Birch pollen grains are one of the most important groups of atmospheric biological particles that induce allergic processes. The fluctuation pattern of birch pollen seasons in selected cities of Poland is presented. Measurements were performed by the volumetric method (Burkard and Lanzoni 2000 pollen samplers). The distributions of the data were not normal (Shapiro–Wilk test) and statistical error risk was estimated at a significance level of <em>α</em> = 0.05. Pollen season was defined as the period in which 95% of the annual total catch occurred. The linear trend for the selected features of the pollen season, skewness, kurtosis and coefficient of variation (<em>V</em>%) were also analyzed. During the 12–14 years of study, the beginnings of birch pollen seasons were observed 7–14 days earlier, the ends were noted 5–10 days earlier, and the days with maximum values occurred 7–14 days earlier compared to the long-term data. The left-skewed distribution of the pollen season starts in most sampling sites confirms the short-lasting occurrence of pollen in the air. The threat of birch pollen allergens was high during the pollen seasons. If vegetation is highly diverse, flowering and pollen release are extended in time, spread over different weeks and occur at different times of the day. Flowering time and pollen release are affected by insolation, convection currents, wind, and turbulence. Therefore, pollen seasons are characterized by great inter-annual variability.

The aim of the study was to compare the pollen season of oak in the cities of Bialystok,

This paper presents the course of alder pollination season in Poland in 2019. The measurements were performed in Bydgoszcz,

This paper presents the course of goosefoot pollination in selected cities of Poland in 2018. The measurements were performed in Bialystok,

The aim of the study was to investigate the concentration of <em>Alnus</em> L., <em>Corylus</em> L. and <em>Betula</em> L. pollen in the village of Gudowo (Western Pomerania, Poland) in the years 2012–2014 in order to estimate the threat of allergenic tree pollen in this rural region. Measurements were performed using the volumetric method (VPPS Lanzoni 2000 pollen sampler). The duration of the pollen season was determined by the 98% method, taking days on which, respectively, 1% and 99% of the annual total pollen grains appeared as the beginning and end of the season. Pollen grains from hazel occurred in the air as the first ones, before pollen grains from alder and birch. The earliest beginning of the hazel pollen season was recorded in 2012, whereas alder and birch pollen seasons started the earliest in 2014. Daily maximum pollen concentrations of the investigated taxa were recorded in 2014. Birch pollen allergens posed the largest threat to pollinosis sufferers. In the years 2012–2014, pollen concentrations equal or higher than threshold values, at which people with pollinosis show allergic symptoms, were recorded most frequently for birch, hazel, and alder (25, 19, and 14 days, respectively). The highest hourly alder pollen concentration was recorded at 16:00 and in the case of hazel at 15:00. The diurnal distribution of birch pollen concentrations does not show any distinct peaks.