Airborne pollen are important aeroallergens affecting human health. Local airborne pollen compositions can pose health-risks for the sensitized population, but at present little is known about fine-scale pollen composition patterns.

The overall objective of this study is to determine local variations in tree pollen composition with passive samplers and to identify the surrounding landscape characteristics that drive them. In February–May 2017, during the tree pollen season, airborne tree pollen were measured by passive sampling at 2 m height above ground-level in 14 sites in the Flanders and Brussels-Capital region (Belgium). Non-metric multidimensional scaling was used to investigate environmental gradients that determine the pollen composition and amounts. Land cover types were identified across spatial scales ranging between 20 m and 5 km.

The passive samplers detected the same pollen taxa during the same time windows as the validated volumetric Burkard samplers. Using passive samplers, we were able to measure local airborne pollen compositions. Corylus and Platanus pollen were associated to urban areas; Populus, Juglans and Fraxinus pollen to agricultural areas; forests and wetlands were sources of Alnus and Quercus pollen. Salix, Populus and Betula pollen were also mainly associated to wetlands. The landscape context drives the airborne tree pollen composition at a meso-scale (1−5 km) rather than at finer scale (20−500 m). Thus, land cover types (e.g. forest, bush land, agricultural lands and wetlands) surrounding urban areas may increase exposure to allergenic pollen in the urban area, potentially affecting the health of a large proportion of the population.

空气中的花粉是影响人体健康的重要空气过敏原。当地的空气传播的花粉成分可能会对致敏人群造成健康风险，但目前对精细的花粉成分模式知之甚少。

这项研究的总体目标是使用被动采样器确定树木花粉成分的局部变化，并确定驱动它们的周围景观特征。2017年2月至5月，在树木花粉季节，在法兰德斯和布鲁塞尔首都大区（比利时）的14个地点，通过被动采样在海拔2 m高的地面上测量了空中树木花粉。使用非度量多维标度来研究确定花粉成分和数量的环境梯度。在20 m至5 km的空间尺度上确定了土地覆盖类型。

被动采样器在与经过验证的体积Burkard采样器相同的时间范围内检测到相同的花粉类群。使用无源采样器，我们能够测量本地空气中的花粉成分。榛属和桔梗花粉与城市地区有关。胡杨，胡桃和水曲柳花粉到农业地区；森林和湿地是Al木和栎花粉的来源。柳，胡杨和桦花粉也主要与湿地有关。景观环境以中尺度（1-5 km）而不是更精细的尺度（20-500 m）驱动空中树木花粉的组成。因此，城市地区周围的土地覆盖类型（例如，森林，灌木丛土地，农业用地和湿地）可能会增加城市地区接触致敏花粉的可能性，从而可能影响很大一部分人口的健康。