Characteristics and trends of selected pollen seasons recorded in Parma (Northern Italy) from 1994 to 2011

This study examines variations in the start date, end date, duration, date of peak, peak value and Seasonal Pollen Index (SPI) of airborne pollen seasons recorded in Parma, Northern Italy, in relation to meteorological data (1994–2011). Pollen data were collected in the city of Parma by volumetric spore trap. The following taxa were analysed: Alnus, Ambrosia, Artemisia, Betula, Amaranthaceae, Corylus, Cupressaceae, Plantago, Platanus, Poaceae and Urticaceae. Spearman’s rank correlation tests were used to establish whether significant relationships existed between the different characteristics of the pollen seasons. Simple linear regression analysis was also carried out in order to investigate trends over time. Only 12 % of the 66 characteristics examined showed significant changes over the study period. Temperatures increased significantly during the spring, but this did not appear to have a corresponding impact on seasonal characteristics related to the timing of pollen seasons (i.e. start date, peak date and end date). All of the observed changes were associated with characteristics that can be related to exposure (i.e. duration, peak value and SPI). For arboreal taxa, the SPI of Betula decreased significantly, and Platanus pollen seasons became significantly shorter. For herbaceous species, the SPI and peak values of Artemisia became significantly lower, whereas the SPI and peak values of Ambrosia became significantly higher. The SPI of Poaceae and Urticaceae also decreased significantly. The results of correlation analysis showed that various characteristics of pollen seasons are significantly related. This study provides an essential baseline for determining exposure of the allergic population to allergenic pollen and aids understanding of the incidence of pollinosis in Parma. Gaps still exist in current knowledge; not least, the need to quantify the degree of influence exerted by some of the principal factors driving environmental change, climate and land use.