Poaceae pollen in Galicia (N.W. Spain): characterisation and recent trends in atmospheric pollen season

Abstract

Airborne Poaceae pollen counts are greatly influenced by weather-related parameters, but may also be governed by other factors. Poaceae pollen is responsible for most allergic reactions in the pollen-sensitive population of Galicia (Spain), and it is therefore essential to determine the risk posed by airborne pollen counts. The global climate change recorded over recent years may prompt changes in the atmospheric pollen season (APS). This survey used airborne Poaceae pollen data recorded for four Galician cities since 1993, in order to characterise the APS and note any trends in its onset, length and severity. Pollen sampling was performed using Hirst-type volumetric traps; data were subjected to Spearman's correlation test and regression models, in order to detect possible correlations between different parameters and trends. The APS was calculated using ten different methods, in order to assess the influence of each on survey results. Finally, trends detected for the major weather-related parameters influencing pollen counts over the study period were compared with those recorded over the last 30 years. All four cities displayed a trend towards lower annual total Poaceae pollen counts, lower peak values and a smaller number of days on which counts exceeded 30, 50 and 100 pollen grains/m(3). Moreover, the survey noted a trend towards delayed onset and shorter duration of the APS, although differences were observed depending on the criteria used to define the first and the last day of the APS.

Main features of Poaceae pollen season in Madeira region (Portugal)

“…2) is in accordance with the reports from other regions [21,22], but contrary to other studies [5,23]. Poaceae pollen was observed during all the year, especially in spring when most grass species bloom [24].…”

Volumetric analysis of airborne pollen grains in the city of Uşak, Turkey

“…This difference between the two years is thought to be due to the high rainfall observed during the spring in the second year (Figure 6). In a similar study by Jato et al (2009), spring rainfall was an important factor affecting the amount of Poaceae pollen. In Uşak Province, the Poaceae species, which are not only among the members of natural flora but also cultivated, are the source of pollen belonging to this family.…”

Climate change: consequences on the pollination of grasses in Perugia (Central Italy). A 33-year-long study

“…For example, water availability and high temperatures prior to flowering seem to have a positive effect on the anthesis and quantity of pollen produced (Sánchez-Mesa et al 2005;Green et al 2004). Obviously, meteorological parameters such as rainfall, relative humidity, wind velocity, and direction also have a strong influence on pollination (Puc and Puc 2004;Sánchez-Mesa et al 2005;Jato et al 2009). Smith et al (2009) have shown that large-scale air mass phenomena like the North Atlantic Oscillation (NAO) may also affect the amounts of airborne grass pollen concentration, even if this influence varies spatially across Europe.…”