Changes in the concentration of grass pollen in the atmosphere of Poznań

The aim of the study was to determine the concentrations of grass pollen during the vegetation season in the atmosphere of Poznań against the background of the content of pollen of other plants and mould fungi. Observations were conducted in 1997. Concentrations of pollen grains and spores of mould fungi in the atmosphere were assessed by the volumetric method. For this purpose, the Burkard apparatus (Seven-Day Recording Volumetric Spore Trap) was set up on the roof of the 8-storey high building of the Maximum College of the Agricultural University in Poznań. The continuous, 24-hour work of the apparatus made possible to monitor concentrations of allergenic pollen throughout the experiment. The tape was glued to a microscopic glass and evaluated under the light microscope. The number of pollen grains and mould spores on individual sections (2 mm per hour) of the tape allowed determining their concentration per 1 m3 of air. Microscopic evaluation was conducted every 24 hours, collecting analytical material from the trap at 10 a.m. in which pollen and spores were determined. From among many wind pollinated taksons of plants, species from the grass family - because of their long period of pollination and clinical significance - play an important role in the structure of allergenic pollen in the atmosphere of Poznań. The highest concentration of grass pollen was recorded during the period from the end of May to the end of the first decade of July. From then on, the concentration of grass pollen in the air dropped rapidly and remained on a low level, not exceeding 7.5 pollen grains calculated per 1 m3 air per 24 hours. The higher concentration of grass pollen was recorded on June 29th - 360.4 grains · m-3. In terms of 24-hour period, the highest concentrations of the pollen grains in the air on a day without rain occurred between 9 and 11 a.m., whereas the lowest - at night.