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The article compares two different methods of defining pollen seasons based on 10 years of birch and grass pollen data from Berlin, Germany, and Vienna, Austria. The study found that the European Academy of Allergy and Clinical Immunology (EAACI) definition correlated significantly with allergic rhinitis symptoms reported by users of electronic diaries. The analysis showed differences in the start, end, and duration of pollen seasons between the two cities, highlighting the importance of accurately defining pollen seasons for clinical trials and allergen immunotherapy. The study confirmed the applicability of both the EAACI and percentage analysis (PA) methods in describing pollen season characteristics for different regions. [Extracted from the article]

The building climatization and its influence on energy consumption have consequences on the environment due to the emission of greenhouse gases. Improving the efficiency of this sector is essential to reduce the effect on climate change. In recent years, the interest in porous materials in applications such as heat pumps has increased because of their promising potential. To assess the performance of adsorption heat pumps and cooling systems, here we discuss a multistep approach based on the processing of adsorption data combined with a thermodynamic model. The process provides properties of interest, such as the coefficient of performance, the working capacity, the specific heat or cooling effect, or the released heat upon adsorption and desorption cycles, and it also has the advantage of identifying the optimal conditions for each adsorbent–fluid pair. To test this method, we select several metal-organic frameworks that differ in topology, chemical composition, and pore size, which we validate with available experiments. Adsorption equilibrium curves were calculated using molecular simulations to describe the adsorption mechanisms of methanol and ethanol as working fluids in the selected adsorbents. Then, using a thermodynamic model we calculate the energetic properties combined with iterative algorithms that simultaneously vary all the required working conditions. We discuss the strong influence of operating temperatures on the performance of heat pump devices. Our findings point to the highly hydrophobic metal azolate framework MAF-6 as a very good candidate for heating and cooling applications for its high working capacity and excellent energy efficiency. [ABSTRACT FROM AUTHOR]

Background and Aims Olive (Olea europaea subsp. europaea var. europaea) is the most extensively cultivated fruit crop worldwide. It is considered a wind-pollinated and strictly outcrossing crop. Thus, elevated pollen production is crucial to guarantee optimum fruit set and yield. Despite these facts, the variability of pollen production within the cultivated olive has been scarcely studied. This study aimed to characterize this feature by analysing a representative set of worldwide olive cultivars. Methods We evaluated the average number of pollen grains per anther in 57 principal cultivars over three consecutive years. We applied a standard generalized linear model (GLM) approach to study the influence of cultivar, year and the previous year's fruit load on the amount of pollen per anther. Additionally, the K -means method was used for cluster analysis to group cultivars based on their pollen production capacity. Key Results Pollen production per anther was highly variable among olive cultivars. The cultivar significantly accounted for 51.3 % of the variance in pollen production and the year for 0.3 %. The interaction between the two factors explained 8.4 % of the variance, indicating that not all cultivars were equally stable in producing pollen across the years. The previous year's fruit load and its interaction with the year were significant, but barely accounted for 1.5 % of the variance. Olive cultivars were classified into four clusters according to their capacity to produce pollen. Interestingly, the fourth cluster was composed of male-sterile cultivars, which presumably share this character by inheritance. Conclusions Pollen production per anther varied extensively within the cultivated olive. This variation was mainly driven by the cultivar and its interaction with the year. The differential capacity of olive cultivars to produce pollen should be considered not only for designing new orchards but also gardens where this species is used as an ornamental. [ABSTRACT FROM AUTHOR]

This study presents the results of a Europe-wide training and Quality Control (QC) exercise carried out within the framework of the European Aerobiology Society's QC Working Group. The main aim of this exercise was to examine the feasibility of carrying out a QC exercise for fungal spore monitoring in Europe, using a similar methodology to the one previously used for pollen. The QC survey was conducted in two parts: (1) Coordinators of national and regional aerobiological networks in Europe involved in the monitoring of atmospheric fungal spores were invited to complete a questionnaire survey related to their network and asked whether they were interested in taking part in an external inter-laboratory QC exercise; (2) Participating networks performed an inter-laboratory ring test with the same sample slide in order to determine the reproducibility of identifying and counting two fungal spore taxa (Alternaria and Epicoccum) in air samples collected by a Hirst-type volumetric spore trap. Participants were instructed to read five separate longitudinal transects in the "effective collecting area" of the slide. Reproducibility of analysis was determined following the method previously used in the European Aerobiology Society's QC exercises for pollen. Thirty-two counters from 16 national or regional networks in Europe participated in the QC exercise. Coefficients of Variation (CV%) ranged from 23.0 to 22.5 when reading one transect and from 14.0 to 16.0 when reading five transects for Alternaria and Epicoccum, respectively. Considering a CV% of 30 as the limit for fungal spores, no significant differences were observed between the absolute errors from two, three, four and five transects. The only significant difference was between one and five transects. We recommend that fungal spore analysis should be carried out on about 5% of the slide (two transects in this study) because results were not significantly different to five transects. [ABSTRACT FROM AUTHOR]

The most common fungal diseases of Vitis vinifera are powdery mildew (Erysiphe necator (Schw.) Burr.), grey mould (Botrytis cinerea Pers.) and downy mildew (Plasmopara viticola (Berk. and Curt.) Berk. and de Toni). Knowledge about the concentration of their spores in the atmosphere of the vineyard is important in order to ascertain the fungal load in the vineyard during the reproductive vine cycle. An aerobiological study was conducted in three vineyards across Europe: in North-Western Spain (Cenlle), South Spain (Montilla) and South-Eastern Poland (Rzeszów). During 2016, three Hirst-type spore traps sampled the airborne particles in each vineyard during the reproductive cycle of grapevine. The main goal of this study was the analysis and comparison of the spore concentrations in the three studied viticultural areas using different statistical tools. The most abundant spores in the vineyards atmosphere were Erysiphe necator. The highest fungal spore concentrations belonged to the North-western Spain zone, due to rainfall and temperature conditions were optimal for mould development in this area. In South Spain and South-eastern Poland, the daily spore peaks took place before than North Spain spore peaks. Average temperature, relative humidity and rainfall were the principal factors affecting the spore concentration in all zones. Redundancy Analysis showed high correlation between meteorological parameters and fungal spore concentrations. [ABSTRACT FROM AUTHOR]

Pollen grains have been a major focus of research mostly in temperate regions due to their effects on human health, especially allergies and asthma. The current study investigates a subtropical region characterized by a Mediterranean climate where Sharav conditions are experienced during the spring and autumn. The aim of the current study was to investigate whether Sharav conditions impacted airborne pollen concentrations of allergenic Amaranthaceae, Poaceae, Morus, Pinus, and Quercus more than standard Warm days during the main pollen seasons in the years 2010-2014 in Tel Aviv and Jerusalem (Israel). Slight variation was observed between the main pollen seasons in Tel Aviv compared to Jerusalem resulting from differences in temperature and relative humidity percentages. Additionally, more Sharav conditions occurred in Jerusalem than in Tel Aviv during the study period. The highest pollen concentrations occurred during Sharav days for Amaranthaceae, Poaceae, and Pinus but not for Morus and Quercus. Therefore, individuals who are allergic to Amaranthaceae, Poaceae, and Pinus pollen, and exposed to high pollen concentrations during Sharav days, might suffer more allergy symptoms than on Warm days. [ABSTRACT FROM AUTHOR]

Phenological and aerobiological research into major crops is of great value in adapting traditional processes to the new conditions prompted by global climate change. Data on flowering phenology and airborne pollen have also proved useful for harvest forecasting purposes. The current paper reports on an agrometeorological study carried out in the Montilla-Moriles Protected Designation of Origin area (Córdoba, southern Spain) in 2015 and 2016. The study focused on four grape cultivars produced at seven local vineyards (Pedro Ximénez, the most widely grown in the area; Verdejo; Muscat blanc à petits grains; and Chardonnay, which has been recently introduced). Phenological observations were performed on a weekly basis using the Biologische Bundesanstalt, Bundessortenamt und Chemische Industrie scale adapted for grapevine. Airborne pollen concentrations were monitored using one Hirst-type volumetric sampler and seven passive samplers. Airborne pollen was mainly detected in vineyards during inflorescence emergence and flowering. Year-on-year differences in climatic conditions led to differences in airborne pollen levels. The main variables affecting pollen concentrations were dew point and temperature. The life-cycles recorded here were shorter than in temperate climates but longer than in tropical climates. In terms of flowering period, the cultivars studied here were classed as 'early cultivars'. Data obtained using local passive samplers located directly in the vineyard confirmed that the airborne pollen concentrations recorded by the volumetric sampler were representative of the study area. [ABSTRACT FROM AUTHOR]

In Andalusia (southern Spain), Pinus species are found in mountainous areas and nature reserves, though some species are also grown as ornamentals in cities. Annual airborne pollen trends are regarded as an indicator of variations in climate prompted by overall climate change. Airborne pollen concentration also provides a useful tool for analyzing alterations in the distribution of vegetation in response to environmental factors and to changes in land use. The present study analyzed the Pinus pollen season over 22 years (1993-2014) in 4 Andalusian cities (Córdoba, Granada, Jaén, and Málaga), and examined correlations between airborne pollen concentrations and meteorological parameters (temperature and rainfall). Pinus pollen season lasted from March to June, starting first in Málaga and later in eastern Andalusia. Differences between the pollen curves for each city were attributable to differing proportions of pine species in each province. Temperatures during the months prior to flowering tended to fall, prompting delayed onset of the pollen season in most cities. No significant results were observed for rainfall patterns in most cities. Total pollen concentrations increased at most sites, suggesting that the recorded decline in pine-nut output was not influenced by flowering rates, but to the impact of a local pest. [ABSTRACT FROM AUTHOR]

This study focused on phenological timing and spatial patterns in 30 Poaceae species flowering in spring in different types of plant cover (scrub, riverbank and pasture). Grass community composition was studied, and the influence of species and plant cover on the start date and duration of flowering was assessed from March to June in both 2014 and 2015. Twenty-nine sampling sites were selected for phenological monitoring using the BBCH scale. Data were subjected to GLMM analyses. Binary discriminant analysis revealed differences in grass community composition as a function of plant cover type; scrub cover comprised a considerably larger number of species than those in riverbank and pasture. Moreover, more species diversity was observed in 2014 than in 2015 with a drier and stressed pre-flowering period. Differences on phenology were also recorded between plant cover types and study years. Species in pasture and riverbank flowered before (113.4 days; 116.1 days) than species in scrub (120.9 days), being these species with shorter flowering length because they are more exposed to the characteristic of the Mediterranean region during the summer. In general, flowering onset occurred later in 2014 (118.2 days) than in 2015 (115.8 days), probably attributable to precipitation occurring during March. On the other hand, spatial autocorrelation within some cover types has been observed, showing spatial patterns exist at a smaller scale. The findings of this study contribute to a better understanding of grass phenology in different environments. [ABSTRACT FROM AUTHOR]

This research reports the phenological trends of four early spring and late winter flowering trees in Spain (south Europe) from a recent period (1986-2012). The studied species were deciduous trees growing in different climatic areas: hazel (Corylus avellana L.), willow (Salix alba L.), ash (Fraxinus angustifolia Vahl.) and white mulberry (Morus alba L.). We analysed the response to climate and the trends of the following phenophases observed at the field: budburst, leaf unfolding, flowering, fruit ripening, fruit harvesting, leaf colour change and leaf-fall. The study was carried out in 17 sampling sites in the country with the aim of detecting the recent phenological response to the climate of these species, and the possible effect of climate change. We have observed differences in the phenological response to climate depending on each species. Sixty-one percent of studied sites suffered an advance of early spring phenophases, especially budburst on average by -0.67 days and flowering on average by -0.15 days during the studied period, and also in the subsequent fruit ripening and harvesting phases on average by -1.06 days. By contrast, it has been detected that 63% of sampling sites showed a delay in autumn vegetative phases, especially leaf-fall events on average by +1.15 days. The statistic correlation analysis shows in the 55% of the studied localities that phenological advances are the consequence of the increasing trend detected for temperature-being minimum temperature the most influential factor-and in the 52% of them, phenological advances occurred by rainfall variations. In general, leaf unfolding and flowering from these species showed negative correlations in relation to temperature and rainfall, whereas that leaf colour change and leaf-fall presented positive correlations. The results obtained have a great relevance due to the fact that they can be considered as reliable bio-indicators of the impact of the recent climate changes in southern Europe. [ABSTRACT FROM AUTHOR]

Olive and grass pollen grains are the major causes of hay fever in the Mediterranean region. A number of samplers and methods have been developed in recent years in order to obtain reliable data regarding airborne allergen concentrations. This paper reports on a detailed comparison of two samplers-Cyclone and ChemVol-and on the parameters that could influence their efficiency. Airborne concentrations of two key olive and grass allergens, Ole e 1 and Phl p 5, respectively, were monitored over two years with different weather patterns, 2012 and 2014. Allergenic particles were quantified by ELISA assay, and results were compared with pollen concentrations monitored using a Hirst-type volumetric spore trap over the same study periods. The influence of weather-related parameters on local airborne pollen and allergen concentrations was also analysed. Although a positive correlation was detected between results obtained using the two samplers during the pollen season, results for the cumulative annual Allergen Index varied considerably. The two samplers revealed a positive correlation between pollen concentrations and both minimum temperature during the warmer year (2012) and maximum temperature during the cooler year (2014); a negative significant correlation was observed in both cases with rainfall and relative humidity. In summary, although some differences were observed between the two samplers studied, both may be regarded as suitable for allergen detection. [ABSTRACT FROM AUTHOR]

This study presents the results of a Europe-wide training and Quality Control (QC) exercise carried out within the framework of the European Aerobiology Society's QC Working Group and European COST Action FA1203 entitled 'sustainable management of Ambrosia artemisiifolia in Europe (SMARTER)' with the aim of ensuring that pollen counters in Europe are confident in the identification of Ambrosia pollen grains. A total of 69 analysts from 20 countries examined a test slide by light microscopy, which contained Ambrosia pollen and pollen from other Asteraceae that could be recorded in the atmosphere at the same time of year (i.e. Artemisia, Iva, and Xanthium). Daily average pollen concentrations produced by individual participants were compared with the assigned value and the bias was measured by z-score. Both the assigned value and standard deviation for proficiency testing were calculated following the consensus value principle (ISO13528:2005) from the results reported by all the participants in the test. It took a total of 531 days from when the exercise commenced until all 69 analysts reported their results. The most outliers were reported for Artemisia pollen concentrations followed by Xanthium and Iva. The poor results for Artemisia and Xanthium were probably caused by low concentrations on the test slide leading to larger bias due to the unequal distribution of pollen over the microscope slide. Participants performed the best in identifying and quantifying Ambrosia pollen. Performing inter-laboratory ring tests with the same sample is very time consuming and might not be appropriate for large-scale proficiency testing in aerobiology. Pollen with similar morphology should be included in the education process of aerobiologists. [ABSTRACT FROM AUTHOR]

This study has been focused on airborne pollen concentration in Northern Tunis. Pollen has been detected by a volumetric Hirst-type spore trap. This suction sampler was placed for two hydrologic years in the area of Mornag, northeastof Tunisia (36°40N; 10°17E). Fifty-two taxa were identified with heterogeneous daily pollen concentrations and a dominance of anemophilous plants. The main pollen types detected in the atmosphere were Olea europaea (38.7 and 20.75%), Cupressus (33.57 and 55.4%) , Urticaceae (9.22 and 12.24%) , Poaceae (3.55 and 3.32%), Mercurialis annua (2.96 and 1.6%) and Amaranthaceae (2.49 and 1.55%). The monthly pollen spectrum indicated a seasonal periodicity of airborne pollen with the main pollen season during spring. Two pollen seasons have been observed during these hydrologic years, due to both Cupressus and Amaranthaceae airborne pollen is represented during winter or spring, and also during autumn and late summer, respectively. Other pollen types represent a long pollen season, i.e., Urticaceae, starting in autumn and following until late spring. Daily pollen concentration showed a different behavior during the flowering season between both years, observing differences related to pollen index. Correlation between daily pollen concentrations of the dominant taxa showed a positive and significant correlation between airborne pollen concentrations of spring-pollinated taxa and mean temperature, but negative with maximum temperature, humidity and rainfall. In the case of minimum temperature, a different response, positive for trees and negative for herbaceous plants, has been observed. [ABSTRACT FROM AUTHOR]

Pollen allergy is among the most widespread allergic disease in Andalusia. However, few studies have examined patient information in conjunction with data on airborne pollen concentrations. This paper sought to identify the airborne pollen types prevalent in Córdoba, to examine the relationship between airborne pollen and the occurrence of allergies, and to investigate the use of drugs to treat various symptoms displayed by pollen-allergy sufferers over the study period. A prospective longitudinal study was conducted in Córdoba City between February and June in 2014 and 2015, using an original specific questionnaire to collect socio-demographic, symptom and pollen-allergy data. Airborne pollen was collected using a Hirst-type volumetric spore trap. Descriptive and inferential statistical analysis was applied. A total of 178 sensitive subjects were included in the study. The prevalence of allergy to olive, grass and plane-tree pollen was 70.73, 73.17 and 19.51%, respectively, in 2014, and 70.83, 70.83 and 21.12%, respectively, in 2015. In both years, rhinitis was the most common allergic symptom (93.90% in 2014, 87.75% in 2015) and a significant correlation between the occurrence of rhinitis and antihistamine consumption was found ( p < 0.05 in 2014, p < 0.001 in 2015). The percentage of asthmatic subjects using an inhaler was significantly higher than those who did not used it (63.16% vs. 26.98%; p < 0.01). In conclusion, this paper supports previous studies showing that the most allergenic pollen types in spring were olive, grass and plane-tree pollen. In addition, we found that rhinitis was the main symptom and antihistamines the medication most widely used by the sensitized population in Córdoba. [ABSTRACT FROM AUTHOR]

Background Clinical efficacy of pollen allergen immunotherapy (AIT) has been broadly documented in randomized controlled trials. The underlying clinical endpoints are analysed in seasonal time periods predefined based on the background pollen concentration. However, any validated or generally accepted definition from academia or regulatory authorities for this relevant pollen exposure intensity or period of time (season) is currently not available. Therefore, this Task Force initiative of the European Academy of Allergy and Clinical Immunology ( EAACI) aimed to propose definitions based on expert consensus. Methods A Task Force of the Immunotherapy and Aerobiology and Pollution Interest Groups of the EAACI reviewed the literature on pollen exposure in the context of defining relevant time intervals for evaluation of efficacy in AIT trials. Underlying principles in measuring pollen exposure and associated methodological problems and limitations were considered to achieve a consensus. Results The Task Force achieved a comprehensive position in defining pollen exposure times for different pollen types. Definitions are presented for 'pollen season', 'high pollen season' (or 'peak pollen period') and 'high pollen days'. Conclusion This EAACI position paper provides definitions of pollen exposures for different pollen types for use in AIT trials. Their validity as standards remains to be tested in future studies. [ABSTRACT FROM AUTHOR]

The main objective of this research was to utilize pollen monitoring methodology to predict olive yields in three Mediterranean olive cultivation areas (Spain, Italy and Tunisia) and their relationships with the olive oil price dynamics. Moreover, olive yield and olive oil production compared with olive oil price trends in the last two decades was evaluated. The statistical analyses confirmed that biological parameters such as the pollen emission, the pollen season start (Pss), the full flowering (Ff) date or the pollen season length (Psl) showed positive correlation values with productive parameters, especially the Pollen Index (Pi). However, the difficulty to define clear relationships with oil price for optimizing the marketing strategies can be due to the olive sector European policy and to the complex international olive oil market situation. The occurrence of unharvested trees was increased and the reduction in agricultural operations as well as non-harvesting could become more widespread above all in traditional extensive systems. [ABSTRACT FROM PUBLISHER]

Olea europaea L. pollen is the second-largest cause of pollinosis in the southern Iberian Peninsula. Airborne-pollen monitoring networks provide essential data on pollen dynamics over a given study area. Recent research, however, has shown that airborne pollen levels alone do not always provide a clear indicator of actual exposure to aeroallergens. This study sought to evaluate correlations between airborne concentrations of olive pollen and Ole e 1 allergen levels in Córdoba (southern Spain), in order to determine whether atmospheric pollen concentrations alone are sufficient to chart changes in hay fever symptoms. The influence of major weather-related variables on local airborne pollen and allergen levels was also examined. Monitoring was carried out from 2012 to 2014. Pollen sampling was performed using a Hirst-type sampler, following the protocol recommended by the Spanish Aerobiology Network. A multi-vial cyclone sampler was used to collect aeroallergens, and allergenic particles were quantified by ELISA assay. Significant positive correlations were found between daily airborne allergen levels and atmospheric pollen concentrations, although there were occasions when allergen was detected before and after the pollen season and in the absence of airborne pollen. The correlation between the two was irregular, and pollen potency displayed year-on-year variations and did not necessarily match pollen-season-intensity. [ABSTRACT FROM AUTHOR]

This paper presents pollen calendars for the capital cities of the eight provinces of Andalusia (south of Spain) based on the airborne pollen counts recorded in a 10-year historical database. Pollen calendars are useful in the prevention and diagnosis of hay fever, in that they enable the timing and severity of the pollen season to be clearly defined. The differences encountered-in terms of both pollen spectra and the length and timing of the pollen season (start date, peak date, peak concentration and end date)-highlight not only the considerable diversity of urban landscapes in the eight Andalusian cities, but also the effect of urban green areas and periurban landscapes on airborne pollen levels. Green areas should be designed with a view to promoting benefits for the local population and avoiding the problems associated with the massive use of allergenic plants. [ABSTRACT FROM AUTHOR]

The impact of regional and local weather and of local topography on intradiurnal variations in airborne pollen levels was assessed by analysing bi-hourly holm oak ( Quercus ilex subsp. ballota (Desf.) Samp.) pollen counts at two sampling stations located 40 km apart, in southwestern Spain (Cordoba city and El Cabril nature reserve) over the period 2010-2011. Pollen grains were captured using Hirst-type volumetric spore traps. Analysis of regional weather conditions was based on the computation of backward trajectories using the HYSPLIT model. Sampling days were selected on the basis of phenological data; rainy days were eliminated, as were days lying outside a given range of percentiles (P95-P5). Analysis of cycles for the study period, as a whole, revealed differences between sampling sites, with peak bi-hourly pollen counts at night in Cordoba and at midday in El Cabril. Differences were also noted in the influence of surface weather conditions (temperature, relative humidity and wind). Cluster analysis of diurnal holm oak pollen cycles revealed the existence of five clusters at each sampling site. Analysis of backward trajectories highlighted specific regional air-flow patterns associated with each site. Findings indicated the contribution of both nearby and distant pollen sources to diurnal cycles. The combined use of cluster analysis and meteorological analysis proved highly suitable for charting the impact of local weather conditions on airborne pollen-count patterns. This method, and the specific tools used here, could be used not only to study diurnal variations in counts for other pollen types and in other biogeographical settings, but also in a number of other research fields involving airborne particle transport modelling, e.g. radionuclide transport in emergency preparedness exercises. [ABSTRACT FROM AUTHOR]

Beer contains hop ( Humulus lupulus L.) as flavoring and preservative. This cannabaceae plant, which possesses sedative and hypnotic properties, is present in non-alcoholic beer as well. Likewise regular beer, non-alcoholic beer includes the essential amino acid lysine with relaxing effects, which are related to the inhibition of serotonin receptors. It is known that the main neuroendocrine signal from stress is the release of the hormone cortisol, alongside with the altered levels of the hormone melatonin and the neurotransmitter serotonin. In this study we aimed to analyze the possible anxiolytic effect of non-alcoholic beer on neuroendocrine levels of cortisol, melatonin and serotonin, in a population under stress. To achieve this goal, a healthy student population was enrolled under the stressful conditions evoked by official academic exams. They consumed 1 non-alcoholic beer (330 mL) at dinner time for 14 nights. Melatonin, serotonin and cortisol levels were measured by quantifying their early morning urinary metabolites collected weekly. The consumption of non-acoholic beer reduced significantly the nocturnal serotonin levels whereas there were no substantial changes on melatonin and cortisol levels. However and in line with this, Anxiety/State parameters underwent a significant decreased after consumption of non-alcoholic beer at dinner time regarding to control values. These results point to the anxiolytic response of non-alcoholic beer is performed through the serotoninergic pathway. All in all, consumption of non-alcoholic beer might be an additional tool to deal with serotonin-related stress profile. [ABSTRACT FROM AUTHOR]

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Airborne pollen transport at micro-, meso-gamma and meso-beta scales must be studied by atmospheric models, having special relevance in complex terrain. In these cases, the accuracy of these models is mainly determined by the spatial resolution of the underlying meteorological dataset. This work examines how meteorological datasets determine the results obtained from atmospheric transport models used to describe pollen transport in the atmosphere. We investigate the effect of the spatial resolution when computing backward trajectories with the HYSPLIT model. We have used meteorological datasets from the WRF model with 27, 9 and 3 km resolutions and from the GDAS files with 1 ° resolution. This work allows characterizing atmospheric transport of Olea pollen in a region with complex flows. The results show that the complex terrain affects the trajectories and this effect varies with the different meteorological datasets. Overall, the change from GDAS to WRF-ARW inputs improves the analyses with the HYSPLIT model, thereby increasing the understanding the pollen episode. The results indicate that a spatial resolution of at least 9 km is needed to simulate atmospheric flows that are considerable affected by the relief of the landscape. The results suggest that the appropriate meteorological files should be considered when atmospheric models are used to characterize the atmospheric transport of pollen on micro-, meso-gamma and meso-beta scales. Furthermore, at these scales, the results are believed to be generally applicable for related areas such as the description of atmospheric transport of radionuclides or in the definition of nuclear-radioactivity emergency preparedness. [ABSTRACT FROM AUTHOR]

Training, quality assurance (QA) and quality control (QC) play an important role in building competence in monitoring and research in aerobiology. The main goals of this paper were to: (a) formulate an updated Minimum Requirements Report for pollen monitoring; (b) carry out a pilot QC exercise of staff involved in pollen counting from various national networks in order to examine between analysts reproducibility and develop a methodology that can be used in future QC exercises. A questionnaire survey was sent to coordinators of participating pollen monitoring networks. In addition, a total of 45 technicians from 15 European countries participated in the pilot QC exercise. All technicians were instructed to analyse two slides containing the following pollen types: (a) Poaceae and Betula pollen grains in the north of Europe; (b) Poaceae and Olea pollen grains in the south of Europe. Minimum Recommendations were produced based on the results of the questionnaire survey, published literature, and the outcomes of a workshop. In the QC exercise, it was noticed that technicians who followed the Minimum Recommendations and examined at least 10 % of the slide tended to have better indicators of precision and accuracy than those technicians who did not follow the Minimum Recommendations. The proposed Minimum Recommendations will help to improve the quality of scientific work, particularly for those who are considering the setting up of new monitoring sites. The results of the pilot QC exercise will help to develop a methodology that can be used again in the future, thereby ensuring data quality. [ABSTRACT FROM AUTHOR]

SILAM atmospheric dispersion model and the HYSPLIT trajectory model were used to detect the source areas and calculate transport dynamics for airborne olive pollen observed in the city of Córdoba, southwest of Iberian Peninsula. The ECMWF weather data with 3-h time interval and spatial resolution of 25 × 25 km and 75 hybrid vertical levels were used as meteorological inputs in both models to produce a coherent set of results in order to compare these two different approaches. Seven episodes recorded before and after the local flowering season in 2006 were analyzed using both models. The results provided an indication of the origins of olive pollen recorded in the city of Córdoba, revealing the influence of three main source areas at specific periods. One area was located nearby, to the southwest of the city (early May), another in the south of the province (mid-May) and the third to the east (late May/early June). The SILAM model yielded more detailed and quantitative results when identifying olive pollen sources and charting transport dynamics. The results from the HYSPLIT trajectory approach and SILAM footprints were qualitatively similar. However, a weak point of back trajectories was their lower sensitivity to details of the transport, as well as the necessity of subjective analysis of the trajectory plots, which were subject for possible misinterpretations. Information on both pollen source locations and local tree flowering phenology was required in order to ensure consistent analysis of the influence of olive sources for both models. Further than this, due to the fact that both models are widely used in other research areas, the results of this work could have a widespread range of application, such as to simulate the transport of radionuclides, e.g., in emergency preparedness exercises. [ABSTRACT FROM AUTHOR]

The objective of the present study was to extend previous findings by examining the relationship between emotional intelligence (EI) and well-being indicators (life satisfaction and happiness) in a 12-week follow-up study. In addition, we examined the influence of perceived stress on the relationship between EI and well-being. Female students from the School of Health Sciences (n = 264) completed an ability measure of emotional intelligence. After 12 weeks, participants completed the Perceived Stress Scale, Satisfaction with Life Scale and Subjective Happiness Scale. Participants with higher EI reported less perceived stress and higher levels of life satisfaction and happiness. The results of this study suggest that perceived stress mediates the relationship between EI and well-being indicators, specifically life satisfaction and happiness. These findings suggest an underlying process by which high emotional intelligence may increase well-being in female students in nursing and allied health sciences by reducing the experience of stress. The implications of these findings for future research and for working with health professions to improve well-being outcomes are discussed. [ABSTRACT FROM AUTHOR]

A number of ornamental plant species produce pollen grains with allergenic properties, thus posing a potential risk to human health. A comparative study of the ecological and aerobiological characteristics of ornamental urban flora in four Andalusian cities revealed the presence of over 100 potentially allergenic ornamental plant species. Most of these were phanerophytes, and species of Asiatic origin predominated, followed by Mediterranean and American species. However, not all potentially allergenic ornamental plants were of aerobiological significance, since some produce only small amounts of pollen, while others were infrequent or were located at a considerable distance from the sampler. Even so, when designing new urban parks and gardens, every effort should be made to ensure maximum species variability avoiding the excessive use of any single species. [ABSTRACT FROM AUTHOR]

The flowering characteristics of plant species of economic interest and the influence of climate on them are of great importance considering the implications for fruit setting and the final harvest: Olive is one of the typical species of the Mediterranean habitat. We have investigated the timing of olive full flowering during the anthesis period and flowering intensity over a period of 20 years (1990-2009), in three major cultivation areas of the Mediterranean basin: Italy, Spain and Tunisia. The importance of these characteristics from a bioclimatic point of view is considered. The biological behaviour was studied to determine its main relationships with temperature and water availability, considering also the different sub-periods and the bio-climatic variations during the study period. The flowering dates and pollen emissions show different behaviours for the Spanish monitoring area in comparison with the other two olive cultivation areas. In the Italian and Tunisian areas, the flowering period over the last decade has become earlier by about 5 and 7 days, respectively, in comparison to the previous decade. Moreover, pollen emissions have decreased in Perugia (Italy) and Zarzis (Tunisia) over the period of 2000-2009, while in Cordoba (Spain), they showed their highest values from 2005 to 2009. The climate analysis has shown an increase in temperature, which results in an increase in the growing degree days for the growth of the olive flower structures, particularly in the more northern areas monitored. Although the olive tree is a parsimonious water consumer that is well adapted to xeric conditions, the increase in the potential evapotranspiration index over the last decade in the Italian and Tunisian olive areas might create problems for olive groves without irrigation, with a negative influence on the flowering intensity. Overall, in all of these Mediterranean monitoring areas, the summer water deficit is an increasingly more important parameter in comparison to the winter parameters, which confirms that the winter period is not as limiting as the summer period for olive tree cultivation in these Mediterranean areas. [ABSTRACT FROM AUTHOR]

It is now widely accepted that weather conditions occurring several months prior to the onset of flowering have a major influence on various aspects of olive reproductive phenology, including flowering intensity. Given the variable characteristics of the Mediterranean climate, we analyse its influence on the registered variations in olive flowering intensity in southern Spain, and relate them to previous climatic parameters using a year-clustering approach, as a first step towards an olive flowering phenology model adapted to different year categories. Phenological data from Cordoba province (Southern Spain) for a 30-year period (1982-2011) were analysed. Meteorological and phenological data were first subjected to both hierarchical and 'K-means' clustering analysis, which yielded four year-categories. For this classification purpose, three different models were tested: (1) discriminant analysis; (2) decision-tree analysis; and (3) neural network analysis. Comparison of the results showed that the neural-networks model was the most effective, classifying four different year categories with clearly distinct weather features. Flowering-intensity models were constructed for each year category using the partial least squares regression method. These category-specific models proved to be more effective than general models. They are better suited to the variability of the Mediterranean climate, due to the different response of plants to the same environmental stimuli depending on the previous weather conditions in any given year. The present detailed analysis of the influence of weather patterns of different years on olive phenology will help us to understand the short-term effects of climate change on olive crop in the Mediterranean area that is highly affected by it. [ABSTRACT FROM AUTHOR]

This paper reports on modelling to predict airborne olive pollen season severity, expressed as a pollen index (PI), in Córdoba province (southern Spain) several weeks prior to the pollen season start. Using a 29-year database (1982-2010), a multivariate regression model based on five indices-the index-based model-was built to enhance the efficacy of prediction models. Four of the indices used were biometeorological indices: thermal index, pre-flowering hydric index, dormancy hydric index and summer index; the fifth was an autoregressive cyclicity index based on pollen data from previous years. The extreme weather events characteristic of the Mediterranean climate were also taken into account by applying different adjustment criteria. The results obtained with this model were compared with those yielded by a traditional meteorological-based model built using multivariate regression analysis of simple meteorological-related variables. The performance of the models (confidence intervals, significance levels and standard errors) was compared, and they were also validated using the bootstrap method. The index-based model built on biometeorological and cyclicity indices was found to perform better for olive pollen forecasting purposes than the traditional meteorological-based model. [ABSTRACT FROM AUTHOR]

Airborne pollen counts are mainly determined using a volumetric suction sampler based on the impact principle, that is, a Hirst-type spore trap. As a consequence of their volumetric nature, samplers detect pollen from a wide area, and therefore, a single sampler is frequently used to acquire information on airborne pollen counts for the whole city. The main goal of the present study was to compare airborne pollen counts at two sites located at opposite ends (south-west vs. north-east) of the southern Spanish city of Córdoba, to assess the advantages and disadvantages of using more than one sampler in the city. Also, a comparative study was carried out using two samplers at the same site, in order to confirm the efficiency of the samplers. Results revealed that data from one volumetric sampler-located within a city of medium size with uniform topography and vegetation conditions-are sufficient to establish monitoring of the main airborne pollen types, the pollen seasons involved and the timing of peak counts. For clinical studies, however, data on pollen counts in specific areas of the city may be of value, since pollen intensity may vary from one district to another, mainly in the case of ornamental plants with a local distribution inside the city. Comparison of data obtained by the two samplers running at the same site indicated that potential inter-site differences could not be attributed to differences in sampler efficiency. [ABSTRACT FROM AUTHOR]

The present study implemented a regional phenological model that was derived through the growing season index and adapted to a widespread Mediterranean species, the olive ( Olea europaea L.). This model considers not only individual phenological events, but also the main vegetative and reproductive phenological phases of the species, in an integrated biological approach. The regional model generally does not need to include specific meteorological variables calculated as weekly or monthly averages which could limit the extrapolation over large areas. The main climatic limitations of the olive cultivation areas in the south Mediterranean at latitudes around 10° (practically speaking, the geographical limits of the olive) are estimated here. This analysis uses information relating to local climatic changes over the last two decades (1990-1999, 2000-2009) to provide interpretations of the temperature, solar radiation rate, and evapotranspiration trends. This has allowed creation of a Mediterranean phenological model adapted to the olive, which presents the contemporary climate requirements during winter and the warm summer season. The climate analysis and comparisons of these two decades has allowed us to reveal a reduction in the index according to the minimum temperature, which has particular consequences in the northern monitoring areas. This phenomenon appears to present new positive scenarios for the future regarding a northward shift of olive cultivation areas, due to the potential enlargement of the growing season in winter. However, negative scenarios can also be foreseen in consideration of the failure to satisfy the minimum chilling requirements in the traditional southern cultivation areas of the olive. [ABSTRACT FROM AUTHOR]

Comparative ecological and aerobiological analyses of ornamental urban flora in the cities of Córdoba (Spain) and Ascoli Piceno (Italy) identified a group of plants with allergenic pollen whose behaviour is influenced by a number of factors. The geographical position and the resulting climate of both cities favoured the presence of Mediterranean species. In Córdoba, strongly allergenic evergreens introduced during the Moorish period predominated ( Cupressus sempervirens, among others), while in the urban area of Ascoli Piceno, Pinaceae were abundant. In both cities, many species of American origin have been introduced for aesthetic reasons, contributing to an increase in the overall allergenicity of urban greenery. The pollen spectrum differed between the two cities: airborne Oleaceae and Cupressaceae pollen abounded in Córdoba, whilst allergenic pollen from surrounding natural environments ( Corylaceae) predominated in Ascoli Piceno. These results pointed to a large number of potentially allergenic species in cities, thus highlighting the importance of greater ecological and aerobiological knowledge of allergenic species of urban ornamental flora. Avoidance of more allergenic species when planning new urban green areas could ensure healthier environments for pollen-allergy sufferers. [ABSTRACT FROM AUTHOR]

The northern area of Córdoba province (southern Spain) is characterised by a high spatial distribution of Quercus species. In Córdoba city, high airborne Quercus pollen counts are detected during spring despite the low presence of Quercus populations in the Guadalquivir Valley, where this city is located. This study sought to clarify and identify the potential origin of the different Quercus peaks detected in this city and chart the possible relationship between Quercus pollen curves and air-mass movements. For this purpose, an integrated study of daily and intra-diurnal Quercus pollen counts and back-trajectory analysis was performed over the March-June period of the years 2006-2008. The application of cluster techniques to back trajectory enabled the identification of six different types of air-mass movement. As a function of frequency, two different air-mass groups were identified: the main group comprised Local, Slower Northwest and Mediterranean movements, characterised by higher frequencies; a second group consisting of North, Faster Northwest and Southwest trajectories occurred less frequently over the study period. Although a significant correlation was observed between Quercus airborne pollen counts recorded in Córdoba city and the influence of the Mediterranean air-mass movements, the strongest positive correlation was found between North and Northwest air-mass movements and daily Quercus pollen counts. These results would confirm both that the major Quercus pollen sources are located at different distances north of the city and a new pollen source is also located south of the province, beyond the Guadalquivir valley, related to the arrival of Mediterranean air masses. The northern source appears to be linked to regional transport and the southern source to long-range transport. [ABSTRACT FROM AUTHOR]

The composition and seasonal distribution of airborne pollen grains in the atmosphere of Bahía Blanca, Argentina, has been studied between June 2001 and December 2003 using the Rotorod sampler (model 40). The results show that the main pollen types during this period were Cupressaceae, Fraxinus, Myrtaceae, Poaceae, Amaranthus/Chenopodiaceae, Pinus, Urticaceae, Ulmus, Olea and Styphnolobium. The highest concentrations occurred from August to December (end of winter and spring), accounting for 80% of the total annual pollen count. The greatest diversity was found in the spring, with the major of pollen coming from short-flowering plant types, such as Populus, Acer, Platanus, Juglans, Tamarix, Ailanthus and Typha. The potential sources of pollen from woody ornamental species are Cupressus sempervirens, Eucalyptus camaldulensis and Fraxinus pennsylvanica. whereas those from herbaceous species are the Chenopodiaceae and Poaceae, which are found within the city and also in the surrounding natural vegetation, and the Urticaceae, which are only present in the city. Marked annual differences were noted during the study period. The increase in 2002 may have been due to the abundant rainfall that occurred prior to the spring season, which would have favored the vegetative stage and flower development of plants. The decrease in pollen concentration in 2003 was mainly due to low rainfall throughout the year. [ABSTRACT FROM AUTHOR]

The main characteristics of Poaceae pollen season at 8 sites in Andalusia were studied. Special attention was paid in the trends of grass pollen-season start and peak dates. Moreover, we analyse the intensity of the grass pollen season over the study period as well as potential temporal and spatial patterns in these data. Statistical analysis was performed to determine the possible influence of weather-related parameters on variations in the grass pollen season. Main results show an advance in the start and peak of grass pollen season and an increase in the annual Pollen Index and in the severity of the season (days > 25 pollen grains/m3). The future consequences of these changes in grass phenology could be related with changes in land use and also in pollinosis symptoms due to the higher concentrations recorded but also to the variations on pollen season dates. [ABSTRACT FROM AUTHOR]

Background In recent years, it has been demonstrated that the air carries not only airborne pollen but also plant particles of smaller size that have allergenic activity, and, being within the respirable range, these particles can trigger rapid attacks in the lower respiratory tract. The study of particles according to size (0.7–40 μm) could provide valuable information on the real allergenic activity in the atmosphere. Objective The purpose of this study was to analyse the dynamics of airborne Olea europaea pollen in contrast to the allergenic activity of Ole e 1 in the atmosphere. Methods The analyses were carried out with a Hirst-type volumetric collector and a cascade impactor simultaneously during the MPS of the olive. The indirect ELISA was used to detect the allergenic activity. The sampling was performed in Granada city centre (S Spain), in the Science Faculty building on the University of Granada from 30 April to 26 June 2005. Results and conclusions This research demonstrates that both the allergenic activity as well as the pollen particles follow in a similar curve, except in periods before or succeeding the main Olea pollen season. The study of the distribution of the allergenic particles according to their sizes reveals that the highest concentrations are between 3.3 and <0.7 μm, thus indicating that allergenic activity primarily involves paucimicronic particles. [ABSTRACT FROM AUTHOR]

A detailed study is presented of the calculation of the surface tension and the surface energy of Lennard–Jones fluids from the radial distribution function and the density profile. To do so, a modification is made to Lekner and Henderson's statistical mechanics approach by introducing two simple analytical expressions for the radial distribution function of the interface zone. In these expressions the radial distribution functions of the liquid and vapour phases are weighted via step or exponential variations. The well- known exponential model for the density profile in the interface zone is considered. Finally, results are compared with values from experiment, from computer simulation and from relevant theoretical developments. It is shown that the use of the proposed radial distribution function in the interface zone represents a significant improvement in applying Lekner and Henderson's approach. [ABSTRACT FROM AUTHOR]

In this work, initially a general mathematical framework for wet deposition processes is developed and followed by an in-depth discussion of the scavenging of material below cloud due to rain. These processes are then integrated into an overall framework focussing mainly on precipitation scavenging by rain. This work studies the scavenging efficiencies of aerosol particles within a given rain regime as a function of time by below-cloud scavenging. The health impact of aerosol before and after rain is also considered by comparing the respirable dust fractions. The well-known equations of below-cloud scavenging are applied to eight different classes of atmospheric aerosols (marine background (MB), clean continental background (CCB), average background (AB), background and aged urban plume (BAUP), background and local sources (BLS), urban average (UA), urban and freeway (UF) and central power plant (CCP)) in two precipitation regimes (drizzle and heavy rain) with one drop size distribution (DSD). From this study it is inferred that respirable dust is scavenged with relative ease by rainout. Compared with the volume of respirable aerosol average urban environment (UA) before rain roughly 5.2% remains after 18 hours of drizzle and 4% after 18 hours of heavy rain. Over a long timescale, the results show that heavy rain is more efficient than drizzle in particle scavenging. [ABSTRACT FROM AUTHOR]

Calculation of the surface tension and surface energy of Lennard-Jones fluids from the radial distribution function and the density profile has been studied in detail, using Lekner and Henderson's approach. Three explicit analytical expressions for the function in the liquid phase are considered, together with very accurate expressions for the liquid and vapour densities. The well-known exponential and hyperbolic tangent models for the density profile in the interface zone are considered. The use of the direct correlation function using the Percus-Yevick and the hypernetted-chain approximations is also considered to calculate the surface tension. Finally, the results obtained are compared with values from experiment, from computer simulation, and from relevant theoretical developments. It is shown that the use of the newer models for the radial distribution function represents a significant improvement in applying Lekner and Henderson's approach. Nevertheless, in order to achieve good numerical agreement it would be desirable to perform calculations with expressions for the radial distribution function in the interface zone rather than in the liquid phase. This will be the subject of future work. [ABSTRACT FROM AUTHOR]

The use of a double-sided self-adhesive tapefor pollen trapping could offer some advantagesover traditional adhesives, manually applied tothe Melinex tape of a Hirst-type spore trap,since variation in terms of adhesiveapplication is nil and additional effort inapplying the adhesive is avoided. Nevertheless,its efficiency with respect to the standardadhesives must be tested. In Cordoba (southwestSpain), the Spanish Aerobiology Network Centreperformed a series of comparative studies andrecommended the use of a silicone fluid as anadhesive. This paper compares the efficiency ofa double-sided self-adhesive tape (3M) withsilicone fluid as adhesive. Sampling wascarried out using a Hirst type 7-day spore traplocated 15 m above ground level. A Melinex tapecoated with silicone fluid covered one half ofthe weekly drum; the other half was coveredwith 3M tape that included the adhesive. It iswidely reported that the physicalcharacteristics of silicone fluid do not varywith temperature (Galán andDomínguez-Vilches, 1997), but this studyshowed that 3M efficiency did vary withtemperature. The results revealed that 3M tapewas less efficacious at low temperatures, whileat high temperatures it becomes stickier. Incontrast, silicone fluid does not vary withtemperature. The efficiency of 3M tape alsoseems to be negatively influenced by rain. [ABSTRACT FROM AUTHOR]

Background: Privet pollen rarely accounts for more than 1% of the annual total of daily pollen concentrations measured in a city; however in areas where these trees are widely used as ornamentals the amounts collected may be high enough to cause allergy symptoms. Methods: Air samples taken with volumetric particle samplers Lanzoni VPPS 1000 (Lanzoni s.r.l., Bologna, Italy) show that there are differences in privet pollen concentrations measured in neighbourhoods with a high incidence of privet trees and in those taken at some distance from the source of emission. Results: The results suggest that differences are due to the short dispersal range of the pollen grains once released from the plant, resulting from both the entomophilous nature of the plant and the large size of the pollen grains. Urban design, moreover, may play an important role in impeding pollen grain dispersion if the air cannot flow freely through long, narrow avenues. Another important consideration is that the last stages of the flowering period of privet overlaps with the flowering period of olive trees, the main allergen in the area. The fact that the two pollen types share common allergens means that there may be a cross-reaction between olive tree pollen and privet pollen. Conclusions: Privet pollen should be considered as a potential causative agent of local allergy problems in areas where its presence is extensive and is in combination with other allergens. [ABSTRACT FROM AUTHOR]

This article presents information related to suspended particles affecting the quality of air in urban environments. When one thinks of air pollution, the first thing that generally comes to mind are emissions from non-natural sources, arising from man's daily activities, such as traffic, industrial production and building work. Airborne material arising from natural sources, such as volcanoes, earthquakes or sand storms, is also sometimes considered pollutant. All these cases involve particles of non-biological composition, which are considered pollutants not only because they alter the composition of pure air, but also because they have detrimental effects on health.

Data on predicted average and maximum airborne pollen concentrations and the dates on which these maximum values are expected are of undoubted value to allergists and allergy sufferers, as well as to agronomists. This paper reports on the development of predictive models for calculating total annual pollen output, on the basis of pollen and weather data compiled over the last 19 years (1982–2000) for Córdoba (Spain). Models were tested in order to predict the 2000 pollen season; in addition, and in view of the heavy rainfall recorded in spring 2000, the 1982–1998 data set was used to test the model for 1999. The results of the multiple regression analysis show that the variables exerting the greatest influence on the pollen index were rainfall in March and temperatures over the months prior to the flowering period. For prediction of maximum values and dates on which these values might be expected, the start of the pollen season was used as an additional independent variable. Temperature proved the best variable for this prediction. Results improved when the 5-day moving average was taken into account. Testing of the predictive model for 1999 and 2000 yielded fairly similar results. In both cases, the difference between expected and observed pollen data was no greater than 10%. However, significant differences were recorded between forecast and expected maximum and minimum values, owing to the influence of rainfall during the flowering period. [ABSTRACT FROM AUTHOR]

Temperature is one of the main factors affecting the flowering of Mediterranean trees. In the case of Olea europaea L., a low-temperature period prior to bud development is essential to interrupt dormancy. After that, and once a base temperature is reached, the plant accumulates heat until flowering starts. Different methods of obtaining the best-forecast model for the onset date of the O. europaea pollen season, using temperature as the predictive parameter, are proposed in this paper. An 18-year pollen and climatic data series (1982–1999) from Cordoba (Spain) was used to perform the study. First a multiple-regression analysis using 15-day average temperatures from the period prior to flowering time was tested. Second, three heat-summation methods were used, determining the the quantities heat units (HU): accumulated daily mean temperature after deducting a threshold, growing degree-days (GDD): proposed by Snyder [J Agric Meteorol 35:353–358 (1985)] as a measure of physiological time, and accumulated maximum temperature. In the first two, the optimum base temperature selected for heat accumulation was 12.5°C. The multiple-regression equation for 1999 gives a 7-day delay from the observed date. The most accurate results were obtained with the GDD method, with a difference of only 4.7 days between predicted and observed dates. The average heat accumulation expressed as GDD was 209.9°C days. The HU method also gives good results, with no significant statistical differences between predictions and observations. [ABSTRACT FROM AUTHOR]

Winter is not traditionally considered to be a risky season for people who suffer from pollen allergies. However, increasing numbers of people are showing symptoms in winter. This prompted our investigation into the levels of solid material in the air, and some of the meteorological phenomena that allow their accumulation. This study showed a possible relationship between the phenomenon of thermal inversion, which occurs when very low temperatures, cloudless skies and atmospheric calms coincide, and an increase in the concentration of solid material in the atmosphere. Frequently, this situation is associated with other predictable phenomena such as fog, dew and frost. This may allow a warning system to be derived for urban pollution episodes. The effect caused by parameters such as wind and rainfall was also analysed. Solid material was differentiated into non-biological material from natural and non-natural sources (e.g. soot, dust, sand, diesel exhaust particles, partially burnt residues) and biological material. The latter mainly comprises pollen grains and fungal spores. Owing to its abundance and importance as a causal agent of winter allergies, Cupressaceae pollen was considered separately. [ABSTRACT FROM AUTHOR]

The influence of meteorological factors on daily Urticaceae pollen counts were studied in Córdoba (southwest Spain) in 1996 and 1997. The daily Urticaceae pollen concentrations were obtained by using a Hirst-type volumetric sampler, and meteorological data were obtained from the Córdoba airport, located near the sampling site. The highest correlation between pollen concentration and meteorological parameters was obtained during non-rainy seasons. Temperature was found to be the most important meteorological parameter influencing pollen counts in spring, as temperature is the main reason for the increase of pollen concentration in the atmosphere. In autumn, humidity was another important parameter influencing pollen counts. Rain, however, did not appear to be significant. The influence of the pollen concentration of the 2 previous days and the pollen concentration of the previous day has been studied. During periods with low precipitation, the pollen concentration of the previous day was a useful predictor of Urticaceae pollen concentrations for the following day. [ABSTRACT FROM AUTHOR]