Aeropalynologic calendars for inland Croatia 2003

A characteristic feature of pollen sensitivity is its seasonal pattern of occurrence at the time when pollen is most frequent in the atmosphere. The aim of the study was to provide data for updated pollen calendars for inland Croatia based on continuous sampling, to document fluctuations in monthly pollen sum, and to list starting and end dates for the key airborne pollen types in the area. The material was collected at 3 sites in inland Croatia. Seven-day Hirst volumetric pollen and spore traps were used for pollen sampling. Pollen concentration was expressed as pollen grain count/m3. The number of identified pollen taxa was 35-37 in inland Croatia, 16 of them highly allergenic. Seven of these highly allergenic taxa produce greatest amount of pollen (Alnus sp., Ambrosia sp., Betula sp., Carpinus sp., Poaceae, Quercus sp. and Taxus/Juniperus). At all monitoring sites, the onset of flowering time for the majority of allergenic trees was recorded in February and March. The lowest air concentration of allergenic pollen was recorded in June, when the pollen season of the majority of allergenic plants had ended. The presence of the highly allergenic ragweed and mugwort pollen at concentrations capable of inducing allergic reaction was observed in July. The onset, duration and termination of plant pollination was found to be rather uniform across the monitoring sites in inland Croatia, without any major deviation. In inland Croatia, the risk of allergic reaction symptoms in individuals with pollen allergy is present from March till October. The composition and concentration of air pollen were observed to vary according to monitoring sites. The onset and termination of pollination varied according to years at the same monitoring sites, pointing to the need of developing yearly pollen calendar as a basis of the mathematical model to predict the occurrence of air pollen in inland Croatia.