Analysis of airborne pollen in the town of Almería (South-East Spain), 1995–1996

The first results are presented of an aerobiological analysis of the atmosphere of the town of Almería, carried out between November 1995 and October 1996. A Lanzoni volumetric spore trap was used for sample collection. The composition and seasonal evolution of the pollen spectrum were determined over a 1-year period in relation to the vegetation and climatic conditions of the study area. Twenty-six pollen types were identified as accounting for >0.05% of the total pollen collected. The main sources of airborne pollen were Palmae (17.76%),Olea (16.10%), Chenopodiaceae/Amaranthaceae (13.99%), Urticaceae (10.18%) and Poaceae (8.64%). The annual pollen variation presented a period of maximum emission from March to June, with a subsequent, less intensive period from August to November. The minimum pollen values were obtained from December to February. The highest concentrations occurred in May, which was also the month which presented the highest pollen diversity, whereas the lowest values were observed in January.     

Annual variation of airborne pollen in the city of Palencia,Spain, 1990–1992

The aim of this work is to present the atmospheric pollen concentrations of Palencia, Spain. Data were collected for three consecutive years (1990–92). An active volumetric pollen trap, type CAP2, was used. During this time, 88 different pollen types were identified, of which 27 occured at more than 0.15% of the total pollen recorded annually. These types formed the main pollen spectrum of this sampling station. Pollen coming from herbs (Poaceae, Chenopodiaceae, Plantago Urticaceae, etc.) was predominant (53.79%); arboreal pollen (Quercus, Populus Cupressaceae, etc.) represented 42.11%, and pollen from shrubs (Ericaceae, Sambucus etc.) only 4.10%.

May and June was the time of the year with maximum pollen emission to the air. This was due to the quantities of pollen coming from Poaceae and Quercus which together represent 47.25% of the pollen recorded over the three‐year sampling period. Herbaceous pollen appeared throughout the year with maximum concentrations recorded in the spring, coinciding with the maximum levels of arboreal pollen in the atmosphere.

An analysis of multiple regression and one‐way anova test between pollen concentrations and selected meteorological parameters show that relative humidity and average temperature are the meteorological factors most correlated with the concentrations of specific pollen types (Plantago, Ligustrum, Sambucus, Carex). In the same way, when the winds are predominantly from the northeast (second quadrant), there are higher pollen concentrations of Sambucus Ericaceae and Mercurialis.     

Temporal and spatial distribution of atmospheric Poaceae pollen in Catalonia (NE Spain) in 1996–2001

A preliminary study to compare Poaceae pollen data and to determine possible differences in pollen productivity and/or seasonality was performed at six locations in Catalonia (Spain): Barcelona, Bellaterra, Girona, Lleida, Manresa and Tarragona over a 6-year period (1996–2001). In the study area, Poaceae pollen grains are an important cause of respiratory allergies. Being present in the atmosphere all year round, the grass pollen concentrations are especially significant between May and August. The absolute peak occurs in June, except in Lleida where the peak comes earlier, possibly due to the early flowering of particular steppe species. Even if there are differences between different years, Girona and Lleida (inland locations) usually present the highest annual grass pollen index with, on average, 2177 pollen grains per year. Barcelona and Tarragona (the coastal sites) show the lowest levels, with around 1140 grass pollen grains per year. The respective local climates are very different, and pollen grains may originate in different grass species. A decreasing trend in the Poaceae annual pollen index was found over the period of the present study.     

Temporal trends of the airborne fungal spores in Catalonia (NE Spain), 1995–2013

To establish the trends in the period 1995–2013 of the annual fungal spore index of 20 taxa in 8 aerobiological sites of Catalonia, located in 4 phytoclimates, we use the nonparametric Spearman’s Rho and Mann–Kendall tests; when significant, we calculate the magnitude of the change applying the Theil–Sen estimator. We analyze whether the proportional annual change is significantly different from zero, according to phytoclimate, station, and spore taxon, with the Wilcoxon–Mann–Whitney test. Cladosporium, Coprinaceae and Agrocybe are the most prevalent taxa. The proportional annual change analysis shows that 12 taxa present significant increasing trends and 2 decreasing, that the Fresh-Continental Oriental-Humid phytoclimate and Agrocybe show the highest significant increase, while Roquetes-Tortosa (Fresh-Tethyc-Semiarid phytoclimate) and Torula the lowest. The greater significant decreasing proportional annual change corresponds to Drechslera–Helminthosporium and the lesser to Curvularia, and there are no results per phytoclimate and locality. The diversity of characteristics of the sites studied brings the opportunity to evaluate the variability of the fungal values and the magnitude of their change across the study period as depending on the intensity of the land use (urbanization versus agriculture) and the distance to the sea (inland versus littoral), but the effect of the change of the meteorological patterns in the recent years is not negligible. The increasing temperatures and precipitation instability established as effects of the climate change in Catalonia in the last 50 years could be stimulating the sporulation in mountain areas and affecting it in the southern Catalan littoral, thus affecting spore counts.     

Annual,daily and dirunal variations of Urticaceae airborne pollen in Málaga (Spain)

In the Mediterranean area, Urticaceae pollen, together with the pollen of olive and grasses, are the aeroallergens with the highest incidence in the population. From October 1991 to September 1993, with the aid of a Burkard spore-trap, we carried out a study on the Urticaceae pollen content in the atmosphere of Málaga, a seaside resort situated in the Costa del Sol (southern Spain). In Málaga, the Urticaceae pollen season is very long and their pollen grains are detected throughout the year. However, peaks were recorded in March and April and the variables most influencing concentration were maximum air temperature, sunshine hours and relative humidity. Diurnal patterns show that peaks occur generally from 10:00 h to 16:00 h when the temperature reaches its highest values.     

Annual,daily and diurnal variations of Urticaceae airborne pollen in Málaga (Spain)

In the Mediterranean area, Urticaceae pollen, together with the pollen of olive and grasses, are the aeroallergens with the highest incidence in the population. From October 1991 to September 1993, with the aid of a Burkard spore-trap, we carried out a study on the Urticaceae pollen content in the atmosphere of Málaga, a seaside resort situated in the Costa del Sol (southern Spain). In Málaga, the Urticaceae pollen season is very long and their pollen grains are detected throughout the year. However, peaks were recorded in March and April and the variables most influencing concentration were maximum air temperature, sunshine hours and relative humidity. Diurnal patterns show that peaks occur generally from 10:00 h to 16:00 h when the temperature reaches its highest values.     

Comparison of airborne herb pollen types in Córdoba (Southwestern Spain) and Poznan (Western Poland)

This study sought to compare airborne pollen counts for a number of common herbaceous species (Plantago, Chenopodiaceae–Amaranthaceae, Rumex, and Urticaceae) in two cities with differing weather conditions, Córdoba (Southwestern Spain) and Poznan (Western Poland). Pollen seasons for these species were studied from 1995 to 2005. Aerobiological sampling was performed using a Hirst type 7-day spore trap, in accordance with the procedure developed by the European Aerobiology Network. A Spearman correlation test was used to test for correlations between meteorological parameters and daily airborne pollen counts. The Spearman correlation test and the Wilcoxon signed ranks test were also used to compare mean daily pollen counts for the two study sites. In Córdoba, the pollen season generally started around two months earlier than in Poznan, and also lasted longer. These findings were attributed to the presence of a larger number of species in Córdoba, with overlapping pollen seasons, and also to more favorable weather conditions. Trends in pollen season start dates were fairly stable over the study period, with a slight tendency to delayed onset in Córdoba and a modest advance in start date in Poznan. The pollen season end date also remained reasonably stable over the study, with only a slight tendency for the season to end earlier in Córdoba and later in Poznan. A clear trend towards declining annual pollen counts was recorded over the study period for all pollen types in both cities.     

A principal component regression model to forecast airborne concentration of Cupressaceae pollen in the city of Granada (SE Spain), during 1995–2006

The problem of developing a 2-week-on ahead forecast of atmospheric cypress pollen levels is tackled in this paper by developing a principal component multiple regression model involving several climatic variables. The efficacy of the proposed model is validated by means of an application to real data of Cupressaceae pollen concentration in the city of Granada (southeast of Spain). The model was applied to data from 11 consecutive years (1995–2005), with 2006 being used to validate the forecasts. Based on the work of different authors, factors as temperature, humidity, hours of sun and wind speed were incorporated in the model. This methodology explains approximately 75–80% of the variability in the airborne Cupressaceae pollen concentration.     

Alnus andBetula pollen content in the atmosphere of santiago de Compostela, North-Western Spain (1993–1995)

The present study analyzes the behaviour ofAlnus andBetula pollen in the atmosphere of the town of Santiago de Compostela (N.W. Spain) from January 1993 to December 1995. The main pollination period of both taxa is identified for each sampling year, which, in the case ofAlnus, took place in January and February and, forBetula, during April.Alnus andBetula pollen are found in very high quantities in the atmosphere of Santiago de Compostela, representing 5% and 12% respectively of the total annual pollen that was counted. We studied the correlation between pollen content each year for both taxa and the main meterological parameters (average, maximum and minimum temperatures, precipitation and hours of sunshine). Finally, we analyzed the diurnal behaviour model for each taxon. ForAlnus, the maximum concentrations were found around 20:00 h, while, in the case ofBetula, the main pollen concentration took place between 15:00 h and 20:00 h in 1993 and 1994, and at 00:00 h in 1995.     

Pollen content in the atmosphere of Lugo (NW Spain) with reference to meteorological factors (1999–2001)

This study shows the results of monitoring thepollen present in the atmosphere of the city ofLugo for three years (1999–2001) using a Hirstvolumetric trap (model Lanzoni VPPS-2000). During the three-year study, 61,381 pollengrains were counted. Poaceae represents 39.5%of the total pollen identified, Pinus12.3%, Quercus 8.7% and Betula8.4%. More than half of the total annualpollen was recorded in June and July. Itscorrelation was positive with temperature,hours of sun and wind speed, and negative withrainfall and relative humidity. The maximumvalues were recorded between 11 am and 8 pm,coinciding with the highest temperatures andlowest relative humidity.     

Comparative study of airborne pollen counts located in different areas of the city of Córdoba (south-western Spain)

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.     

An observation study of airborne pollen fall in Didim (SW Turkey): years 2004–2005

Pollen grains in the atmosphere of Didim, collected using a Durham sampler, were investigated in 2004 and 2005. Weekly pollen grains per square centimetre were calculated. Over a period of 2 years, 17,518 pollen grains/cm² belonging to 40 taxa and unidentified pollen grains were recorded. In 2004, 9,879 pollen grains were counted per cm², and in 2005 the value was 7,639 per cm². The majority of pollen grains investigated were Pinus spp. (45.58%), Cupressaceae/Taxaceae (13.49%), Olea spp. (9.19%), Platanus spp. (7.62%), Gramineae (6.33%), Pistacia spp. (4.34%), Morus spp. (3.81%), Quercus spp. (2.02%), Abies spp. (1.39%), and Plantago spp. (1.11%). During the month of April, 40.46% of total pollen grains were recorded. According to our results, pollen season durations for the dominated pollen grains in Didim were: the 7th–33rd weeks for Pinus spp., nearly the whole year except summer for Cupressaceae/Taxaceae, the 17th–29th weeks for Olea spp., the 10th–24th weeks for Platanus spp., the 8th–46th weeks for Gramineae, the 8th–20th weeks for Pistacia spp., the 11th–21st weeks for Morus spp., the 17th–21st weeks for Quercus spp., the 9th–27th weeks for Abies spp., and the 7th–26th weeks for Plantago spp.     

Altering airborne pollen concentrations due to the Global Warming. A comparative analysis of airborne pollen records from Innsbruck and Obergurgl (Austria) for the period 1980–2001

Airborne pollen concentration was analysed for six plant taxa for the years 1980–2001 and related to temperature records for the same interval in two different areas in Austria. Both in valley areas (Innsbruck) and at higher altitudes (Obergurgl) the flowering period starts earlier, and lasts longer, and the peak values and pollen production were found to increase. Thus the potential for allergic responses to pollen has considerably increased.     

Study of seasonal and daily variations in airborneOlea europaea L. pollen in Jaén (Spain), 1993–1995

A study is made of the seasonal and daily variations in the concentrations of pollen ofOlea europaea L. over three consecutive years (1993–1995) in the atmosphere of Jaén (southern Spain). A Burkard volumetric spore trap was used for sampling. The results show that the highest concentrations of airborne olive pollen occur during May and the first 2 weeks of June, when levels often exceed 500 grains/m³ and occasionally reach nearly 5000 grains/m³ (the levels of allergenic pollen in the atmosphere of Jaén are among the highest in Europe). Over the 3-year study period a significant seasonal variation was detected, not only in the development of the principal pollination period, but also in the value of the maximum pollen concentrations recorded.     

Trends in airborne pollen: An overview of 21 years of data in Neuchâtel (Switzerland)

Airborne pollen analysis has been carried outin Neuchâtel (Switzerland) since 1979. Inthe context of increasing prevalence of pollenallergies and global climate warming, thisstudy attempts to confirm whether airbornepollen may be responsible for the former orindicative of the latter, and presents somegeneral features of pollen flight in westernSwitzerland. The most common pollen types are Taxus/Cupressaceae, Quercus, Poaceae, Pinus,Betula, Urticaceae and Fraxinus. Duringthe 21 years studied, there was no major changein the abundance of pollen. Among thetwenty-five taxa studied only five presented asignificant trend: an increase of pollenquantities was observed for Alnus,Ambrosia, Artemisia and Taxus/Cupressaceae and a decrease for Ulmus. The plant species flowering in winterand in spring were influenced by the mildwinters of the 1990s: 71% of the dates of theonset or the end of the pollen seasons nowadaysoccur significantly earlier in the year. Theobserved advance reaches 0.84 days/year. Treesappear to react stronger to the climate changethan grass and weeds. No pollen type present aprolonged season, so the trend appears to betowards a shift in the timing of pollenpresence in the air. These observations show that the main cause ofthe spectacular increase of pollinosisprevalence in industrialised countries isprobably not to be found in the weak tendencytowards a rise of pollen abundance, except forsome particular pollen types which can broadenthe spectra and/or intensify the abundance ofmajor allergens present in an area. However,airborne pollen is confirmed to be a sensitiveindicator of climate change. The observedshifts in the pollen seasons make necessary theadequate information for people concerned withpollen allergies, in particular for preventionand therapy purposes.     

Airborne pollen and spores of León (Spain)

A qualitative and quantitative analysis of airborne pollen and spores was carried out over 2 years (from September 1987 to August 1989) in the city of León. Slides were prepared daily using a volumetric pollen trap, which was placed on the Faculty of Veterinary Science building (University of León) 12m above ground-level. Fifty-one pollen types were observed; the most important of these were: Cupressaceae during the winter,Pinus andQuercus in spring, and Poaceae, Leguminosae and Chenopodiaceae in the summer. The results also showed the existence of a rich mould spore assemblage in the atmosphere. The group of Amerospores (Penicillium, Aspergillus andCladosporium) as well as Dictyospores (Alternaria) were the most abundant;Puccinia was common in the air in August. Fluctuations in the total pollen and spores m³ of air were compared with meteorological parameters (temperature, relative humidity and rainfall). From the daily sampling of the atmosphere of León, considering the maximum and minimum temperature and duration of rainfall, the start of the pollen grain season was observed generally to coincide with a rise in temperature in the absence of rain.     

Species distinction in the “Potentilla pollen type” (Rosaceae) of NW Europe

Pollen grains of eight different species from the genera Comarum, Fragaria, Potentilla and Sibbaldia, usually considered as one type, the “Potentilla type”, were examined and morphological features making distinction possible are described     

Airborne pollen of Ambrosia in Burgundy (France) 1996–1997

Pollen counts in Burgundy were monitored by means of four Hirst volumetric traps. Their analysis revealed a sharp rise of Ambrosia from 1996 to 1997. The minimum amount of ragweed pollen likely to provoke allergies (13 grains m–3) was reached or exceeded several days every year, but without leading to clinical symptoms. The circadian variation of Ambrosia pollen showed two peaks: the first one in the morning was suggested to coincide with local pollination, although the second one, in the afternoon, seemed to result from a long range transport which was confirmed by the study of wind roses.     

Does insect netting affect the containment of airborne pollen from (GM-) plants in greenhouses?

Greenhouses are a well-accepted containment strategy to grow and study genetically modified plants (GM) before release into the environment. Various containment levels are requested by national regulations to minimize GM pollen escape. We tested the amount of pollen escaping from a standard greenhouse, which can be used for EU containment classes 1 and 2. More specifically, we investigated the hypothesis whether pollen escape could be minimized by insect-proof netting in front of the roof windows, since the turbulent airflow around the mesh wiring could avoid pollen from escaping. We studied the pollen flow out of greenhouses with and without insect netting of two non-transgenic crops, Ryegrass (Loliummultiflorum) and Corn (Zea Mays). Pollen flow was assessed with Rotorod(?) pollen samplers positioned inside and outside the greenhouse' roof windows. A significant proportion of airborne pollen inside the greenhouse leaves through roof windows. Moreover, the lighter pollen of Lolium escaped more readily than the heavier pollen of Maize. In contrast to our expectations, we did not identify any reduction in pollen flow with insect netting in front of open windows, even under induced airflow conditions. We conclude that insect netting, often present by default in greenhouses, is not effective in preventing pollen escape from greenhouses of wind-pollinated plants for containment classes 1 or 2. Further research would be needed to investigate whether other alternative strategies, including biotic ones, are more effective. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10453-011-9237-8) contains supplementary material, which is available to authorized users.