The variability of pollen concentrations at two stations in the city of Wrocław in Poland

Abstract

The aim of the study was to investigate the variability of Alnus and Corylus pollen concentrations at two stations located in the city of Wrocław, Poland-one at the city centre and the other 4 km from the city centre. Our goal was to compare measurements from these stations in relation to meteorology and land cover. We used Spearman's correlation coefficient to investigate any dependence between meteorological factors and pollen concentration. Additionally, to check the relation between the direction of inflow of air masses and pollen concentration, we calculated the backward trajectories using the HYSPLIT model. The results have shown that despite the short distance between the stations, the characteristic of the pollen season is different for both stations (i.a. date of start and end of pollen season, duration of the season). The Spearman's correlation coefficient between relative humidity and air temperature and pollen concentration was found to be statistically significant. The backward trajectories calculated with HYSPLIT suggested a different origin of air masses between stations for high-concentration episodes in the case of Alnus. Our study has shown that analysis of meteorological conditions and influence of air transport into pollen concentration makes it possible to ascertain the reasons for differences in pollen level at these two stations, both of which are located in the same climatological domain. The study also shows that the aerobiological condition may change significantly over a short distance, which is a major challenge, for example, for pollen emission, transport, and concentration modelling.Keywords Pollen Á HYSPLIT Á Meteorological conditions Á Back-trajectories IntroductionCorylus (hazel) and Alnus (alder) are trees which release first pollen grains that are measured in the air of Poland each year (Puc and Kasprzyk 2013). According to research conducted by Rapiejko et al. (2007) in Poland, the first symptoms of allergy of sensitized people to these taxa appear in low concentrations of pollen: for hazel, the threshold value is 35 pollen grains per cubic meter of air (pollen grains m -3 ) and for alder 45 pollen grains m -3 , whereas symptoms for all sensitized people are observed at slightly higher pollen concentration amounting to 80 pollen grains m -3 in the case of Corylus and 85 pollen grains m -3 in the case of Alnus.

Alder pollen concentrations in the air during snowfall

“…This contributed to a very similar pattern of pollen seasons in almost every region of Poland (Rapiejko et al 2018). We think that such a remarkable increase in temperature, as well as the high solar radiation and extended duration of sunlight, most probably caused the intense pollen release (Bilińska et al 2019). Furthermore, the peak airborne pollen concentrations were recorded on the same days at almost all locations (Rapiejko et al 2018).…”

“…In the areas of the city where alder trees are not grown, the number of pollen grains deposited on snow was remarkably lower than those recorded among samples collected at sites where alders are grown in large numbers. Similar to Bilińska et al (2019), we assume that in spite of the enormous dispersal capacity of pollen grains, local vegetation is the main source of airborne pollen. The differences observed in the deposition of pollen among subsamples could be attributed to local conditions, such as the height and layout of buildings, and type of land use.…”

Analysis of changes in Betula pollen season start including the cycle of pollen concentration in atmospheric air

“…Application of this method eliminates low concentrations of pollen at the beginning and end of the season, which usually originate from long-distance transport or redeposition [ 32 – 34 ]. This method is the most frequently used in aerobiological studies [ 5 , 35 – 40 ]. However, other direction of research may be based on the use of different approaches, e.g.…”

Application of the HYSPLIT model for birch pollen modelling in Poland

“…The allergenic symptoms depend on pollen concentration (Rapiejko et al, 2007), whereas pollen concentration can vary greatly, depending on the vegetation's composition (Bilin ´ska et al, 2019a(Bilin ´ska et al, , 2019bCharalampopoulos et al, 2018;Myszkowska et al, 2010) and meteorology, i.e. temperature, wind speed, relative humidity (Kaszewski et al, 2008;Majeed et al, 2018;Puc et al, 2015).…”

“…temperature, wind speed, relative humidity (Kaszewski et al, 2008;Majeed et al, 2018;Puc et al, 2015). Previous studies have shown that even pollen stations located close to each other may differ significantly with regard to the amount of pollen (Bilin ´ska et al, 2019a(Bilin ´ska et al, , 2019b. In this case, the modelling of pollen distribution is very important, especially for people allergic to it.…”