Airborne Pollen Sampling Research Articles

Determination of potentially toxic metals and natural radionuclides in airborne pollens produced different urban environments in Turkey and health risk assessment

ABSTRACT Air pollutants are associated with potentially toxic metals (PTMs) and natural and/or artificial radionuclides, which can pose a major threat to human and environmental health. Pollens can be utilized as a bioindicator to determine the level of air pollution in urban areas. In this study, the concentrations of PTMs and natural radionuclides in 35 airborne pollen samples of 22 species belonging to Pinaceae, Cupressaceae, Araucariaceae, Betulaceae, Salicaceae, and Oleaceae families grown in different urban areas in Turkey were determined using an energy-dispersive X-ray fluorescence spectrometry. For the first time, non-carcinogenic and radiologic health risk assessments for adults were done, estimating hazard index (HI) and annual effective dose (AED), respectively. The concentrations of Fe, Mn, Zn, Ti, Sr, Cu, Ni, Co, Cr, V and Pb analyzed in airborne pollen samples varied from 52.1 to 3078.0, 26.1 to 159.6, 15.6 to 199.7, 9.1 to 282.2, 1.0 to 128.4, 5.0 to 40.1, 5.4 to 23.6, <LD to 11.3, 1.6 to 26.6, <LD to 11.1 and <LD to 5.7 mg/kg, respectively. The average concentrations of K (2%), Th (1.3 mg/kg) and U (1.0 mg/kg) were converted into the activity concentrations (in Bq/kg) of 40K (595.8), 232Th (5.2) and 238U (11.8), respectively. All HI and AED values revealed a very low non-carcinogenic and radiological health risk due to exposure to all PTMs and radionuclides in the pollen samples studied.

Aerobiological Monitoring and Metabarcoding of Grass Pollen.

Grass pollen is one of the leading causes of pollinosis, affecting 10-30% of the world's population. The allergenicity of pollen from different Poaceae species is not the same and is estimated from moderate to high. Aerobiological monitoring is a standard method that allows one to track and predict the dynamics of allergen concentration in the air. Poaceae is a stenopalynous family, and thus grass pollen can usually be identified only at the family level with optical microscopy. Molecular methods, in particular the DNA barcoding technique, can be used to conduct a more accurate analysis of aerobiological samples containing the DNA of various plant species. This study aimed to test the possibility of using the ITS1 and ITS2 nuclear loci for determining the presence of grass pollen from air samples via metabarcoding and to compare the analysis results with the results of phenological observations. Based on the high-throughput sequencing data, we analyzed the changes in the composition of aerobiological samples taken in the Moscow and Ryazan regions for three years during the period of active flowering of grasses. Ten genera of the Poaceae family were detected in airborne pollen samples. The representation for most of them for ITS1 and ITS2 barcodes was similar. At the same time, in some samples, the presence of specific genera was characterized by only one sequence: either ITS1 or ITS2. Based on the analysis of the abundance of both barcode reads in the samples, the following order could describe the change with time in the dominant species in the air: Poa, Alopecurus, and Arrhenatherum in early mid-June, Lolium, Bromus, Dactylis, and Briza in mid-late June, Phleum, Elymus in late June to early July, and Calamagrostis in early mid-July. In most samples, the number of taxa found via metabarcoding analysis was higher compared to that in the phenological observations. The semi-quantitative analysis of high-throughput sequencing data well reflects the abundance of only major grass species at the flowering stage.

Determining if honey bees (Apis mellifera) collect pollen from anemophilous plants in the UK

Whether insect pollinators use wind-pollinated plants have implications for insect monitoring and conservation strategies in a wide range of environments. Habitats, such as coniferous plantations and arable crops of the Poaceae family are not typically considered priority for the monitoring of insect pollinators or habitat enhancement. Further many pollinator monitoring techniques focus on flowers and do not count insect interactions with wind-pollinated plants. Using two honey bee colonies from distinct environments (urban and rural) in north east England, we investigate the use of wind-pollinated plants over the summer of 2021. We combine honey bee pollen pellet analysis with airborne pollen sampling to investigate whether honey bees use three common wind-pollinated plant groups (Pinus sp., Plantago sp. and Poaceae) that have previously been considered sources of forage. Our results show that honey bees do forage on Plantago and Poaceae pollen, in line with previous studies. However, we show statistically that Pinus pollen is contamination from the atmosphere and not actively collected. It is important to consider airborne contamination before making interpretations based on small amounts of pollen in samples of bee products. The use of members of the Poaceae has implications for insect pollinator monitoring in urban environments, which has not always been considered in past studies.

Relationship among airborne pollen, sensitization, and pollen food allergy syndrome in Asian allergic children.

Causes of pediatric pollen food allergy syndrome (PFAS) differ depending on airborne pollen levels in a particular region. We aimed to analyze airborne pollen counts, IgE sensitization rates, and PFAS incidence among children with allergies in South Korea and Japan. This cross-sectional study included children aged 5-17 years with allergies in 2017. Airborne pollen samples were collected from Busan in South Korea, and Fukuoka and Tochigi in Japan. Questionnaires were used to assess bronchial asthma, seasonal allergic rhinitis, atopic dermatitis, food allergy, and PFAS. The serum IgE specific to Dermatophagoides pteronyssinus, pollen, tomato, and peach were investigated. In total, 57, 56, and 20 patients from Busan, Fukuoka, and Tochigi, respectively, were enrolled. Airborne Japanese cedar and cypress pollen were predominant in Fukuoka and Tochigi, whereas pine and alder pollen were predominant in Busan. Children with allergies in Fukuoka and Tochigi had a significantly higher sensitization rate to Japanese cedar, cypress, juniper, orchard grass, ragweed, Japanese hop, and tomato compared with children in Busan. In Fukuoka and Tochigi, where Japanese cedar and cypress pollen were frequently scattered, high sensitizations among allergic children were observed. The sensitization rate was not affected by the pollen count in alder, grass, ragweed, and Japanese hop. In multivariable analysis, only alder sensitization was found to be associated with PFAS (odds ratio: 6.62, 95% confidence interval: 1.63-26.87, p = 0.008). In patients with PFAS in Busan and Tochigi, peach associated with birch allergen Bet v 1 was a causative food item for PFAS. Moreover, PFAS was associated with ragweed and Japanese hop pollen sensitization in Fukuoka. Regardless of pollen counts, alder pollen sensitization was associated with PFAS in children. Ragweed and Japanese hop pollen sensitization were associated with PFAS, particularly among children in southern Japan.

Tracking seasonal changes in diversity of pollen allergen exposure: Targeted metabarcoding of a subtropical aerobiome

The importance of grass pollen to the global burden of allergic respiratory disease is well established but exposure to subtropical and temperate pollens is difficult to discern. Current monitoring of airborne pollen relies on light microscopy, limiting identification of taxa to family level. This informs seasonal fluctuations in pollen aerobiology but restricts analysis of aerobiological composition. We aimed to test the utility of DNA metabarcoding to identify specific taxa contributing to the aerobiome of environmental air samples, using routine pollen and spore monitoring equipment, as well as assess temporal variation of Poaceae pollen across an entire season. Airborne pollen concentrations were determined by light microscopy over two pollen seasons in the subtropical city of Brisbane (27°32′S, 153°00E), Australia. Thirty daily pollen samples were subjected to high throughput sequencing of the plastid rbcL amplicon. Amplicons corresponded to plants observed in the local biogeographical region with up to 3238 different operational taxonomic units (OTU) detected. The aerobiome sequencing data frequently identified pollen to genus levels with significant quantitative differences in aerobiome diversity between the months and seasons detected. Moreover, multiple peaks of Chloridoideae and Panicoideae pollen were evident over the collection period confirming these grasses as the dominant Poaceae pollen source across the season. Targeted high throughput sequencing of routinely collected airborne pollen samples appears to offer utility to track temporal changes in the aerobiome and shifts in pollen exposure. Precise identification of the composition and temporal distributions of airborne pollen is important for tracking biodiversity and for management of allergic respiratory disease.

The use of cyclohexane as new solvent for airborne pollen sampling

Almost all the aerobiological networks used the non-volatile silicone fluid as a capture medium adhesive on the Melinex tape of Hirst-type volumetric samplers. This adhesive was prepared with carbon tetrachloride, considered as a carcinogenic agent. Since that, there is a spreading interest to find an alternative solvent for continuing the aerobiological sampling. In this study, we examined the impaction efficiency of the cyclohexane and carbon tetrachloride solvent, widely used in aerobiological studies. The results revealed that there is no significant difference between the two solvents and that cyclohexane can be used as a new solvent of the adhesive substance for airborne pollen sampling.

Aerobiology of Cupressaceae in Porto city, Portugal

In the last years, pollen-related respiratory allergies have increased worldwide. In the case of Cupressaceae pollen, allergy symptoms appearing during the winter are often confused with generic respiratory diseases such as the common cold, influenza syndrome, among others. The aim of our study was to monitor the atmospheric of Cupressaceae pollen in the city of Porto, investigate its diurnal variation, as well as find the meteorological factors influencing its atmospheric concentration. Airborne pollen sampling was performed using a 7-day Hirst-type volumetric spore trap for 5 years (2013–2017). Cupressaceae main pollen season, interannual and diurnal variations, as well as correlations with the meteorological parameters were determined. During the study period, 2015 was the year that registered the highest annual pollen concentration, while 2016 presented the lowest. Cupressaceae pollen season occurred during the winter, being February the month with the highest concentration. The diurnal distribution pattern presents a well-defined peak concentration in the morning hours (9 a.m.–12 a.m.), which decays abruptly in the early afternoon. Finally, airborne pollen concentration and meteorological factors presented significant correlations, with temperature being the most influent variable.

Modern pollen distribution in the northeastern Indian Ocean and its significance.

In order to provide a reference for reconstructing the paleoclimate of the northeastern Indian Ocean, 36 airborne pollen samples were analyzed using methods for airborne pollen, and 26 surface water samples were analyzed using a lab method for surface water. We found that little pollen is airborne over the Indian Ocean in spring, but airborne pollen types and concentrations can help to deduce paleomonsoon strength and direction. The conclusions included the following: (1) Pollen in the sediment was transported mainly via ocean currents instead of the early summer or spring wind. (2) Airborne pollen types and concentrations are proportional to the wind speed and inversely proportional to the pollen distance transported and depend on whether the wind is from the land or from the sea. If the wind is from the land, the pollen concentration is proportional to the angle between the wind direction and the coastline. (3) The pollen concentration in the sample collected from a water depth of 30-45m is higher than in the samples collected from a depth of 5m. The pollen concentration and salinity are higher in the equatorial area than in the Northern Hemisphere.

Longitudinal Investigation on Allergenic Conifer Pollen in Japan for Successful Prevention and Treatment against Japanese Cedar Pollinosis

Longitudinal Investigation on Allergenic Conifer Pollen in Japan for Successful Prevention and Treatment against Japanese Cedar Pollinosis In Japan allergic people has been recognized increasing according to the increase of Japanese cedar, Cryptomeria japonica (JC) pollinosis since first reported in 1964. We have detected allergenic airborne pollen when Japanese government has begun to investigate the background and treatment on JC pollinosis as a serious social problem since July1986. Urgently the gravitational method with Durham’s sampler has been adopted to know huge number of JC and cypress family, Cupressaceae family (Cypress) pollen grains as causative agent. The area of national artificial forest of over 31 years old has become about 7 times from1970. We have estimated annual fluctuation of Japanese important allergenic pollen, with climatic factor during about 30 years for successful treatment of pollinosis in near future. There are institutions in fifteen locations monitoring airborne pollen by Durham’s sampler in Japan between the latitude of 30 to 40 degrees north. Airborne pollen samples were collected at each institute and were sent to our hospital on a daily basis. We counted pollen grains per cm2 through microscope, classifying and summarizing them. From 1986 to 2014 we have referred to the change in meteorological condition at the close to 9 of the pollen monitoring locations and estimated statically. JC and Cypress pollen counts have shown huge but remarkable annual fluctuation and they have been increasing gradually according to over 31 y-old conifer planting area expanding. The mean temperature in summer time, JC male flower formation, has a significant correlation with next year pollen counts. The pollination season has started earlier in north and later in central Japan gradually through a changing on mean temperature. In Japan allergenic conifer pollen counts have been increasing because of over 31 y-old conifer plantations area increase through the climate change about 30 years. Moreover, it has changed the start of pollination season.

Effect of Climate Change on Fagaceae Airborne Pollen in Japan as Allergic Causative Agent Associated with Food Allergy

Rational: It is no exaggeration to say that Japanese allergic people has increased according to the increase of Japanese Cedar (JC) pollinosis since the first case report, 1964. In Japan allergenic conifer airborne pollen counts have been increasing with a concomitant change in the start of pollination as a result of climate change during about 30 years. We also investigated as if Fagaceae pollen counts have been affected on climate change. In Japan patients with Fagaceae pollinosis is not so clear although this vegetation distributed almost all of Japan Island. Fagaceae pollen antigen has cross-reactivity to Betula (birch) pollen antigen observed in north part of Japan. Especially in Hokkaido district, a lot of patients with birch pollen have rhinoconjunctivitis and pollen related food allergy, oral allergy syndrome (OAS). In order to analyze and ameliorate the suffering of those with pollinosis, we have estimated the correlation between the Fagaceae pollen counts and meteorological conditions affecting those counts and we will inform the tendency of the pollen disperse for prevent and treatment against Fagaceae pollinosis. Method: There are institutions in fifteen locations monitoring airborne pollen by Durham sampler in Japan between the latitude of 30 to 40 degrees north. At each institute daily airborne pollen samples were collected including holidays and sent to our hospital. We counted pollen grains per cm2 through 100 to 400-power microscopes, classifying and summarizing them. From 1986 to 2014 we have referred to the change in monthly mean temperature, humidity, total monthly sunshine duration and amount of global solar radiation at the close to 9 of the pollen monitoring locations by the Meteorological Agency open data. Result: Fagaceae pollen counts have not shown annual fluctuation compared to conifer but have increased gradually. Only total monthly sunshine duration before the pollination in March has a weak significant correlation with Fagaceae pollen counts (r=0.4~0.53, p<0.05) only in some cities. The start of pollination season has been earlier except north of Japan and correlated with March/April mean temperature significantly with the prolongation of pollination season. Conclusion: Fagaceae pollen counts in Japan have been increasing and in the south of Japan Island the pollination season has prolonged during about 30 years climate change. In near future patients with Fagaceae pollinosis will increase in the southern part of Japan and birch/alder pollinosis with oral allergy syndrome will exacerbate during Fagaceae pollination season. We will inform Fagaceae pollen allergen is important for Japanese allergic people from aerobiology site.

Transportation modes of pollen in surface waters in the South China Sea and their environmental significance

This is the first study to determine the main source of pollen in surface-water samples from the South China Sea. Forty-four surface-water samples were taken at a water depth of 5m in the South China Sea 2010 and 2011. Palynological analyses show that the distribution of pollen in surface water is strongly influenced by ocean currents and rivers, particularly in the northern South China Sea. The Pearl River, the surface boundary current, and the Kuroshio Current are the main suppliers of pollen. The number of pollen and spores in the surface-water samples from the South China Sea shows little relationship with sampling seasons but is proportional to the sediment deposition rate. The number of airborne pollen and total concentrations of airborne pollen reveal a close relationship with the sampling season, wind direction, and sampling locations. There is no close relationship between the total pollen concentration of surface sediment and the sediment deposition rate. Therefore, we conclude that the main pollen transport factor of seabed-surface sediment samples in the South China Sea during autumn is wind, whereas both wind and currents are the main transport factors in winter because the pollen number of airborne pollen samples is significantly higher than that of sea surface-water samples in autumn. In addition, the number of pollen in airborne samples is as small as that in sea surface-water samples in winter.

Morphological characteristics of major airborne pollen in Korea peninsula

【Although airborne pollen is invisible to the eye, it has been known as a major source to respiratory allergic reactions. For this reason, airborne pollen is monitoring in many countries to predict pollen concentration based on locality and season. However, the morphological characteristics of airborne pollen and their potential tendency as an allergen are still obscure. In the present study, we selected 52 airborne pollen samples based on previously reported data and investigated their detail pollen characteristics using LM and SEM. Major airborne pollen in Korea has sorted in 19 families (most angiosperms except four gymnosperm families), and all pollen grains are small to medium in size ( $P=17.34-49.86{\mu}m$ ) apart from the bisaccate pollen grains of Pinaceae ( $P=46.49-106.20{\mu}m$ ). The aperture number and shape vary from sulcate to polyporate. While the inaperture pollen has found only in gymnosperm (Cupressaceae and Taxaceae), triporate or polyporate is common pollen type in angiosperm. The sexine ornamentations could divide into several types, but the most sculpturing types are inconspicuous like psilate, rugulate and granulate. Reticulate pollen grains as a semitectum have occurred the species of genera Platanus and Fraxinus only. To estimate the possible relationships between pollen features and allergen, the results are discussed in botanical context.】

Airborne pollen sampling on the Caribbean Island of Trinidad and Tobago, WI

Probable associations which exist between airborne pollen and respiratory diseases remain underappreciated, particularly within the Caribbean region, due to limited research. In an effort to better appreciate these relationships, further investigation into local airborne pollen on a sustained long-term basis is required. As a first step, using a 7-day-recording volumetric spore trap, air sampling was carried out in the St. Augustine area on the Caribbean Island of Trinidad to expand the limited data presently available to allergists on local pollen varieties. This sampling was a component of broader research on the association between airborne pollen, Saharan Dust, and pediatric asthma. During the 2-year sampling period, several varieties of pollen were found and classified and are presented in this article. The photographic pollen image compilation created can be used as a baseline to further investigate the aerospora in Trinidad which can address the current lack of documented records of local airborne pollen, thereby improving local scientific knowledge in this area.

Pollen Raman spectra database: Application to the identification of airborne pollen

Raman microspectroscopy allows a non-destructive identification of airborne particles. However, the identification of particles such as pollen is hindered by the absence of a spectral library. Although reference spectra of pollen have been published before, they have always been limited to a certain number of species. In this work, Raman spectra of 34 pollen types are presented and were used to build a pollen spectra primary library. Afterward, the applicability of this database for detecting and identifying pollen in airborne samples was tested. Airborne pollen samples collected during April, May and August were compared with blank pollen spectra by means of Hit Quality Index. Although a much larger library would be required, our results showed that all first hits correspond to the same blank pollen species of the questioned sample from the air. This possibility is an innovative idea and a promising line of investigation for future RAMAN technology development in the area of aerobiology.

Elemental characterization of the airborne pollen surface using Electron Probe Microanalysis (EPMA)

Recent worldwide increase in pollinoses has been attributed to the synergy between pollen and pollutants. We used EPMA for the elemental characterization of the airborne pollen surface in order to find out what occurs to the wall of pollen grains when they are together with other atmospheric pollutants. Analyses were performed both to airborne pollen and to pollen that was collected from Acer spp., Platanus spp. and Pinus spp. trees. Airborne samples were assembled using a Hirst-type volumetric spore sampler set in the coastal city of Porto, Portugal. Airborne pollen samples showed major elemental differences when compared to the control pollen sample of the same species, namely in the amounts of Cl, Na and Mg, which very significantly increased on airborne samples, revealing an important influence of the ocean. Mineral dust also contributed to modify the pollen surface, by increasing Si contents on Acer spp. and Platanus spp. airborne pollen. Our results revealed consistent positive effects of the relative humidity and the precipitation in the increase of Cl, Na and Mg relative amounts on the pollen surface. This study shows that pollen grains have the ability to adsorb and/or absorb other materials, which may contribute to enhance pollen's harmful effects on people's health.

Airborne pollen concentrations and the incidence of allergic asthma and rhinoconjunctivitis in Lebanon

Abstract Background Pollen monitoring is essential in the case of pollen-related allergic diseases. It may guide physicians and patients towards better prevention strategies, diagnosis, and treatment. Methods One hundred and twenty four patients suffering from rhinoconjunctivitis and/or asthma from different cities around the country, and consulting our allergy clinic between January 2008 and December 2008, were reviewed in a randomized, retrospective study. Skin prick-tests to a battery of perennial or seasonal allergens were performed to all patients during their visit. An airborne pollen investigation was performed in different cities around the country during this period. The Rhinoconjunctivitis Quality of Life (RQLQ) and the Asthma Quality of Life (AQLQ) questionnaires were used to assess the severity of symptoms. Results of the symptoms evaluation were then correlated to the peaks and total concentrations of airborne pollens. Results The airborne pollen sampling showed that Cupressaceae species were the dominant pollen persisting almost at all seasons. A tremendous surge in pollen count was noted in March at all stations with remarkably high level of pollen averaging about 400 pollen/m 3 /day in the one station. Pollens such as olive, and grass were noted as the spring developed. Urticaceae most likely of the Parietaria species, the pollen specific to the Mediterranean area was noted starting in the spring at all stations. The incidence of exacerbations of rhinoconjunctivitis or asthma was highest during the spring season with a frequency of 58.87%. There was another lower peak in the fall with a frequency of 23.3%. A total of 15.32% of patients were allergic to Cupressaceae; 73.68% of them experienced symptoms during spring and 52.63% during fall. A total of 17.75% were allergic to grass; 59.1% of these patients suffered of symptoms during spring and 36.36% during the fall. A total of 24.2% were allergic to Parietaria; 76.67% of these patients endured symptoms during spring and 43.3% during fall. A total of 16.2% were allergic to olive; 70% of these patients experienced symptoms during spring and 30% during fall. A total of 24.2% were allergic to mites; 36.67% of these patients experienced symptoms during spring and 30% during fall. Conclusion There was a good correlation between the peaks of the pollen count and the exacerbations of rhinoconjunctivitis and asthma symptoms. To our knowledge, this is the first study of clinical correlation with pollen count done in Lebanon. Continued monitoring and further studies will confirm our data, and support in better diagnosis and treatment of pollen-related allergic diseases.

Detection of airborne genetically modified maize pollen by real‐time PCR

The cultivation of genetically modified (GM) crops has raised numerous concerns in the European Union and other parts of the world about their environmental and economic impact. Especially outcrossing of genetically modified organisms (GMO) was from the beginning a critical issue as airborne pollen has been considered an important way of GMO dispersal. Here, we investigate the use of airborne pollen sampling combined with microscopic analysis and molecular PCR analysis as an approach to monitor GM maize cultivations in a specific area. Field trial experiments in the European Union and South America demonstrated the applicability of the approach under different climate conditions, in rural and semi-urban environment, even at very low levels of airborne pollen. The study documents in detail the sampling of GM pollen, sample DNA extraction and real-time PCR analysis. Our results suggest that this 'GM pollen monitoring by bioaerosol sampling and PCR screening' approach might represent an useful aid in the surveillance of GM-free areas, centres of origin and natural reserves.

277 Testing the analysis of airborne pollen samples with an automated trainable system

277 Testing the analysis of airborne pollen samples with an automated trainable system

Airborne pollen sampling in a wildlife reserve in the south of Buenos Aires province, Argentina

The objective of this project was to study the pollen spectrum of the MarahueWildlife Reserve (Central Argentina), the quantity and quality of airborne pollen grains, and to evaluate the contribu- tion of outside sources, to protect a natural habitat with xerophytic shrub vegetation (''monte'') (the term ''monte'' is used for the dominant xerophytic shrub vegetation in the ''partido'' of Villarino) approximately 90 km south of Baho ´a Blanca. Sam- pling was performed weekly throughout a whole calendar year (January-December, 2003) using a volumetric impact sampler. Observations of flower- ing in the field were performed at the same time as the aerial sampling. Herbarium specimens were collected to make pollen collections of the species found in the study area, for reference purposes. The most abundant pollen types were Poaceae (31.3% total annual pollen), Amaranthus/Chenopodiaceae (25.3%), Eucalyptus (5%), Brassicaceae (3.9%), and Plantago (3.9%). This study showed the dispersion dynamics of pollen grains from characteristic species of the ''partido'' (the province of Buenos Aires is divided into partidos which are roughly equivalent to counties) of Villarino, the exotic flora of the surrounding area, and the pollen types from outside the region.

Airborne pollen sampling in Toledo, Central Spain

Toledo is one of the main tourist spots of Spain, attracting around two million visitors per year. Its geographical situation in the vast and scarcely monitored Region of Castilla La Mancha and the high number of tourists (especially in the spring) has resulted in the Spanish Aerobiology Network (REA) making this city a major study objective. Air monitoring studies carried out using REA sampling procedures commenced in October 2002. Thirty-two pollen types were identified during the sampling period (October 2002 to October 2004). The annual Pollen Index (PI) was 44124 for the agricultural year October 2002–October 2003, and 29666 in the same period of 2003–2004. The most abundant taxa were, in decreasing order of dominance: Cupressaceae, Quercus, Poaceae, Populus, Olea, Urticaceae, Platanus, Pinus and Ulmus. Other, less well-represented pollen taxa included Salix, Alnus, Fraxinus and Tamarix, which were characteristic of riverside areas, and Morus, Artemisia and Chenopodiaceae. The presence of Castanea pollen grains originating from chestnut crops far away from the city was clearly an example of long-distance transport. The highest concentrations of airborne pollen were detected from March to May and also in January, due to the flowering of Cupressaceae species. In general, there was a correlation between pollen and meteorological parameters: a positive correlation with temperature and a negative correlation with rainfall and humidity during the pre-peak period. A negative correlation between temperature and some tree pollen taxa was detected in the principal pollen period correlation analysis due to their long pollination periods.