Characteristic of pollen seasons in the most sensitizing plants based on 15 years of observation in Warsaw
Authors: Lipiec Agnieszka , Rapiejko Piotr , Furmańczyk Konrad , Jurkiewicz Dariusz 
Published: September 2018

Introduction Allergic rhinitis concerns nearly 25% of the Polish population. Among pollen allergens, the most common reasons for allergic rhinitis are: grass, birch and mugwort. Knowledge of the characteristics of pollen seasons is necessary in diagnostics, monitoring of therapy and prevention of allergic rhinitis.
Purpose This work aims to analyze the pollen seasons of the most commonly sensitizing plants in the Polish population; grass, birch and mugwort in the years 2003-2017 in Warsaw.
Material and methods Measurements of pollen concentration were carried out using the Burkard volumetric apparatus operating in continuous volumetric mode. The analysis of pollen seasons was conducted based on the following characteristics: beginning, end, and length of season, annual sum of daily pollen concentrations, maximum daily concentration, number of days with maximum and threshold concentration. Linear regression together with the Pearson correlation coefficient were used in statistical analysis to study the relationship between variables; furthermore, descriptive characteristics of distributions studied were determined.
Results	The average date of the beginning of the birch pollen season in the analyzed period is April 10th, and it belongs to seasons of average length (47 days on average). Concentration above 75z/m3, when most allergic people expect allergic symptoms, was recorded for an average of 18 days. The highest daily concentration of birch pollen reaching 6321 grains/m3 (2006, 2012, 2016) exceeded the lowest value of the maximum concentration by almost 20 times (2015). Among the taxa analyzed, the highest values of daily concentration and annual sums were recorded for birch pollen. The average date for the beginning of grass pollination season is on May 13th. It is the longest pollen season (on average 134 days), and the period when concentration exceeded 50z/m3 covered an average of 26 days. The highest daily concentration of grass pollen reaching 496 grains/m3 (2005 and 2007) exceeded the lowest value of maximum concentration by 3.5 times (2016). The average date of the beginning of the brackish pollen season is July 16th. The season lasts 65 days on average, when concentration exceeding 30z/m3 was registered for an average of 12 days. The highest daily concentration of mugwort pollen reaching 154 grains/m3 (2007) exceeded the lowest value of maximum concentration by 4 times (2013). For all analyzed taxa, the strongest correlated variables are the annual sum of daily pollen concentrations (Seasonal Pollen Index) and daily maximum concentration (correlation for birch pollen = 0.92, for grass pollen = 0.88, and for mugwort pollen = 0.91)
Conclusions Periods of pollen in the air show certain variation in the analyzed 15-year period. The maximum concentration in the pollen season for the analyzed taxa and the annual sum of daily concentrations of pollen show the highest variability, particularly strongly expressed in the case of birch pollen. There is a linear relationship between the annual sum of daily pollen concentrations and the maximum concentration value as well as the number of days with the threshold concentration for all analyzed taxa. Variability of parameters describing the dynamics of pollen seasons indicates the need to monitor, both by patients with hay fever and physicians, the current information about the concentration of pollen in the air during the pollen season.