Variations in mugwort (Artemisia spp.) airborne pollen concentrations at three sites in central Croatia, in period from 2002 to 2003

In spite of the low atmospheric pollen levels, Artemisia sensitisation and allergy has been reported widely. The aim of the study was to determine the length of pollen season, intradiurnal, daily and monthly pollen variation, and the effect of some meteorological parameters on atmospheric pollen concentrations in Central Croatia. Seven-day Hirst volumetric pollen and spore traps were used for pollen sampling. The Artemisia pollen season lasted from the end of July until the end of September with the highest concentrations in August. The percentage of the total pollen count ranged from 0.52% to 0.92%. The intradiurnal peak occurred between 10 a.m. and 12 a.m. Statistical analysis showed a significant correlations between higher air temperature and high pollen concentration as well as high precipitation and low pollen concentration. Results of this study are expected to help in preventing the symptoms of allergic reaction in individuals with Artemisia pollen hypersensitivity.     

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.     

Airborne ragweed (Ambrosia artemisiifolia L.) pollen concentrations in Croatia, 2002–2004

The aim of this study was to determine the onset, length and end of the ragweed pollen season, taking into account diurnal, day-to-day, monthly and annual pollen variations, the effect of some meteorological parameters on atmospheric pollen concentrations and possible differences in the airborne pollen season and concentration due to sampling site. Airborne pollen was collected at three sites in central Croatia (Zagreb, Samobor and Ivanić Grad) during three pollen seasons (2002–2004). Seven-day Hirst-type volumetric pollen traps were used for pollen sampling. Ragweed pollen was the third most abundant pollen type to occur in the atmosphere of central Croatia. Total Ambrosia pollen concentration was the highest in the 2003 pollen season and the lowest in 2004 at all sampling sites. Maximum emissions were restricted to August and September. Intradiurnal periodicity showed a peak from 1000 to 1200 hours. The concentration of ragweed pollen during the pollen season was greatly influenced by temperature and precipitation: on rainy days accompanied by temperature decline, the air pollen concentration decreased abruptly. The results of this study are aimed at helping to alleviate the symptoms of allergic reactions in individuals with ragweed pollen hypersensitivity, thus improving their quality of life.     

Effect of meteorological parameters on Poaceae pollen in the atmosphere of Tetouan (NW Morocco)

Poaceae pollen is one of the most prevalent aeroallergens causing allergenic reactions. The aim of this study was to characterise the grass pollen season in Tetouan during the years 2008–2010, to analyse the effect of some meteorological parameters on the incidence of the airborne Poaceae pollen, and to establish forecasting variables for daily pollen concentrations. Aerobiological sampling was undertaken over three seasons using the volumetric method. The pollen season started in April and showed the highest pollen index in May and June, when the maximum temperature ranged from 23 to 27 °C, respectively. The annual pollen score recorded varied from year to year between 2,588 and 5,404. The main pollen season lasted 114–173 days, with peak days occurring mainly in May; the highest concentration reached 308 pollen grains/m³. Air temperature was the most important meteorological parameter and correlated positively to daily pollen concentration increase. An increase in relative humidity and precipitation was usually related to a decrease in airborne pollen content. External validation of the models performed using data from 2011 showed that Poaceae pollen concentration can be highly predicted (64.2–78.6 %) from the maximum temperature, its mean concentration for the same day in other years, and its concentration recorded on the previous day. Sensitive patients suffering allergy to Poaceae pollen are at moderate to highest risk of manifesting allergic symptoms to grass pollen over 33–42 days. The results obtained provide new information on the quantitative contribution of the Poaceae pollen to the airborne pollen of Tetouan and on its temporal distribution. Airborne pollen can be surveyed and forecast in order to warn the atopic population.     

Comparative study of seasonal and intradiurnal variation of airborne herbaceous pollen in urban and rural areas

The content of herbaceous pollen in the atmosphere depends on the vegetal cover, climate and the weather and geographical conditions. The aim of the study reported here was to compare aerobiological data obtained from pollen monitoring stations located at sites differing with respect to their flora and microclimate – i.e. a town and a rural area. A volumetric method was used for sampling. In each microscopic preparation 12 vertical strips corresponding with 2-h intervals were analysed. A 90% method was used to determine the pollen season. The results were statistically verified using the u test and the Kolmogorov-Smirnov, Spearman and Wilcoxon tests. Higher values of the Seasonal Pollen Index (SPI), higher daily average concentrations and higher peak values were recorded in the rural area. An analysis of intradiurnal variations of airborne pollen showed that apart from the Poaceae the number of pollen grains in the air began to increase earlier in the day in the rural area; in the case of Rumex and Ambrosia, the maximum values also appeared a few hours earlier. For all the taxa investigated, the analysis of correlation showed a significant association between the daily average concentrations at both sites. The weakest association occurred for Plantago lanceolata; for all other taxa, the determination coefficients (R ²) were high. The results of the Wilcoxon test showed that, despite the strong positive association between daily concentrations of the pollen types investigated, there were differences in mean pollen concentrations in the overlapping pollen season. Mean concentrations of Poaceae and Rumex airborne pollen were significantly higher in the rural area in both years, and those of Urtica and P. lanceolata were significantly higher only in 2002.     

Study of the pollen emissions of Urticaceae, Plantaginaceae and Poaceae at five sites in western Spain

A comparative study is presented of the pollen emissions of Urticaceae, Plantaginaceae and Poaceae, collected during 1995 with Hirst samplers (Burkard or Lanzoni) at five sites in western Spain: two Mediterranean sites located in the south (Huelva and Seville) and three Atlantic sites in the north (Orense, Vigo and Santiago). The annual pollen of Poaceae and Plantaginaceae collected in the Atlantic cities was found to be twice that in the Mediterranean sites, and the total amount of Urticaceae was higher at sites with an urban environment and subject to sea influence (Vigo, Huelva and Seville). At all the sites, the start of the main pollination periods (MPP) took place in the following order: Urticaceae, Plantaginaceae and Poaceae. It was also observed that the MPP of these three pollen types began earlier in Huelva and Seville, where the mean temperatures necessary for the beginning of pollen emissions are recorded very early. Regarding the variation in pollen concentrations throughout the year, Urticaceae presented peaks of maximum concentration in March (Huelva, Seville, Vigo and Orense) and June (Santiago); Plantaginaceae in March (south) and June (north); and Poaceae in May (south) and June–July (north). At northern sites, pollen emissions of Urticaceae and Plantaginaceae continued throughout the summer, while in the south they decreased considerably from May onwards. From the allergenic point of view, the indices of reactivity described for Urticaceae and Poaceae were exceeded more often at northern sites, in particular at Vigo. The meteorological conditions associated with periods of highest pollen emission of these three herbaceous types are a rise in mean temperature, light or absent rainfall, and abundant sunshine. The statistical correlations between pollen emissions and meteorological factors were not well-defined, either for the stations or for all the taxa, although they were clearer for the Atlantic cities and for Urticaceae.     

The diurnal variation of Poaceae pollen concentrations in a rural area

Records of Poaceae pollen concentration from three years of sampling in a rural area of West Wales have revealed distinctive circadian patterns of variation. Maximum pollen concentrations are typically recorded between 14.00 and 16.00 hours, on days both above and below an average daily Poaceae pollen count of 50 grains m^-3, although later peaks in concentration may be recorded during periods with no precipitation. Variations in the periodicity of Poaceae pollen are analysed in relation to meteorological conditions, phenological patterns of pollen release, pollen source area, and the magnitude of the average daily pollen count. The time of peak pollen concentration in West Wales is generally earlier than in other studies and this is explained by this study being conducted closer to Poaceae pollen source areas than most urban-based studies.     

Intradiurnal fluctuation of pollen in La Plata, Argentina. Part I, herbaceous pollen types

A pollen analysis was carried out on six herbaceous pollen types whose annual concentration represents a percentage higher than 0.3% in the atmosphere of the city of La Plata, Argentina, from July 1998 to June 2001. They are: Ambrosia, Cyperaceae, Chenopodiaceae-Amaranthaceae, Plantago, Poaceae and Urticaceae. Hourly patterns of the pollen types analysed with the intradiurnal daily index (IDI) could be grouped into three categories account the percentage that represent of pollen concentration registered during five hourly periods of the day. Group I includes pollen types that show a sharp peak in abundance gust one at hour of the day. Group II is formed by pollen types that show high concentrations in more than one hourly band during the daylight. Group III is characterized by the pollen types that show lower concentrations over a broad hourly band during the day.     

First aerobiological study in Mediterranean part of Croatia (Dalmatia): pollen spectrum and seasonal dynamics in the air of Split

The aim of this study was to investigate aerobiological dynamics of pollen in the Mediterranean part of Croatia in the air of the city of Split. Pollen monitoring during the period from 2005 to 2013 was performed using a Hirst volumetric trap. Among the identified pollen of 50 taxa, 21 were allergenic. The average annual pollen index was 33,513. Three pollination seasons were established: early winter season dominated by tree pollen, spring–summer season dominated by herbaceous plants and summer–autumn season with lower amounts of Parietaria and Cupressaceae pollen. According to the abundance, the main taxa were: Cupressaceae, Parietaria/Urtica, Pinus, Quercus, Olea, Carpinus/Ostrya, Poaceae, Platanus and Ambrosia. The annual pollen index together with the daily maximum concentrations showed an upward trend for selected taxa during the study period. The highest monthly pollen index and the highest biodiversity were recorded in April and the lowest during the late autumn and winter months. The pollen calendar created for the city of Split confirmed Mediterranean features of the pollen spectrum. The longest pollen seasons were recorded for Cupressaceae, Parietaria/Urtica and Poaceae pollen types. The correlations between pollen concentrations and meteorological parameters were analyzed. The correlations between pollen concentrations and temperature were positive, while the humidity and the precipitation mostly showed negative influence.     

Intradiurnal patterns of allergenic airborne pollen near a city motorway in Berlin,Germany

In this study, the seasonally averaged intradiurnal patterns of four different pollen types (Fraxinus, Betula, Poaceae and Artemisia) and the role of traffic volume, air pollution and selected weather parameters were investigated. Measurements were carried out with a 7-day recording volumetric spore trap (Hirst type) near a congested city motorway (the A 100) in Berlin, Germany, in 2012, 2013 and partly 2011. Both Poaceae and Artemisia pollen showed distinct patterns which were similar across the years. The main period of grass pollen concentrations in the air was from 8 a.m. to 10 p.m. with peaks about midday or in the afternoon. Mugwort pollen mainly occurred between 6 a.m. and 2 p.m. with a clear maximum from 8 to 10 a.m. With regard to Fraxinus and Betula pollen, the patterns were not as clear and showed differences throughout the years. The intradiurnal patterns of traffic volume and pollen load, mainly of Poaceae in the afternoon and Artemisia in the morning, were partly coincident. The combination of both a high pollen count and air pollution, due to exhaust emissions, represents a special health threat which could result in a double burden for allergy sufferers. In the case of the daily means of Betula and Poaceae, relative humidity had a significantly negative effect on pollen concentrations on the same and/or next day/s, sunshine duration (Poaceae) and air temperature (Artemisia) a positive one.     

Poaceae pollen in the atmosphere of Zagreb (Croatia), 2002 – 2005

Pollen of grasses (Poaceae) is one of the most important airborne allergen sources worldwide. The aim of the study was to determine diurnal, day‐to‐day, weekly, monthly and annual pollen variation, and the effect of selected meteorological parameters on atmospheric pollen concentrations in Zagreb. A preliminary study was carried out during four seasons (2002 – 2005), using a 7‐day VPPS 2000 Hirst volumetric pollen trap. Total annual grass pollen concentrations in Zagreb were constant (2 673 – 3 074 p.g.m^?3), with a relative drop in 2004 (1 196 p.g.m^?3). The beginning of the grass pollen season is usually observed when the average daily temperature exceeds 13.5°C (max. daily temp. 19.5°C), without precipitation. In all four study years the absolute peak of concentrations occurs in the second half of May. The length of pollen season during the study period was 157 – 173 days. A high variability was observed in the maximal concentration and in the number of days when grass pollen concentration exceeded the threshold value of 30 p.g.m^?3 (9 – 40 days). Statistically significant correlations were found between airborne grass pollen concentrations and air temperature, level of precipitation and relative humidity.     

Poaceae pollen in the atmosphere of Tetouan (NW Morocco): effect of meteorological parameters and forecast of daily pollen concentration

The Poaceae pollen season has been characterized in Tetouan during a 7-year period, and the effect of weather conditions on daily concentrations was examined. The forecast models were produced using a stepwise multiple regression analyses. Firstly, three models were constructed to predict daily Poaceae pollen concentrations during the main pollen season, as well as the pre-peak and post-peak periods with data from 2008 to 2012 and tested on data from 2013 and 2014. Secondly, the regression models using leave-one-out cross-validation were produced with data obtained during 2008–2014 taking into account meteorological parameters and mean pollen concentrations of the same day in other years. The duration of the season ranged from 70 days in 2009 to 158 days in 2012. The highest amount of Poaceae pollen was detected in spring and the first fortnight of July. The annual sum of airborne Poaceae pollen concentrations varied between 2100 and 6251. The peak of anthesis was recorded in May in six of the other years studied. The regression models accounted for 36.3–85.7% of variance in daily Poaceae pollen concentrations. The models fitted best when the mean pollen concentration of the same day in other years was added to meteorological variables, and explained 78.4–85.7% of variance of the daily pollen changes. When the year 2014 was used for validating the models, the lowest root-mean-square errors values were found between the observed and estimated data (around 13). The reasonable predictor variables were the mean pollen concentration of the same day in other years, mean temperature, precipitations, and maximum relative humidity.     

Trends in grass pollen season in southern Spain

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.     

Olea Europaea Pollen in the Atmosphere of Málaga (S. Spain) and its Relationship with Meteorological Parameters

The atmosphere of Málaga was sampled from 1992 to 1995 for the pollen of Olea europaea L., one of the most common airborne allergens in the Mediterranean area. A Burkard seven-day-recording trap showed that the pollen of this species is principally detected during spring with the highest concentrations occurring in May. During the main pollination period, the 24 hour intradiurnal variation pattern showed a high degree of homogeneity with no noteworthy peaks. The correlations between the pollen concentrations recorded and the different meteorological parameters show that temperature, sunshine hours and wind direction are those most closely correlated with variations in the daily pollen count.     

Pollen diversity in the atmosphere of Havana,Cuba

With a view to obtaining fuller information on airborne pollen content in the city of Havana, pollen sampling was carried out using a volumetric capture method, for the first time in Cuba. The study was conducted during 2 years (2011 and 2015). An annual pollen integral of 3414 grains was registered during the first year of study, whereas 5120 grains were observed along the 2015. Monthly maximum concentrations were recorded during April, June and July with total values close to 800 pollen grains. Of the 45 pollen types identified, Cecropia (38% of the total pollen identified in both years), Poaceae (18%), Urera type (9%) and Casuarina (6%) were particularly abundant. Although the main pollen types differed in terms of intradiurnal distribution, the highest concentrations were in all cases recorded between 0900 and 1300 hours. Maximum temperature was the variable most influencing airborne pollen counts in the air, with the exception of Casuarina. This paper sought to establish a methodological basis for the further development of aerobiological research in Cuba, thus helping to enhance the prevention and diagnosis of pollen allergies in the affected island population.     

Differences in atmospheric emissions of Poaceae pollen and Lol p 1 allergen

The allergens of different grass species share similar physicochemical and immunological features that account for the high incidence of allergenic cross-reactivity. We aimed to gain more information on the correlation between Poaceae airborne pollen and allergen concentration and hence make a reliable assessment of true pollen exposure in different bioclimatic areas. The release of Lol p 1 allergen from grass pollen differs between years and areas depending on variables like meteorological factors, biological sources, and cross-reactions with homologous allergens. This study monitored airborne pollen concentrations of grasses and Lol p 1 aeroallergen in León and Ourense, two cities with different climatic conditions located in northwestern Spain. Lol p 1 content in aerosol samples was quantified using specific ELISA antibody plates. Some our results show that Lol p 1 concentration increases when the atmospheric relative humidity is below 70%. This could explain the appearance of protein peaks at times when little or no grass pollen is present, especially after a short and heavy storm.     

Atmospheric pollen in Santiago,Chile

In the city of Santiago (33°27'S70°38'W), Chile, an atmospheric pollen was monitored for three years using a volumetric Hirst-type pollen trap. The aims of the study were: to assess the pollen types present in the atmosphere, their actual concentrations and dynamics (means and maxima); to establish the pollen calendar for Santiago; and to analyze the aerobiologic characteristics distinguishing introduced and native taxa. Results show that atmospheric pollen mainly originates from the following taxa: Platanus , Poaceae, Acer , Cupressus , Chenopodiaceae, Urticaceae, Morus , Plantago and Oleaceae. For the most frequent pollen types graphs of their atmospheric presence constructed and a table with relevant yearly data for the three studied (July-June) is presented. It is concluded, that the airborne pollen is originating mainly from introduced taxa, many of which are considered allergenic. Native taxa showed no high concentrations. The highest aiborne pollen concentrations where observed in September, however, atmospheric pollen thought to be capable of causing pollinosis, where present during the whole year. The highest pollen concentrations are mostly from trees.     

Atmospheric Poaceae pollen frequencies and associations with meteorological parameters in Brisbane,Australia: a 5-year record, 1994–1999

Grass pollen is an important risk factor for allergic rhinitis and asthma in Australia and is the most prevalent pollen component of the aerospora of Brisbane, accounting for 71.6% of the annual airborne pollen load. A 5-year (June 1994–May 1999) monitoring program shows the grass pollen season to occur during the summer and autumn months (December–April), however the timing of onset and intensity of the season vary from year to year. During the pollen season, Poaceae counts exceeding 30 grains m^–3 were recorded on 244 days and coincided with maximum temperatures of 28.1 ± 2.0 °C. In this study, statistical associations between atmospheric grass pollen loads and several weather parameters, including maximum temperature, minimum temperature and precipitation, were investigated. Spearmans correlation analysis demonstrated that daily grass pollen counts were positively associated (P < 0.0001) with maximum and minimum temperature during each sampling year. Precipitation, although considered a less important daily factor (P < 0.05), was observed to remove pollen grains from the atmosphere during significant periods of rainfall. This study provides the first insight into the influence of meteorological variables, in particular temperature, on atmospheric Poaceae pollen counts in Brisbane. An awareness of these associations is critical for the prevention and management of allergy and asthma for atopic individuals within this region.     

The combination of airborne pollen and allergen quantification to reliably assess the real pollinosis risk in different bioclimatic areas

Exposure to allergens represents a key factor among the environmental determinants of asthma. The most common information available for pollinosis patients is the concentration of pollen grains in the bioaerosol and their temporal distribution. However, in recent years, discordance between pollen concentrations and allergic symptoms has been detected. The purpose of this research is to evaluate the relationship between pollen counts and the atmospheric aeroallergen concentrations in different Spanish bioclimatic areas. For the monitoring of allergen content in the air, a quantitative antigen–antibody technique combined with the Cyclone sampling methodology was used. The study was conducted during 2007 by considering some of the most common allergens that induce pollinosis in each area: Platanus and Urticaceae in Ourense and Cartagena, and Poaceae in Ourense and León. In Ourense, pollen counts and aeroallergen concentrations coincided for the three pollen types studied, and the pollen and allergen data associated with the meteorological factors were highly significant for the pollen counts. In Cartagena (for Platanus and Urticaceae) and León (for Poaceae), the low correlations between pollen counts and allergen concentrations obtained could be due to the specific bioclimatic conditions. In contrast, the higher allergen concentrations found in the atmosphere in Cartagena and León compared to Ourense could be related to the existing pollutant levels there, inducing a higher expression of plant pathogenesis-related proteins in the plants of polluted cities. The combination of pollen counts and allergen quantification must be assessed to reliably estimate exposure of allergic people to allergens in different bioclimatic areas.     

Airspora of Durban: a sub-tropical,coastal South African city

The atmospheric pollen of Durban has been monitored since 1989 using a Burkard sampler. Data are presented here for the three-year period ending in 1991. The results do not reflect the indigenous sub-tropical vegetation of the area, but rather exotic elements that are either naturalised (Morus) or cultivated (Cannabis and Poaceae). The only indigenous pollen that was recorded in any number was that of the lawn grass Cynodon dactylodon and the tree Celtis africana. However, these two plant types are found country-wide, and are not restricted to sub-tropical regions. All major pollen types recorded have been implicated as allergens.