Burkard Sampler Research Articles

Behavior of Autumn Airborne Ragweed Pollen and Its Size-Segregated Allergens (Amb a 1): A study in Urban Saitama, Japan

The prevalence of ragweed (Ambrosia artemisiifolia) pollinosis has been increasing worldwide. This study focused on the behavior of autumn airborne pollen and the major ragweed allergen -Amb a 1 particle in urban Saitama, Japan, in 2016. Burkard sampler results showed that the airborne ragweed pollen scattering season was from September 1st to October 9th. Over 83% of sampling events had pollen counts of over 13 grains/m3, indicating the high potential health risks of ragweed pollen in the atmosphere. The results of a surface plasmon resonance immunoassay (SPR) indicated that the average Amb a 1 count was about 16.5 pg /pollen. The airborne Amb a 1 concentration was up to 4.7 ng/m3, of which about 45% was accumulated in ultrafine particles, such as particulate matter with a diameter ≤1.1 µm (PM1.1). Although ragweed pollen was hardly observed during the October 14th–17th sampling campaign, the concentration of ambient Amb a 1 particles in PM1.1 was also determined to be 4.59 ng/m3, which could be explained by the longer scattering of fine particles in the atmosphere. Pearson correlation coefficient analysis results showed that temperature (daily, r = 0.41; event, r = 0.87) could affect the behavior of the airborne pollen counts, and ambient water-soluble ions (such as Ca2+ and NO3−) could affect Amb a 1 in PM1.1. Additionally, air mass trajectories and wind rose results indicated that air masses with long-range transportation could also influence the temporary behavior of Amb a 1 and pollen counts via the wind. Mugwort and Humulus japonicus pollens were also observed to extend pollen scattering periods. Airborne pollen and allergenic particles could be considered air pollutants, as they pose health risks and are susceptible to environmental influences.

Mitigation of indoor parthenium weed pollen exposure by protective window screens evaluated in chamber study

Pollen from Parthenium weed is a well-known aeroallergen. Infestation of Parthenium weed is found in many countries including Taiwan, especially in central and southern regions. Most houses in Taiwan are equipped with window screens to keep flies and mosquitoes away. Natural ventilation would allow pollens to infiltrate indoors. Hence, preventing pollen infiltration would be a strategy for allergic disease control.A full-scale exposure chamber comprising a main (outdoor) cabin and an auxiliary (indoor) cabin connected by six types of window screen was used in the test. In both cabins, two Burkard samplers continuously collected pollens emitted from Parthenium hysterophorus weed. The filtration efficacy of different window screens under three wind velocities were assessed by counting the number of pollens in both cabins using an optical microscope. Light transmittance was evaluated by picturing the parthenium plant behind the different screen materials. Natural ventilation performance in the two cabins was evaluated using a vane anemometer.Protective window screen D made of long-lasting electrostatic fiber with high pollen filtration efficacy, adequate ventilation, and clear visibility is recommended for naturally ventilated residential buildings, especially for allergic individuals.

Environmental DNA reveals diversity and abundance of Alternaria species in neighbouring heterogeneous landscapes in Worcester, UK

Alternaria is a pathogenic and allergenic fungus affecting 400 plant species and 334 million people globally. This study aimed at assessing the diversity of Alternaria species in airborne samples collected from closely located (7 km apart) and heterogeneous sites (rural, urban and unmanaged grassland) in Worcester and Lakeside, the UK. A secondary objective was to examine how the ITS1 subregion varies from ITS2 in Alternaria species diversity and composition. Airborne spores were collected using Burkard 7-day and multi-vial Cyclone samplers for the period 5 July 2016–9 October 2019. Air samples from the Cyclone were amplified using the ITS1and ITS2 subregions and sequenced using Illumina MiSeq platform whereas those from the Burkard sampler were identified and quantified using optical microscopy. Optical microscopy and eDNA revealed a high abundance of Alternaria in the rural, urban and unmanaged sites. ITS1 and ITS2 detected five and seven different Alternaria species at the three sampling sites, respectively. A. dactylidicola, A. metachromatica and A. infectoria were the most abundant. The rural, urban and unmanaged grassland sites had similar diversity (PERMANOVA) of the species due to similarity in land use and proximity of the sites. Overall, the study showed that heterogeneous and neighbouring sites with similar land uses can have similar Alternaria species. It also demonstrated that an eDNA approach can complement the classical optical microscopy method in providing more precise information on fungal species diversity in an environment for targeted management. Similar studies can be replicated for other allergenic and pathogenic fungi.

Association between local airborne tree pollen composition and surrounding land cover across different spatial scales in Northern Belgium

Airborne pollen are important aeroallergens affecting human health. Local airborne pollen compositions can pose health-risks for the sensitized population, but at present little is known about fine-scale pollen composition patterns.The overall objective of this study is to determine local variations in tree pollen composition with passive samplers and to identify the surrounding landscape characteristics that drive them. In February–May 2017, during the tree pollen season, airborne tree pollen were measured by passive sampling at 2 m height above ground-level in 14 sites in the Flanders and Brussels-Capital region (Belgium). Non-metric multidimensional scaling was used to investigate environmental gradients that determine the pollen composition and amounts. Land cover types were identified across spatial scales ranging between 20 m and 5 km.The passive samplers detected the same pollen taxa during the same time windows as the validated volumetric Burkard samplers. Using passive samplers, we were able to measure local airborne pollen compositions. Corylus and Platanus pollen were associated to urban areas; Populus, Juglans and Fraxinus pollen to agricultural areas; forests and wetlands were sources of Alnus and Quercus pollen. Salix, Populus and Betula pollen were also mainly associated to wetlands. The landscape context drives the airborne tree pollen composition at a meso-scale (1−5 km) rather than at finer scale (20−500 m). Thus, land cover types (e.g. forest, bush land, agricultural lands and wetlands) surrounding urban areas may increase exposure to allergenic pollen in the urban area, potentially affecting the health of a large proportion of the population.

Visual Machine Learning and Artificial Intelligence Application in Aeroallergen Identification During Spring, Summer, and Fall Pollen Season

Continued validation of automated pollen identification (API) is needed. We performed a side-by-side device comparison of pollen counts identified using a Burkard sampler (BS) and an Automate Pollen Sampler (APS) by Pollen SenseTM. The designated gold standard device for comparison, the BS, was co-located with the APS in Waterloo, Iowa. Pollen collection, processing, and identification were performed following NAB requirements. The APS was provided by Pollen SenseTM. The APS collects particulate matter volumetrically from ambient air, automatically images the particulates, and uses a convolutional neural network to identify the individual pollen species. For this first iteration, 57 days were compared in the fall 2019 and spring-summer 2020. The top 10 pollen reported to the NAB in the upper Midwest were chosen for reporting. Accuracy is determined as the number of days a species was identified as present or absent in the APS that matches the Burkard, divided by the number of counting days x 100. Accuracy: ragweed 96, mulberry 50, juniper 8, oak 46, nettle 0, grass 65, ash 58, elm 8, pine 65, birch 23. Current accuracy of APS needs continued improvement. Varying correctness in pollen species identification rely on several factors including whether the APS was trained for that pollen species, morphology complexity, and amount of debris in the background. Identification and enumeration using visual machine learning methods in artificial intelligence is a process that improves automatically through experience. It requires multiple iterations of repetitive learning to achieve desired accuracy.

Optical characterization of pure pollen types using a multi-wavelength Raman polarization lidar

Abstract. We present a novel algorithm for characterizing the optical properties of pure pollen particles, based on the depolarization ratio values obtained in lidar measurements. The algorithm was first tested and validated through a simulator and then applied to the lidar observations during a 4-month pollen campaign from May to August 2016 at the European Aerosol Research Lidar Network (EARLINET) station in Kuopio (62∘44′ N, 27∘33′ E), in Eastern Finland. With a Burkard sampler, 20 types of pollen were observed and identified from concurrent measurements, with birch (Betula), pine (Pinus), spruce (Picea), and nettle (Urtica) pollen being the most abundant, contributing more than 90 % of the total pollen load, regarding number concentrations. Mean values of lidar-derived optical properties in the pollen layer were retrieved for four intense pollination periods (IPPs). Lidar ratios at both 355 and 532 nm ranged from 55 to 70 sr for all pollen types, without significant wavelength dependence. An enhanced depolarization ratio was found when there were pollen grains in the atmosphere, and an even higher depolarization ratio (with mean values of 0.25 or 0.14) was observed with the presence of the more non-spherical spruce or pine pollen. Under the assumption that the backscatter-related Ångström exponent between 355 and 532 nm should be zero for pure pollen, the depolarization ratio of pure pollen particles at 532 nm was assessed, resulting in 0.24±0.01 and 0.36±0.01 for birch and pine pollen, respectively. Pollen optical properties at 1064 and 355 nm were also estimated. The backscatter-related Ångström exponent between 532 and 1064 nm was assessed to be ∼0.8 (∼0.5) for pure birch (pine) pollen; thus the longer wavelength would be a better choice to trace pollen in the air. Pollen depolarization ratios of 0.17 and 0.30 at 355 nm were found for birch and pine pollen, respectively. The depolarization values show a wavelength dependence for pollen. This can be the key parameter for pollen detection and characterization.

Detection of Airborne Sporangia of Pseudoperonospora cubensis and P. humuli in Michigan Using Burkard Spore Traps Coupled to Quantitative PCR.

Cucurbit downy mildew (CDM), caused by the oomycete pathogen Pseudoperonospora cubensis, is a devastating foliar disease on cucumber resulting in reduced yields. In 2004, the pathogen re-emerged in the United States, infecting historically resistant cucumber cultivars and requiring the adoption of an intensive fungicide program. The pathogen cannot overwinter in Michigan fields but because of an influx of airborne sporangia CDM occurs annually. In Michigan, spore traps are used to monitor the presence of airborne P. cubensis sporangia in cucumber growing regions to guide the initiation of a fungicide program. However, Pseudoperonospora humuli sporangia, the causal agent of downy mildew on hop, are morphologically indistinguishable from P. cubensis sporangia. This morphological similarity reduces the ability to accurately detect P. cubensis from spore trap samples when examined with the aid of light microscopy. To improve P. cubensis detection, we adapted a qPCR-based assay to allow the differentiation between P. cubensis and P. humuli on Burkard spore trap samples collected in the field. Specifically, we evaluated the specificity and sensitivity of P. cubensis detection on Burkard spore trap tapes using a morphological-based and quantitative-PCR (qPCR)-based identification assay and determined whether sporangia of P. cubensis and P. humuli on Burkard samples could be distinguished using qPCR. We found that the qPCR assay was able to detect a single sporangium of each species on spore trap samples collected in the field with Cq values <35.5. The qPCR assay also allowed the detection of P. cubensis and P. humuli in samples containing sporangia from both species. However, the number of sporangia quantified using light microscopy explained only 54 and 10% of the variation in the Cq values of P. cubensis and P. humuli, respectively, suggesting a limited capacity of the qPCR assay for the absolute quantification of sporangia in field samples. After 2 years of monitoring using Burkard spore traps coupled with the qPCR in cucumber fields, P. humuli sporangia were detected more frequently than P. cubensis early in the growing season (May and June). P. cubensis sporangia were detected ∼5 to 10 days before CDM symptoms were first observed in cucumber fields during both years. This research describes an improved sporangial detection system that is key for the monitoring and management of P. cubensis in Michigan.

Allergenic fungal spores in the air of urban parks

Urban green spaces, especially urban parks, are essential for the proper functioning of cities, but they can be a serious source of airborne fungal spores. Aerobiological monitoring was carried out in urban parks of different typology to estimate the risk associated with fungal spores for citizens. Volumetric method was applied with the use of portable Burkard Sampler. In the air of the studied parks, the most dominant spores are strong allergenic or considered as potentially allergenic. Cladosporium spores were found in enormous concentrations in all studied parks, and it affected the low biodiversity of fungal spores in the parks. Compared to Cladosporium, concentrations of Alternaria spores in the air were several dozen times lower, but still a risk for people who are allergic. The fungal spores spectra and their seasonal occurrence in each park were similar. The highest similarities in the patterns of the season were found in the case of Cladosporium, Alternaria, Epicoccum, and the lowest in the case of Torula and Drechslera type. Due to the fact that allergy sufferers are most often polysensitized, the period when they should limit long visits in the urban parks is July–August, when the concentration of allergenic fungal spores of many taxa is the highest.

Atmospheric pollutants and their association with olive and grass aeroallergen concentrations in C\xf3rdoba (Spain)

Cumulative data indicate that pollen grains and air pollution reciprocally interact. Climate changes seem also to influence pollen allergenicity. Depending on the plant species and on the pollutant type and concentration, this interaction may modify the features and metabolism of the pollen grain. Previous results revealed a significant positive correlation between pollen and aeroallergen, even using two different samplers. However, some discrepancy days have been also detected with low pollen but high aeroallergen concentrations. The main aim of the present paper is to find how the environmental factors, and specially pollutants, could affect the amount of allergens from olive and grass airborne pollen. Pollen grains were collected by a Hirst-type volumetric spore trap. Aeroallergen was simultaneously sampled by a low-volume Cyclone Burkard sampler. Phl p 5 and Ole e 1 aeroallergen were quantified by double-sandwich ELISA test. The data related to air pollutants, pollen grains, and aeroallergens were analyzed with descriptive statistic. Spearman’s correlation test was used to identify potential correlations between these variables. There is a significant positive correlation between aeroallergens and airborne pollen concentrations, in both studied pollen types, so allergen concentrations could be explained with the pollen concentration. The days with unlinked events coincide between olive and grass allergens. Nevertheless, concerning to our results, pollutants do not affect the amount of allergens per pollen. Even if diverse pollutants show an unclear relationship with the allergen concentration, this association seems to be a casual effect of the leading role of some meteorological parameters.

Fungal contaminants of indoor air in the National Library of Greece

The presence of fungal particulate matter in libraries air is a key issue due to its dual impact on the valuable artifacts and on humans. Indoor air fungal composition has been investigated with a volumetric culture-based method only once before in a National Library. The qualitative and quantitative spatiotemporal fluctuations of airborne fungi were evaluated in the National Library of Greece. A portable Burkard sampler was used for the collection of air samples onto Petri dishes with MA2%. Totally, 33 genera of fungi were recovered and identified, with Cladosporium, Penicillium and Aspergillus dominant in indoor air. The genus Aspergillus, in particular, was studied by morphological and molecular analysis, and the prevalent species were assigned to the sections Nidulantes, Nigri and Circumdati. The concentration range of fungal aerosol was 0–2368 CFU/m3 in the first study period and 0–3183 CFU/m3 in the second study period indoors and 51–1997 CFU/m3 outdoors. The mean concentration in indoor air, depending on the site, ranged from 180 to 410 CFU/m3 in the first period and 210–405 CFU/m3 in the second versus 678 CFU/m3 and 516 CFU/m3, respectively, outdoors. The indoor/outdoor concentration ratio (I/O) was 0.5 for total fungi, 0.3 for Cladosporium, 1.1 for Penicillium and 1.4 for Aspergillus. The higher spore concentration and diversity of the genera Penicillium and Aspergillus indoors and the occurrence of less common genera suggest the existence of internal emission sources. The characterization of the fungal community dynamic patterns is an important tool for implementing targeted preventive measures for human safety and conservation of the valuable documentary heritage.

Impact of a green roof system on indoor fungal aerosol in a primary school in Greece

A primary school was investigated for airborne fungi by a culture-based method, in classrooms underneath a green roof in comparison to conventional concrete roofs. A portable Burkard sampler was used for the collection of air samples onto petri dishes with 2% Malt Extract Agar. The fungal aerosol mean concentration was 71 CFU m−3 (range 17–176 CFU m−3, median 51) in the classroom directly under the green roof, significantly lower than 192–228 CFU m−3 (range 0–1090 CFU m−3, median 69) under the concrete roofs and 188–412 CFU m−3 (range 0–2183 CFU m−3, median 771) in ground floor classrooms. The Indoor/Outdoor ratio was 0.4 for total fungi and 0.2–1.1 for predominant genera underneath the green roof, whereas 1–2.1 and 0.3–3.2 respectively for the rest of classrooms. The Potential Exposure Dose (PED) for fungal particles was calculated to 4.6 CFU kg−1 and 9.3–35.3 CFU kg−1 respectively. The genera Penicillium, Cladosporium and Aspergillus prevailed indoors and in ambient air. Aspergillus concentrations indoors correlated significantly with the concentration of the coarse fraction (PM10) of particulate matter. The genus Penicillium increased indoors during late spring and summer, in temperature 20–23 °C and relative humidity 42–53% and also predominated in ambient air, both indicative of multiple anthropogenic sources of amplification. The evidence about the green roof positive effect on microbial indoor air quality (mIAQ) is a matter of concern for further investigation.

Identification of airborne pollen allergens from two avenue trees of India

ABSTRACTAn attempt has been made to detect airborne pollen of Lagerstroemia speciosa (LS) and Spathodea campanulata (SC) – two common avenue trees of India as potential sources of aeroallergens and also to identify the major IgE-reactive components present in them. The airborne pollen concentration was assessed using a Burkard sampler. A detailed questionnaire on clinical data of 1490 patients was recorded based on hospital data. We assessed the allergenicity of pollen by in vivo and in vitro tests. The correlation among meteorological factors, pollen seasons and allergenic potency of patients was assessed by multiple regression analysis. The sensitivity of patients to pollen antigens was highly correlated with pollen seasons. In SDS–PAGE, 15 protein bands were detected from LS pollen, while 14 bands from SC. The IgE-specific immunoblotting with patients’ sera allergic to LS displayed five major allergens, while four major allergens were detected from SC. This would be the first report from India to prove the allergenic potentiality of airborne pollen of these two common avenue trees of India.

Increasing Juniperus virginiana L. pollen in the Tulsa atmosphere: long-term trends, variability, and influence of meteorological conditions.

In the Tulsa area, the Cupressaceae is largely represented by eastern red cedar (Juniperus virginiana L.). The encroachment of this species into the grasslands of Oklahoma has been well documented, and it is believed this trend will continue. The pollen is known to be allergenic and is a major component of the Tulsa atmosphere in February and March. This study examined airborne Cupressaceae pollen data from 1987 to 2016 to determine long-term trends, pollen seasonal variability, and influence of meteorological variables on airborne pollen concentrations. Pollen was collected through means of a Burkard sampler and analyzed with microscopy. Daily pollen concentrations and yearly pollen metrics showed a high degree of variability. In addition, there were significant increases over time in the seasonal pollen index and in peak concentrations. These increases parallel the increasing population of J. virginiana in the region. Pollen data were split into pre- and post-peak categories for statistical analyses, which revealed significant differences in correlations of the two datasets when analyzed with meteorological conditions. While temperature and dew point, among others were significant in both datasets, other factors, like relative humidity, were significant only in one dataset. Analyses using wind direction showed that southerly and southwestern winds contributed to increased pollen concentrations. This study confirms that J. virginiana pollen has become an increasing risk for individuals sensitive to this pollen and emphasizes the need for long-term aerobiological monitoring in other areas.

Rapid Quantification of Juniperus Pollen Proves Overlapping Pollen Seasons

Rashmi Prava Mohanty, Mark A. Buchheim, PhD, Estelle Levetin, PhD, FAAAAI; University of Tulsa, Tulsa, OK, University of Tulsa. RATIONALE: Microscopic analysis of air samples fails to determine the pollination season overlap between various species with morphologically similar pollen such as members of the Cupressaceae and Poaceae. Previously, we showed it was possible to use PCR to identify Juniperus ashei pollen from air samples. The present study was undertaken to determine if qPCR could be used to determine airborne pollen counts for three Juniperus species and define the pollination season overlap. METHODS: The atmosphere in Tulsa, OK(USA) was monitored with a Burkard sampler and analyzed by microscopy using standard methods. A second Burkard sampler was used from 2013 to 2015 for molecular analysis; 109 samples were tested with species-specific primers and probes designed for J.ashei, J.pinchotii and J.virginiana. Numbers of pollen grains obtained from microscopy were compared with numbers obtained from qPCR by Spearman correlation coefficient. RESULTS: Cupressaceae pollen was detected in the Tulsa atmosphere from October through April. The qPCR counts for total Juniperus pollen showed a significant correlation with the microscope counts, R50.92, p<0.001. Quantitative PCR data showed overlapping pollen seasons. In the fall, data indicated five days (in two years) with both J.pinchotii and J.ashei pollen. Similarly, in January and February eight days (in two years) indicated both J.ashei and J.virginiana pollen in the air. CONCLUSIONS: This approach is a rapidmethod to identify and quantify specific pollen types and the pollen season overlap where species and genera cannot be distinguished by microscopy. Defining the exact pollination season will be a benefit for patients sensitive to pollen from specific taxa.

Aerobiology of Yeasts: Viable Colonies and Molecular Identification from Burkard Samples

Aerobiology of Yeasts: Viable Colonies and Molecular Identification from Burkard Samples

Certified Pollen and Mold Counter

Pollen and mold counters use many types of air samplers to collect pollen grains and mold spores that are then counted using a microscope [2]. I prefer the Burkard 7 day recording volumetric spore trap. Advantages of using the Burkard include: high efficiency, greater accuracy for small fungal spores and it permits analysis for diurnal rhythms and permanent slides for future reference. The Burkard should be placed 3 to 6 stories above ground away from overhanging vegetation and unobstructed air flow from nearby buildings or structural features. The Burkard sampler head moves by orifice at 2mm per hour and air is brought in at 10 l/min. Cornstarch, skin cells, exhaust particles, and ink are among the many debris captured on a slide in addition to pollen and mold. When the wind is strong, performing the count can be time consuming. Sometimes it’s like trying to find a needle in a haystack. When preparing a slide for collection in a Burkard you’ll need lubriseal or high vacuum grease to spread a thin layer as smoothly as possible on to the slide. On a Burkard, use the formula below when calculating a single longitudinal traverse sweep along the slide.

Biomonitoring of pollen grains of a river bank suburban city, Konnagar, Calcutta, India, and its link and impact on local people.

Pollen grains released by plants are dispersed into the air and can become trapped in human nasal mucosa, causing immediate release of allergens triggering severe Type 1 hypersensitivity reactions in susceptible allergic patients. Recent epidemiologic data show that 11-12% of people suffer from this type of disorders in India. Hence, it is important to examine whether pollen grains have a role in dissipating respiratory problems, including allergy and astma, in a subtropical suburban city. Meteorological data were collected for a period of two years, together with aerobiological sampling with a Burkard sampler. A pollen calendar was prepared for the city. A health survey and the hospitalization rate of local people for the above problems were documented following statistical analysis between pollen counts and the data from the two above-mentioned sources. Skin Prick Test and Indirect ELISA were performer for the identification of allergenic pollen grains. Bio-monitoring results showed that a total of 36 species of pollen grains were located in the air of the study area, where their presence is controlled by many important meteorological parameters proved from SPSS statistical analysis and by their blooming periods. Statistical analysis showed that there is a high positive correlation of monthly pollen counts with the data from the survey and hospital. Biochemical tests revealed the allergic nature of pollen grains of many local species found in the sampler. Bio-monitoring, together with statistical and biochemical results, leave no doubt about the role of pollen as a bio-pollutant. General knowledge about pollen allergy and specific allergenic pollen grains of a particular locality could be a good step towards better health for the cosmopolitan suburban city.

Detection of Airborne Juniperus Pollen By Conventional and Real-Time PCR from Burkard Air Samples

M O N D A Y 746 Detection of Airborne Juniperus Pollen By Conventional and Real-Time PCR from Burkard Air Samples Rashmi Prava Mohanty, MS, Mark A. Buchheim, PhD, James Anderson, Estelle Levetin, PhD, FAAAAI; University of Tulsa, Tulsa, OK, University of Tulsa, oshtech inc. RATIONALE: Microscopic detection of pollen requires considerable expertise, and identification is limited to genus or family level. Cupressaceae pollen is detected in the Tulsa atmosphere for seven months each year; however, local members of this family only pollinate from February throughApril. Here, we developedmolecularmethods to identify multiple Juniperus species from air samples. METHODS: Air samples from January to March were collected with a Burkard 7-day sampler located in Tulsa, OK. One-day segments of exposed Melenex tape were cut into smaller pieces and DNA extracted. Species-specificmatK primers for J.ashei and J.virginianawere developed for conventional PCR and leafy primers/probe pairs were developed for real-time PCR for Juniperus. An air sample collected on 15 January in London, Ontario(CANADA) using a Buck Bioslide sampler was also analyzed. RESULTS: Serial dilution of J.asheii pollen demonstrated that specific matK primers were able to detect the presence of 2 to 3 pollen grains indicating this method would be useful for Burkard samples. Using matK primers, J.ashei pollen was confirmed from air samples collected in Tulsa in January as well as from Canada. Primers for matK in J.virginiana confirmed the presence of that pollen in Tulsa air sampled in February and March. Primer/probe pairs for leafy were successful in real-time PCR and can be used to quantify Juniperus pollen from Burkard samples. CONCLUSIONS: This study provides an effective alternative to microscopy for identification of pollen from Burkard air samplers and Bioslide samplers. These data also confirm the long distance transport of J.ashei pollen up to 2400 km.

Evaluation of Air Sampling and Detection Methods to Quantify Airborne Ascospores of Sclerotinia sclerotiorum.

Detection and quantification of airborne ascospores as a component of the Sclerotinia rot of carrot (SRC) forecast model is currently accomplished using the blue plate test (BPT), which uses Sclerotinia semiselective medium (SSM). A quantitative polymerase chain reaction (qPCR) assay was developed to reduce the time to specifically quantify ascospores of Sclerotinia sclerotiorum from air samples collected using a Burkard Multi-Vial Cyclone Sampler. The qPCR assay was highly sensitive and detected DNA from 0.5 to 5 × 104 ascospores within a linear range (R2 = 0.99). The qPCR assay was used to quantify ascospores of S. sclerotiorum in air samples collected over three growing seasons. Initial SRC disease was observed 8 and 34 days following detection of 9.5 and 2 ascospores m-3 of air, respectively. Results from air samples collected using an Andersen N6 Sampler and the qPCR assay were compared with the BPT. Ascospore counts from a Burkard Sampler coupled with the qPCR assay and the BPT followed similar trends. In general, fewer ascospores were detected and bioaerosol sampling efficiency was low using an Anderson Sampler. Three days were required to confirm the number of ascospores using SSM in the BPT and with an Andersen Sampler, whereas results from a Burkard Sampler coupled with the qPCR assay can provide results within 5 h of air sampling. The choice of method will depend on the available resources.

Climate Variability and Pollen: More Hay Fever or Less?

RationaleAlthough studies have documented the effects of global warming on the pollen season, the influence of extreme weather and year to year climate variability must not be overlooked. This study examined the effects of the extreme heat and drought in Oklahoma during the summer of 2011 as well as the unusually warm winter of 2011-12 on airborne pollen levels.MethodsThe atmosphere has been monitored with Burkard samplers in Tulsa, Oklahoma since December 1986. Standard methods were used to collect, process, and analyze Burkard samples. Sampling data were log transformed prior to statistical analysis.ResultsIn Oklahoma, the summer of 2011 was the hottest on record, and the 2011-12 winter temperatures were the third warmest. The hot summer resulted in lower ragweed levels in fall. The cumulative seasonal ragweed pollen total for 2011 was 8106 compared to the 24 year average of 12364. The mean daily concentration for the 2011 season (103 pollen/m3) was significantly lower (t(77) = 7.306, p<0.0001) than the collective mean for the previous 24 years (159 pollen/m3). By contrast, the warm winter resulted in an earlier pollen season for many spring pollinating trees. Season start date for various trees was up to 20 days earlier than the 24 year average. Season end was also early for several pollen types; therefore, season length did not differ for most taxa.ConclusionsAlthough global warming may alter the phenology and distribution of plants, climate extremes may have more abrupt and dramatic effects of pollen levels. All of which can affect sensitive individuals. RationaleAlthough studies have documented the effects of global warming on the pollen season, the influence of extreme weather and year to year climate variability must not be overlooked. This study examined the effects of the extreme heat and drought in Oklahoma during the summer of 2011 as well as the unusually warm winter of 2011-12 on airborne pollen levels. Although studies have documented the effects of global warming on the pollen season, the influence of extreme weather and year to year climate variability must not be overlooked. This study examined the effects of the extreme heat and drought in Oklahoma during the summer of 2011 as well as the unusually warm winter of 2011-12 on airborne pollen levels. MethodsThe atmosphere has been monitored with Burkard samplers in Tulsa, Oklahoma since December 1986. Standard methods were used to collect, process, and analyze Burkard samples. Sampling data were log transformed prior to statistical analysis. The atmosphere has been monitored with Burkard samplers in Tulsa, Oklahoma since December 1986. Standard methods were used to collect, process, and analyze Burkard samples. Sampling data were log transformed prior to statistical analysis. ResultsIn Oklahoma, the summer of 2011 was the hottest on record, and the 2011-12 winter temperatures were the third warmest. The hot summer resulted in lower ragweed levels in fall. The cumulative seasonal ragweed pollen total for 2011 was 8106 compared to the 24 year average of 12364. The mean daily concentration for the 2011 season (103 pollen/m3) was significantly lower (t(77) = 7.306, p<0.0001) than the collective mean for the previous 24 years (159 pollen/m3). By contrast, the warm winter resulted in an earlier pollen season for many spring pollinating trees. Season start date for various trees was up to 20 days earlier than the 24 year average. Season end was also early for several pollen types; therefore, season length did not differ for most taxa. In Oklahoma, the summer of 2011 was the hottest on record, and the 2011-12 winter temperatures were the third warmest. The hot summer resulted in lower ragweed levels in fall. The cumulative seasonal ragweed pollen total for 2011 was 8106 compared to the 24 year average of 12364. The mean daily concentration for the 2011 season (103 pollen/m3) was significantly lower (t(77) = 7.306, p<0.0001) than the collective mean for the previous 24 years (159 pollen/m3). By contrast, the warm winter resulted in an earlier pollen season for many spring pollinating trees. Season start date for various trees was up to 20 days earlier than the 24 year average. Season end was also early for several pollen types; therefore, season length did not differ for most taxa. ConclusionsAlthough global warming may alter the phenology and distribution of plants, climate extremes may have more abrupt and dramatic effects of pollen levels. All of which can affect sensitive individuals. Although global warming may alter the phenology and distribution of plants, climate extremes may have more abrupt and dramatic effects of pollen levels. All of which can affect sensitive individuals.