Duration Of Pollen Season Research Articles

Pollen- and Weather-Based Machine Learning Models for Estimating Regional Olive Production

The olive tree is one of the most common type of cultivation in the Mediterranean area, having high economic and social importance. The Alentejo region, Portugal, is an area with a high presence of olive groves, which in 2022 accounted for 201,474 hectares. The aim of this study was to assess the relationship between olive pollen, weather data, and olive tree production, between the years 2002 and 2022. Pollen data were obtained from an urban station located in Évora, in the Alentejo region, and were used to calculate several metrics, such as the Pollen Season Duration (PSD), Seasonal Pollen Index (SPIn), peak value, and weekly pollen accumulation values. Monthly minimum, maximum, and mean temperature and precipitation sums were obtained from the E-OBS observational dataset. Considering the relationship between pollen/weather and olive production, mutual information and correlation analyses were conducted. Subsequently, several machine learning algorithms were trained using pollen and weather datasets, and we obtained suitable forecast models for olive tree production after cross-validation. The results showed high variability in pollen concentrations in Évora over the years. Complex associations were found, with certain weeks of pollen accumulation showing significant mutual information with olive production, particularly during June. The analyzed linear correlation coefficients remained generally low, underscoring the challenge of predicting olive production based on linear relationships. Among the machine learning algorithms employed to predict olive production, Decision Trees, Extreme Gradient Boosting, and Gradient Boosting Regressor were the most robust performers (r2 > 0.70), while linear models displayed a subpar performance (r2 < 0.5), emphasizing the complexity of this approach. These models highlight the roles of maximum and minimum temperatures during March and May and pollen accumulation during the second half of June. The developed models may be used as decision-support tools by growers and stakeholders to further enhance the sustainability of the thriving olive sector in southern Portugal.

Grass flowering times determined using herbarium specimens for modeling grass pollen under a warming climate

The grass family is responsible for most of peoples pollen allergies, and the severity of pollen-based asthma and allergies is expected to increase with global climate change. Identifying grass species through standard pollen monitoring techniques have limitations due to challenges in species-specific pollen identification. As a result, these monitoring methods end up grouping all Poaceae species together, even though there are hundreds of grass species in Europe with flowering times that may vary drastically among species. Given this lack of specificity, it is hard to know which grass species are responsible for causing allergies over the pollen season, and how different species are affected by climate change. To address these issues, we obtained phenological data from thousands of herbarium specimens collected across Denmark spanning 190 years and used pollen monitoring data collected over the last four decades to determine the response of flowering time to climate change for 12 allergenic grass species, and identify which species are likely the biggest contributors to grass pollen loads throughout the pollen season. We find that pollen season duration is lasting longer and starting earlier, and the maximum pollen loads are occurring earlier in response to climate warming. Herbarium specimens provide taxonomic resolution and reveal that many grass species are flowering earlier in response to warmer spring temperatures. Seven out of the 12 species studied in Denmark are identified as major contributors to airborne pollen based on their flowering times, relative abundance and overlap with the time of the year when maximum pollen loads are detected. Four species (Poa pratensis, Dactylis glomerata, Festuca rubra, Holcus lanatus) significantly shifted their flowering time in response to warming temperatures and are flagged as of particular concern to allergy sufferers. Using data derived from natural history collections can contribute to the advancement of pollen forecasting for asthma and allergy patients under both current conditions and amidst future global changes.

Hazel pollen in the air of selected Polish cities in 2022

Hazel is an important source of tree pollen allergens, which are responsible for inhalant allergy symptoms in early spring. The aim of the study was to compare Corylus pollen season in 2022 in 12 cities located in different regions of Poland: Bialystok, Bydgoszcz, Cracow, Kielce, Lublin, Olsztyn, Piotrkow Trybunalski, Sosnowiec, Szczecin, Warsaw, Wroclaw and Zielona Gora. The measurements were conducted using a Burkard- type volumetric sampler, operating in continuous volumetric mode. The following parameters were analyzed: pollen season duration, peak value and peak date, seasonal pollen integral and number of days with concentration exceeding the threshold values triggering allergy symptoms in sensitized individuals. The hazel pollen season in 2022 began in January and the first decade of February. The earliest it began in the western regions, and the latest in eastern Poland. In most cities, maximum daily pollen concentrations were registered between February 5th and 24th. The 2022 hazel pollen season, compared to the 2021 season, was characterized by higher maximum daily pollen concentrations, higher seasonal pollen integrals (SPI) and higher number of days exceeding the threshold value for triggering allergy symptoms in most of the analyzed cities. The highest peak was recorded in Lublin (290 grains/m3) and the highest annual sum (SPI) in Cracow (2071). In 2022 the highest risk of allergy symptoms to hazel pollen allergens in sensitized individuals was found in Lublin, Cracow, Kielce and Sosnowiec.

Seasonal variation in the allergenic potency of airborne grass pollen in Bratislava (Slovakia) urban environment.

The Phl p 5 allergen of the plant species Phleum pratense is considered one of the most crucial grass pollen allergenic molecules inducing respiratory allergies. In this study, we evaluated seasonal variation in the concentration of both grass pollen and Phl p 5 allergens as well as the ratio allergen/pollen (pollen potency) in the air of Bratislava during two consecutive years, 2019–2020. These 2 years differed in terms of air pollution, as COVID-19 lockdown in spring 2020 considerably improved air quality in the study area. Air samples were collected using a Hirst-type sampler for pollen detection and the cyclone sampler for aeroallergen detection. In 2020, we observed 80.3% higher seasonal pollen integral, probably associated with the longer pollen season duration, however, 43.6% lower mean daily pollen potency than in 2019. The mean daily pollen value was 37.5% higher in 2020 than in the previous year, while the mean daily allergen value was 14.9% lower in 2020. To evaluate the relationship between the amount of pollen or allergen in the air and selected meteorological factors and air pollution parameters, we used multiple regression analysis. Regarding weather factors, precipitation and relative humidity were significantly associated with pollen and/or allergen concentration, though these associations were negative. Atmospheric pollutants, especially CO, NO2 and O3 were significantly associated with pollen and/or allergen levels. The associations with CO and O3 were positive, while the association with NO2 was negative. Our results indicate that for grasses, an air pollutant that has a significant positive relationship to the ratio of allergen/pollen is nitrogen dioxide.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11356-021-15179-5.

Analysis of Corylus pollen season in Poland in 2021

Corylus produces allergenic pollen grains that appear in the air in early spring and cause pollen allergy in sensitive people. The aim of this study was to compare the Corylus pollen seasons in 2021 in the following 11 cities in Poland: Bialystok, Bydgoszcz, Cracow, Sosnowiec, Lublin, Olsztyn, Piotrkow Trybunalski, Szczecin, Warsaw, Wroclaw, and Zielona Gora. This research was conducted using the volumetric method and Burkard or Lanzoni pollen samplers. Pollen season duration was determined by the 95% method. The hazel pollen season in 2021 began relatively late, between February 20 and March 1. The season start was recorded earliest in Zielona Gora, while latest in Olsztyn. The highest values of maximum Corylus pollen concentration were recorded in Sosnowiec (230 P/m3) and Zielona Gora (213 P/m3), whereas the lowest ones in Bialystok (27 P/m3) and Bydgoszcz (54 P/m3). In most of these cities, the maximum daily concentration of Corylus pollen grains was recorded in the third 10 days of February or at the beginning of March and only in Lublin and Bialystok the peak value occurred later, on March 16 and March 26, respectively. The highest risk of allergy in people sensitive to the pollen of this taxon was found in Lublin, Olsztyn, and Zielona Gora. The highest values of the annual pollen integral were determined in Lublin, similarly to the previous years.

Tree pollen allergy risks and changes across scenarios in urban green spaces in Brussels, Belgium

Urban green spaces may improve human health and well-being. However, green spaces may also emit allergenic pollen and these may trigger asthma, allergic disease, and respiratory infections. How allergy risks in green spaces may be modified by environmental change is still not widely understood. This study analyzed tree inventory data of 18 urban green spaces (5940 trees; 278 taxa; 93 ha) in the Brussels Capital Region, Belgium. We investigated present tree pollen allergy risk (AR) and changes in AR driven by changes in tree species composition, allergenic potential and pollen season duration. AR was estimated by calculating the allergenicity index I UGZA (range 0–1, 1 worst) for the present situation and 13 scenarios.The average AR was 0.08 (SD 0.05; range 0.002–0.17). The AR increased by 11–27% in increased allergenic potential scenarios, and by 44% in the increased pollen season duration scenario. Preventive removal of birch, hazel and alder reduced the AR by 13%. The AR increased by 99–111% in combined scenarios with and without preventive removal of the main allergenic taxa.These findings indicate that tree pollen allergy risks could considerably rise when ongoing environmental changes lead to a combination of longer pollen seasons, increased pollen allergen potency, and increased sensitization for one or more species. The preventive removal of the main allergenic tree species cannot sufficiently counter allergy risks caused by other species and that are amplified by environmental change, highlighting the importance of careful tree species selection in urban green space policy and planning.

The impact of weather conditions on hazel pollen concentration in Sosnowiec (Poland) in 1997\u20132019

The goal of this study was to compare hazel pollen seasons in Sosnowiec in 1997–2019 and to analyse the impact of weather conditions on these seasons. The measurements were conducted using a volumetric method with a Burkard spore trap. The duration of pollen seasons was determined using the 98% method. SPI (Seasonal Pollen Index) was calculated as the sum of daily pollen concentrations in a given season. The measurements showed that high temperatures in January and February had an impact on the beginning of the hazel pollen season. They revealed that there are positive correlations with temperatures and sunshine hours long before the season, i.e. 210–180 days before. The daily hazel pollen concentration in Sosnowiec showed a positive and statistically significant correlation with air temperature, sunshine hours, and average and maximum wind speed. Negative correlation was demonstrated for snow cover depth and relative humidity of the air. Daily concentration levels depend also on the type of weather front as well as direction of air mass flow and its type. Variance analysis showed that the highest concentrations of hazel pollen grains were recorded when warm air moves from the south and south–western direction, whereas the lowest ones were noted for air moving from the east, south–east, north and north–east directions. Atmospheric precipitation, snow cover depth, and average, maximum, minimum and near-the-ground temperatures in the season also had an impact on the SPI of hazel pollen grains. High positive correlation coefficients were also observed in the case of thermal conditions, sunshine hours, relative humidity and precipitation from July to September in the year preceding a given pollen season. The duration of the hazel pollen season depends on precipitation, snow cover depth and temperature during a given season.

Analysis of Corylus pollen season in Poland in 2020

In Poland hazel is one of the earliest flowering plants and in phenology it belongs to indicator plants that mark the beginning of early spring. Hazel pollen grains contain allergens that are a cause of pollen allergy during the early spring period. The aim of the present study was to compare Corylus pollen seasons in 2020 in the following 11 cities located in different regions of Poland: Szczecin, Bydgoszcz, Zielona Gora, Wroclaw, Opole, Sosnowiec, Piotrkow Trybunalski, Warsaw, Lublin, Olsztyn, and Bialystok. This research was conducted using the volumetric method and Burkard or Lanzoni pollen samplers. Pollen season duration was determined by the 95% method. This study analyzed the specific parameters of the pollen season (start, end, peak value, peak date, annual total) and also determined the number of days with a concentration exceeding the threshold values at which the first allergy symptoms in people sensitized to hazel pollen and symptoms in all allergic patients occur, respectively. The hazel pollen season in 2020 began relatively early, between January 11th and February 2nd. The season start was recorded earliest in Opole and latest in Olsztyn and Bialystok. The study found that the pollen season started earlier in the western part of Poland than in the eastern regions. The highest maximum Corylus pollen concentration was recorded in Lublin (388 P/m3), whereas the lowest one in Bydgoszcz (48 P/m3). The maximum daily concentration of Corylus pollen grains was recorded in different periods in the individual cities, while the peak concentration values occurred between January 31th and March 4th. The highest risk of allergy in people sensitive to the pollen of this taxon was found in Lublin since the most days with a pollen concentration exceeding the threshold value were observed in this city. Lublin was found to have the highest annual total values and they were 1.6–5.6 times higher than in the other cities. The highest annual pollen sums and peak values as well as the highest number of days with a concentration exceeding the threshold value had also been recorded in Lublin previously.

Temperature-related changes in airborne allergenic pollen abundance and seasonality across the northern hemisphere: a retrospective data analysis

Ongoing climate change might, through rising temperatures, alter allergenic pollen biology across the northern hemisphere. We aimed to analyse trends in pollen seasonality and pollen load and to establish whether there are specific climate-related links to any observed changes. For this retrospective data analysis, we did an extensive search for global datasets with 20 years or more of airborne pollen data that consistently recorded pollen season indices (eg, duration and intensity). 17 locations across three continents with long-term (approximately 26 years on average) quantitative records of seasonal concentrations of multiple pollen (aeroallergen) taxa met the selection criteria. These datasets were analysed in the context of recent annual changes in maximum temperature (Tmax) and minimum temperature (Tmin) associated with anthropogenic climate change. Seasonal regressions (slopes) of variation in pollen load and pollen season duration over time were compared to Tmax, cumulative degree day Tmax, Tmin, cumulative degree day Tmin, and frost-free days among all 17 locations to ascertain significant correlations. 12 (71%) of the 17 locations showed significant increases in seasonal cumulative pollen or annual pollen load. Similarly, 11 (65%) of the 17 locations showed a significant increase in pollen season duration over time, increasing, on average, 0·9 days per year. Across the northern hemisphere locations analysed, annual cumulative increases in Tmax over time were significantly associated with percentage increases in seasonal pollen load (r=0·52, p=0·034) as were annual cumulative increases in Tmin (r=0·61, p=0·010). Similar results were observed for pollen season duration, but only for cumulative degree days (higher than the freezing point [0°C or 32°F]) for Tmax (r=0·53, p=0·030) and Tmin (r=0·48, p=0·05). Additionally, temporal increases in frost-free days per year were significantly correlated with increases in both pollen load (r=0·62, p=0·008) and pollen season duration (r=0·68, p=0·003) when averaged for all 17 locations. Our findings reveal that the ongoing increase in temperature extremes (Tmin and Tmax) might already be contributing to extended seasonal duration and increased pollen load for multiple aeroallergenic pollen taxa in diverse locations across the northern hemisphere. This study, done across multiple continents, highlights an important link between ongoing global warming and public health-one that could be exacerbated as temperatures continue to increase. None.

Impact of weather and climate change with indoor and outdoor air quality in asthma: A Work Group Report of the AAAAI Environmental Exposure and Respiratory Health Committee

Weather and climate change are constant and ever-changing processes that affect allergy and asthma. The purpose of this report is to provide information since the last climate change review with a focus on asthmatic disease. PubMed and Internet searches for topics included climate and weather change, air pollution, particulates, greenhouse gasses, traffic, insect habitat, and mitigation in addition to references contributed by the individual authors. Changes in patterns of outdoor aeroallergens caused by increasing temperatures and amounts of carbon dioxide in the atmosphere are major factors linked to increased duration of pollen seasons, increased pollen production, and possibly increased allergenicity of pollen. Indoor air pollution threats anticipated from climate changes include microbial and mold growth secondary to flooding, resulting in displacement of persons and need for respiratory protection of exposed workers. Air pollution from indoor burning of mosquito repellants is a potential anticipatory result of an increase in habitat regions. Air pollution from fossil fuel burning and traffic-related emissions can alter respiratory defense mechanisms and work synergistically with specific allergens to enhance immunogenicity to worsen asthma in susceptible subjects. Community efforts can significantly reduce air pollution, thereby reducing greenhouse gas emission and improving air quality. The allergist's approach to weather pattern changes should be integrated and anticipatory to protect at-risk patients.

The impact of meteorological conditions on the concentration of alder pollen in Sosnowiec (Poland) in the years 1997\u20132017

The aim of the work was to compare the alder pollen seasons in the years 1997–2017 in Sosnowiec. The measurements of pollen concentration were taken with the volumetric method using Burkard’s apparatus. The impact of atmospheric conditions on the daily alder pollen grain concentration, the annual totals, and the duration of pollen seasons were studied. The dependency between each meteorological condition and different features of the alder pollen season was determined by using Pearson’s correlation coefficients, variance analysis with multiple comparison tests, and the linear regression model using backward elimination. It was proven that the temperatures directly preceding the pollination, i.e. the January and February temperatures as well as those from the period from 210 to 180 days preceding the beginning of the season, have the greatest impact on the beginning of the alder pollen season. The value of the daily alder pollen concentration in Sosnowiec showed a positive statistically significant correlation with the air temperature and sunshine duration and a negative correlation with the thickness of the snow cover and air relative humidity. The daily concentration also depended on the type of the weather front, direction of air mass inflow, and the type of the inflowing air mass. The season temperatures and the thermal conditions which were present in the summer of the preceding year impacted the annual totals (SPI) of the alder pollen grains.

Plant Responses to Climate Change: The Case Study of Betulaceae and Poaceae Pollen Seasons (Northern Italy, Vignola, Emilia-Romagna).

Aerobiological data have especially demonstrated that there is correlation between climate warming and the pollination season of plants. This paper focuses on airborne pollen monitoring of Betulaceae and Poaceae, two of the main plant groups with anemophilous pollen and allergenic proprieties in Northern Italy. The aim is to investigate plant responses to temperature variations by considering long-term pollen series. The 15-year aerobiological analysis is reported from the monitoring station of Vignola (located near Modena, in the Emilia-Romagna region) that had operated in the years 1990–2004 with a Hirst spore trap. The Yearly Pollen Index calculated for these two botanical families has shown contrasting trends in pollen production and release. These trends were well identifiable but fairly variable, depending on both meteorological variables and anthropogenic causes. Based on recent reference literature, we considered that some oscillations in pollen concentration could have been a main effect of temperature variability reflecting global warming. The duration of pollen seasons of Betulaceae and Poaceae, depending on the different species included in each family, has not unequivocally been determined. Phenological responses were particularly evident in Alnus and especially in Corylus as a general moving up of the end of pollination. The study shows that these trees can be affected by global warming more than other, more tolerant, plants. The research can be a contribution to the understanding of phenological plant responses to climate change and suggests that alder and hazelnut trees have to be taken into high consideration as sensible markers of plant responses to climate change.

Characterization of Allergen Emission Sources in Urban Areas

Pollen released by urban flora-a major contributor to airborne allergen content during the pollen season-has a considerable adverse impact on human health. Using aerobiological techniques to sample and characterize airborne biological particulate matter (BPM), we can identify the main species contributing to the pollen spectrum and chart variations in counts and overall pollen dynamics throughout the year. However, given the exponential increase in the number of pollen allergy sufferers in built-up areas, new strategies are required to improve the biological quality of urban air. This paper reports on a novel characterization of the potential allergenicity of the tree species most commonly used as ornamentals in Mediterranean cities. Values were assigned to each species based on a number of intrinsic features including pollination strategy, pollen season duration, and allergenic capacity as reported in the specialist literature. Findings were used to generate a database in which groups of conifers, broadleaves, and palm trees were assigned a value of between 0 and 36, enabling their allergenicity to be rated as nil, low, moderate, high, or very high. The case study presented here focuses on the city of Granada in southern Spain. The major airborne-pollen-producing species were identified and the allergenicity of species growing in urban green zones was estimated. Corrective measures are proposed to prevent high allergen levels and thus improve biological air quality.

Influence of airborne pollen counts and length of pollen season of selected allergenic plants on the concentration of sIgE antibodies on the population of Bratislava, Slovakia.

The association between airborne pollen counts or duration of pollen season and allergy symptoms is not always distinguished. The purpose of this study was to examine the correlation between pollen exposure (annual total pollen quantity and main pollen season length) of selected allergenic plants in the atmosphere of Bratislava, and concentration of allergen-specific immunoglobulin E (sIgE) in serum of patients with seasonal allergy during 2002-2003. The concentration of pollen was monitored by a Burkard volumetric pollen trap. At the same time, 198 pollen allergic patients were testing to determine the values of sIgE antibodies against selected pollen allergens; a panel of 8 purified allergens was used. The highest percentages of sensitization were detected for Poaceae and Ambrosia pollen allergens. The most abundant airborne pollen types were Urticaceae, Betula, Populus, Fraxinus, Pinus and Poaceae. The length of the pollen season varied. The longest pollen season was that of the Plantago - 105 days, and the shortest, Corylus - 20 days. A significant correlation was found between annual total pollen quantity and median sIgE values, especially in 2002. A strong and significant positive correlation was observed between pollen counts, excluding Betula, and sIgE levels in both analysed years. The correlation was weaker and negative in the case of length of pollen season and sIgE values.

Trends in atmospheric concentrations of weed pollen in the context of recent climate warming in Poznań (Western Poland)

A significant increase in summer temperatures has been observed for the period 1996–2011 in Poznań, Poland. The phenological response of four weed taxa, widely represented by anemophilous species (Artemisia spp., Rumex spp. and Poaceae and Urticaceae species) to this recent climate warming has been analysed in Poznań by examining the variations in the course of airborne pollen seasons. Pollen data were collected by 7-day Hirst-type volumetric trap. Trends in pollen seasons were determined using Mann–Kendall test and Sen’s slope estimator, whereas the relationships between meteorological and aerobiological data were established by Spearman’s rank correlation coefficient. Significant trends in pollen data were detected. The duration of pollen seasons of all analysed taxa increased (from +2.0 days/year for Urticaceae to +3.8 days/year for Rumex), which can be attributed to a delay in pollen season end dates rather than earlier start dates. In addition, the intensity of Artemisia pollen seasons significantly decreased and correlates with mean July–September daily minimum temperatures (r = −0.644, p < 0.01). In contrast, no significant correlations were found between temperature and characteristics of Rumex pollen seasons. The results of this study show that observed shifts in weed pollen seasons in Poznań, i.e. longer duration and later end dates, might be caused by the recorded increase in summer temperature. This influence was the strongest in relation to Artemisia, which is the taxon that flowers latest in the year. The general lack of significant correlations between Rumex and Urticaceae pollen seasons and spring and/or summer temperature suggests that other factors, e.g. land use practices, could also be partially responsible for the observed shifts in pollen seasons.

Statistical approach to the analysis of olive long-term pollen season trends in southern Spain

Analysis of long-term airborne pollen counts makes it possible not only to chart pollen-season trends but also to track changing patterns in flowering phenology. Changes in higher plant response over a long interval are considered among the most valuable bioindicators of climate change impact. Phenological-trend models can also provide information regarding crop production and pollen–allergen emission. The interest of this information makes essential the election of the statistical analysis for time series study.We analysed trends and variations in the olive flowering season over a 30-year period (1982–2011) in southern Europe (Córdoba, Spain), focussing on: annual Pollen Index (PI); Pollen Season Start (PSS), Peak Date (PD), Pollen Season End (PSE) and Pollen Season Duration (PSD). Apart from the traditional Linear Regression analysis, a Seasonal-Trend Decomposition procedure based on Loess (STL) and an ARIMA model were performed.Linear regression results indicated a trend toward delayed PSE and earlier PSS and PD, probably influenced by the rise in temperature. These changes are provoking longer flowering periods in the study area.The use of the STL technique provided a clearer picture of phenological behaviour. Data decomposition on pollination dynamics enabled the trend toward an alternate bearing cycle to be distinguished from the influence of other stochastic fluctuations. Results pointed to show a rising trend in pollen production.With a view toward forecasting future phenological trends, ARIMA models were constructed to predict PSD, PSS and PI until 2016. Projections displayed a better goodness of fit than those derived from linear regression.Findings suggest that olive reproductive cycle is changing considerably over the last 30years due to climate change. Further conclusions are that STL improves the effectiveness of traditional linear regression in trend analysis, and ARIMA models can provide reliable trend projections for future years taking into account the internal fluctuations in time series.

Grass pollen (Poaceae) in the air of Sosnowiec (Poland), 1997 - 2006

The article presents the analysis results of the grass pollen seasons from 1997 to 2006 in Sosnowiec. The research was carried out by means of the volumetric method with the use of a Burkard device. The duration of the pollen seasons was determined by means of the 98% method. The influence of meteorological conditions on the starting date and duration of the grass pollen seasons has been estimated in the article. The beginning of the pollen seasons was recorded between 23 April and 23 May. It has been demonstrated that the average duration of the pollen season amounted to 138 days. The period of maximum concentrations was recorded in June and the first half of July. The highest daily concentration was found in 2000 (495 grains in m&lt;sup&gt;3&lt;/sup&gt;) and the highest annual sums in 2002 and 2000. The daily concentration distribution curve has shown three peaks. The highest values were recorded from 7 am until 11 am, from 13 pm until 17 pm and from 19 pm until 21 pm. It has been found that there is a significant influence of weather conditions (temperature, precipitation and relative humidity) on the beginning and duration of the pollen seasons and the period of maximum concentrations.

Types of hazel (Corylus spp.) and alder (Alnus spp.) pollen seasons in Sosnowiec 1997 - 2007 (Poland)

This paper investigates pollen seasons for &lt;i&gt;Corylus&lt;/i&gt; spp. and Alnus spp. for the years 1997-2007 in Sosnowiec, southern Poland. The research was conducted by means of the volumetric method using a Burkard-type spore trap. The duration of pollen seasons was determined by means of the 98% method. The aim of this study was to distinguish the types of the course of hazel and alder pollen seasons using cluster analysis, including non-hierarchical clustering of multi-feature objects - k-means clustering. The pollen seasons were divided into five types because of considerable variations from one year to another. For both taxons one dominant type was found, which was characterized by a very long period of compact pollen release with low values of the pollen count and by the occurrence of several maximums divided by periods of a lower pollen count. This work contains only a preliminary analysis on the types of pollen seasons because of relatively short data set. Future research on a larger series of measurements should be proved.

The influence of meteorological factors on the hazel (Corylus L.) pollen concentration in Sosnowiec in the years 1997-2007

An analysis of hazel pollen seasons in Sosnowiec was presented on the basis of data from the years 1997-2007. The research was conducted by means of the volumetric method using a Burkard-type spore trap. The duration of pollen seasons was determined by means of the 98% method. The research demonstrated statistically significant correlations between the average, maximum and minimum temperature, relative humidity as well as the number of days with sub-zero temperature and the beginning of the hazel pollen season. It was demonstrated that the duration of the pollen season depended on air relative humidity, insolation and precipitation during the season and the annual sum depended on the weather conditions of the year preceding pollen production and also the weather conditions two years earlier. Significant correlations were also found between weather conditions and the daily concentration of pollen grains. The daily concentration decreased when relative humidity was high and increased with high insolation and air temperature.

Analysis of the grass (Poaceae L.) pollen seasons in Wrocław, 2003-2010

The aim of the study was to analyse the grass pollen season dynamics in Wrocław in 2003-2010. The studies were carried out using volumetric method (Burkard trap). Special attentions was paid to differences in pollen season duration and patterns. The pollen season started on average on the 130th day of the year (±10 days) and ended on the 240&lt;sup&gt;th&lt;/sup&gt; (±11 days). Peak of pollen seasons occurred between 156&lt;sup&gt;th&lt;/sup&gt; and 185&lt;sup&gt;th&lt;/sup&gt; day of the year. The mean of SPI value was 2805 (±380). On average, 18 days (±4 days) with a grass pollen concentration of more than 50 grains × m&lt;sup&gt;-3&lt;/sup&gt;, and 2 days (±1 day) with concentration of more than 120 grains × m&lt;sup&gt;-3&lt;/sup&gt; were recorded during the seasons analysed. Three types of pollen seasons were distinguished on the basis of cluster analysis (the non-hierarchical method of multifeature clustering - the k-means method).