Air pollution in the places of Betula pendula growth and development changes the physicochemical properties and the main allergen content of its pollen.

Pollen allergy becomes an increasing problem for humans, especially in the regions, where the air pollution level increases due to the traffic and urbanization. These factors may also affect the physiological activity of plants, causing changes in pollen allergenicity. The aim of the study was to estimate the influence of air pollutants on the chemical composition of birch pollen and the secondary structures of the Bet v1 protein. The research was conducted in seven locations in Malopolska region, South of Poland of a different pollution level. We have found slight fluctuations in the values of parameters describing the photosynthetic light reactions, similar spectra of leaf reflectance and the negligible differences in the discrimination values of the δ13C carbon isotope were found. The obtained results show a minor effect of a degree of pollution on the physiological condition B. pendula specimen. On the other hand, mean Bet v1 concentration measured in pollen samples collected in Kraków was significantly higher than in less polluted places (p = .03886), while FT-Raman spectra showed the most distinct variations in the wavenumbers characteristic of proteins. Pollen collected at sites of the increased NOx and PM concentration, show the highest percentage values of potential aggregated forms and antiparallel ß-sheets in the expense of α-helix, presenting a substantial impact on chemical compounds of pollen, Bet v1 concentration and on formation of the secondary structure of proteins, what can influence their functions.

The impact of data assimilation into the meteorological WRF model on birch pollen modelling.

We analyse the impact of ground-based data assimilation to the Weather Research and Forecasting (WRF) meteorological model on parameters relevant for birch pollen emission calculations. Then, we use two different emission databases (BASE - no data assimilation, OBSNUD - data assimilation for the meteorological model) in the chemical transport model and evaluate birch pollen concentrations. Finally, we apply a scaling factor for the emissions (BASE and OBSNUD), based on the ratio between simulated and observed seasonal pollen integral (SPIn) to analyse its impact on birch concentrations over Central Europe. Assimilation of observational data significantly reduces model overestimation of air temperature, which is the main parameter responsible for the start of pollen emission and amount of released pollen. The results also show that a relatively small bias in air temperature from the model can lead to significant differences in heating degree days (HDD) value. This may cause the HDD threshold to be attained several days earlier/later than indicated from observational data which has further impact on the start of pollen emission. Even though the bias for air temperature was reduced for OBSNUD, the model indicates a start for the birch pollen season that is too early compared to observations. The start date of the season was improved at two of the 11 stations in Poland. Data assimilation does not have a significant impact on the season's end or SPIn value. The application of the SPIn factor for the emissions results in a much closer birch pollen concentration level to observations even though the factor does not improve the start or end of the pollen season. The post-processing of modelled meteorological fields, such as the application of bias correction, can be considered as a way to further improve the pollen emission modelling.

Changes in qualitative and quantitative traits of birch (Betula pendula) pollen allergenic proteins in relation to the pollution contamination.

Birch (Betula pendula) pollen causes inhalant allergy in about 20% of human population in Europe, most of which is sensitive to the main birch allergen, Bet v1. The aim of the study was to find out (i) whether and how the analysed birch individuals differ in regard to composition of individual subunits of pollen proteins and to protein content in these subunits; (ii) whether the level of particulate matter relates to concentration of Bet v1 allergen. Study was performed in Southern Poland, in 2017-2019. Pollen material was collected at 20 sites, of highly or less polluted areas. Protein composition was analysed by SDS-PAGE, while the concentration of Bet v1 was evaluated by ELISA. The obtained results were estimated at the background of the particulate matter (PM10) level and the birch pollen seasons in Kraków. The electrophoregrams of pollen samples collected at different sites showed huge differences in staining intensities of individual protein subunits, also among important birch allergens: Bet v1, Bet v2, Bet v6 and Bet v7. The level of Bet v1 was significantly higher in the pollen samples collected at the more polluted sites. While the birch pollen allergenic potential is determined, the both pollen exposure and the content of the main allergenic components should be considered, as factors causing immunological response and clinical symptoms manifestation in sensitive individuals.

Extension of WRF-Chem for birch pollen modelling-a case study for Poland.

In recent years, allergies due to airborne pollen allergens have shown an increasing trend, along with the severity of allergic symptoms in most industrialized countries, while synergism with other common atmospheric pollutants has also been identified as affecting the overall quality of citizenly life. In this study, we propose the state-of-the-art WRF-Chem model, which is a complex Eulerian meteorological model integrated on-line with atmospheric chemistry. We used a combination of the WRF-Chem extended towards birch pollen, and the emission module based on heating degree days, which has not been tested before. The simulations were run for the moderate season in terms of birch pollen concentrations (year 2015) and high season (year 2016) over Central Europe, which were validated against 11 observational stations located in Poland. The results show that there is a big difference in the model's performance for the two modelled years. In general, the model overestimates birch pollen concentrations for the moderate season and highly underestimates birch pollen concentrations for the year 2016. The model was able to predict birch pollen concentrations for first allergy symptoms (above 20 pollen m-3) as well as for severe symptoms (above 90 pollen m-3) with probability of detection at 0.78 and 0.68 and success ratio at 0.75 and 0.57, respectively for the year 2015. However, the model failed to reproduce these parameters for the year 2016. The results indicate the potential role of correcting the total seasonal pollen emission in improving the model's performance, especially for specific years in terms of pollen productivity. The application of chemical transport models such as WRF-Chem for pollen modelling provides a great opportunity for simultaneous simulations of chemical air pollution and allergic pollen with one goal, which is a step forward for studying and understanding the co-exposure of these particles in the air.

A study on the spatial and temporal variability in airborne Betula pollen concentration in five cities in Poland using multivariate analyses.

During the spring period, Betula pollen is the main cause of inhalant allergies in Poland and therefore it is important to monitor and forecast airborne pollen concentrations of this taxon. This study conducted a comparative analysis of the basic characteristics of Betula pollen seasons at the regional scale. The study was carried out from 2001 to 2016 in five cities in Poland: Lublin, Warsaw, Cracow, Sosnowiec, and Szczecin. To find the attributes of birch pollen seasons that mostly differentiated the individual cities, a general discriminant analysis (GDA) was performed, while a principal component analysis (PCA) allowed us to reduce the data space and present a scatterplot of PCA scores in order to compare pollen seasons in the individual cities. The contingency table was also analyzed to check whether there was a significant relationship between pollen counts in the studied years and cities. At most of the sites, biennial cycles of low and high pollen concentrations can be observed. Due to the high variation in seasons in each of these cities, two data groups were distinguished: Group 1 was composed of seasons with high pollen deposition (2001, 2003, 2006, 2008, 2010, 2012, 2014, 2016), and Group 2 comprising the other seasons. Multivariate analyses were performed on both these groups as well as in the entire dataset. End98, Peak Value, and Annual Total had the highest discriminant power. In Group 1, Warsaw and Sosnowiec differed the most in the investigated parameters, while Cracow and Szczecin differed the least. In both groups, most seasons with the highest pollen birch concentration were observed in Lublin, followed by Warsaw, while in Cracow, the number of such seasons was the smallest.

Masting in wind-pollinated trees: system-specific roles of weather and pollination dynamics in driving seed production.

Masting, the highly variable production of synchronized large seed crops, is a common reproductive strategy in plant populations. In wind-pollinated trees, flowering and pollination dynamics are hypothesized to provide the mechanistic link for the well-known relationship between weather and population-level seed production. Several hypotheses make predictions about the effect of weather on annual pollination success. The pollen coupling hypothesis predicts that weather and plant resources drive the flowering effort of trees, which directly translates into the size of seed crops through efficient pollination. In contrast, the pollination Moran effect hypothesis predicts that weather affects pollination efficiency, leading to occasional bumper crops. Furthermore, the recently formulated phenology synchrony hypothesis predicts that Moran effects can arise because of weather effects on flowering synchrony, which, in turn, drives pollination efficiency. We investigated the relationship between weather, airborne pollen, and seed production in common European trees, two oak species (Quercus petraea and Q. robur) and beech (Fagus sylvatica) with a 19-yr data set from three sites in Poland. Our results show that warm summers preceding flowering correlated with high pollen abundance and warm springs resulted in short pollen seasons (i.e., high flowering synchrony) for all three species. Pollen abundance was the best predictor for seed crops in beech, as predicted under pollen coupling. In oaks, short pollen seasons, rather than pollen abundance, correlated with large seed crops, providing support for the pollination Moran effect and phenology synchrony hypotheses. Fundamentally different mechanisms may therefore drive masting in species of the family Fagacae.

[Clinical symptoms of the allergic rhinitis and coexisting cross reactions in patients treated with the birch and/or grasses allergens against a background of the pollen exposure].

During specific immunotherapy (SIT) it is recommended to monitor the patient symptoms in relation to the exposure of allergen which the patient is treated. The aim of the study was to analyze the clinical symptoms of allergic rhinitis (AR) and cross reactivity in patients undergoing specific immunotherapy using pollen allergens (SIT) (birch and/or grasses) against the pollen exposure in 2014-2016. The study group, consisted of patients with pollen allergy, treated by SIT with birch and grasses allergens, who showed oral allergy symptoms. Patients of the control group were sensitive to birch and/or grasses allergens and they were not treated with SIT. The analyses were based on the results of questionnaires and patient symptom diaries. Timing of the pollen seasons of birch and grasses were similar, however the significantly higher concentration of birch pollen was found in 2014 and 2016, comparing to 2015. The strongest relationship between the pollen concentration and symptoms severity was revealed in the study group in patients desensitized by combined vaccine (birch/grasses), while in the control group, in patients sensitive to both taxa. In 35.3% of patients in the study group, a significant decrease in symptoms after foods was found, especially in patients desensitized with mixed vaccine (birch, grasses) after consumption of vegetables and in patients desensitized with grasses allergens after the fruits and nuts. SIT has a significant impact on the symptoms score reduction, which could be modified by the changeable seasonal pollen exposure.

[Exposure to alder, hazel and birch pollen and PM10 dust concentration in Krakow in 2010-2015].

PM10, one of the air pollution components has a significant effect on plant pollen by the deposition on the surface of pollen grains, morphological changes of pollen walls and interference in the structure of the allergenic proteins. The aim of the study was to verify whether and in what weather conditions the concentration of pollen of alder, hazel and birch coincides with the elevated level of PM10 in Kraków, in 2010-2015. In the days when the alder pollen concentration exceeded 95 PG/m3, causing severe inhalant allergy symptoms and the concentration of hazel pollen was >80 PG/m3 and the admissible level of PM10 was exceeded, the maximum air temperature ranged from 5.1 to 22.6oC, the days were dry (humidity <60%), without precipitation and mostly windless. High concentration of birch pollen and exceeded admissible level of PM10 concentration were found in more than 60% of the days in the city center. In 70.3% of the days in which the birch pollen concentration reached values that caused the symptoms of asthma (>155 PG/m3), the dust concentration was exceeded (>50µg/m3), and rainfall and wind speed of 1-3 m/s occurred. Symptoms in people allergic to trees pollen in Kraków can be exacerbated during periods when the standard limits of PM10 are exceeded. Such situations have occurred mostly in March (pollen of alder and hazel) and April (birch pollen), especially in the city center.