In this paper, we analyse the relationship between meteorology and Castanea airborne pollen. Chestnut is a tree broadly represented in the north of Spain. In view of its abundant pollen production and the high dispersal capacity of its pollen grains, atmospheric levels of Castanea airborne pollen (daily and hourly) in two localities in northwest Spain (Santiago de Compostela and Ourense) were studied from 1993 to 2001. The obtained results indicate the onset of flowering in the second fortnight in June, with the flowering maximum in July. Temperature was used as a predictive variable for predicting the onset of the pollen season and pollen concentrations. The forecast capacity of the sum temperature method in order to predict the onset of the pollen season was good, with a difference of 2-5 days between the real and the predicted onset dates in the year 2002. The time series regression lines well fitted the observed values during the year 2002. The proposed models are especially suitable for evaluating short-term effects of time-varying pollen appearance in the atmosphere. The obtained models of the hourly distribution did not reflect the hourly rhythm of pollen dispersion but rather the rhythm of pollen capture from the trees located at different distances and in different directions from the pollen trap.
