During recent years a gradual decrease in allergenic airborne pollen concentration has been observed in the monitoring station of Padua (Italy). Because technical checks of the sampler were not able to explain this trend, the results obtained from two twin pollen-samplers (Lanzoni VPPS 2000), placed two metres apart, were compared. An eight-week sampling was carried out during the year 2000 from July to September. Subsequent analysis revealed no statistically significant difference between the data obtained with the two instruments. On the other hand, both samplers captured high levels of fungal spores. We conclude that the observed negative trend in pollen count is real and not related to technical biases.