Peak Pollen Research Articles

Cannabis pollen sources and dispersal in the Iberian Pyrenees during the last century: Preliminary results and proposals for future studies

Meta-analyses of past pollen records have provided insights into the historical biogeography of Cannabis across the Iberian Peninsula (IP), with the southern Pyrenean flank being key to understanding cannabis cultivation and use during the Middle and Modern ages. However, studies on more recent times are rare. This paper offers a high-resolution comparison of the last century, particularly the significant Cannabis pollen peak observed in the mid-elevation Lake Montcortès between 1980 and 2000 CE, which was absent in the nearby highland Lake Sant Maurici. The Montcortès peak is linked to a phase of extensive hemp cultivation (1972–2006 CE) in the southeastern lowlands. The absence of a similar peak in Sant Maurici, despite the presence of other lowland pollen taxa, notably Olea and Quercus, suggests regional differences in pollen origin and dispersal likely influenced by wind patterns and rainfall. Studies on Cannabis pollen sources and dispersal are comparatively scarce and insufficient to provide a regional picture across the IP, similar to Olea or Quercus. However, the available data suggest that cannabis pollen is abundant mostly locally, in the vicinity of cannabis crops. The persistent presence of Cannabis pollen in Montcortès after 2000 CE likely reflects ongoing illegal cultivation. The study recommends combining paleoecological and aerobiological surveys to better understand pollen dynamics in the Iberian Pyrenees, with suggestions for future research based on these findings.

A second Artemisia pollen peak in autumn in Vienna: reaching the point of no return?

AbstractThe Artemisia (mugwort) pollen season usually ranges from July until September, with one peak period around mid-August in Vienna (Austria). During the last decade, Artemisia pollen was also recorded later in September. This pattern was concluded by a significant peak pollen concentration day in autumn of 2023, which exceeded the usual summer peak pollen concentration day. The Artemisia pollen data from Vienna for the last ten years (2014–2023) were therefore analysed for a temporal trend. In addition, weather data from Vienna (temperature, precipitation, and relative humidity and sun hours) were retrieved and analysed to find a possible association with Artemisia pollen indices. No significant trend could be observed regarding the Artemisia pollen season parameters and no correlation was found between the weather data and the Artemisia pollen integrals during summertime. However, a significant positive correlation was found between higher temperatures during autumn and the occurrence of Artemisia pollen during this time. This suggests that a significant change in the Artemisia pollen season can be expected during years with a mild, summer-like autumn. Until now, it is not clear which species of Artemisia cause the pollination in autumn. A. annua and A. verlotiorum are two major suspects that could have established themselves in Vienna, but further evidence is needed. Considering the impact of global climate change, the shift in the pollen season for Artemisia described in this study could represent a point of no return.

Aerobiology of Olive Pollen (Olea europaea L.) in the Atmosphere of the Iberian Peninsula

Olea europaea L. pollen is one of the main causes of pollinosis and respiratory diseases in the Iberian Peninsula (IP). The aim of this study was to provide a pollen calendar in different regions of the IP, which could help allergists and allergic patients in the management of Olea europaea allergic diseases, and to update/complement what has already been reported on olive trees’ aeropalynology in this region. Airborne Olea pollen dynamics were analyzed over a period of 8 years in a total of 21 localities, 7 in Portugal and 14 in Spain. Airborne pollen monitoring was carried out using the Hirst-type spore trap method and following the recommendations of the Quality Control Working Group of the European Aerobiology Society. The daily pollen count, the annual pollen profile, the Annual Pollen Integral (APIn), the Seasonal Pollen Integral (SPIn) and the Pollen Peak, all expressed in number of pollen grains per cubic metre of air, together with the main pollen season and its characteristics, the Start Day, the End Day and the length of the pollen season, were calculated for each sampling station. Differences in mean Olea pollen concentration between odd and even years were also analyzed. On average, the main pollen season (MPS) started in April/May and ended in June, with Pollen Peaks recorded in May, except in Burgos, where it was recorded in June. The longest MPS occurred in Lisbon, Oviedo and Valencia (53 days) and the shortest in Vitoria (25 days). A high daily pollen concentration (i.e., >200 grains/m3) was recorded between 1 and 38 days along the year in all sampling stations of the southwest quadrant of the IP and in Jaén. A biannual pattern, characterized by alternating years of high and low pollen production, was found in the southwest of the IP. In conclusion, the study provided a deeper understanding of the pollination behaviour of olive trees in the IP and allowed the establishment of a representative Olea pollen calendar for this region. In addition, our results suggest the usefulness of investigating more detailed relationships between annual Olea pollen, allergen sensitization and symptoms, both for allergists involved in the study and management of allergic respiratory diseases caused by this species and for the self-management of disease in allergic subjects.

Pollen and viruses contribute to spatio-temporal variation in asthma-related emergency department visits

BackgroundAsthma exacerbations are an important cause of emergency department visits but much remains unknown about the role of environmental triggers including viruses and allergenic pollen. A better understanding of spatio-temporal variation in exposure and risk posed by viruses and pollen types could help prioritize public health interventions. ObjectiveHere we quantify the effects of regionally important Cupressaceae pollen, tree pollen, other pollen types, rhinovirus, seasonal coronavirus, respiratory syncytial virus, and influenza on asthma-related emergency department visits for people living near eight pollen monitoring stations in Texas. MethodsWe used age stratified Poisson regression analyses to quantify the effects of allergenic pollen and viruses on asthma-related emergency department visits. ResultsYoung children (<5 years of age) had high asthma-related emergency department rates (24.1 visits/1,000,000 person-days), which were mainly attributed to viruses (51.2%). School-aged children also had high rates (20.7 visits/1,000,000 person-days), which were attributed to viruses (57.0%), Cupressaceae pollen (0.7%), and tree pollen (2.8%). Adults had lower rates (8.1 visits/1,000,000 person-days) which were attributed to viruses (25.4%), Cupressaceae pollen (0.8%), and tree pollen (2.3%). This risk was spread unevenly across space and time; for example, during peak Cuppressaceae season, this pollen accounted for 8.2% of adult emergency department visits near Austin where these plants are abundant, but 0.4% in cities like Houston where they are not; results for other age groups were similar. ConclusionsAlthough viruses are a major contributor to asthma-related emergency department visits, airborne pollen can explain a meaningful portion of visits during peak pollen season and this risk varies over both time and space because of differences in plant composition.

Investigation analysis of the acute asthma risk factor and phenotype based on relational analysis with outdoor air pollutants in Xi'an, China.

Asthma is a common chronic heterogeneous disease. Outdoor air pollutants are an important cause of acute asthma. Until now, the association between the risk of acute asthma and outdoor air pollutants is unclear. And the relationship between the different phenotypes of asthma and outdoor air pollutants has not been reported. Thus, an analysis of the association between outdoor air pollutants and daily acute asthma inpatient and outpatient visits in Xi'an, China, from January 1 to December 31, 2018, was conducted. A total of 3395 people were included in the study. The statistical analysis and relational analysis based on the logistic regression were used for illustrating the relatedness of the acute asthma risk factor and phenotype with outdoor air pollutants, while the age, gender, pollen peak and non-pollen peak periods, high type 2 (T2) asthma and non-high T2 asthma were also stratified. Results showed that particulate matter with particle size below 10μm and 2.5μm (PM10 and PM2.5), sulfur dioxide(SO2), nitrogen dioxide(NO2), and carbon monoxide(CO) increase the risk of acute asthma and that air pollutants have a lagged effect on asthma patients. PM10, NO2, CO, and Ozone (O3) are associated with an increased risk of acute attacks of high T2 asthma. PM10, PM2.5, SO2, NO2 and CO are associated with an increased risk of acute asthma in males of 0-16years old. PM10 and PM2.5 are more harmful to asthma patients with abnormal lung function.

Environmental DNA analysis of airborne poaceae (grass) pollen reveals taxonomic diversity across seasons and climate zones

BackgroundGrasses populate most biogeographical zones, and their diversity influences allergic sensitisation to pollen. Previously, the contribution of different Poaceae subfamilies to airborne pollen has mostly been inferred from historical herbarium records. We recently applied environmental (e)DNA metabarcoding at one subtropical site revealing that successive airborne grass pollen peaks were derived from repeated flowering of Chloridoid and Panicoid grasses over a season. This study aimed to compare spatiotemporal patterns in grass pollen exposure across seasons and climate zones. MethodsAirborne pollen concentrations across two austral pollen seasons spanning 2017–2019 at subtropical (Mutdapilly and Rocklea, Queensland) and temperate (Macquarie Park and Richmond, New South Wales) sites, were determined with a routine volumetric impaction sampler and counting by light microscopy. Poaceae rbcL metabarcode sequences amplified from daily pollen samples collected once per week were assigned to subfamily and genus using a ribosomal classifier and compared with Atlas of Living Australia sighting records. ResultseDNA analysis revealed distinct dominance patterns of grass pollen at various sites: Panicoid grasses prevailed in both subtropical Mutdapilly and temperate Macquarie Park, whilst Chloridoid grasses dominated the subtropical Rocklea site. Overall, subtropical sites showed significantly higher proportion of pollen from Chloridoid grasses than temperate sites, whereas the temperate sites showed a significantly higher proportion of pollen from Pooideae grasses than subtropical sites. Timing of airborne Pooid (spring), Panicoid and Chloridoid (late spring to autumn), and Arundinoid (autumn) pollen were significantly related to number of days from mid-winter. Proportions of eDNA for subfamilies correlated with distributions grass sighting records between climate zones. ConclusionseDNA analysis enabled finer taxonomic discernment of Poaceae pollen records across seasons and climate zones with implications for understanding adaptation of grasslands to climate change, and the complexity of pollen exposure for patients with allergic respiratory diseases.

Effects of airborne pollen on allergic rhinitis and asthma across different age groups in Beijing, China

In the context of global warming and rapid urbanization, pollen has become a significant public health concern for Chinese citizens. However, there is a paucity of epidemiological research on the impact of pollen on allergen-linked diseases, such as allergic rhinitis and asthma, in China. Using data from the Beijing Chaoyang Hospital between 2013 and 2019, which included allergic rhinitis and asthma incidence, meteorological records, and air pollution data, we employed a Generalized Additive Model (GAM) to examine the relationship between overall and type-specific pollen concentrations in relation to varying population exposures. We found that increased overall pollen concentrations significantly increased the risks of allergic rhinitis and asthma in diverse populations. Notably, the risk of allergic rhinitis was higher than that of asthma at equivalent pollen concentrations. Seasonal trends indicated that spring pollen peaks, primarily from trees, were associated with a lower risk of both allergic rhinitis and asthma than autumn peaks, predominantly from weeds. This study underscores the importance of identifying pollen species that pose heightened risks to different demographic groups across seasons, thereby providing targeted interventions for public health agencies.

The Effect of Pollen on Coral Health.

Corals are facing a range of threats, including rises in sea surface temperature and ocean acidification. Some now argue that keeping corals ex situ (in aquaria), may be not only important but necessary to prevent local extinction, for example in the Florida Reef Tract. Such collections or are already becoming common place, especially in the Caribbean, and may act as an ark, preserving and growing rare or endangered species in years to come. However, corals housed in aquaria face their own unique set of threats. For example, hobbyists (who have housed corals for decades) have noticed seasonal mortality is commonplace, incidentally following months of peak pollen production. So, could corals suffer from hay fever? If so, what does the future hold? In short, the answer to the first question is simple, and it is no, corals cannot suffer from hay fever, primarily because corals lack an adaptive immune system, which is necessary for the diagnosis of such an allergy. However, the threat from pollen could still be real. In this review, we explore how such seasonal mortality could play out. We explore increases in reactive oxygen species, the role of additional nutrients and how the microbiome of the pollen may introduce disease or cause dysbiosis in the holobiont.

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.

Investigation and analysis of airborne allergenic pollen in 4 districts and 5 counties of Hohhot City

Objective: To investigate the species, concentration and seasonal trends of main airborne allergenic pollen in 4 districts and 5 counties of Hohhot City. Methods: The Department of allergy, Beijing Shijitan Hospital Affiliated to Capital Medical University conducted a cross-sectional study about monitoring the airborne allergenic pollen from August 1, 2021 to July 31, 2022 by the gravitational method in 4 districts and 5 counties of Hohhot City, which include Yuquan District, Xincheng District, Huimin District, Saihan District, Tuoketuo County, Helingeer County, Tumotezuoqi County, Wuchuan County and Qingshuihe County. Daily pollens were counted and identified by optical microscopy, and the data were analyzed. Results: The airborne allergenic pollen was collected every month all year round in 4 districts and 5 counties of Hohhot city. Through the whole year of the total quantity of pollens ranged from 24 850 to 50 154 grains per 1 000 mm2 and two peaks of pollen concentration in air were observed,which happened in spring (from March to May) and in summer and autumn (from July to September). In spring, the main pollens were tree pollens, which principally distributed in Populus pollen (18.29%), Ulmus pollen (8.36%), Pinus pollen (6.20%), Cupressaceae pollen (5.23%), Betulaceae pollen (2.73%), Salix pollen (1.80%) and Quercus pollen (1.16%). In summer and autumn, the main pollens were weed pollens, which mainly included Artemisia pollen (42.73%), Chenopodiaceae pollen or Amaranthaceae pollen (7.46%), Poaceae pollen (2.26%), Humulus pollen or Cannabis pollen (0.60%). Conclusion: There were two peaks of main airborne allergenic pollen in 4 districts and 5 counties of Hohhot City. In the spring peak of pollen, the main airborne pollens were tree pollens. In the summer and autumn peak of pollen, the main airborne pollens were weed pollens. The Artemisia pollen was the most major airborne pollen in this area.

Alnus Airborne Pollen Trends during the Last 26 Years for Improving Machine Learning-Based Forecasting Methods

Black alder (Alnus glutinosa (L.) Gaertn.) is a species of tree widespread along Europe and belongs to mixed hardwood forests. In urban environments, the tree is usually located along watercourses, as is the case in the city of Ourense. This taxon belongs to the betulaceae family, so it has a high allergenic potential in sensitive people. Due to the high allergenic capacity of this pollen type and the increase in global temperature produced by climate change, which induces a greater allergenicity, the present study proposes the implementation of a Machine Learning (ML) model capable of accurately predicting high-risk periods for allergies among sensitive people. The study was carried out in the city of Ourense for 28 years and pollen data were collected by means of the Hirst trap model Lanzoni VPPS-2000. During the same period, meteorological data were obtained from the meteorological station of METEOGALICIA in Ourense. We observed that Alnus airborne pollen was present in the study area during winter months, mainly in January and February. We found statistically significant trends for the end of the main pollen season with a lag trend of 0.68 days per year, and an increase in the annual pollen integral of 112 pollen grains per year and approximately 12 pollen grains/m3 per year during the pollen peak. A Spearman correlation test was carried out in order to select the variables for the ML model. The best ML model was Random Forest, which was able to detect those days with medium and high labels.

Clinical efficacy in one-year treatment with Artemisia annua-SLIT drops in monosensitized and polysensitized individuals

PurposeSeasonal allergic rhinoconjunctivitis (SARC) caused by Artemisia seriously affects patients' quality of life in northern China. This study aimed to estimate further the efficacy and safety of a one-year course of Artemisia annua-sublingual immunotherapy (SLIT) on SARC patients. Materials and methodsThis was an open-label, randomized, controlled, single-centre study involving 150 SARC patients induced by Artemisia, randomized to SLIT group (n = 75, SLIT along with pharmacotherapy) or control group (n = 75, pharmacotherapy only). According to the skin prick test (SPT) results, the SLIT group was divided into monosensitized and polysensitized groups to analyze the influence of sensitization status on the efficacy of Artemisia annua-SLIT. The clinical indicators of this study were total rhinoconjunctivitis symptom score (TRSS), total medication score (TMS), combined scores of medication and rhinoconjunctivitis symptom (CSMRS), and score of visual analog scale (VAS). Safety was evaluated by the occurrence of adverse events (AEs). Daily administration of the drops was recorded in diaries by the patients. ResultsAfter nearly one year of treatment and follow-ups, there was a significant decline in TRSS, TMS, CSMRS, and VAS from the baseline scores in the SLIT group (p < 0.001). However, as pollen counts increased in 2022, indicators above in the control group increased significantly during the peak pollen phase (PPP) in 2022 grass pollen season (GPS) compared to the baseline. Meanwhile, we found no significant difference in TRSS, TMS, CSMRS, and VAS between the monosensitized and polysensitized groups (p > 0.05). Moreover, the result indicated that the clinical improvement in TRSS, TMS, CSMRS, and VAS was still observed in polysensitized patients who were allergic to Artemisia pollen and sensitized to house dust mite (HDM) (n = 15) in PPP of 2022, compared to the baseline value (p < 0.001). ConclusionArtemisia annua-SLIT was proven effective, tolerable and safe in patients with SARC after nearly one year of treatment, whether monosensitization or polysensitization.

Birch-induced allergic rhinitis: Results of exposure during nasal allergen challenge, environmental chamber, and pollen season

BackgroundPollen variation can affect field study data quality. Nasal allergen challenge (NAC) is considered the gold standard for evaluating allergic rhinitis, while environmental exposure chambers (EECs) are mainly used in phase 2 drug development studies. We aimed to study birch-induced allergic rhinitis under 3 different conditions. MethodsThis study included 30 participants allergic to birch pollen, based on birch skin prick test, specific immunoglobulin E (IgE), and positive NAC. Participants were exposed to placebo twice, followed by 2 consecutive 4-h birch airborne exposures, repeated on 2 occasions to evaluate reproducibility and priming effect. Nasal response was defined as total corrected nasal symptom score (ΔTNSS) ≥ 5 during NAC and EEC. The primary end-point was to measure TNSS during the last 2 h of first allergen exposure. TNSS was also analyzed during natural exposure. ResultsThe dose most commonly yielding positive TNSS during NAC was 175.2 ng/200 μL. Eighteen participants experienced ΔTNSS ≥5 during the last 2 h of the first exposure, whereas 21 had positive responses at all 4 exposures. Mean ΔTNSS was 1 with placebo versus 6 with birch. Exposures were reproducible, with no observed priming effect. Airborne Bet v 1 was 25 ng/m3, while the pollen measurement was 279/m3 during pollen season. TNSS reached 5 in 67.9% of participants during peak pollen season. ConclusionEEC outcomes were similar to those obtained with NAC and natural exposure, suggesting the usefulness of EEC in allergic rhinitis studies. The primary end-point was reached, as 60% of participants experienced nasal responses.

Clinical response to varying pollen exposure in allergic rhinitis in children in The Netherlands

BackgroundAllergic rhinitis (AR) affects 10–15% of children. Symptoms in seasonal AR are influenced by pollen exposure. Pollen counts vary throughout the pollen season and therefore, symptom severity fluctuates. This study investigates the correlation between pollen concentration and symptom load in children with AR in The Netherlands.MethodsA secondary analysis was performed in a study determining the most effective treatment for children with seasonal AR. Symptoms were measured during three months in 2013 and 2014 using a daily symptom diary. The pollen concentration was measured with a Hirst type volumetric spore trap sampler. A correlation coefficient was calculated for the correlation between the pollen concentration and the mean daily symptom score. The study protocol was approved by the medical ethical review committee of the Erasmus MC and is incorporated in the International Clinical Trials Registry Platform (EUCTR2012-001,591–11-NL).ResultsIn 2014, the correlation coefficient for birch pollen concentration and symptom score was 0.423 (p = 0.000). The correlation coefficient for grass pollen concentration and symptom score was 0.413 (p = 0.000) and 0.655 (p = 0.000) in 2013 and 2014, respectively. A delayed correlation between the birch pollen concentration and the symptom scores was seen up to two days after the pollen measurement (0.151, p = 0.031). For grass pollen this effect lasted up to three days after the pollen measurement (0.194, p = 0.000).ConclusionWe found comparable correlations between symptom score and pollen concentration as found by EAACI. Birch and grass pollen have an elongated influence on symptom score of several days. This implies patients need to continue on demand medication longer after a measured pollen peak.

Pollinator visitation closely tracks diurnal patterns in pollen release.

Animal-pollinated plants face a high risk of pollen loss during its transfer. To limit the negative effect of pollen losses by pollen consumption and heterospecific transfer, plant species may adjust and stratify their pollen availability during the day (i.e., "schedule" their pollen presentation) and attract pollinators in specific time frames. We investigated diurnal patterns of pollen availability and pollinator visitation in three coflowering plant species: Succisa pratensis with open flowers and accessible pollen, pollinated mainly by pollen-feeding hoverflies; Centaurea jacea with open flowers and less accessible pollen, pollinated mainly by pollen-collecting bees; and Trifolium hybridum with closed flowers and pollen accessible only after the active opening of the flower, pollinated exclusively by bees. The three plant species differed in the peak pollen availability, tracked by the visitation activity of their pollinators. Succisa pratensis released all pollen in the morning, while pollinator activity was still low and peaked with a slight delay. In contrast, C. jacea and T. hybridum had distinct pollen presentation schedules, peaking in the early afternoon. The pollinator visitation to both of these species closely matched their pollen availability. Stratifying pollen availability to pollinators during the day may be one of several mechanisms that allow coflowering plants to share their pollinators and decrease the probability of heterospecific pollen transfer.

Understanding reproductive biology for realization of conservation and sustainable development of Swertia thomsonii C. B. Clarke-an endemic medicinal plant of Western Himalaya

Swertia thomsonii an important medicinal plant of Himalaya is more susceptible to extinction in the scenario of anthropogenic threats and global climate change. Therefore a detailed study on reproductive biology was undertaken for its conservation and sustainable use. The present study was conducted with the aim to understand reproductive strategies, breeding behaviour and pollination ecology of this prized, endemic medicinal plant species. It is a perennial rhizomatous herb growing along an altitudinal gradient of 2550–3400 m a.s.l. The flowering commences from the month of August and continuous till September. The variation in floral traits was observed across the altitudinal gradients, which reflects its phenotypic plasticity in these characters that helps the species to get adapted in different environmental conditions. The pollen viability recorded in three study sites viz. Gulmarg (SS-I), Doodhpathri (SS-II), Pahalgam (SS-III) was 89.83 ± 3.1, 75.86 ± 5 and 84.5 ± 2.5% respectively. Stigma becomes receptive 4–5 days after anthesis and reaches its peak on 6–7th day. The presence of typical floral characteristics such as asynchronous anthesis, conspicuous nectaries, spiny exine of pollen, dichogamy, and herkogamy points towards entomophilous and outcrossing nature. Reproductive indices like outcrossing index (OCI), self-incompatibility index (SI) and selfing rate (S) as well as results of bagging experiments also revealed that the species is self as well as cross-compatible. However, fruit and seed set recorded in insect exclusion experiments confirmed its anemophilous nature and therefore species exhibits an ambophilous mode of pollination. Mixed matting is operative in the target plant species, preferring xenogamy followed by geitonogamy and autogamy. The species is pollinated by specialized pollinators which mostly belong to the Order Hymenoptera. Suitable media for in-vitro pollen germination has also been identified; the knowledge about peak stigma receptivity and pollen germination is indispensable for breeding programmes. Thus the scientific information generated in the present study may prove useful in different breeding programmes and conservation of this valuable plant species.

The use of asthma and allergy medicines is associated with exposure to smoking

Exposure to ambient air pollution and tobacco smoking have been reported to trigger asthma and allergies, but these risk factors have typically not been assessed together. Here we collected and analysed daily wastewater samples from an urban population of approximately 500,000 people in Southern China between November 2017 and October 2018 for biomarkers of asthma and allergy medicines and exposure to tobacco smoke. Daily air pollution data (PM2.5, PM10, SO2, NO2, CO and O3) were obtained from the nearest air quality monitoring station. Using time-series linear regression, we show a significantly higher use of antihistamine medicines in spring and in autumn, associated with peak pollen levels, but with no significant association between the use of asthma and allergy medications and ambient air pollution levels. There were significant positive associations between biomarkers of exposure to tobacco smoke and the use of selected medicines. Wastewater-based epidemiology can be a cost-effective way to assess the health impacts of multiple environmental factors at the population level. The exposure to both air pollution and cigarette smoke can trigger asthma. Wastewater surveillance was used to demonstrate the possibility of distinguishing between these two factors.

Effects of pollen concentration on allergic rhinitis in children: A retrospective study from Beijing, a Chinese megacity

With global climate change and rapid urbanization, the prevalence of allergic diseases caused by pollen is rising dramatically worldwide with unprecedented complexity and severity, especially for children in mega-cities. However, because of the lack of long time-series pollen concentrations data, the accurate evaluation of the impact of pollen on allergic rhinitis (AR) was scarce in the Chinese metropolis. A generalized additive model was used to assess the effect of pollen concentration on pediatric AR outpatient visits in Beijing from 2014 to 2019. A stratified analysis of 10 pollen species and age-gender-specific groups was also conducted during the spring and summer-autumn peak pollen periods separately. Positive associations between pollen concentration and pediatric AR varied with the season and pollen species were detected. Although the average daily pollen concentration is higher during the spring tree pollen peak, the influence was stronger at the summer-autumn weed pollen peak with the maximum relative risk 1.010 (95% CI 1.009, 1.011), which was higher than the greatest relative risk, 1.003 (95% CI 1.002, 1.004) in the spring peak. The significant adverse effects can be sustained to lag10 during the study period, and longer in the summer-autumn peak (lag13) than in the spring peak (lag8). There are thresholds for the health effects and they varied between seasons. The significant effect appeared when the pollen concentration was higher than 3.74 × 105 grain·m−2·d−1 during the spring tree pollen peaks and 4.70 × 104 grain·m−2·d−1 during the summer-autumn weed pollen peaks. The stratified results suggested that the species-specific effects were heterogeneous. It further highlights that enough attention should be paid to the problem of pollen allergy in children, especially school-aged children aged 7–18 years and weed pollen in the summer-autumn peak pollen period. These findings provide a more accurate reference for the rational coordination of medical resources and improvement of public health.

M2 Macrophages Upregulated by Allergen Exposure in Seasonal Allergic Rhinitis

Introduction: Macrophages play a central role in balancing the immune response by switching phenotypes between the M1 and M2 profiles according to a delicate equilibrium. Based on a previous clinical trial (NCT 03649139), this study aimed to evaluate the change in M2 macrophages during pollen exposure in seasonal allergic rhinitis (SAR). Methods: Nasal symptom scores were recorded. Peripheral M2 macrophages were investigated according to cell surface markers, and M2-associated cytokine/chemokine release in serum and nasal secretion were assessed. In vitro pollen stimulation tests were performed, and polarized macrophage subsets were analyzed by flow cytometry. Results: Compared to baseline, the percentage of peripheral CD163+ M2 macrophages in CD14+ monocytes increased during the pollen season (p < 0.001) and at the end of treatment (p = 0.004) in the SLIT group. The percentage of CD206+CD86− M2 cells in M2 macrophages during the pollen season was higher than that at baseline and at the end of SLIT. On the other hand, the percentage of CD206−CD86+ M2 cells in M2 macrophages significantly increased at the end of treatment in the SLIT group compared to baseline (p = 0.049), the peak pollen period (p = 0.017), and the placebo group (p = 0.0023). M2-associated chemokines CCL26 and YKL-40 were significantly increased during the pollen season in the SLIT group and remained higher at the end of SLIT than at baseline. Correspondingly, in vitro study demonstrated that Artemisia annua promoted M2 macrophage polarization in pollen-induced AR patients. Conclusion: Significant M2 macrophage polarization was promoted when patients with SAR were exposed to the allergen, either naturally exposed in pollen seasons or subjectively continuously exposed during the course of SLIT.

Comparison of perennial and preseasonal allergoid immunotherapy in grass pollen allergic patients.

The clinical and immunological efficacy of preseasonal allergoid immunotherapy has been previously investigated, however, studies comparing the effectiveness of the two protocols are limited in the literature. The aim of this study is to compare the clinical and immunological efficacy of pre-seasonal and perennial allergoid immunotherapy. This is a prospective cross sectional two-arm study. During the season; symptom and medication scores were filled. Before and at the end of the season; RQLQ was applied, Phl p sIgE, sIgG4 and IL-10 levels were measured. In preseasonal group patients had better symptom control for most of the weeks, particularly during the peak pollen period (April: w-2 & w-4, p = 0.04; May: w-2, p = 0.02; June: w-1, w-2, p = 0.02; w-3, w-5, p = 0.03; July: w-2, p = 0.01; w-3, p = 0.02; w-4, p = 0.04). In the perennial group, sIgG4 [1st time point: preseasonal 0.02 mgA/L vs perennial 0.13 mgA/L (p < 0.0001); 2nd time point: preseasonal 0.52 mgA/L vs perennial 0.33 mgA/L; 3rd time point: preseasonal 0.04 mgA/L vs perennial 0.12 mgA/L (p < 0.0001)] and IL-10 (1st time point: preseasonal 1.45 pg/ml vs perennial 2.03 pg/ml; 2nd time point: preseasonal 2.29 pg/ml vs perennial 2.19 pg/ml; 3rd time point: preseasonal 2.32 pg/ml vs perennial 2.16 pg/ml) levels were higher and more stable. Preseasonal immunotherapy provided better control of symptoms throughout the pollen season. However, the blocking antibody response was stronger and more permanent in the perennial immunotherapy group.