Fraxinus l. pollen dynamics in Ankara atmosphere

Abstract

Fraxinus L. (Ash) is a deciduous wind-pollinated tree of the Oleaceae family widely extended intemperate zones of the North and Central Europe. In general, Ash trees are one of the most frequent natural species of riversides, forests, nonetheless, they are also commonly used as ornamental plants in parks and gardens of urban areas in Europe and Turkey as well. It is not clear whether ash pollen is a primary cause of sensitization or whether it is implied through cross-sensitization of other Oleaceae pollen. In aerobiological studies, Fraxinus pollen was the secondly dominant pollen types after Cupressaceae pollen during early spring. The aim of this study was to analyze Fraxinus airborne pollen dynamics in Ankara, describe their pollen season and effects of meteorological parameters on them. A 7day volumetric trap, running continuously throughout the year, was used to collect circulating pollen and aerobiological sampling was carried out three years (20142016). Fraxinus pollen was counted as grains/m3 and the main pollen season was deduced from these data. Correlations with climatic factors (temperature, rainfall, humidity, wind speed) impacts on pollen were assessed by Spearman’s rank correlation test. Risky days for allergic individuals were determined due to the AAAAI classification. Fraxinus pollen were observed from the second part of February to the end of the March during three years. The pollen seasons pattern was found quite similar and the peak days were in the last week of February in 2014 (523 pollen grains/m3) and 2016 (669 pollen grains/m3). However in 2015, the pollen concentrations was quite lower (204 pollen grains/m3) and the peak day was later than the other years. While the pollen levels of Fraxinus were positively correlated with mean daily temperature (99% probability), they were negatively correlated relative humidity (95% probability) and the total rainfall in 2015. The days number with moderate level, which have more than 15 pollen grains, were found higher in 2014 and 2016. Also, only one day was found with high level risky for both 2014 and 2016 years. However, there were only four days were observed with the moderate level risky in 2015.