Start Dates Of Pollen Seasons Research Articles

Trends and future projections of Olea flowering in the western Mediterranean: The example of the Alentejo region (Portugal)

Olives are one of the most economically relevant crops in the Mediterranean area but this region is experiencing a strong warming due to climate change. Therefore, it would be of great interest to estimate the possible implications of climate change on olive flowering timing by modelling its thermal requirements, and aerobiological records have proved to be a useful tool for monitoring regional olive phenology. Recently, a new phenological modelling framework has been developed called PhenoFlex. It has shown excellent results in estimating the thermal requirements of fruit trees. However, this framework has not previously been applied to olive trees or tested using aerobiological data, which could present greater spatial distribution than in situ phenological observations. This study has a threefold aim: i) to detect the trends in the main pollen season start date of Olea during the past 25 years in a western Mediterranean region (Alentejo, Portugal); ii) to evaluate the applicability of the PhenoFlex modelling framework to olive aerobiological data, and iii) to use the modelled parameter estimates to evaluate the influence of projected future climate change scenarios on Olea flowering regional onset dates. Our results showed that global warming had not produced any significant trend in the olive flowering onset dates until the present time, and they are not expected to do so in the near future, either. A temperature increase during winter was observed that is delaying the fulfilment of the Olea chilling requirements, but this is compensated for by a reduction in the forcing period due to higher temperatures observed during spring. However, our study points out a significant increase in the interannual variability of flowering onset dates, which could compromise fruit development and adversely affect the yield, raising uncertainty in olive fruit production in the near future.

Aeroallergens and Climate Change in Tulsa, Oklahoma: Long-Term Trends in the South Central United States.

Climate change is having a significant effect on many allergenic plants resulting in increased pollen production and shifts in plant phenology. Although these effects have been well-studied in some areas of the world, few studies have focused on long-term changes in allergenic pollen in the South Central United States. This study examined airborne pollen, temperature, and precipitation in Tulsa, Oklahoma over 25 to 34 years. Pollen was monitored with a Hirst-type spore trap on the roof of a building at the University of Tulsa and meteorology data were obtained from the National Weather Service. Changes in total pollen intensity were examined along with detailed analyses of the eight most abundant pollen types in the Tulsa atmosphere. In addition to pollen intensity, changes in pollen season start date, end date, peak date and season duration were also analyzed. Results show a trend to increasing temperatures with a significant increase in annual maximum temperature. There was a non-significant trend toward increasing total pollen and a significant increase in tree pollen over time. Several individual taxa showed significant increases in pollen intensity over the study period including spring Cupressaceae and Quercus pollen, while Ambrosia pollen showed a significant decrease. Data from the current study also indicated that the pollen season started earlier for spring pollinating trees and Poaceae. Significant correlations with preseason temperature may explain the earlier pollen season start dates along with a trend toward increasing March temperatures. More research is needed to understand the global impact of climate change on allergenic species, especially from other regions that have not been studied.

Analysis of changes in Betula pollen season start including the cycle of pollen concentration in atmospheric air.

Birch belongs to the most important allergenic taxa in Europe, therefore information on the start dates of the pollen season is very important for allergists and their patients as well as for climatologists. The study examined changes in the start of the birch pollen season as well as determined the trend of these changes. Pollen monitoring was performed in Lublin (eastern Poland) in the period 2001–2019 using the volumetric method. The Makra-test was used to detect periods with significantly higher or lower average of the onset than the average for the whole dataset. Two significant falls in the average of the pollen season start were found in 2007 and 2014. Besides, taking into account the 2-3-year rhythm of high and low concentrations of birch pollen in the atmospheric air, linear trends were fitted for the subsets of high and low abundance seasons. Significant changes in Betula pollen season start dates were only determined for the highly abundance seasons, while the results for seasons with a low concentration did not allow rejecting the hypothesis about the lack of a linear trend in the changes in the studied parameter. Moreover, a significant polynomial relationship was found between the beginning of a pollen season and the average values of monthly temperatures preceded a season. These analyses show that the start dates of the Betula pollen season are getting significantly earlier. The dynamics of changes differ between seasons with high and low concentrations of pollen.

A systematic review of the effects of temperature and precipitation on pollen concentrations and season timing, and implications for human health.

Climate and weather directly impact plant phenology, affecting airborne pollen. The objective of this systematic review is to examine the impacts of meteorological variables on airborne pollen concentrations and pollen season timing. Using PRISMA methodology, we reviewed literature that assessed whether there was a relationship between local temperature and precipitation and measured airborne pollen. The search strategy included terms related to pollen, trends or measurements, and season timing. For inclusion, studies must have conducted a correlation analysis of at least 5 years of airborne pollen data to local meteorological data and report quantitative results. Data from peer-reviewed articles were extracted on the correlations between seven pollen indicators (main pollen season start date, end date, peak date, and length, annual pollen integral, average daily pollen concentration, and peak pollen concentration), and two meteorological variables (temperature and precipitation). Ninety-three articles were included in the analysis out of 9,679 articles screened. Overall, warmer temperatures correlated with earlier and longer pollen seasons and higher pollen concentrations. Precipitation had varying effects on pollen concentration and pollen season timing indicators. Increased precipitation may have a short-term effect causing low pollen concentrations potentially due to "wash out" effect. Long-term effects of precipitation varied for trees and weeds and had a positive correlation with grass pollen levels. With increases in temperature due to climate change, pollen seasons for some taxa in some regions may start earlier, last longer, and be more intense, which may be associated with adverse health impacts, as pollen exposure has well-known health effects in sensitized individuals.

A First Pre-season Pollen Transport Climatology to Bavaria, Germany.

Climate impacts on the pollen season are well-described however less is known on how frequently atmospheric transport influences the start of the pollen season. Based on long-term phenological flowering and airborne pollen data (1987–2017) for six stations and seven taxa across Bavaria, Germany, we studied changes in the pollen season, compared pollen and flowering season start dates to determine pollen sources, and analyzed the likelihood of pollen transport by HYSPLIT back trajectories. Species advanced their pollen season more in early spring (e.g., Corylus and Alnus by up to 2 days yr−1) than in mid spring (Betula, Fraxinus, Pinus); Poaceae and Artemisia exhibited mixed trends in summer. Annual pollen sums mainly increased for Corylus and decreased for Poaceae and Artemisia. Start of pollen season trends largely deviated from flowering trends, especially for Corylus and Alnus. Transport phenomena, which rely on comparisons between flowering and pollen dates, were determined for 2005–2015 at three stations. Pre-season pollen was a common phenomenon: airborne pollen was predominantly observed earlier than flowering (median 17 days) and in general, in 63% of the cases (except for Artemisia and Poaceae, and the alpine location) the pollen sources were non-local (transported). In 54% (35%) of these cases, back trajectories confirmed (partly confirmed) the pre-season transport, only in 11% of the cases transport modeling failed to explain the records. Even within the main pollen season, 70% of pollen season start dates were linked to transport. At the alpine station, non-local pollen sources (both from outside Bavaria as well as Bavarian lowlands) predominated, in only 13% of these cases transport could not be confirmed by back trajectories. This prominent role of pollen transport has important implications for the length, the timing, and the severity of the allergenic pollen season, indicating only a weak dependency on flowering of local pollen sources.

Variability in the Betula pollen concentrations in the atmosphere of six urban areas in Slovakia in 2018

Betula pollen is one of the most important aeroallergens during the spring months in the central European countries. In 2018, pollen monitoring was conducted in six urban areas (Bratislava, Banská Bystrica, Košice, Nitra, Trnava, and Žilina) in Slovakia. Investigations were carried out using a volumetric Hirst-type pollen trap (Burkard). Betula pollen season timing was determined by the 90% method when the start and end of the season were defined as the date when 5% and 95%, respectively of the total pollen sum was reached. The pollen season start date was recorded earliest in Bratislava (April 8th) and latest in Banská Bystrica (April 12th). The highest both seasonal total pollen concentration (7,390 P/m3) and birch pollen allergen risk were found in Banská Bystrica. The shortest pollen season was recorded in Žilina (13 days) and the longest in Košice (25 days). Peak daily pollen concentrations ranged between 1,567 P/m3 in Žilina and 202 P/m3 in Košice.

Grass pollen season in selected cities of Poland in 2019

The pollen of grass is the primary trigger of pollen allergies during the summer months. It causes some of the most severe and difficult-to-treat symptoms. During the flowering of grass, over 90% of patients allergic to grass pollen suffer from allergic conditions. The symptoms caused by grass pollen allergens appear in some patients after exceeding the concentration of 20 grains in m3 of air. The aim of this study was to compare Poaceae pollen seasons in 2019 in 11 cities located in different regions of Poland. Pollen monitoring was conducted in Bialystok, Bydgoszcz, Sosnowiec, Lublin, Olsztyn, Szczecin, Piotrkow Trybunalski, Warsaw, Opole, Zielona Gora and Wroclaw. Airborne pollen was monitored by the volumetric method using Burkard or Lanzoni pollen samplers. Pollen season length was determined by the 98% method, where the start of the season was defined as the date when 1% of the seasonal pollen total was trapped and the end of the season as the date, when 99% of the seasonal pollen total was reached.The pollen season start date was recorded earliest in Zielona Gora (April 27th), latest in Szczecin (May 25th). The highest grass pollen concentration values were found in Lublin, Piotrkow Trybunalski and Warsaw, whereas the lowest ones in Bialystok. The annual grass pollen sum was highest in Lublin (4715 pollen grains), whereas it was lowest in Bialystok (1256 pollen grains). A relatively high pollen count was also recorded in Warsaw (4106 pollen grains) and Zielona Gora (4077 pollen grains). The longest grass pollination season was recorded in Zielona Gora (139 days) and the shortest in Szczecin (110 days). In the remaining measuring points, grass pollen in the air maintained from 112 to 131 days. The highest grass pollen allergen risk occurred in Lublin, Olsztyn and Zielona Gora and the lowest in Bialystok.

The analysis of Betula pollen season in Poland in 2019

The aim of this study was to compare Betula pollen seasons in 2019 in 12 cities located in different regions of Poland. Pollen monitoring was conducted in Bialystok, Bydgoszcz, Cracow, Lublin, Olsztyn, Opole, Piotrkow Trybunalski, Sosnowiec, Szczecin, Warsaw, Wroclaw, and Zielona Gora. Airborne pollen was monitored by the volumetric method using Burkard or Lanzoni pollen samplers. Pollen season length was determined by the 98% method. The pollen season start date was recorded earliest in Wroclaw and Zielona Gora, and latest in Bialystok. The highest Betulapollen concentration values were found in Lublin, whereas the lowest ones in Bialystok. In most of the cities, the maximum daily Betula pollen concentration was recorded on April 19th or 20th. Exceptionally, in Wroclaw the peak value occurred on April 8th, while in Bialystok as late as April 29th. The annual pollen sum reached the highest values in Warsaw and the lowest ones in Bialystok. The highest risk of allergy in people sensitive to the pollen of this taxon was found in Bydgoszcz, Zielona Gora, Szczecin, Opole, and Warsaw

Temporal trends in airborne pollen seasonality: evidence from the Italian POLLnet network data

Airborne pollen reflects local vegetative composition and is a proxy for flowering phase. Long-term pollen data might reflect changes in biodiversity and phenology, attributable also to the effect of climate change. The present study, based on pollen data collected within the Italian aerobiological network POLLnet, aimed to verify whether there is any evidence of temporal changes in pollen season timing and its relation with meteorological variables. To this purpose, nine stations located in North and Central Italy were selected, and twelve pollen taxa, both arboreal and herbaceous, were considered. For each taxon and station, 11–17-year datasets of airborne pollen concentration within the period 2000–2016 were analysed. Four different pollen season descriptors were elaborated (start, end and peak date, season length) and analysed their temporal trend, also in relation to temperature and precipitation. Overall, the results showed a negative temporal trend in pollen season starting date, which indicates a tendency towards an earlier flowering for Corylus, Quercus, Gramineae and Urticaceae in all stations (even if statistically significant in six out of 36 cases). The effect of meteorological parameters was evidenced by negative correlations between pollen season starting date and temperature. With the exception of Olea, Ambrosia and Artemisia, all the remaining pollen taxa showed significant (negative) correlations between pollen season start date and average temperature of the previous months in at least half of the stations. As for precipitation, no relevant correlations were detected with pollen season parameters. The results are also interpreted considering the different biogeographic areas in which the nine stations are located. Long-term pollen dataset is useful in phenological studies and for the detection of climate change effects.

Alder pollen season in selected cities of Poland in 2019

The pollen of grass is the primary trigger of pollen allergies during the summer months. It causes some of the most severe and difficult-to-treat symptoms. During the flowering of grass, over 90% of patients allergic to grass pollen suffer from allergic conditions. The symptoms caused by grass pollen allergens appear in some patients after exceeding the concentration of 20 grains in m3 of air. The aim of this study was to compare Poaceae pollen seasons in 2019 in 11 cities located in different regions of Poland. Pollen monitoring was conducted in Bialystok, Bydgoszcz, Sosnowiec, Lublin, Olsztyn, Szczecin, Piotrkow Trybunalski, Warsaw, Opole, Zielona Gora and Wroclaw. Airborne pollen was monitored by the volumetric method using Burkard or Lanzoni pollen samplers. Pollen season length was determined by the 98% method, where the start of the season was defined as the date when 1% of the seasonal pollen total was trapped and the end of the season as the date, when 99% of the seasonal pollen total was reached.The pollen season start date was recorded earliest in Zielona Gora (April 27th), latest in Szczecin (May 25th). The highest grass pollen concentration values were found in Lublin, Piotrkow Trybunalski and Warsaw, whereas the lowest ones in Bialystok. The annual grass pollen sum was highest in Lublin (4715 pollen grains), whereas it was lowest in Bialystok (1256 pollen grains). A relatively high pollen count was also recorded in Warsaw (4106 pollen grains) and Zielona Gora (4077 pollen grains). The longest grass pollination season was recorded in Zielona Gora (139 days) and the shortest in Szczecin (110 days). In the remaining measuring points, grass pollen in the air maintained from 112 to 131 days. The highest grass pollen allergen risk occurred in Lublin, Olsztyn and Zielona Gora and the lowest in Bialystok.

Ambrosia pollen season in selected cities in Poland in 2018

Ambrosia causes most pollen allergies in North America. After several Ambrosia species were introduced to Europe, an increase in the incidence of allergy to pollen of these plants has been observed in many countries. The aim of this study was to compare Ambrosia pollen seasons in 2018 in 13 cities located in different regions of Poland: Bialystok, Bydgoszcz, Cracow, Drawsko Pomorskie, Lublin, Olsztyn, Opole, Piotrkow Trybunalski, Sosnowiec, Szczecin, Warsaw, Wroclaw and Zielona Gora. The study was conducted by the volumetric method using Burkard or Lanzoni pollen samplers. The pollen season was determined by the 98% method. The earliest pollen season start dates (the end of July) were recorded in Zielona Gora, Bydgoszcz, Opole and Szczecin, while the latest ones in Drawsko Pomorskie and Bialystok. The longest pollen seasons occurred in Opole, Szczecin and Zielona Gora (79 days). The highest average daily concentrations of Ambrosia pollen were recorded in Bialystok (129 P/m3) and Lublin (99 P/m3), while the lowest ones in Drawsko Pomorskie and Szczecin (4 and 10 P/m3, respectively). The annual pollen sum reached the highest value in Opole (567 pollen grains) and Zielona Gora (555 pollen grains). It can be concluded from the pattern of Ambrosia pollen seasons at the monitoring sites studied that pollen of this taxon originates not only from Ambrosia locations in Poland but also from long-distance transport.

Analysis of Fraxinus pollen seasons and forecast models based on meteorological factors.

The timings of Fraxinus and Betula flowering and pollen release overlap, which may cause increased allergic reactions in sensitive people. The aim of the present study was to characterize Fraxinus pollen seasons in Lublin (central-eastern Poland) and to identify meteorological factors that most determine the occurrence of airborne pollen of this taxon, as well as obtain forecast models for the basic characteristics of the pollen season. The study was conducted in Lublin during the period 2001-2016, employing the volumetric method. The seasons were compared by PCA (Principal Component Analysis). To determine relationships between meteorological conditions and the pattern of pollen seasons, regression analysis was used. Data for the period 2001-2015 were used to create forecast models by applying regression analysis, while the 2016 data served to verify these models. Season end date and seasonal peak date were characterized by the lowest variation. The biggest differences were found for peak value and total annual pollen sum. The average dates of occurrence of ash pollen grains in the air of Lublin were between 13 April 13 - 3 May 3, whereas, on average, the pollen peak date occurred on 23 April. The factor loading values for the PC1 variable indicate that it is most strongly correlated with peak value and total pollen sum, while the PC2 variable correlated with the pollen season start date and season duration (a negative correlation). Regression models were developed for the following pollen season characteristics: season start, end and duration, seasonal peak date, and total annual pollen sum. The fit of the forecast models was at the level of 62-94%. Analysis of the data showed that weather conditions mainly in February were important factors controlling the Fraxinus pollen season.

A prognostic pollen emissions model for climate models (PECM1.0)

Abstract. We develop a prognostic model called Pollen Emissions for Climate Models (PECM) for use within regional and global climate models to simulate pollen counts over the seasonal cycle based on geography, vegetation type, and meteorological parameters. Using modern surface pollen count data, empirical relationships between prior-year annual average temperature and pollen season start dates and end dates are developed for deciduous broadleaf trees (Acer, Alnus, Betula, Fraxinus, Morus, Platanus, Populus, Quercus, Ulmus), evergreen needleleaf trees (Cupressaceae, Pinaceae), grasses (Poaceae; C3, C4), and ragweed (Ambrosia). This regression model explains as much as 57 % of the variance in pollen phenological dates, and it is used to create a climate-flexible phenology that can be used to study the response of wind-driven pollen emissions to climate change. The emissions model is evaluated in the Regional Climate Model version 4 (RegCM4) over the continental United States by prescribing an emission potential from PECM and transporting pollen as aerosol tracers. We evaluate two different pollen emissions scenarios in the model using (1) a taxa-specific land cover database, phenology, and emission potential, and (2) a plant functional type (PFT) land cover, phenology, and emission potential. The simulated surface pollen concentrations for both simulations are evaluated against observed surface pollen counts in five climatic subregions. Given prescribed pollen emissions, the RegCM4 simulates observed concentrations within an order of magnitude, although the performance of the simulations in any subregion is strongly related to the land cover representation and the number of observation sites used to create the empirical phenological relationship. The taxa-based model provides a better representation of the phenology of tree-based pollen counts than the PFT-based model; however, we note that the PFT-based version provides a useful and climate-flexible emissions model for the general representation of the pollen phenology over the United States.

Comparison of Poaceae pollen counts recorded at sites in Portugal, Spain and the UK

The main aim of this study was to analyse the temporal and spatial variations in grass (Poaceae) pollen counts (2005–2011) recorded in Evora (Portugal), Badajoz (Spain) and Worcester (UK). Weekly average data were examined using nonparametric statistics to compare differences between places. On average, Evora recorded the earliest start dates of the Poaceae pollen seasons and Worcester the latest. The intensity of the Poaceae pollen season varied between sites, with Worcester usually recording the least and Evora the most grass pollen in a season. Mean durations of grass pollen seasons were 77 days in Evora, 78 days in Badajoz and 59 days in Worcester. Overall, longer Poaceae pollen seasons coincided with earlier pollen season start dates. Weekly pollen data, from March to September, from the three pollen-monitoring stations studied were compared. The best fit and most statistically significant correlations were obtained by moving Worcester data backward by 4 weeks (Evora, r = 0.810, p < 0.001) and 5 weeks (Badajoz,r = 0.849, p < 0.001). Weekly data from Worcester therefore followed a similar pattern to that of Badajoz and Evora but at a distance of more than 1,500 km and 4–5 weeks later. The sum of pollen recorded in a season was compared with monthly rainfall between January and May. The strongest positive relationship between season intensity and rainfall was between the annual sum of Poaceae pollen recorded in the season at Badajoz and Evora and total rainfall during January and February. Winter rainfall noticeably affects the intensity of Poaceae pollen seasons in Mediterranean areas, but this was not as important in Worcester.

Predicting tree pollen season start dates using thermal conditions.

Thermal conditions at the beginning of the year determine the timing of pollen seasons of early flowering trees. The aims of this study were to quantify the relationship between the tree pollen season start dates and the thermal conditions just before the beginning of the season and to construct models predicting the start of the pollen season in a given year. The study was performed in Krakow (Southern Poland); the pollen data of Alnus, Corylus and Betula were obtained in 1991–2012 using a volumetric method. The relationship between the tree pollen season start, calculated by the cumulated pollen grain sum method, and a 5-day running means of maximum (for Alnus and Corylus) and mean (for Betula) daily temperature was found and used in the logistic regression models. The estimation of model parameters indicated their statistically significance for all studied taxa; the odds ratio was higher in models for Betula, comparing to Alnus and Corylus. The proposed model makes the accuracy of prediction in 83.58 % of cases for Alnus, in 84.29 % of cases for Corylus and in 90.41 % of cases for Betula. In years of model verification (2011 and 2012), the season start of Alnus and Corylus was predicted more precisely in 2011, while in case of Betula, the model predictions achieved 100 % of accuracy in both years. The correctness of prediction indicated that the data used for the model arrangement fitted the models well and stressed the high efficacy of model prediction estimated using the pollen data in 1991–2010.

Variations in Quercus sp. pollen seasons (1996-2011) in Poznań, Poland, in relation to meteorological parameters.

The aim of this study is to supply detailed information about oak (Quercus sp.) pollen seasons in Poznań, Poland, based on a 16-year aerobiological data series (1996–2011). The pollen data were collected using a volumetric spore trap of the Hirst design located in Poznań city center. The limits of the pollen seasons were calculated using the 95 % method. The influence of meteorological parameters on temporal variations in airborne pollen was examined using correlation analysis. Start and end dates of oak pollen seasons in Poznań varied markedly from year-to-year (14 and 17 days, respectively). Most of the pollen grains (around 75 % of the seasonal pollen index) were recorded within the first 2 weeks of the pollen season. The tenfold variation was observed between the least and the most intensive pollen seasons. These fluctuations were significantly related to the variation in the sum of rain during the period second fortnight of March to first fortnight of April the year before pollination (r = 0.799; p < 0.001). During the analyzing period, a significant advance in oak pollen season start dates was observed (−0.55 day/year; p = 0.021), which was linked with an increase in the mean temperature during the second half of March and first half of April (+0.2 °C; p = 0.014). Daily average oak pollen counts correlated positively with mean and maximum daily temperatures, and negatively with daily rainfall and daily mean relative humidity.

The effect of the meteorological factors on the Alnus pollen season in Lublin (Poland)

Alder pollen seasons and the effect of meteorological conditions on daily average pollen counts in the air of Lublin (Poland) were analysed. Alnus pollen grains reach very high concentrations in the atmosphere of this city during the early spring period and the parameters of pollen seasons were very different in the particular years studied. The pollen season lasted on average one month. The highest variation was observed for the peak value and the Seasonal Pollen Index (SPI). The pollen seasons, which started later, had shorter duration. Peak daily average pollen counts and SPI value were higher during the shorter seasons. Similarities in the stages of pollen seasons designated by the percentage method depended on the start date of the pollen season. Season parameters were mainly correlated with thermal conditions at the beginning of the year. Regression analysis was used to predict certain characteristics of the alder pollen season. The highest level of explanation of the variation in Alnus pollen season start and peak dates was obtained in the model using mean temperature in February. The obtained regression models may predict 82% of the variation in the pollen season start date, 73% of the variation in the duration, and 62% in the peak date.

Shifting Trends of Ragweed (Ambrosia) Measurements During a 22 Year Period in Northern and Southern New Jersey (NJ)

Ragweed is a clinically significant aeroallergen. Total pollen production (TPD), pollen season start dates (PSSD), peak dates (PPD), season duration (PSD), count annual mean (PCAM), and peak values (PPV) for Ragweed changed over a 22 year period.

Analysis of Alnus spp. pollen seasons in Lublin and Warszawa (Poland), 2001-2007

The course of &lt;i&gt;Alnus&lt;/i&gt; spp. pollen seasons was compared in two cities, Lublin and Warsaw, located at a small distance from each other but included in different climatic regions of Poland. The studies were conducted using the volumetric method. It was shown that &lt;i&gt;Alnus&lt;/i&gt; pollen seasons started in Warsaw earlier and were much shorter than in Lublin. The span between the start dates of pollen seasons was similar and it was 53-54 days. Peak days occurred in both cities most often in the second decade of March, but in Warsaw they were recorded several days earlier. Maximum concentrations reached higher values in Lublin, whereas annual totals were higher in Warsaw. The number of days with the concentration &gt; 50 pollen grains × m&lt;sup&gt;-3&lt;/sup&gt; per 24 hours was 5-27 days for Warsaw and 10-19 days for Lublin over 7 years of study.

Platanus pollen season in Andalusia (southern Spain): trends and modeling

Platanus is a major cause of pollen allergy in many Spanish cities. The present paper reports an analysis of Platanus pollen season throughout the Andalusia region (southern Spain), which has among the highest pollen counts and the highest incidence of Platanus-related allergies in Europe. The main aim was to analyze pollen season trends from 1992 to 2010 in Andalusia; models were also constructed to forecast the start of the season. Daily pollen counts were recorded using Hirst-type volumetric spore-traps. Pollen season start-dates were very similar at all sites, usually occurring in March. The pollen season was delayed over the study period. The Pollen-season duration and Pollen index generally increased throughout the study period. The starting date for temperature accumulation was around the 10th February, although the threshold temperatures varied by site. The regional model for Andalusia failed to provide sufficiently accurate results compared with sub-regional or local models. For modeling purposes, three sub-regions are recommended: Inland, East Coast and West Coast.