Aprpaoches to airborne pollen in SE spain. First survey in murcia: one year of pollen monitoring (1993–94)

First data from a pollen survey carried out in the city of Murcia (SE Spain) are given in this paper. Using a Burkard Volumetric Spore Trap, daily slides were prepared and 80 pollen types belonging to 51 families andAlternaria spores were identified and counted. Special attention was paid to 14 relevant taxa: Cupressaceae,Pinus, Genisteae,Olea, Morus, Acer, Platanus, Plantago, Quercus, Urticaceae, Poaceae, Chenopodiaceae,Artemisia andAlternaria. The main sources of airborne particles wereAlternaria (27.7%), Cupressaceae (13.5%),Olea (9.36%), Chenopodiaceae (8.31%) and Urticaceae (5.8%). Annual variations in pollen abundance and length of the flowering seasons are given for individual species and are related to environmental factors. Results indicate a main pollen season from March to June and a second minor season in September to October. The relatively high concentrations of Genisteae and the appearance of anArtemisia winter season were noted.     

Aerobiology of Fagaceae pollen in Trieste (NE Italy)

The aerobiological behaviour of Fagaceae in Trieste and the correlations with the meteorological parameters were examined. Airborne pollen grains of Castanea, Fagus and Quercus were collected from 1990 to 2003 using a Hirst type spore trap. The main pollen season (MPS) takes place in April and May for Quercus and Fagus, in June and July for Castanea. The highest values occur in year 1993 for Quercus, in 1998 for Castanea and in 1992 for Fagus. The Fagaceae content of the air is mainly due to Quercus and Castanea pollen, Fagus usually having a scarce pollen shedding in Trieste. The highest counts of Fagaceae pollen grains are found from late April to mid May and are mainly due to the pollen shedding of oaks. The cumulative counts vary over the years, with a mean value of 2.719 pollen grains, a lowest total of 1.341 in 2002 and a highest total of 4.704 in 1993. No positive nor negative long-term trends in pollen shedding are found. No cyclic variations were observed. Spearman’s correlation was used to establish the relationship between the daily pollen counts and the daily meteorological data. Daily pollen concentrations present sometimes positive correlation with temperature, negative with rainfall and wind speed, and no correlation with humidity. Fagus and Quercus start dates result positively correlated between themselves. Significant correlations are found between the start of MPS and the mean and maximum temperature in March for Fagus and Quercus, and May for Castanea.     

A comparative study on the effects of altitude on daily and hourly airborne pollen counts

The concentration of pollen grains in the air was studied using two aerobiological volumetric Hirst-type spore traps, one at ground level and the other at a height of 16 m on a terrace. The study was carried out between 2009 and 2011, from March to June in Badajoz (SW Spain). Intradiurnal and daily pollen counts were compared with both, different meteorological parameters and the distribution of local pollen sources. Forty-six pollen types were identified and 89 % of the total grains corresponded to Quercus, Poaceae, Olea, Pinaceae and Plantago pollen types, in descending order. The mean height ratio of the daily pollen count was 1.02. Significant correlations were observed when comparing daily pollen counts for predominant pollen types at both levels. The comparisons have shown significant differences in the daily pollen count between the two samplers in the case of Olea and Pinaceae, but not for Quercus, Poaceae and Plantago. Similar results were obtained using the intradiurnal airborne pollen database. No significant correlation has been found between pollen count and the different meteorological parameters, showing no dependence on height. These differences of Olea and Pinaceae may be explained in part by the uneven distribution of the pollen sources and the disturbance by nearby buildings. The temporal variation patterns between the two sites were similar; however, taking into account the average of the data, the higher values were obtained first at the ground level and later at 16 m.     

Pollen calendar of malaga (Southern Spain), 1991–1995

A pollen calendar has been constructed for Malaga (Southern Spain) based on the data obtained during 5 years (1991–95) using a Burkard spore trap set up approximately 1 km west of the city. The calendar only reflects taxa which showed a 10-day mean pollen concentration equal to or greater than 1 grain of pollen/m³ of air. Twenty nine taxa are included, of which the three commonest (Olea europaea, Cupressaceae andQuercus) represent approximately 54% of the total annual count and the following four (Chenopodiaceae-Amaranthaceae, Gramineae, Urticaceae andPlantago) represent 21.3%. The greatest diversity of pollen types occurs during Spring and the highest concentrations from February to June, when approximately 85% of the total annual pollen is registered. Several peaks occur during the year principally due to Cupressaceae in February,Quercus in April,Olea europaea in May andCasuarina in October, although substantial quantities of Urticaceae, Chenopodiaceae-Amaranthaceae,Plantago and Gramineae are also detected in April and May. The pollination of important allergy-producing taxa such as olive and grass takes place earlier in Malaga than in cities more inland, so that the data presented here may be useful in predicting the beginning of the pollination season of these localities.     

Variations in airborne pollen in central and south-western Spain in relation to the distribution of potential sources

The present study seeks to compare daily and hourly airborne pollen concentrations at eight different stations in Castilla-La Mancha (central Spain) and Extremadura (south-western Spain) and assess pollen distribution sources. Sampling stations were located 69–440 km apart in a straight line in Albacete, Toledo, Talavera de la Reina and Ciudad Real in Castilla-La Mancha, and in Badajoz, Plasencia, Santa Amalia and Zafra in Extremadura. Airborne pollen was collected using Hirst-type volumetric spore traps. Quercus was the most abundant pollen type at all stations except for Ciudad Real, where Olea pollen predominated. Comparisons of daily data between pairs of stations revealed statistically significant positive correlations in all cases for Poaceae and Olea. Comparisons of hourly data between stations indicated greater differences than daily data. Analysis of correlation coefficients and straight-line distances between stations revealed a strong negative correlation. Analysis of total airborne pollen data for the eight sampling stations suggests that airborne pollen concentrations decrease from west to east and from south to north, partly reflecting dominant wind patterns. A clear correlation was observed between airborne pollen concentrations and the surface area covered by olive crops in a 50 km radius around the sampling stations.     

Monitoring of airborne pollen and pollen calendar of Cosenza,Southern Italy

Summary From May 1986 to May 1989 surveys of airborne biological particles have been performed in the atmosphere of Cosenza, Italy with the aim of monitoring the presence of airborne pollen. The survey station is situated at Arcavacata of Rende, a hilly area 474 meters above sea level, 7 km north-west of the main town. The sampler (VPPS 2000) is located about 20 meters above ground level. The monitoring, performed in accordance with the criteria suggested by the Italian Association of Aerobiology (A.I.A.), enabled the identification of 26 different pollen types. The pollination graphics show: 1) a late winter period in which pollen from trees appears; 2) a spring period with a prevalence of Gramineae, Fagaceae, Oleaceae andParietaria pollen; 3) a late spring-summer period during which Fagaceae,Pinus and Compositae pollen grains are present; 4) a late summer-autumn and winter period characterized by a drastic reduction of airborne pollen. A study of the calendar reveals, furthermore, that: 1) Gramineae pollen is, amongst those of allergological importance, the most representative; 2)Parietaria is not perennial and is present in modest concentrations; 3)Olea reaches a high peak in June, but not as high as in other southern regions; 3) pollen from arboreal plants is prevalent compared to that of herbaceous plants.     

Aerobiological study of Fagaceae pollen in the middle-west of Spain

The concentration of airborne Fagaceae pollen in Salamanca and the correlations with some meteorological parameters have been examined. Castanea and Quercus pollen grains were collected from 1998 to 2004 using a Burkard spore trap. No pollen grains of Fagus were found. The main pollen season took place in April and May for Quercus and in June and July for Castanea. Yearly variations on these dates could be related to the influence of meteorological factors such as rainfall, temperature, or dominant winds. The highest values appeared in the year 2004 for both taxa. The Fagaceae airborne content was mainly due to Quercus pollen, Castanea having a scarce pollen content in the city of Salamanca. The highest counts of Fagaceae pollen grains were found from mid May to early June due to the pollen behavior of oaks. The cumulative counts varied over the years, with a mean value of 2,384 pollen grains, a highest total of 6,036 in 2004 and a lowest total of 954 in 2001. No cyclic variations were observed. Daily pollen concentrations presented positive correlation with temperature, negative with relative humidity and slightly negative with rainfall using Spearman's correlation coefficients, only in the case of Castanea, because the particular hourly distribution of rainfall during the spring might affect Quercus airborne pollen.     

A long-term study of winter and early spring tree pollen in the Tulsa, Oklahoma atmosphere

Since 1986 the atmosphere in Tulsa, Oklahoma has been monitored for airborne pollen and spores with a Burkard 7-day spore trap situated on the roof of a building at The University of Tulsa. The present study specifically examined the early spring tree pollen season for several local taxa and the occurrence of pre-season pollen during December and January. Knowledge of the local pollen season will help identify the presence of out-of-season pollen and possible long distance transport (LDT) events. Average daily concentrations of airborne pollen for species ofBetula, Quercus, Ulmus, and Cupressaceae were determined for each year from 1987 to 1996. The data showed that during the early spring the precise pollination periods for these allergenic tree species are highly variable. There were considerable variations in start date, season length, peak concentration, date of peak, and cumulative season total. The start dates forUlmus, Betula, andQuercus varied by 30 days or more, while the early spring Cupressaceae pollen showed the least variation in start date (only 23 days). More research is needed to understand the mechanisms which govern the onset and magnitude of pollen release. Although several reports have documented episodes of long distance transport (LDT) of pollen, the actual contribution of out-of-season or out-of-region pollen to local air spora is poorly known. The current study also re-examined the LDT ofJuniperus ashei pollen in Oklahoma.Juniperus pollen appeared in the Tulsa atmosphere on 40% of the days in December and January with concentrations as high as 2400 pollen grains/m³ of air; however, no local populations ofJuniperus pollinate at this time of the year. High concentrations occurred on days with southerly winds suggesting thatJuniperus ashei populations in southern Oklahoma and Texas were the pollen source. Since no local pollen is present in the Tulsa atmosphere in December and January, this example of LDT has been easy to document.     

Aeropalynological study of <Emphasis Type="Italic">Vitis vinifera</Emphasis> in the Braga region (1999–2003)

This study shows the results of Vitis vinifera pollen season in the atmosphere of the Braga region (Portugal) for the last 5 years (1999–2003). The fluctuations in the airborne pollen concentration, the synchronic rhythms in the annual pollen trends and their relationship to the main meteorological parameters were investigated. The vineyard pollen season extends from late May to early July, presenting always a bimodal pattern. During the studied period several pollen types such as Poaceae, Castanea, Olea, Urticaceae, Quercus, Plantago, Rumex, Asteraceae, Pinaceae, Ericaceae and Eucalyptus were also observed. Airborne pollen concentration is highly influenced by mean temperature, rain, number of days with rain and wind direction.     

Source areas and long-range transport of pollen from continental land to Tenerife (Canary Islands)

The Canary Islands, due to their geographical position, constitute an adequate site for the study of long-range pollen transport from the surrounding land masses. In this study, we analyzed airborne pollen counts at two sites: Santa Cruz de Tenerife (SCO), at sea level corresponding to the marine boundary layer (MBL), and Izaña at 2,367 m.a.s.l. corresponding to the free troposphere (FT), for the years 2006 and 2007. We used three approaches to describe pollen transport: (1) a classification of provenances with an ANOVA test to describe pollen count differences between sectors; (2) a study of special events of high pollen concentrations, taking into consideration the corresponding meteorological synoptic pattern responsible for transport and back trajectories; and (3) a source–receptor model applied to a selection of the pollen taxa to show pollen source areas. Our results indicate several extra-regional pollen transport episodes to Tenerife. The main provenances were: (1) the Mediterranean region, especially the southern Iberian Peninsula and Morocco, through the trade winds in the MBL. These episodes were characterized by the presence of pollen from trees (Casuarina, Olea, Quercus perennial and deciduous types) mixed with pollen from herbs (Artemisia, Chenopodiaceae/Amaranthaceae and Poaceae wild type). (2) The Saharan sector, through transport at the MBL level carrying pollen principally from herbs (Chenopodiaceae-Amaranthaceae, Cyperaceae and Poaceae wild type) and, in one case, Casuarina pollen, uplifted to the free troposphere. And (3) the Sahel, characterized by low pollen concentrations of Arecaceae, Chenopodiaceae-Amaranthaceae, Cyperaceae and Poaceae wild type in sporadic episodes. This research shows that sporadic events of long-range pollen transport need to be taken into consideration in Tenerife as possible responsible agents in respiratory allergy episodes. In particular, it is estimated that 89–97% of annual counts of the highly allergenous Olea originates from extra-regional sources in southern Iberia and northern Africa.     

Influence of meteorological parameters on Olea flowering date and airborne pollen concentration in four regions of Portugal

For calculating the total annual Olea pollen concentration, the onset of the main pollen season and the peak pollen concentration dates, using data from 1998 to 2004, predictive models were developed using multiple regression analysis. Four Portuguese regions were studied: Reguengos de Monsaraz, Valença do Douro, Braga and Elvas. The effect of some meteorological parameters such as temperature and precipitation on Olea spatial and temporal airborne pollen distribution was studied. The best correlations were found when only the pre‐peak period was used, with thermal parameters (maximum temperature) showing the highest correlation with airborne pollen distribution. Independent variables, selected by regression analysis for the predictive models, with the greatest influence on the Olea main pollen season features were accumulated number of days with rain and rainfall in the previous autumn, and temperatures (average and minimum) from January through March. The models predict 59 to 99% of the total airborne pollen concentration recorded and the initial and peak concentration dates of the main Olea pollen season.     

Use of <Emphasis Type="Italic">Quercus ilex</Emphasis> subsp. <Emphasis Type="Italic">ballota</Emphasis> phenological and pollen-production data for interpreting <Emphasis Type="Italic">Quercus</Emphasis> pollen curves

Although aerobiological data are often used in phenological research as an indicator of flowering, airborne pollen concentrations are influenced by a number of factors that could affect pollen curves. This paper reports on a study of various aspects of reproductive biology in Q. ilex subsp. ballota, together with environmental factors influencing pollen release and transport, with a view of achieving reliable interpretation of Quercus pollen curves in Ourense (NW Spain). Aerobiological data were recorded from 2002 to 2004 at two sites in the province of Ourense. From 1st February to the end of the flowering period, phenological observations were carried out on 19 trees from the Q. ilex subsp. ballota population found in the Ourense area. Pollen production was calculated for the same trees. The chilling and heating requirements for triggering development were also calculated. The mean flowering period lasted 11-15 days. Reduced pollen output per catkin and, especially, a reduced number of catkins per tree in 2003 and 2004, prompted a marked decline in overall pollen production. Major differences observed in Q. ilex subsp. ballota pollen curves were attributed to the considerable influence both of weather conditions during pollination and pollen production. In years with high pollen production and weather conditions favouring pollen release, Q. ilex subsp. ballota contributed almost 10% to the total Quercus pollen curve. Around 20% of the pollen trapped was captured before or after flowering periods.     

Airborne-pollen map for Olea europaea L. in eastern Andalusia (Spain) using GIS: Estimation models

Estimations based upon geostatistics and mapping have enabled the construction of a spatial model to predict the presence of biological particles in a particular region. This methodological proposal has been tested in a case study, at a regional scale, of airborne Olea pollen, using the data acquired from␣various sampling stations that are designed for the aerobiological monitoring of pollen levels. These sampling stations have been set up in cities throughout the region of Andalusia (southern Spain) at sites with very different characteristics in terms of biogeography, bioclimate, topography and vegetation. Pollen counts were made daily at all sites during 2003 using a volumetric spore-trap. Data were comparatively analysed in classical diagrams and by means of spatial-temporal maps. Space-time models were constructed using three coordinates, x, y (the UTM coordinates of each sampling station) and z, (the aerobiological data compiled for a specific period). The aerobiological data were interpolated by applying the traditional geostatistical method of Kriging. The introduction of the variable “space” into the model allowed us to predict pollen levels in different areas throughout the region. The interpolation method was used to make weekly estimations of Olea pollen values in areas where there was no aerobiological sampling station. In addition, the maps generated present a two-dimensional vision of the study area, showing that bioclimatic diversity of this region promotes a step-wise flowering of Olea.     

Phenological records as a complement to aerobiological data

Phenological studies in combination with aerobiological studies enable one to observe the relationship between the release of pollen and its presence in the atmosphere. To obtain a suitable comparison between the daily variation of airborne pollen concentrations and flowering, it is necessary for the level of accuracy of both sets of data to be as similar as possible. To analyse the correlation between locally observed flowering data and pollen counts in pollen traps in order to set pollen information forecasts, pollen was sampled using a Burkard volumetric pollen trap working continuously from May 1993. For the phenological study we selected the main pollen sources of the six pollen types most abundant in our area: Cupressaceae, Platanus, Quercus, Plantago, Olea, and Poaceae with a total of 35 species. We selected seven sites to register flowering or pollination, two with semi-natural vegetation, the rest being urban sites. The sites were visited weekly from March to June in 2007, and from January to June in 2008 and 2009. Pollen shedding was checked at each visit, and recorded as the percentage of flowers or microsporangia in that state. There was an association between flowering phenology and airborne pollen records for some of the pollen types (Platanus, Quercus, Olea and Plantago). Nevertheless, for the other types (Cupressaceae and Poaceae) the flowering and airborne pollen peaks did not coincide, with up to 1 week difference in phase. Some arguments are put forward in explanation of this phenomenon. Phenological studies have shown that airborne pollen results from both local and distant sources, although the pollen peaks usually appear when local sources are shedding the greatest amounts of pollen. Resuspension phenomena are probably more important than long-distance transport in explaining the presence of airborne pollen outside the flowering period. This information could be used to improve pollen forecasts.     

Transport of airborne pollen into the city of Thessaloniki: the effects of wind direction, speed and persistence

We examined the effect of the wind vector analyzed into its three components (direction, speed and persistence), on the circulation of pollen from different plant taxa prominent in the Thessaloniki area for a 4-year period (1996–1999). These plant taxa were Ambrosia spp., Artemisia spp., Chenopodiaceae, Corylus spp., Cupressaceae, Olea europaea, Pinaceae, Platanus spp., Poaceae, Populus spp., Quercus spp., and Urticaceae. Airborne pollen of Cupressaceae, Urticaceae, Quercus spp. and O. europaea make up approximately 70% of the total average annual pollen counts. The set of data that we worked with represented days without precipitation and time intervals during which winds blew from the same direction for at least 4 consecutive hours. We did this in order to study the effect of the different wind components independently of precipitation, and to avoid secondary effects produced by pollen resuspension phenomena. Factorial regression analysis among the summed bi-hourly pollen counts for each taxon and the values of wind speed and persistence per wind direction gave significant results in 22 cases (combinations of plant taxa and wind directions). The pollen concentrations of all taxa correlated significantly with at least one of the three wind components. In seven out of the 22 taxon-wind direction combinations, the pollen counts correlated positively with wind persistence, whereas this was the case for only two of the taxon-wind speed combinations. In seven cases, pollen counts correlated with the interaction effect of wind speed and persistence. This shows the importance of wind persistence in pollen transport, particularly when weak winds prevail for a considerable part of the year, as is the case for Thessaloniki. Medium/long-distance pollen transport was evidenced for Olea (NW, SW directions), Corylus (NW, SW), Poaceae (SW) and Populus (NW).     

Winter blooming ofArtemisia. A 2-year survey in murcia (Spain)

This paper presents a 2-year survey ofArtemisia airborne pollen concentrations in Murcia. An importantArtemisia blooming taking place in winter is confirmed in Murcia (SE Spain). This phenomenon could explain the incidence of winter pollinosis in Murcia. On the other hand, for the first time, three consecutive pollen seasons ofArtemisia, corresponding to three different species (A. campestris, A. herba-alba andA. barrelieri) have been noted. Mathematical analyses show the relations between pollen concentrations ofArtemisia in summer and autumn, and precipitation occurring 6–8 weeks before. Blooming outsets seem to be related to cumulative percentage of isolation from 1 March. Meteorological factors do not seem to influence pollen concentration in any significant way once pollination has begun.     

Characteristics of the aeropollen dynamics at several localities in Spain

In the Iberian Peninsula and Balearic Islands there are several bioclimatic regions which result in many different and fragmentary landscapes. Results obtained from monitoring 18 localities in Spain allow an outline of the aeropollen dynamics of some of these environments. The major pollen types are: I. trees: Pinus, Qvercus, Olea, Cupressaceae, 2. shrubs: Corylus, Pislacia and 3. herbs: Poaccae, Urticaceae, Chenopodiaceae-Amaranthaceae, Plantago and Asteraceae. In some locations Alnus, Artemisia, Buxus, Betula, Castanea, Eucalyptus, Populus, Ulmus, and Ephedra also have to be considered. Quantitatively, pollen from trees predominates over that from herbs and shrubs, although at some localities this trend varies. The first pollen grains found in the weekly atmospheric analyses are from trees (winter). In spring tree pollen grains share the atmosphere with herb pollen. For this reason it is usual to find peak values of pollen content in the atmosphere during this part of the year, while winter and autumn are characterized by low pollen counts.     

An automated system for surveying and forecasting Olea pollen dispersion

An automated system for Olea pollensurveying and forecasting is being developedfor the province of Cordoba, Spain, within theframework of the European ASTHMA project.Required input data have been split into threecategories: static data, calibration parametersand dynamic data. A 200 × 200 km potential pollenproduction map, centred on the city of Cordoba,was drawn up using digital high-resolutionsatellite data and reflecting average plantdensity, as derived from the observed spatialseparation of trees in 28 different locations.Based on archives of pollen data from 1982, thestart of the pollen season was determined byapplying both heat accumulation methods andneural network analysis including furthermeteorological parameters. The forecast andsurvey system is based on a set of twoelementary atmospheric physics modules andbiological models: emission and dispersionmodules. The system can run in different modes,allowing forecasting of the floweringstart-date and, from that date, charting theemission and dispersion of pollenconcentrations in the area. Also, wind andtemperature fields are regularly computed andupdated using deterministic numerical models tochart the spatial and temporal concentration ofOlea pollen.     

Comparison between the allergenic airborne pollen in Trieste and at Lozzo di Cadore (Italy) in 1989

Summary A comparative study was carried out between aeroallergenic pollen spectra in Trieste and at Lozzo di Cadore. The two localities were found to be different on a five-day running mean basis as to the 8 pollen taxa monitored by the National Aerobiological Monitoring Network managed by the Italian Association of Aerobiology (AIA). In the zone of Lozzo the pollination curve of the spring flowering taxa showed a lag of about one month due to the colder climate. Lozzo di Cadore showed a poor airborne pollen content,Corylus and Graminaceae being prevailing. Trieste has a higher airborne pollen diversity and longer pollination times because of its higher floristic and vegetational complexity. In Trieste the allergenic pollen spectrum showed great quantities ofOstrya, Quercus, Oleaceae, Graminaceae and of ruderal taxa, widespread over the area, due to man's influence.     

Influence of wind direction on pollen concentration in the atmosphere

The daily pollen concentration in the atmosphere of Badajoz (SW Spain) was analysed over a 6-year period (1993–1998) using a volumetric aerobiological trap. The results for the main pollination period are compared with the number of hours of wind each day in the four quadrants: 1 (NE), 2 (SE), 3 (SW) and 4 (NW). The pollen source distribution allowed 16 pollen types to be analysed as a function of their distribution in the four quadrants with respect to the location of the trap. Four of them correspond to species growing in an irrigated farmland environment (Amaranthaceae-Chenopodiaceae, Plantago, Scirpus, and Typha), five to riparian and woodland species (Salix, Fraxinus, Alnus, Populus, and Eucalyptus), four to urban ornamentals (Ulmus, Arecaceae, Cupressaceae, and Casuarina), and three which include the most frequent pollen grains of widely distributed species (Poaceae, Quercus, and Olea). The results show that the distribution of the sources and the wind direction play a very major role in determining the pollen concentration in the atmosphere when these sources are located in certain quadrants, and that the widely distributed pollen sources show no relationship with wind direction. In some years the values of the correlations were not maintained, which leads one to presume that, in order to draw significant conclusions and establish clear patterns of the influence of wind direction, a continuous and more prolonged study will be required. Received: 6 May 1999 / Revised: 30 March 2000 / Accepted: 31 March 2000