Diurnal variation of airborne pollen at two different heights.

The diurnal variation in airborne pollen concentrations in the air of Córdoba at two different heights (1.5 m and 15 m) was studied during 2 consecutive years with the help of two Hirst volumetric samplers. According to pollen percentages obtained every hour, we determined whether every taxon studied presented a morning or an afternoon pattern, and whether this model was homogeneous (with a slight difference between the time of maximum and minimum reading) or heterogeneous (with a large difference between the two readings). We observed that the taxa that had many species in the area, such as Plantago, Poaceae, and Chenopodiaceae-Amaranthaceae showed a homogeneous model, while those taxa with few species present, such as Cupressaceae and Urticaceae showed a more heterogeneous model. Furthermore, the pattern of the plants with a large presence in the study area was more heterogeneous at 1.5 m because the pollen collected at this height is released from anthers. In the sampler placed at 15 m we detected airborne pollen, found that the curves were smoother and also observed a slight time delay for the taxa that were highly present in the area of study.