Pollen Particles Research Articles

Morphological Changes in Allergenic Pollen as a Bioindicator

Since the anther opens and the pollen grains travel in the atmosphere, they can come into contact with solid and gaseous particles, and the exine can become contaminated with various adherent particles. Pollen and solid particles are among the most common triggers of bronchial asthma. Increased allergenicity of pollen grains will be determined by chemical reactions between pollutants and pollen, as well as non-specific modulation of the mechanisms of synthesis of many proteins, lipids and enzymes in response to environmental stress due to urbanization and climate change. This situation seriously complicates the identification of pollen to a taxon during traditional monitoring and further complicates the calculation and interpretation of the results obtained during research and automatic determination. To classify tetramorphic pollen from aerobiological samples and explain the mechanism of the identified changes. Determination of mutagenic contamination and a method for integral assessment of pollen viability and damage under a light microscope. Pollen from aerobiological samples was examined under a scanning electron microscope (Hitachi): a high-power imaging technique that uses electron beams to create detailed images of the ultrastructure of pollen grains. Unidentified, tetramorphic pollen from aerobiological samples from sites with varying degrees of contamination can be conditionally classified into 4 types: 1) shapeless lumps of sporopollenin with various outgrowths, cracks and cavities that arose during pollen ontogenesis; 2) atypical ornamentation of sculpture, such as large tubercles - swellings with a smooth surface; 3) atypical form, but with partially preserved sculpture, where in places species-specific features can be identified and pollen can be identified to a taxon; 4) conglomerates. The study of the vitality (viability) and damage of the cocksfoot pollen under a light microscope from observation points with different anthropogenic loads showed the dependence of these indicators on the level of pollutants: with their increase, viability decreases, although it remains quite high. The data obtained are important for assessing allergenic pollen as a bioindicator of environmental changes. An integrated assessment of the enzymatic activity of pollen and the degree of its damage can be used for the purposes of bioecological monitoring.

Measuring the Adsorption Cross Section of YOYO-1 to Immobilized DNA Molecules.

Many interactions between small molecules and particles occur in solutions. They are surrounded by other molecules that do not react, for example, biological processes in water, chemical reactions in gas or liquid solutions, and environmental reactions in air and water. However, predicting the rate of such diffusive interactions remains challenging, due to the random motion of molecules in solutions, as exampled by the famous Brownian motion of pollen particles. In this report, we experimentally confirmed that a disruptive rate equation we have published before can predict the association rate of typical adsorption at interfaces, which has a surprising fraction order of 4/3 that has not been considered before. This could be an important step toward a generalized method to predict the adsorption rate of many reactions.

Exploring dispersion modelling for resuspended pollen particles in a heterogeneous urban environment

ABSTRACT Urban air quality assessment in regard to biogenic emissions such as airborne pollen grains (PGs) is indispensable in the urban environment which significantly affects human health, climates, ecosystems, and energy production. Dispersion and deposition of PGs because of resuspension events (ReSE) are investigated using computational fluid dynamics (CFD). The mechanisms in PGs movement are achieved through the Lagrangian formulation-based discrete-phase model (DPM). The observed pollen grains distribution pattern is highly spatially dependent on heterogeneous urban obstacles as it induces modified characteristics of the wind flow field. Wind-urban structure interplays in PGs concentration variation. The simulated results identify the pollen hot-spot zones, where vortical flow features and low wind speed dominate. This approach offers a detailed understanding of the dispersion patterns of airborne PGs in urban environments because of ReSE with high resolution.

Natural Aerosols, Gaseous Precursors and Their Impacts in Greece: A Review from the Remote Sensing Perspective

The Mediterranean, and particularly its Eastern basin, is a crossroad of air masses advected from Europe, Asia and Africa. Anthropogenic emissions from its megacities meet over the Eastern Mediterranean, with natural emissions from the Saharan and Middle East deserts, smoke from frequent forest fires, background marine and pollen particles emitted from ocean and vegetation, respectively. This mixture of natural aerosols and gaseous precursors (Short-Lived Climate Forcers—SLCFs in IPCC has short atmospheric residence times but strongly affects radiation and cloud formation, contributing the largest uncertainty to estimates and interpretations of the changing cloud and precipitation patterns across the basin. The SLCFs’ global forcing is comparable in magnitude to that of the long-lived greenhouse gases; however, the local forcing by SLCFs can far exceed those of the long-lived gases, according to the Intergovernmental Panel on Climate Change (IPCC). Monitoring the spatiotemporal distribution of SLCFs using remote sensing techniques is important for understanding their properties along with aging processes and impacts on radiation, clouds, weather and climate. This article reviews the current state of scientific know-how on the properties and trends of SLCFs in the Eastern Mediterranean along with their regional interactions and impacts, depicted by ground- and space-based remote sensing techniques.

From Ponds to Pine Plantations in 9000 Years: The Environmental Archaeology of Beck Burn, Solway Moss, Cumbria

ABSTRACT This article explores the evidence for environmental change at Beck Burn, Solway Moss, on the English/Scottish border. The analysed pollen, non-pollen palynomorphs (NPP) and microscopic charcoal particles permit several palaeoenvironmental events to be interpreted, supported by radiocarbon dating. These and previously published data suggest the presence of very early Mesolithic water-edge activity, later Mesolithic woodland management, clearance and small-scale cultivation during the early Neolithic period, followed by low-level disturbance for pastoral farming in the early Bronze Age. Woodland clearance and cereal cultivation are dated to the middle Bronze Age, with significant clearance and cultivation identified during the late Iron Age or early Roman period. The medieval period is characterised by evidence for a mixed subsistence economy, with reduced activity possibly coincident with the Wars of Scottish Independence, famines and the Black Death of the fourteenth century, as well as the Little Ice Age. Renewed activity, with evidence for both arable and pastoral farming, is dated to the late medieval to early post-medieval period. Pine plantations were then created, possibly in the eighteenth century or later. The data reveal the importance of palaeoenvironmental archaeology, in the absence of significant finds or features, in creating a link with the past.

Calibration and measurement of micrometre-scale pollen particles for discrete element method parameters based on the Johnson-Kendal-Roberts model

Discrete element method (DEM) parameters are the basis for modelling the motion of particle systems. To verify the practicality of calibrating DEM simulation parameters for micrometre-sized pollen particles, spherical micrometre-sized tomato pollen was selected as the research object for a parameter calibration experiment. Constitutive parameters such as the pollen morphology, diameter, and density were obtained through experimental measurements. Then, the contact and collision process of pollen was measured and analysed using an atomic force microscope, and Young's modulus, surface energy, and recovery coefficient of pollen were calculated using the Johnson-Kendal-Roberts (JKR) contact model. A Plackett-Burman test was designed, and the significant factors were determined using the DEM simulation test for Young's modulus of pollen grains, pollen-pollen static friction coefficient, and the pollen-polypropylene static friction coefficient for the plastic floor. The parameter range was reduced using the steepest climbing test. A regression equation was determined according to the results of the Box-Behnken response surface analysis. When this equation was solved, Young's modulus of pollen grains was 5.25 × 106 Pa, the pollen-pollen static friction coefficient was 0.466, and the pollen-polypropylene plastic static friction coefficient was 0.417. From the accumulation verification experiment the relative error between measurement and the simulation was 1.01%, which indicates that a calibration experiment of micrometre-sized pollen particle parameters is feasible. Furthermore, the parameters obtained here can be used to calculate and predict the pollen pollination process.

Optical properties from extinction cross-section of single pollen particles under laboratory-controlled relative humidity

A growing body of research suggests that pollen suspended in the atmosphere have a major environmental and climatic impact. However, our current knowledge of pollen is rather limited with respect to its extinction capacity, its optical properties and how these vary with atmospheric water content. Understanding their water absorption capacity can improve our understanding of their radiative effects and, thus, improve climate models. In this work, an electrodynamic Paul trap was coupled to a cavity ring down spectroscopy (CRDS) to directly measure the ring down time (τ) of four individual types of pollen particles: Olea, Fraxinus, Populus and Salix exposed to changing relative humidity (RH). Resonant structures in τ values between ∼90 and 45 % RH indicated that pollen was wettable at high RHs. τ was used to calculate light extinction cross-section (σext) at 532 nm as a function of RH. Optical growth factor (fRH) was evaluated as the ratio between σext(∼80%RH) and σext(dry). From fRH, the semi-empirical single hygroscopicity parameter (κemp) was found to be 0.038–0.058 for the four pollen types. Under controllable treatment of the water content and an adequate selection of complex refractive index (m), CRDS-σext data was fitted to theoretical σext from Mie theory. The reasonable agreement achieved allowed for gaining knowledge about the m and how particle size shrugged during dehydration. As a result, a climate-lowering effect of Olea pollen particles, which contain a fraction of scattered aerosol, should be considered in the models.

Vibration inducing and airflow guiding coupled tomato pollination method research based on gas–solid two-phase flow model

Supplementary pollination helps to improve yield and quality for tomato planting in greenhouse. Current tomato supplementary pollination methods with vibrator or blower can only realize the vibration induced pollen release without particles guiding. The vibration pollen release inducing and airflow pollen movement guiding coupled tomato pollination method and numeric simulation model were imposed in this paper. Firstly, the numeric simulation model based on gas–solid two-phase flow model of tomato pollination under vibration inducing and airflow guiding was established which considering the shape and surface characteristics of tomato pollen particles. Then, the response surface test of three factors and three levels was conducted using the numerical model by taking airflow angle, airflow start time and airflow velocity as factors, the effective pollination amount as pollination effect evaluation indicators. The test result showed that the maximum effective pollinated pollen particles could be acquired with airflow angle of 12.67°, airflow start time of 519.45 ms and airflow velocity of 0.72 m·s−1. Finally, the movement characteristics of tomato pollen particles in the simulation model were compared with the actual high-speed photography observation. The pollen particles movement trajectories in the simulation model were similar to them in actual observation. And the average movement velocities of the pollen particles moving downward and upward were only 7.59 % and 8.33 % differences between the results in simulation model and in actual observation. The average coverage rate of pollen particles on the stigma was 9.59 % with the vibration inducing and airflow guiding coupled pollination method, which was 85.85 % and 100.63 % relatively higher than vibration pollination and airflow pollination. The results show that vibration inducing and airflow guiding coupled pollination method with the optimized airflow parameters can improve the pollination effect, and the numerical simulation model established in this paper were reliable. The research results in this paper lays a foundation for the design and optimization of tomato pollination method and provides a theoretical basis for the application of gas–solid two-phase flow model in the design of supplementary pollination equipment.

Comparison of pollen indoor/outdoor ratios during off-peak and peak periods in Japan

Outdoor pollen particles can invade indoor spaces through various pathways, causing hay fever. This study aimed to investigate the effect of pollen diameter and shape on indoor invasion ratio (indoor/outdoor [I/O] ratio) during off-peak and peak pollen periods as well as the pollen types that easily invade indoor spaces. The measurement site was located in an apartment in Tokyo, Japan. Daily pollen sampling was performed from November 2021 to May 2022. The I/O ratios were analyzed for six pollen diameter ranges (0–2.5 μm, 2.5−10 μm, 10−20 μm, 20−30 μm, 30−40 μm, and >40 μm), four pollen shapes (monomer, ruptured, agglomerate, and unknown pollen), and 14 pollen types. The results showed that the total I/O ratio per day during the peak pollen period (0−2.8) was larger than during the off-peak period (0−1.2). The highest I/O ratio values (mean: 0.68, median: 0.47) were observed for pollen >40 μm in diameter during the off-peak period. Regarding their shape, the highest I/O ratio values (mean: 0.70, median: 0.28) were observed for ruptured pollen during the peak period. The most abundant pollen types were Corynespora (off-peak period) and Japanese cedar (peak period) indoors.

Numerical and experimental analysis of pollen inhalation exposure in nasal airways following various middle turbinectomy

BackgroundMiddle turbinectomy (MT) has always been controversial. MT significantly alters the anatomy and redistributes the inhaled air. The current study is designed to quantify the effect of MT with varying resection volumes on airflow and associated pollen inhalation exposure characteristics in the nasal airways. MethodsSix realistic models following bilateral comprehensive Functional Endoscopic Sinus Surgery (FESS) deriving from CT images were constructed and their corresponding post-MT models with four types of MT procedures were virtually conducted. Inhalation exposure to pollen particles was simulated by the Computational Fluid-Particle Dynamics (CFPD) approach and validated through in vitro experiments. ResultsFollowing the excision of the middle turbinate, a significant escalation in airflow was observed within the upper-middle region of the nasal cavities. Pollen deposition was observed to be more prominent in the nasal septum, laryngopharynx, and maxillary sinus, varying with the types of MT procedures. Notably, particles with diameters smaller than 50 μm exhibited two distinct “high peaks” and three “small peaks” within the nasal airways. ConclusionMT resulted in increased airflow volume within the upper-middle region of the nasal cavities. Following MT, notable shifts in pollen particle deposition hot spots were observed, transitioning from the nasal vestibule, nasal septum, and middle meatus to the nasal septum and laryngopharynx. These findings are anticipated to contribute valuable perspectives on pollen inhalation exposure risk assessments following diverse MT surgical interventions.

Spectral dependence of birch and pine pollen optical properties using a synergy of lidar instruments

Abstract. Active remote sensors equipped with the capability to detect polarization, a shape-relevant parameter, are essential to aerosol particle identification in the vertical domain. Most commonly, the linear particle depolarization ratio has been available at the shorter wavelengths of 355 and/or 532 nm. Recently, linear particle depolarization ratios at longer wavelengths (910, 1064, and 1565 nm) have emerged in lidar aerosol research. In this study, a synergy of three lidars, namely a PollyXT lidar, a Vaisala CL61 ceilometer, and a HALO Photonics StreamLine Pro Doppler lidar, as well as in situ aerosol and pollen observations have been utilized to investigate the spectral dependence of birch and pine pollen particles. We found that, regardless of the pollen type, the linear particle depolarization ratio was subject to the amount of pollen and its relative contribution to the aerosol mixture in the air. More specifically, during birch pollination, characteristic linear particle depolarization ratios of 5 ± 2 % (355 nm), 28 ± 6 % (532 nm), 23 ± 6 % (910 nm), and 33 ± 4 % (1565 nm) were retrieved at the pollen layer. Regarding the pine-dominant period, characteristic linear particle depolarization ratios of 6 ± 2 %, 43 ± 11 %, 22 ± 6 %, and 26 ± 3 % were determined at wavelengths of 355, 532, 910, and 1565 nm, respectively. For birch, the linear particle depolarization ratio at 1565 nm was the highest, followed by the 532 and 910 nm wavelengths, respectively. A sharp decrease at 355 nm was evident for birch pollen. For pine pollen, a maximum at the 532 nm wavelength was observed. There was no significant change in the linear particle depolarization ratio at 910 nm for the pollen types considered in this study. Given the low concentration of pollen in the air, the inclusion of the longer wavelengths (910 and 1565 nm) for the detection of birch and pine can be beneficial due to their sensitivity to trace large aerosol particles.

Cloud condensation nuclei activation properties of Mediterranean pollen types considering organic chemical composition and surface tension effects

Wind-dispersed pollen grains emitted from vegetation are directly injected into the atmosphere being an important source of natural aerosols globally. These coarse particles of pollen can rupture into smaller particles, known as subpollen particles (SPPs), that may act as cloud condensation nuclei (CCN) and affect the climate. In this study, we characterize and investigate the ability of SPPs of 10 Mediterranean-climate pollen types to activate as CCN. A continuous flow CCN counter (CCNC) was used to measure the activation of size-selected (80, 100 and 200 nm dry mobility diameter) particles at different supersaturations (SS). Hygroscopicity parameter (κ) for each SPP type and size has been calculated using κ-Köhler theory. Organic chemical speciation and protein content has been determined to further characterize pollen solutions. Furthermore, the surface activity of SPPs has also been investigated by using pendant drop tensiometry. All studied SPP samples show critical supersaturation (SSCrit) values that are atmospherically relevant SS conditions. Hygroscopicity κ values are in the range characteristic of organic compounds (0.1–0.3). We found that organic speciation and protein content vary substantially among pollen types, with saccharides and fatty acids being the only organic compounds found in all pollen types. A clear relationship between SPP activation and its organic composition was not observed. This study also reveals that all SPPs investigated reduce the surface tension of water at high concentrations but at diluted concentrations (such as those of activation in the CCNC), the water surface tension value is a good approximation in Köhler theory. Overall, this analysis points out that pollen particles might be an important source of CCN in the atmosphere and should be considered in aerosol-cloud interactions processes.

Effect of nasal swell body on nasal airflow and Artemisia pollen deposition

Objective:The nasal swell body（NSB） consists of the nasal septal cartilage, nasal bone, and swollen soft tissue, all of which are visible during endoscopic and imaging examinations. Although the function of the NSB remains uncertain, there is evidence to suggest that it plays a vital role in regulating nasal airflow and filtering inhaled air. Based on anatomical and histological evidence, it is hypothesized that the NSB is indispensable in these processes. This study aims to investigate the impact of NSB on nasal aerodynamics and the deposition of allergen particles under physiological conditions. Methods:The three-dimensional （3D） nasal models were reconstructed from computed tomography （CT） scans of the paranasal sinus and nasal cavity in 30 healthy adult volunteers from Northwest China, providing basis for the construction of models without NSB following virtual NSB-removal surgery. To analyze the distribution of airflow in the nasal cavity, nasal resistance, heating and humidification efficiency, and pollen particle deposition rate at various anatomical sites, we employed the computed fluid dynamics（CFD） method for numerical simulation and quantitative analysis. In addition, we created fully transparent segmented nasal cavity models through 3D printing, which were used to conduct bionic experiments to measure nasal resistance and allergen particle deposition. Results:①The average width and length of the NSB in healthy adults in Northwest China were （12.85±1.74） mm and （28.30±1.92） mm, respectively. ②After NSB removal, there was no significant change in total nasal resistance, and cross-sectional airflow velocity remained essentially unaltered except for a decrease in topical airflow velocity in the NSB plane. ③There was no discernible difference in the nasal heating and humidification function following the removal of the NSB; ④After NSB removal, the deposition fraction（DF） of Artemisia pollen in the nasal septum decreased, and the DFs post-and pre-NSB removal were（22.79±6.61）% vs （30.70±12.27）%, respectively; the DF in the lower airway increased, and the DFs post-and pre-NSB removal were（24.12±6.59）% vs （17.00±5.57）%, respectively. Conclusion:This study is the first to explore the effects of NSB on nasal airflow, heating and humidification, and allergen particle deposition in a healthy population. After NSB removal from the healthy nasal cavities: ①nasal airflow distribution was mildly altered while nasal resistance showed no significantly changed; ②nasal heating and humidification were not significantly changed; ③the nasal septum's ability to filter out Artemisia pollen was diminished, which could lead to increased deposition of Artemisia pollen in the lower airway.

Moment‐Based Shape‐Learning Holography for Fast Classification of Microparticles

Compact computational in‐line holography based on deep learning is an attractive single‐shot approach to image microparticles dispersed in 3D volume. The particle shape contains valuable information for species classification, but the dataset acquisition process for network training suffers from labor consuming and low efficiency due to the complex and varied 2D shapes of different particle species. Herein, a moment‐based shape‐learning holography (MSLH) is proposed where the shape of a microparticle is mathematically characterized using varying weights of Zernike moments. By decomposing and recombining feature shapes of pollen particles into numerous new characteristic shapes as incremental data, MSLH improves the efficiency of dataset preparation. The depth‐encoded shape‐learning is achieved using a U‐net with self‐attention mechanism, which enables fast axial depth determination. The shape reconstruction uses a wavelet‐based method with more explicit physical meanings, making MSLH a hybrid data‐and‐model driven approach that requires fewer primary data. Validation results show that MSLH achieves high accuracy in axial position and shape reconstruction, while maintaining good classification effectiveness. It is believed that MSLH is an easy‐to‐setup, efficient‐to‐construct, and fast‐to‐output approach for shape‐based classifications of 3D distributed microparticles in dynamic fluid.

A Laboratory Evaluation of the New Automated Pollen Sensor Beenose: Pollen Discrimination Using Machine Learning Techniques.

The monitoring of airborne pollen has received much attention over the last decade, as the prevalence of pollen-induced allergies is constantly increasing. Today, the most common technique to identify airborne pollen species and to monitor their concentrations is based on manual analysis. Here, we present a new, low-cost, real-time optical pollen sensor, called Beenose, that automatically counts and identifies pollen grains by performing measurements at multiple scattering angles. We describe the data pre-processing steps and discuss the various statistical and machine learning methods that have been implemented to distinguish different pollen species. The analysis is based on a set of 12 pollen species, several of which were selected for their allergic potency. Our results show that Beenose can provide a consistent clustering of the pollen species based on their size properties, and that pollen particles can be separated from non-pollen ones. More importantly, 9 out of 12 pollen species were correctly identified with a prediction score exceeding 78%. Classification errors occur for species with similar optical behaviour, suggesting that other parameters should be considered to provide even more robust pollen identification.

Simulating the Transport and Rupture of Pollen in the Atmosphere

AbstractPollen, one type of primary biological aerosol particle (PBAP), is emitted from the terrestrial biosphere and can undergo physical changes in the atmosphere via particle rupture. To examine the fate of pollen and its atmospheric processing, a pollen emission and transport scheme is coupled to the Weather Research and Forecasting Model with Chemistry (WRF‐Chem). We simulate the emission of pollen and its impacts on the cloud properties and precipitation in the Southern Great Plains from 12 to 19 April 2013, a period with both high pollen emissions and convective activity. We conduct a suite of ensemble runs that simulate primary pollen and three different pollen rupture mechanisms that generate subpollen particles, including (a) high humidity‐induced surface rupture, (b) high humidity‐induced in‐atmosphere plus surface rupture, and (c) lightning‐induced rupture, where in‐cloud and cloud‐to‐ground lightning strikes trigger pollen rupture events. When relative humidity is high (>80%), coarse primary pollen (∼1 μg m−3) is converted into fine subpollen particles (∼1.2e−4 μg m−3), which produces 80% more subpollen particles than lightning‐induced rupture. The in‐atmosphere humidity‐driven rupture predominantly produces subpollen particles, which is further enhanced during a frontal thunderstorm. During strong convection, vertical updrafts lift primary pollen and subpollen particles (∼0.5e−4 μg m−3) to the upper troposphere (∼12 km) and laterally transports the ruptured pollen in the anvil top outflow. In regions of high pollen and strong convection, ruptured pollen can influence warm cloud formation by decreasing low cloud (<4 km) cloud water mixing ratios and increasing ice phase hydrometeors aloft (>10 km).

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.

A numerical study on the relationship between particle dispersion, accumulation, and indoor airflow in different ventilated rooms

AbstractThis study serves as a basic study of the indoor dispersion of pollen particles, simulating the flow field and discussing the behavior of particles of different diameters in different rooms. By comparing the vertical velocity components of particles () and the mean flow velocity of z‐direction component () plus the terminal settling velocity in a gravitational field (), the differences between values and plus values are found to occur mainly at locations close to the opposite wall of the inlet. The location of the differences between values and plus values is important findings of this study, which facilitates the improvement of the simulation method at a later stage and the rational design of indoor ventilation patterns to easily remove particles from the room.

Prediction of airborne pollen and sub-pollen particles for thunderstorm asthma outbreaks assessment

When exposed to convective thunderstorm conditions, pollen grains can rupture and release large numbers of allergenic sub-pollen particles (SPPs). These sub-pollen particles easily enter deep into human lungs, causing an asthmatic response named thunderstorm asthma (TA). Up to now, efforts to numerically predict the airborne SPP process and to forecast the occurrence of TAs are unsatisfactory. To overcome this problem, we have developed a physically-based pollen model (DREAM-POLL) with parameterized formation of airborne SPPs caused by convective atmospheric conditions. We ran the model over the Southern Australian grass fields for 2010 and 2016 pollen seasons when four largest decadal TA epidemics happened in Melbourne. One of these TA events (in November 2016) was the worldwide most extreme one which resulted to nine deaths and hundreds of hospital patient presentations. By executing the model on a day-by-day basis in a hindcast real-time mode we predicted SPP peaks exclusively only when the four major TA outbreaks happened, thus achieving a high forecasting success rate. The proposed modelling system can be easily implemented for other geographical domains and for different pollen types.

Correlation of Pollen Concentration and Meteorological Factors with Medical Condition of Allergic Rhinitis in Shenyang Area.

Background The pathogenesis of allergic rhinitis (AR) was affected by meteorological and environmental factors. This study investigated the association between clinical symptoms of AR patients with pollen dispersal and meteorological conditions. Methods The clinical features of 10,838 AR patients who were treated in the Department of Otorhinolaryngology, The First Hospital of China Medical University, Shenyang, from March 2021 to October 2021 were retrospectively analyzed. We collected pollen by a pollen collector, read and counted it under a microscope, identified the species of the pollen particles, and recorded meteorological data (average daily temperature, maximum and minimum temperature, average daily wind, average daily precipitation, average daily humidity, average pressure, air quality index, PM2.5, PM10, SO2, NO2, CO, and O3), to analyze the correlation among meteorological conditions, pollen dispersal, and number of AR visits. Finally, pollen allergen-positive and symptoms were scored. Results Among the AR visits, patients >41 years old accounted for the highest proportion (64.15%). 43.67% of the patients were complicated with bronchial asthma, and the disease incidence peaked in September. During the period of the study, a total of 27,512 pollen grains were collected, and 17 species were identified. The pollens of Compositae and Moraceae were the main allergenic sources leading to the increase in AR visits from August to September. The peak of pollen dispersal was in spring, summer, and autumn. The total amount of pollen was not only related to the average daily minimum temperature, average daily precipitation, and average daily humidity but also had a significant correlation with air quality index and air pollutants (PM2.5 and PM10, SO2, NO2, and CO). In addition, there was a significant correlation between the number of daily pollen allergen-positive patients and the pollen concentration of Compositae and Moraceae as well as air pollution components. The clinical symptoms of pollen allergen-positive patients were mainly nasal congestion, red/itchy eyes, and epiphora. Conclusion The peak seasons of pollen dispersal in Shenyang were in spring, summer, and autumn, and the allergenic pollens were mainly Compositae and Moraceae. In addition, AR was substantially correlated with pollen concentration and meteorological factors. This study may help provide early warning information and prevention for AR patients.