The Eucalyptus pollea and its incidence in the atmosphere of Vigo (N. W. Spain)

Abstract

Eucalyptus globulus Labill. is the most frequent arboreal species of the Myrtaceac family in the surroundings of the city of Vigo, and it constitues abundant and dense forestal masses. Although its pollen can be considered as a moderated allergen, in areas in which Eucalyptus was used in extended reafforestations, it can cause allergenic problems. From 1995 to 2000 a Hirst-type volumetric sampler (Hirst, 1952), LANZONI VPPS 2000 placed in the left bank of the Vigo estuary (42°14'15"N, 8°43'30"W) was used for collecting airborne pollen. From year to year important oscillations in the annual total pollen was observed, alternating years of high concentrations with other of lower values. Eucalyptus pollen counts represent a percentage that vary between 1% to 3% of the total pollen, the high quantity being collected in 1997 with 1,147 pollen grains. The Myrtaceae pollen appears in the atmosphere of Vigo all over the year, although the more important concentrations are registered during March and April. Moreover, maximum daily concentrations occur between 17.00 and 18.00 hours. Finally, a statistical analysis has been carried out in order to search for the possible correlations between pollen concentration and the main meteorological parameters. The N-NE wind and relative humidity were the parameters that show the highest correlation coefficients, positive and negative respectively.