Pollen season variations during the last 26 years: a case study in Trentino, North Italy

Airborne pollen records are strongly correlated with flowering intensity of the anemophilous species in the trap location site and surroundings. Studies during recent decades have revealed a trend towards rising airborne pollen counts in Europe and a clear advance in flowering dates. In the present study* a long data series (1989-2014) of daily airborne pollen concentration was considered. Data were collected at S. Michele all’Adige (46°12′N, 11°08′E), Trentino, North Italy, following standardized procedures (UNI 11108:2004). The sampler is located at the bottom of an alpine valley surrounded by high mountains that make it a perfect experimental lab to study the alpine environment. A total of 38 taxa representative of the local pollen spectrum were considered and ten aerobiological parameters were calculated, including, among others, pollen index, pollen season start date and duration. The aim of the study is to detect if there are significant trends in airborne pollen amounts and in pollen season start dates. The results show a statistically significant increasing trend for 35 pollen taxa (Makesens statistic; p<0.05). Only Poaceae family shows a decreasing (but not significant) trend, probably due to land use changes in the study area with a consistent reduction of open green areas for new buildings construction. Sixteen (11 woody species) taxa anticipate the pollen season start date. The results of this local study are generally in agreement with other largescale studies. Considering that a larger amount of pollen and a longer season of allergenic pollen might increase the risk for allergic people, aerobiological monitoring assumes a great importance as human health protection tool. *The study was partially founded by Provincia Autonoma di Trento.