合影响，以确定大部分花粉进入城市的区域。研究表明，柏科、油橄榄和栎属花粉的花粉浓度与其来源地理分布呈正相关。最大风速的总体影响大于静风日数。后者仅对柏科和油橄榄的花粉有意义，它们的树木位于城市南部的市区附近。结果表明，土地覆盖配置强烈影响体积捕集器捕获的空气传播花粉；尽管风向普遍，但城市周围浮雕的植被可以被认为是花粉贡献最大的区域。