Pollen Counts Research Articles

More sneezing, less crime? Health shocks and the market for offenses

A large literature points out that exposure to criminal victimization has far-reaching effects on public health. What remains surprisingly unexplored is that role that health shocks play in explaining aggregate fluctuations in offending. This research finds novel evidence that crime is sensitive to health shocks. We consider the responsiveness of crime to a pervasive and common health shock which we argue shifts costs and benefits for offenders and victims: seasonal allergies. Leveraging daily variation in city-specific pollen counts, we present evidence that violent crime declines in U.S. cities on days in which the local pollen count is unusually high and that these effects are driven by residential violence. While past literature suggests that property crimes have more instrumental motives, require planning, and hence are particularly sensitive to permanent changes in the cost and benefits of crime, we find that violence may be especially sensitive to health shocks.

Review: Floral resources diversity of honeybees in important types of vegetation of Ethiopia

Abstract. Addi A, Bareke T. 2019. Review: Floral resources diversity of honeybees in important types of vegetation of Ethiopia. Asian J For 3: 64-68. The high biodiversity of Ethiopia is attributed to its wide ranges of altitude and great geo-morphological diversity. This has resulted in the existence of the region has diverse floral resources of which majority of them are honeybee flora. In this paper bee resources identification and reviewing bee forages were made to determine types of bee plants, floral diversity, flowering period and food source offered by the plants. Moreover, pollen analysis of honey from different regions of Ethiopia was analyzed for determination of major and minor honey source plants. Accordingly, over 1500 species of indigenous and exotic of plants belongs to 105 bee plant families were identified. The growth form analysis of bee forage comprising 41.6% herb, 28.7% shrubs, 21.7% trees, and 8% climbers. The majority of bee plant species flowered from September to November and April to May resulting in two major honey flow periods in the country. Melissopalynological analysis of the honey samples indicated that Schefflera abyssinica, Croton macrostachyus, Syzygium guineense, Vernonia amygdalina and Coffea arabica contributed for 80%, 64%, 86%, 77% and 75% of the total pollen count respectively from southwest and southeastern part of the country while Becium grandiflorum, Hypoestes forskaolii, Leucas abyssinica and Acacia spp. an accounting for 71%, 75.1%, 62%, and 70.5%, respectively from northern Ethiopia. On the other hand, Eucalyptus globulus and Guizotia scabra honey were from central Ethiopia, contributing to 94% of the pollen frequency. From this information, Ethiopia has rich bee forage diversity different vegetation types however, further collection and documentation of bee flora are required in unaddressed areas of the country. Thus in situ conservation, by ecological restoration, and raising and planting of seedlings of bee forages should be promoted for sustainable honey production.

Spruce representation in zonal woodlands may be overestimated when using pollen spectra from peatlands

The proportion of taxa in a pollen spectrum may not correspond to their proportion in vegetation. Quantitative reconstruction models therefore consider pollen productivities or fall speeds. We argue that azonal presence of spruce, an otherwise zonal tree species, in wetlands may confound the pollen-inferred reconstructions of vegetation cover as well. Based on a large database of vegetation plots from the Western Carpathians, we demonstrate that spruce is the tree species which most frequently colonizes peatlands, more so than alder, whose effect on local pollen spectra has been frequently admitted. Using 73 sequences we further demonstrated significantly greater pollen percentages of spruce of about 20–25% when the sediments contain spruce macrofossils. Finally, we compared the proportions of spruce and beech in modern surface pollen spectra with their real proportions in the surrounding landscape where beech acts as zonal tree. We found that even a small patch of spruce alters the proportion of spruce to beech. By contrast in an open fen we observed pollen spectrum corresponding well with the real proportions of spruce and beech. All these results suggest, contrary to the premises of current models of pollen-based quantitative reconstructions in Central Europe, that fossil pollen counts from wetlands did not underestimate the representation of spruce. Instead, its representation may even be overestimated where it occurred within or in close vicinity of a wetland. We appeal to palynologists to consider macrofossils or stomata in interpretations, and to adjust quantitative reconstruction models for sites that have experienced a woodland history.

Precise Pollen Grain Detection in Bright Field Microscopy Using Deep Learning Techniques.

The determination of daily concentrations of atmospheric pollen is important in the medical and biological fields. Obtaining pollen concentrations is a complex and time-consuming task for specialized personnel. The automatic location of pollen grains is a handicap due to the high complexity of the images to be processed, with polymorphic and clumped pollen grains, dust, or debris. The purpose of this study is to analyze the feasibility of implementing a reliable pollen grain detection system based on a convolutional neural network architecture, which will be used later as a critical part of an automated pollen concentration estimation system. We used a training set of 251 videos to train our system. As the videos record the process of focusing the samples, this system makes use of the 3D information presented by several focal planes. Besides, a separate set of 135 videos (containing 1234 pollen grains of 11 pollen types) was used to evaluate detection performance. The results are promising in detection (98.54% of recall and 99.75% of precision) and location accuracy (0.89 IoU as the average value). These results suggest that this technique can provide a reliable basis for the development of an automated pollen counting system.

Pollen-based quantitative land-cover reconstruction for northern Asia covering the last 40 ka cal BP

Abstract. We collected the available relative pollen productivity estimates (PPEs) for 27 major pollen taxa from Eurasia and applied them to estimate plant abundances during the last 40 ka cal BP (calibrated thousand years before present) using pollen counts from 203 fossil pollen records in northern Asia (north of 40∘ N). These pollen records were organized into 42 site groups and regional mean plant abundances calculated using the REVEALS (Regional Estimates of Vegetation Abundance from Large Sites) model. Time-series clustering, constrained hierarchical clustering, and detrended canonical correspondence analysis were performed to investigate the regional pattern, time, and strength of vegetation changes, respectively. Reconstructed regional plant functional type (PFT) components for each site group are generally consistent with modern vegetation in that vegetation changes within the regions are characterized by minor changes in the abundance of PFTs rather than by an increase in new PFTs, particularly during the Holocene. We argue that pollen-based REVEALS estimates of plant abundances should be a more reliable reflection of the vegetation as pollen may overestimate the turnover, particularly when a high pollen producer invades areas dominated by low pollen producers. Comparisons with vegetation-independent climate records show that climate change is the primary factor driving land-cover changes at broad spatial and temporal scales. Vegetation changes in certain regions or periods, however, could not be explained by direct climate change, e.g. inland Siberia, where a sharp increase in evergreen conifer tree abundance occurred at ca. 7–8 ka cal BP despite an unchanging climate, potentially reflecting their response to complex climate–permafrost–fire–vegetation interactions and thus a possible long-term lagged climate response.

The impact of weather and climate on pollen concentrations in Denver, Colorado, 2010-2018

BackgroundIncreasing evidence indicates that climate change is affecting the timing of pollen season and concentrations of allergenic pollens. To date, pollen trends and their associations with meteorological variables have not been studied in most of the United States. ObjectiveThe purpose of this study was to investigate the effects of weather and climate on pollen concentrations and pollen season timing in Denver, Colorado. MethodsWe retrospectively analyzed tree, grass, and weed pollen counts and meteorological variables from 2010-2018 using linear and Poisson regression models. ResultsPollen season timing did not demonstrate uniform trends from 2010 to 2018. Certain species demonstrated earlier season start dates (linden, oak) or end dates (birch, maple), and others had later end dates (oak, grass). Only a few species demonstrated changes in season duration (linden, oak, maple, birch) and peak date (maple, birch). Pollen concentrations either remained stable or increased over the years. Temperature and carbon dioxide levels increased over the study period, with the exception of decreased temperature in August. Wind speed remained stable or decreased over the study period. ConclusionThis study illustrates the complex interactions between pollens and meteorology. Meteorological variables associated with climate change do appear to affect allergenic pollens, though the relationship is variable both amongst pollens and from year to year.

Exposure to Cypress Pollens and Subsequent Symptoms: A Panel Study

Objective: The objective of this panel study was to document the relationship between exposure to cypress pollen and allergic symptoms. Methods: The study group included 47 patients with allergy to cypress pollen who completed a daily diary and a weekly evaluation of quality of life (QoL) during the cypress pollen season. Different patients were included in three consecutive pollen seasons: 2014–2015, 2015–2016, and 2016–2017. Daily cypress pollen counts were obtained from the National Aerobiological Network. Air pollution and meteorological data were recorded on a daily basis. The pollen-symptoms relationship was quantified by calculating odds ratios for an increase of 1 log of grains of pollen/m³, taking into account potential confounding factors. The QoL score was expressed with a beta coefficient that increased with 1 grain of pollen/m³. Results: There was a marked increase in rhinitis and ocular symptoms during the pollen season, with a plateau effect at high levels of exposure, but no relationship with bronchial symptoms. The QoL score had a linear and significant relationship with the cypress pollen count. We did not detect any threshold level. Conclusion: This panel study demonstrated a significant association between exposure to cypress pollens and allergic symptoms, with a plateau effect for high exposures.

Epidemiology of allergic rhinitis in children in grassland of Inner mongolia

Objective: To investigate the self-reported prevalence, clinical characteristics, complications of allergic rhinitis (AR) and the sensitization of outdoor air pollen allergens in children in the Inner mongolia grassland region. Methods: A multistage, stratified and random clustered sampling with a face-to-face interview survey study in children from 0 to 17 years old was performed together with 10 common allergen skin prick tests (SPT) and measurements of the daily pollen count in 6 regions in the Inner mongolia grassland region from May to August of 2015. SAS 9.4 software was used for data analysis. Results: A total of 2 443 subjects completed the study. The self-reported prevalence of AR was 26.6%. The prevalence of boys was higher than that of girls (28.8% vs 24.3%, χ(2)=6.157, P<0.05). Subjects from urban areas showed higher prevalence than rural areas (34.7% vs 18.8%, χ(2)=79.107, P<0.05). There was significant regional difference in the prevalence of AR among the six areas investigated (χ(2)=221.416, P<0.05). The main clinical symptoms of AR were sneezing (88.2%) and nasal congestion (78.6%). Among combined diseases, asthma accounted for 16.5% (107/650), rhinoconjunctivitis accounted for 47.9% (311/650). The peak season of AR was April and July, with the top SPT positive allergens of Artemisia species and chenopodium in this area. Conclusions: The prevalence AR in children in the Inner mongolia grassland region is extremely high. Sneezing is the main clinical symptom. Rhinoconjunctivitis is the most common combined disease. High summer and autumn pollen exposure is the main cause of AR.

The nesting habits and flower relationships of the bee Melitoma ameghinoi (Holmberg) (Hymenoptera, Apidae), with notes on its taxonomy and distribution

ABSTRACTThe nesting behaviour of Melitoma ameghinoi was studied in the province of Chaco, Argentina. Contrary to other Melitoma species, which are known to nest on banks or other vertical or sloping surfaces, the nests were found on horizontal ground, in extremely hard clay soil. The nests were shallow, with three to four vertical cells. The short turrets pointed upwards for a short stretch and then were strongly curved, with the entrance directed towards the soil surface. The floral relationships of this species were studied by pollen analysis of faeces from cells, a pollen mass, scopal loads of specimens, and direct observation of floral visits. Pollen counts and field observations indicate that M. ameghinoi collects pollen exclusively from Ipomoea species. A compilation of pollen sources for species of Melitoma is presented. All known species, including M. ameghinoi, fall in the category of narrowly oligolectic. A discussion of the taxonomic relationships of the species is presented, and a lectotype is designated.

Multi-point analysis of airborne Japanese cedar (Cryptomeria japonica D. Don) pollen by Pollen Robo and the relationship between pollen count and the severity of symptoms

An important theme related to aerobiology is the spatial distribution of airborne pollen, which is a final goal of our research efforts. In relation to this, pursuing the severity of pollinosis symptoms and problems with airborne pollen and allergens is required. In the past, we simulated the distribution of airborne Japanese cedar (Cryptomeria japonica D. Don) pollen (Kawashima and Takahashi in Grana 34:142–150, 1995, Grana 38:316–324, 1999). The simulation results of recent years will be published in the near future. At the time, it was not possible to compare the results of actual airborne pollen data observed from multiple points at the same time. However, now we can achieve this objective if using C. japonica pollen characteristics. The pollen is dispersed in large quantities over a long distance, remains in the air for a long time, and most airborne pollen at this time is C. japonica pollen. Recently, several automatic C. japonica pollen monitoring systems have been developed and deployed nationwide. Pollen Robo is one and is the most widely installed nationwide. In this study, we addressed Pollen Robo. First, we examined whether Pollen Robo can accurately count C. japonica pollen and found that Pollen Robo was useful during the major pollen season. However, it sometimes counts non-pollen particles and other pollen rather than C. japonica pollen. Therefore, it is not useful when a small amount of pollen is dispersed such as the start day of the pollen season. Next, we examined the daily dispersion of C. japonica pollen and it was shown that it is related to the distance between sampling locations. However, factors other than distance may be involved. Another matter of concern is the relationship between the number of airborne pollen and pollinosis symptoms. Symptoms began to appear from approximately the start day of the pollen season in moderate and light cases. The most serious symptoms occurred when the pollen count was the highest. Meanwhile, in severe cases, symptoms were observed at the time the pollen was scarcely detected and plateaued when the pollen count reached 100 counts/m3 on average over 6 days. Thus, Pollen Robo was not useful when symptoms began in severe cases. This problem was solved using pollen antigen measurement. The time for the symptoms to begin in severe cases is between 2 and 4 weeks before the start day of the pollen season. The amount of Cry j 1 on the start day during some years was considerably larger than that calculated from the number of pollen. The results obtained in this study will be the basic data used for achieving our final goal.

Unexploited Biodiversity Data Sources: The case of airborne pollen

With more than one billion primary biodiversity data records (PBR), the Global Biodiversity Information Facility (GBIF) is the largest and, arguably, most comprehensive and accurate resource about the biodiversity data on the planet. Yet, its gaps (taxonomical, geographical or chronological, among others) have often been brought to attention (Gaijy et al. 2013) and efforts are continuously made to ensure more uniform coverage. Especially as data obtained through this resource are increasingly being used for science, policy, and conservation (Ariño et al. 2018), drawing on every possible source of information to complement already existing data opens new opportunities for supplying the integrative knowledge required for global endeavors, such as understanding the global patterns of ecosystem and environment changes. One such potential source that exists, but so far has experienced little integration, is the vast body of data acquired through airborne particle monitoring systems (for example, the European Aeroallergen Network, EAN). A large portion of pollen data is comprised of quantitative sampling of airborne pollen collected through semi-automated spore traps throughout the world. Its main use is clinical, as it forms the basis of the widespread allergen forecast bulletins. While geolocating the source of airborne pollen is fraught with obviously large uncertainty radii, the time and taxon components of the PBR remain highly precise and are therefore fit for many other uses (Hill et al. 2010). Presence data, and under certain circumstances, frequency data inferred from pollen counts have been often proposed as an excellent proxy for past climate change assessments as far back as the start of the Holocene (Mauri et al. 2015) and might therefore also be possibly used for current climate change detection. We call for a concerted effort throughout the palynological community to first increase harmonizing, and then eventually standardizing, pollen data acquisition through the adoption of Darwin Core (DwC) and, eventually, DwC extensions to mine current data and pipeline future airborne pollen data as PBR. mine current data and pipeline future airborne pollen data as PBR. Success in this endeavor may contribute to a better understanding of global change.

Fungal spores and pollen are correlated with meteorological variables: effects in human health at Hermosillo, Sonora, Mexico

ABSTRACT We conducted the first study of air pollen and fungal spores for Hermosillo, Sonora, where the human population is exposed to high temperatures and high levels of dust and suffers from diseases related to air quality. We sampled pollen and fungal spores daily in the air during 2016 using a volumetric spore trap Hirst-type sampler. We used simple linear correlation to investigate the association between pollen and spore counts and daily weather conditions. We found an Annual Pollen Integral of 16,243 pollen day/m3 and an Annual Spore Integral higher 222,365 spore day/m3. We identified 32 pollen taxa and 15 different spores. We found two periods of higher pollen and spore concentrations: March to May and August to October, the latter was the most severe. Spore and pollen concentrations in the air increased at higher temperature and higher relative humidity but decreased at higher precipitation. We detected negative impacts during summer and fall on population health, with 13,454 cases of people who presented diseases related to allergies. A peak in allergies is centered during October and correlates well with our peaks in pollen and spore concentrations; it seems that pollen of Poaceae is the one that generates most effects in allergic people.

Alder pollen season in selected cities of Poland in 2019

The pollen of grass is the primary trigger of pollen allergies during the summer months. It causes some of the most severe and difficult-to-treat symptoms. During the flowering of grass, over 90% of patients allergic to grass pollen suffer from allergic conditions. The symptoms caused by grass pollen allergens appear in some patients after exceeding the concentration of 20 grains in m3 of air. The aim of this study was to compare Poaceae pollen seasons in 2019 in 11 cities located in different regions of Poland. Pollen monitoring was conducted in Bialystok, Bydgoszcz, Sosnowiec, Lublin, Olsztyn, Szczecin, Piotrkow Trybunalski, Warsaw, Opole, Zielona Gora and Wroclaw. Airborne pollen was monitored by the volumetric method using Burkard or Lanzoni pollen samplers. Pollen season length was determined by the 98% method, where the start of the season was defined as the date when 1% of the seasonal pollen total was trapped and the end of the season as the date, when 99% of the seasonal pollen total was reached.The pollen season start date was recorded earliest in Zielona Gora (April 27th), latest in Szczecin (May 25th). The highest grass pollen concentration values were found in Lublin, Piotrkow Trybunalski and Warsaw, whereas the lowest ones in Bialystok. The annual grass pollen sum was highest in Lublin (4715 pollen grains), whereas it was lowest in Bialystok (1256 pollen grains). A relatively high pollen count was also recorded in Warsaw (4106 pollen grains) and Zielona Gora (4077 pollen grains). The longest grass pollination season was recorded in Zielona Gora (139 days) and the shortest in Szczecin (110 days). In the remaining measuring points, grass pollen in the air maintained from 112 to 131 days. The highest grass pollen allergen risk occurred in Lublin, Olsztyn and Zielona Gora and the lowest in Bialystok.

Meet the pollen counters

Every spring, microscopic grains of tree, weed, and grass pollen are released, bringing seasonal allergies with them. It’s a busy time of year for both allergists and certified pollen counters, who...

Relationship of NDVI and oak (Quercus) pollen including a predictive model in the SW Mediterranean region

Techniques of remote sensing are being used to develop phenological studies. Our goal is to study the correlation among the Normalized Difference Vegetation Index (NDVI) related with oak trees included in three set data polygons (15, 25 and 50 km to aerobiological sampling point as NDVI-15, 25 and 50), and oak (Quercus) daily average pollen counts from 1994 to 2013. The study was developed in the SW Mediterranean region with continuous pollen recording within the mean pollen season of each studied year. These pollen concentrations were compared with NDVI values in the locations containing the vegetation under a study based on two cartographic sources: the Extremadura Forest Map (MFEx) of Spain and the Fifth National Forest Inventory (IFN5) from Portugal. The importance of this work is to propose the relationship among data related in space and time by Spearman and Granger causality tests. 9 out of 20 studied years have shown significant results with the Granger causality test between NDVI and pollen concentration, and in 12 years, significant values were obtained by Spearman test. The distances of influence on the contribution of Quercus pollen to the sampler showed statistically significant results depending on the year. Moreover, a predictive model by using Artificial Neural Network (ANN) was applied with better results in NDVI25 than for NDVI15 or NDVI50. The addition of NDVI25 with the lag of 5 days and some weather parameters in the model was applied with a RMSE of 4.26 (Spearman coefficient r = 0.77) between observed and predicted values. Based on these results, NDVI seems to be a useful parameter to predict airborne pollen.

Hay fever, allergies and the joys of summer!

Charlotte Wake suggest dental teams should spare a thought for those patients who struggle as we swing into a new season and the pollen count hits a high

Pollen exposure at birth and adolescent lung function, and modification by residential greenness.

Exposure to high levels of pollen in infancy is a risk factor for allergic respiratory diseases in later childhood, but effects on lung function are not fully understood. We aim to examine associations between grass pollen exposure in the first months of life and lung function at 12 and 18years, and explore potential modification. Using the Melbourne Atopy Cohort Study, a birth cohort of children with a family history of allergic diseases, we modeled the association between cumulative grass pollen exposure up to 3months after birth, on FEV1 , FVC, and FEV1 /FVC ratio at 12 and 18years. We also assessed modifying effects of residential greenness levels (derived from satellite imagery), asthma, and early life sensitization to ryegrass. Grass pollen exposure in the first 7days was associated with a reduction in FEV1 (-15.5mL; 95% CI: -27.6, -3.3 per doubling of pollen count) and FVC (-20.8mL; -35.4, -6.1) at 12years, but not at 18years. Increase in cumulative grass pollen exposure up to 3months was negatively associated with FVC at 12 and 18. Exposure to high residential greenness modified the association at 18 years. Early exposure to grass pollen was associated with decreased lung function in children and adolescents. Targeted interventions for pollen avoidance strategies that take into account local topography could be implemented alongside other clinical interventions such as immunotherapy.

Exposure to pollen allergens in allergic rhinitis expressed by diurnal variation of airborne tree pollen in urban and rural area.

Exposure to airborne pollen allergens results in allergic symptoms in subjects who are sensitized. The paper presents diurnal variation in the counts of airborne allergenic pollen of selected trees (Betula L., Alnus Mill., Corylus L., Fagus L. and Ulmus L.) in two localities differing in the degree of urbanization: the city of Szczecin (urban) and the village of Gudowo, West Pomerania in northwest Poland (rural) in the years 2012-2014. The measurements were made by the volumetric method using a Burkardtype sampler operating in a continuous mode. The greatest similarities in the beginning of the main pollen season between the two sites studied were observed for birch and elm trees, while in the length of the main pollen season, for birch and alder trees. Pollen counts of alder and hazel reached higher levels in the rural area, while the levels of ash tree pollen counts were higher in the urban area. The level of birch tree pollen counts was similar in the two sites studied. For the majority of taxons observed in the urban and rural areas the dynamics of hourly changes in tree pollen counts were similar. The pollination peak was noted in the daytime, usually in the afternoon. For ash and elm trees increased pollen counts were observed at nighttime, while the birch tree pollen counts were at a high level for most of the 24 h cycle. The knowledge of seasonal and diurnal variations in tree pollen counts is crucial for prevention in patients with allergic rhinitis, sensitized to tree pollen allergens.

Quality control of pollen identification and quantification exercise for the AusPollen Aerobiology Collaboration Network: a pilot study

Pollen monitoring in Australia has rapidly expanded, particularly in response to needs identified following the world’s most devastating thunderstorm asthma epidemic in Melbourne, 2016. Pollen identification and quantification are integral processes of establishing a standardised pollen monitoring network. A pilot study was designed to assess proficiency in these processes of counters who contribute to daily pollen information at established pollen monitoring sites of the AusPollen Aerobiology Collaboration Network. Counters were instructed to count grass and other pollen along four longitudinal transects of two reference slides at lens magnification of 400×. Participants were asked about their experience, training and usual practice in pollen counting via an online questionnaire. Of the 44 counters invited, 15 consented to participate. Reported pollen concentration values were compared to an approximation of the assigned true concentration values. Overall, 86% of reported values were within acceptable ranges of variation from assigned values. Apparent courting proficiency could have been affected by study limitations including slide quality and high/low pollen concentrations. Although counting performance did not appear to be related to experience and amount of training received, the majority of participants were not highly experienced or trained and the number of participants was small. It was not possible in this pilot study to make conclusions regarding relationships between training or experience and counter proficiency. Evaluation of counter proficiency is an important step in providing more accurate pollen concentrations, which are integral to local daily pollen forecasts for optimum day-to-day management of pollen-related conditions.

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

IntroductionDespite 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.AimTo 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 methodsCompleted 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.ResultsWe 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.ConclusionsOur findings do not confirm the hypothesis of a positive association between pollen exposure and the prevalence of allergic rhinitis and asthma.