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.

Prevalence of allergic rhinitis and asthma in Poland in relation to pollen counts.

INTRODUCTION: Despite the known role of pollen allergens in causing allergy symptoms in sensitized individuals, there are few publications investigating the relationship between pollen exposure in different regions and the prevalence of inhalant allergy. AIM: To assess the association between the prevalence of allergic rhinitis and asthma and the degree of exposure to pollen in various regions of Poland. MATERIAL AND METHODS: Completed questionnaires of 9,443 subjects living in four urban centres (Wroclaw, Katowice, Warsaw, Bialystok), collected within part of the ECAP project, were analyzed. Children aged 6-7 (n = 2,278), adolescents aged 13-14 (n = 2,418), and adults aged 20-44 (n = 4,747) constituted 24.2%, 25.6% and 50.3% of the respondents, respectively. The clinical part (including skin prick tests, an assay of Timothy grass-specific IgE), was attended by 24% of the respondents. Data from 6-year pollen monitoring served to characterize birch and grass pollen seasons. RESULTS: We found insignificant negative associations between the duration of birch pollen season and the prevalence of declared allergic rhinitis and asthma during the season across all age groups. There were insignificant inverse associations between the number of days with above-threshold and high grass pollen concentrations, total grass pollen count and the prevalence of declared allergic rhinitis and asthma during the season across all age groups. Associations noted in the clinical part were also non-significant; however, these trends were not uniform across the age groups. CONCLUSIONS: Our findings do not confirm the hypothesis of a positive association between pollen exposure and the prevalence of allergic rhinitis and asthma.

Source regions of ragweed pollen arriving in south-western Poland and the influence of meteorological data on the HYSPLIT model results.

We have investigated the relationship between the inflow of air masses and the ragweed pollen concentration in SW Poland (Wroclaw) for a 10-year period of 2005-2014. The HYSPLIT trajectory model was used to verify whether episodes of high concentrations can be related to regions outside of the main known ragweed centres in Europe, like Pannonian Plain, northern Italy and Ukraine. Furthermore, we used two different meteorological data sets (the global GDAS data set and from the WRF mesoscale model; the meteorological parameters were: U and V wind components, temperature and relative humidity) into HYSPLIT to evaluate the influence of meteorological input on calculated trajectories for high concentration ragweed episodes. The results show that the episodes of high pollen concentration (above 20 pm-3) represent a great part of total recorded ragweed pollen in Wroclaw, but occur rarely and not in all years. High pollen episodes are connected with air masses coming from south and south-west Europe, which confirms the existence of expected ragweed centres but showed that other centres near Wroclaw are not present. The HYSPLIT simulations with two different meteorological inputs indicated that footprint studies on ragweed benefit from a higher resolution meteorological data sets.