Airborne pollen data of Platanaceae in Santiago de Compostela (Iberian Peninsula)

The pollen count of the Platanus genus in the atmosphere of Santiago de Compostela (Galicia, Spain) was carried out from 1993 to 1998, with the pollen of this taxon representing 6% of total identified pollen. The principal pollination period (P.P.P.) was centred on the months of March and April, with an average duration of 23 days.During the study period we obtained negative correlations with precipitation and humidity and positive ones with temperature and hours of sunshine, with a confidence index of more than 90%. On the basis of the six-year study period, we also calculated the average accumulated temperature required to trigger the onset of flowering, which oscillated between 330 and 456 °C, with this result being confirmed for 1999 (437 °C). We also observed that the values of maximum pollen concentration of this taxon in the last 7 years (1993–1999), were obtained on days during the P.P.P. with maximum temperatures above 18 °C. The model of intradiurnal variation reflects, for the majority of years, a greater representation during the central hours of the day.