Airborne pollen spectra at three sites in inland Croatia, 2003

The aim of this study was to determine whether there were major differences in the seasonal incidence and abundance of pollen grains and pollen types in pollen fall between sites of different land use. The material was collected from 5 January until 20 December 2003 at three sites in central Croatia. The sampling sites were located in an average urban setting (Zagreb), a rural setting (Ivanic Grad), and a small town surrounded by a large woodland with partially thermophilic vegetation (Samobor). Using the volumetric method of pollen collection, pollen grains of 35-37 taxa were identified, depending on the sampling site, eight of them producing the greatest amount of pollen (Alnus sp., Ambrosia sp., Betula sp., Carpinus sp., Poaceae, Quercus sp., Taxus/Juniperus, and Urticaceae). Differences among the sampling sites were recorded according to seasonal pollen concentration, total monthly pollen count, and total annual pollen count. The proportion of particular plant classes (tree, grass and weed) was quite comparable among the three sampling sites because of their relative geographic proximity (i.e. within the same climatic region). A difference was observed in the air pollen concentration. All three monitoring sites revealed the total annual airborne pollen concentration in inland Croatia to be dominated by highly allergenic pollen (Zagreb 54%, Samobor 58% and Ivanic Grad 82%) of the following taxa: Alnus sp., Ambrosia sp., Betula sp., Carpinus sp., Corylus sp., Poaceae, Urticaceae and Artemisia sp. Accordingly, there were no distinct phenologically induced differences in pollen species recorded at the three monitoring sites. However, substantial differences were observed in seasonal pollen grain count and in the percentage proportion of some allergenic pollen grains (Ambrosia sp., Betula sp., Carpinus sp., Poaceae), providing valuable information to individuals suffering from pollen allergy.