May the definition of pollen season influence aerobiological results?

Abstract

This paper reviews the terms and major criteria used to define and limit the pollen season. Pollen data from Cordoba (Spain), Ourense (Spain) and Bologna (Italy) were used to ascertain the extent to which aerobiological results and pollen curves are modified by the criteria selected. Results were analysed using SpearmanÕs correlation test. Phenological observations were also used to determine synchronization between pollen curves and plant phenology. The criteria for limiting the shortest and longest pollen season periods, as well as the earliest and latest start and end dates, varied according to the city and the taxon under study; in many cases, results for a given taxon also depended on the year. The smallest differences were obtained for Platanus and the greatest for Poaceae.

Reproducibility between counts of airborne allergenic pollen from two cities in the East Midlands, UK

“…At least ten different criteria for calculating the length of pollen seasons have been published (Jato et al 2006). The two most popular methods involve either defining the start of the season as the date in which the cumulative count reaches a pre-defined quantity, eg.…”

“…The retrospective percentage technique eliminates the long tails of low values at the start and end of the seasons which could otherwise introduce bias to the results during statistical analysis (Galán et al 1995). The 98% criterion was shown to yield the longest grass season in a multi-year, multi-city study and resulted in a long tail at the end of the season (Jato et al 2006). When applied to the data in this study, the 90% criterion shortened the season to an extent that excluded the first high (>50 grains m -3 air day -1 ) grass day of the year (data not shown).…”

Comparison of phenological, aerobiological and melissopalynological patterns of Olea europaea

“…Thus, several authors have proposed methods to define the pollen season duration or phases such as the start, peak and end date (Nilsson and Persson, 1981;Lejoly-Gabriel and Leuschner, 1983;Andersen, 1991;Spieksma et al, 1995;Jager et al, 1996;Feher and Jarai-Komlodi, 1997;Giorato et al, 2000;Sanchez-Mesa et al, 2003). However, the accuracy of these methods is strongly connected to the taxon, the location and the large-scale weather conditions (Estrella et al, 2006;Jato et al, 2006).…”

“…Indeed, the start and end date as well as the peak day of the pollen season can be influenced by the long-range transport phenomena of olive pollen from neighbour regions (Vázquez et al, 2003;Galan et al, 2004;Galán et al, 2008). Thus, several authors point out that phenological data should also be obtained in order to specify the aerobiological pollen season with respect to the local flowering in a more accurate way (Fornaciari et al, 2000;Garcıa-Mozo et al, 2009;Jato et al, 2006).…”

“…In general, aerobiological observations about the pollen season are strongly influenced by the taxon, the location and the large-scale weather conditions (Estrella et al, 2006;Jato et al, 2006). Thus, phenological observations should be made in order to define the aerobiological pollen season according to the local flowering, especially when airborne pollen is used as bioindicator of flowering phenophase in climate changes investigations (Fornaciari et al, 2000;Garcıa-Mozo et al, 2009;Jato et al, 2006).…”