High Pollen Levels Research Articles

Data mining assessment of Poaceae pollen influencing factors and its environmental implications

Poaceae pollen is highly allergenic, with a marked contribution to the pollen worldwide allergy prevalence. Pollen counts are defined by the species present in the considered area, although year-to-year oscillations may be triggered by different parameters, among which are weather conditions. Due to the predominant role of Poaceae pollen in the allergenicity in urban green areas, the aim of this study was the analysis of pollen trends and the influence of meteorology to forecast relevant variations in airborne pollen levels. The study was carried out during the 1993–2020 period in Ourense, in NW Iberian Peninsula. We used a volumetric Lanzoni VPPS 2000 trap for recording Poaceae airborne pollen grains, and meteorological daily data were obtained from the Galician Institute for Meteorology and Oceanography. The main indexes of the pollen season and their trends were calculated. A correlation analysis and ‘C5.0 Decision Trees and Rule-Based Models’ data mining algorithm were applied to determine the influence of meteorological conditions on pollen levels. We detected atmospheric Poaceae pollen during 139 days on average, mainly from April to August. The mean pollen grains amount recorded during the pollen season was 4608 pollen grains, with the pollen maximum peak of 276 pollen/m3 on 27 June. We found no statistically significant trends and slight slopes for the seasonal indexes, similarly to previous Poaceae studies in the same region. The calculated C5.0 model offered defined results, indicating that the combination of mean temperature above 17.46 °C and sunlight exposure higher than 12.7 h is conductive to significantly high pollen levels. The obtained results make possible the identification of risk moments during the pollen season for the activation of protective measures for sensitized population to grass pollen.

Assessing pollen extreme events over a Mediterranean site: Role of local surface meteorology

The presence of very high pollen levels in the atmosphere is associated with a strong impact on health and a worsening of symptoms in people who already have a respiratory disease. However, there is no specification on the aerobiological, environmental and meteorological factors that allow for characterizing a pollen event as of great magnitude due to the significant impact it can cause on the population and the environment. This work proposes criteria to typify the levels of atmospheric pollen as an extreme pollen event (EPE), and aims to determine the meteorological variables that can affect the presence and permanence of high pollen concentrations over a period of time. To address this goal, the quasi-climatological pollen dataset recorded in Granada (Southeastern Spain) during the period 1992–2019, has been used. On the daily accumulated pollen concentrations, the 95th, 97th and 99th percentiles were calculated. Spearman's correlation between the pollen concentration exceeding the proposed thresholds (C > P95, C > P97, C > P99) and surface meteorological variables recorded during up to five days before the event were established in order to identify the meteorological conditions that might affect the EPEs. As for the number of days with values higher than the established percentiles, it has been seen that in the case of total pollen and Olea, Cupressaceae and Pinus, there is a robust monotonically ascending trend throughout the study period. Regarding meteorological variables, relative humidity and 24-h accumulated precipitation are shown as the two most influential variables up to three days before the event, although temperatures, visibility and wind direction also show a correlation with some pollen types. The criteria proposed in this work allow us for classifying high levels of pollen as an EPE, and lay the foundations of these extreme events in a context of climate change in which they will become more frequent.

Identifying patterns of airborne pollen distribution using a synoptic climatology approach

Understanding the mechanisms of pollen release and dispersion in the atmosphere is of high importance, not only for getting an insight on the patterns of movement of these biological particles that are necessary for plants' reproduction, but also because exposure to airborne pollen is a major concern for respiratory allergies worldwide. In this work, a synoptic circulation-to-environment classification method was adopted to elucidate the relationship between distinct atmospheric patterns and pollen levels for the 11 most abundant but also allergenic taxa in Thessaloniki, Greece, for the 15-year period 1987–2001. It was found that the NW1 depressional weather type is associated with the “low winter pollen season” and high levels of pollen from Carpinus spp., Corylus spp., Cupressaceae, Platanus spp., Pinaceae, Quercus spp. and Urticaceae. In contrast, the SW1 cyclonic type is linked to the “high spring-summer pollen season” and high levels of pollen from Oleaceae and Urticaceae. On the other hand, anticyclonic weather is associated with the “summer-autumn pollen season” and high levels of Poaceae and Chenopodiaceae pollen in the atmosphere. Regional transport of Alnus pollen is linked to a strong high-pressure system centered over Italy, giving light NE winds over northern Greece. These findings shed light to the synoptic climatology of airborne pollen in Thessaloniki and could feed early-warning systems for alerting vulnerable groups of the allergic population.

Pollen exposure at birth and adolescent lung function, and modification by residential greenness.

Exposure to high levels of pollen in infancy is a risk factor for allergic respiratory diseases in later childhood, but effects on lung function are not fully understood. We aim to examine associations between grass pollen exposure in the first months of life and lung function at 12 and 18years, and explore potential modification. Using the Melbourne Atopy Cohort Study, a birth cohort of children with a family history of allergic diseases, we modeled the association between cumulative grass pollen exposure up to 3months after birth, on FEV1 , FVC, and FEV1 /FVC ratio at 12 and 18years. We also assessed modifying effects of residential greenness levels (derived from satellite imagery), asthma, and early life sensitization to ryegrass. Grass pollen exposure in the first 7days was associated with a reduction in FEV1 (-15.5mL; 95% CI: -27.6, -3.3 per doubling of pollen count) and FVC (-20.8mL; -35.4, -6.1) at 12years, but not at 18years. Increase in cumulative grass pollen exposure up to 3months was negatively associated with FVC at 12 and 18. Exposure to high residential greenness modified the association at 18 years. Early exposure to grass pollen was associated with decreased lung function in children and adolescents. Targeted interventions for pollen avoidance strategies that take into account local topography could be implemented alongside other clinical interventions such as immunotherapy.

Something in the air? Air quality and children's educational outcomes

Poor air quality has been shown to harm the health and development of children. Research on these relationships has focused almost exclusively on the effects of human-made pollutants, and has not fully distinguished between contemporaneous and long-run effects. This paper contributes on both of these fronts. Merging data on ambient levels of human-made pollutants and plant pollen with detailed panel data of children beginning kindergarten in 2010, I study the relationship between poor air quality on achievement in early grades. I also provide tentative estimates of the effects of air quality in the first years of life on school-readiness. I find that students score between 1 to 2 percent lower on math and reading scores on days with high levels of pollen or fine airborne particulate matter, and that asthmatic students score about 10 percent lower on days with high levels of ozone. I find suggestive evidence that poor air quality during early childhood negatively affects school readiness.

Suicide risk in relation to air pollen counts: a study based on data from Danish registers

ObjectivesSince the well-observed spring peak of suicide incidents coincides with the peak of seasonal aeroallergens as tree-pollen, we want to document an association between suicide and pollen exposure with empirical...

Pollen exposure in pregnancy and infancy and risk of asthma hospitalisation - a register based cohort study

BackgroundA seasonal effect of month of birth and risk of allergic disease has been suggested by numerous studies. Few studies have directly measured pollen exposures at different points during pregnancy and in early life, and assessed their effects on risk of respiratory disease outcomes.MethodsPollen exposure was calculated for the first and last 12 weeks of pregnancy and the first 12 weeks of infancy for all children conceived by women residing in Stockholm, Sweden, between 1988 and 1995. Hospital admission data for respiratory conditions in the first year of life was also collected.ResultsOut of 110,381 children, 940 had been hospitalised for asthma by 12-months of age. Pollen levels showed both marked seasonal variations and between year differences. Exposure to high levels of pollen in the last 12 weeks of pregnancy was associated with an increased risk of asthma hospitalisation (aOR = 1.35, 95% CI = 1.07-1.71 for highest quartile versus remaining infants). Exposure to high levels of pollen in the first three months of life was associated with a reduced risk (aOR = 0.76, 95% CI = 0.59-0.98) but only in children of heavy smoking mothers.ConclusionsHigh levels of pollen exposure during late pregnancy were somewhat unexpectedly associated with an elevated risk of hospitalisation for asthma within the first year of life.

Relationship between climate, pollen concentrations of Ambrosia and medical consultations for allergic rhinitis in Montreal, 1994–2002

The aim of this study is to evaluate the influence of meteorological factors on Ambrosia pollen concentrations and its impact on medical consultations for allergic rhinitis of residents from various socio-economic levels in Montréal (Québec, Canada) between 1994 and 2002. The study was conducted to recognize the sensitivity of pollen productivity to daily climate variability in order to estimate the consequences on human health vulnerability in the context of global climate change. Information related to medical consultations for allergic rhinitis due to pollen comes from the Quebec Health Insurance Board (Régie de l'assurance-maladie du Québec). Ambrosia pollen concentration was measured by the Aerobiology Research Laboratories (Nepean, Ontario). Daily temperature (maximum, minimum, and mean) and precipitation data were obtained from the Meteorological Service of Canada. Socio-economic data come from the 1996 and 2001 census data of Statistics Canada. Between 1994 and 2002, during the Ambrosia pollen season, 7667 consultations for allergic rhinitis due to pollen were recorded. We found a significant association between the number of medical consultations and pollen levels. Significant associations were detected for over-consultation the day of exposure, 1, 2, 3 and 5 days after exposure to high levels of pollen. The consultation rate is higher from low-income residents (3.10 consultations per 10,000 inhabitants) than for high-income (1.65 consultations per 10,000 inhabitants). Considering the demonstrated impact of pollen levels on health, it has become critical to ensure adequate monitoring of Ambrosia and its meteorological sensivity in the context of the anticipated climate change and its potential consequences on human health.

Barrier to gene flow between two ecologically divergent Populus species, P. alba (white poplar) and P. tremula (European aspen): the role of ecology and life history in gene introgression

The renewed interest in the use of hybrid zones for studying speciation calls for the identification and study of hybrid zones across a wide range of organisms, especially in long-lived taxa for which it is often difficult to generate interpopulation variation through controlled crosses. Here, we report on the extent and direction of introgression between two members of the "model tree" genus Populus: Populus alba (white poplar) and Populus tremula (European aspen), across a large zone of sympatry located in the Danube valley. We genotyped 93 hybrid morphotypes and samples from four parental reference populations from within and outside the zone of sympatry for a genome-wide set of 20 nuclear microsatellites and eight plastid DNA restriction site polymorphisms. Our results indicate that introgression occurs preferentially from P. tremula to P. alba via P. tremula pollen. This unidirectional pattern is facilitated by high levels of pollen vs. seed dispersal in P. tremula (pollen/seed flow = 23.9) and by great ecological opportunity in the lowland floodplain forest in proximity to P. alba seed parents, which maintains gene flow in the direction of P. alba despite smaller effective population sizes (N(e)) in this species (P. alba N(e)c. 500-550; P. tremula N(e)c. 550-700). Our results indicate that hybrid zones will be valuable tools for studying the genetic architecture of the barrier to gene flow between these two ecologically divergent Populus species.

Ragweed pollen forecasting

Rationale Pollen from Ambrosia species are the most important pollen allergens in North America, and the ability to accurately predict day to day pollen levels could provide important benefit to sensitive individuals. Methods Daily ragweed pollen concentrations from 1987 to 2001 collected with a Burkard spore trap were analyzed to determine pollen season characteristics. Daily concentrations were also compared with data from the National Weather Service to determine the effects of meteorological conditions on airborne pollen levels and to develop an empirical forecasting model. The model was used to predict daily pollen levels during the 2002 ragweed season. Results Pollen data from 1987 to 2001 showed that the mean start date (5% of season total) was 27 Aug; the mean date of the season peak was 10 Sep; and the mean ending date (95% of season total) was 11 Oct. Meteorological parameters used in model development include temperature, relative humidity, wind speed, and rainfall. Forecasts were generated each morning from 1 Sep to 31 Oct and published on the internet at http://pollen.utulsa.edu. Pollen levels were predicted as Low, Moderate, High, and Very High as defined by the National Allergy Bureau. In addition, intermediate levels were also used. Following the ragweed season, forecasts were compared with the daily pollen concentration. Analysis showed that the model successfully predicted pollen severity on 84% of the days during the 2002 ragweed season. Conclusions Pollen forecasting can provide predictions of daily pollen levels and enable sensitive individuals to avoid exposure to high pollen levels or take prophylactic medication.

VEGETATIVE AND FLORAL CHARACTERISTICS OF SIX STRAWBERRY CULTIVARS ASSOCIATED WITH FRUIT SIZE, YIELD AND SUSCEPTIBILITY TO TARNISHED PLANT BUG INJURY

Strawberry cultivars can differ in their susceptibility to tarnished plant bug injury, but the mechanisms for such differences have not been determined. Isolating such mechanisms could allow breeders to develop significant insect resistance in commercial strawberry cultivars. Selected vegetative and floral characteristics were measured in six strawberry cultivars grown in a perennial matted row system and compared to the yield data and levels of tarnished plant bug injury. 'Mira' and 'Mesabi' had the highest marketable yields, followed by 'Jewel' and 'Sable'. 'Cabot' and 'Northeaster' had the lowest yields. 'Cabot' had the largest fruit size, followed by 'Jewel', 'Mira', 'Northeaster', 'Sable' and 'Mesabi'. Naturally occurring levels of tarnished plant bug injury were lower than expected, but some significant differences were observed among the six cultivars. 'Mire', 'Northeaster' and 'Cabot' had the highest levels of tarnished plant bug injury. 'Jewel', 'Mesabi' and 'Sable' had lower levels of injury. There was no significant correlation between yield and levels of tarnished plant bug injury, reflecting the low levels of injury in this experiment. Of the parameters evaluated, only high pollen levels were significantly correlated with higher levels of tarnished plant bug injury. Flower size, flower number, pedicel length, peduncle length and petiole lengths were not significantly correlated with injury. Primary flower diameter and flower dry weight were positively correlated with average fruit weight.

Pollen count forecasting.

Pollen forecasting is becoming increasingly important to allergists as an adjunct to effective patient care. Forecasts allow patients to avoid exposure to high pollen levels and prompt them to take prophylactic medication and to plan outdoor activities for periods of low pollen levels. Investigators are making progress in developing effective models for daily and seasonal forecasts for important pollen allergens; however, current models are limited to specific geographic areas. Models for the onset of the season for spring tree pollen are based on the chilling and heat units that are required before flowering can occur. Models for pollen season severity are based on regression analysis of preseason meteorologic conditions, and models for daily forecasts are based on the normal pollen curve and responses to day-to-day meteorologic conditions. When winds are favorable, long-distance transport can introduce allergenic pollen types into a local area. The Mountain Cedar Pollen Forecasting model, which combines day-to-day release forecasts at source areas and dispersion forecasts to downwind areas, has been reasonablly successful over the past 4 years. All pollen forecasting models are dependent on accurate meteorologic forecasts, and pollen forecasting will become more accurate as meteorologic forecasts improve.

Allergenic pollens in south-east Spain.

. MANY of the 93 airborne pollen types found in the Murcia area occur in notably different patterns to those reported in other Spanish sites and from those shown in European calendars (4). These calendars have been used for many years as the ‘classical’ reference source because of the poor development of aerobiology in Spain until recently. The particular climate in Murcia area (mean annual temperature of 16.88C) allows many species to flower repeatedly throughout the year. That is why some pollen taxa .(Fig. 1) show especially long pollen seasons which have been rarely described or, as in the case of Phoenix and Artemisia, have not been reported outside south-east Spain (1). High incidence of Chenopodiaceae-Amaranthaceae in Murcia (49.5%) is probably due to these high pollen levels. Brassicaceae is seldom referred to as an airborne pollen and usually occurs for periods not exceeding one month, but in Murcia this pollen occurs continuously for almost five months. Certain other taxa (Fig. 1) are unusual because they bloom outside the ‘‘classical’’ times. Casuarina pollen occurs in February and June (not reported hitherto in Europe), and Artemisia shows an autumnal pollen season and a very important winter one that does not occur out of south-east Spain (1); these are the more interesting and noteworthy ‘‘out of season’’ pollen taxa. Finally, consideration must be given to some unique pollen types (Fig. 1), which are rarely referred to as airborne or which are totally absent in other localities. Among these are Zygophyllum which has been reported only in the Murcia region, and which was recently identified as an allergen (4). Records of pollen levels for Caryophyllaceae are up to 37 times higher in Murcia than those referred to in Italian sites, and four times higher than those recorded in other Spanish localities. We compared ordinary pollen skin prick test protocols of the major Murcian hospitals with protocols of several allergologists, and found that no more than seven pollen types are customarily included, namely Artemisia (incidence of 23.5%), Chenopodiaceae (49.5%), Olea (68.4%), Parietaria (51.0%), Plantago (17.9%), Poaceae (55.1%), and Rumex (9.7%). Yet up to 21 pollen taxa occurring in concentrations hypothetically high enough to provoke local or regional allergic disease could be .systematically ignored in skin prick test protocols. Nine of them have been positively identified as allergens affecting the Murcia population: Acer (incidence of 10.2%), Cupressus (2.5%), Mercurialis (9.7%), Morus (8.7%), Pinus (1.0%), Platanus (11.2%), Quercus (2.5%), Robinia (7.6%) and recently Zygophyllum (15.3%). For another 12 species the incidence is still unknown: Apiaceae, Brassicaceae, Caryophyllaceae, Casuarina, Cyperaceae, Eucalyptus, Fraxinus, Ligustrum, Phoenix, Pistacia, Populus and Thymelaea. All in all, we strongly recommend allergologists to consider these new types of plant pollen and evaluate the convenience of including them in the standard skin prick test. A example of the importance of considering minority pollen types is the recent discovery of Zygophyllum as an Of the 93 species some

A springtime Olympics demands special consideration for allergic athletes

Background: The Sydney Olympic and Paralympic Games will be held in September-October 2000, which is early to mid-spring in the southern hemisphere. Pollen-sensitive athletes may encounter problems with allergic symptoms triggered by pollen exposure, thus compromising their ability to attain peak performance. Objective: We sought to monitor pollen levels at the major Olympic venues to provide information for allergic athletes and their team doctors in order to adequately prepare them for Olympic competition. Methods: We performed aerobiologic monitoring of the major Olympic venues to provide a profile of the most prevalent pollen species appearing during the spring. In the second part of this study, we surveyed a population of elite Australian athletes from Olympic sports to ascertain the prevalence of allergic rhinoconjunctivitis, to investigate the major allergens involved in sensitization, and to conduct a pilot study to assess the effect of allergic rhinoconjunctivitis on quality of life. Results: The pollen counts obtained at the 3 major sites were high over the period of Olympic competition. Tree pollens appeared from July, and grasses appeared from early September and peaked in the second week of October, the beginning of Paralympic competition. A relatively small number of pollen varieties comprise the majority of the total pollen count. Two hundred fourteen athletes (61% male; mean age, 21 ± 16 years) representing 12 Olympic sports participated in the study. Fifty-six percent gave a symptom history consistent with allergic rhinoconjunctivitis, 41% had symptoms of allergic rhinoconjunctivitis and a positive test response to any one allergen, and 29% had seasonal allergic rhinoconjunctivitis (a positive history and at least one positive skin prick test response to a seasonal allergen). Athletes from aquatic sports were more likely to have symptoms than those from other sports. Symptom scores were higher and quality of life ratings were poorer in allergic compared with nonallergic athletes over the spring period. Conclusion: Olympic team managers and medical officers need to adequately prepare Olympic athletes for the possibility of exposure to high pollen levels in the weeks leading up to this most important sporting event. Symptoms of pollen sensitivity, such as rhinoconjunctivitis and exacerbation of asthma, could be devastating to athletes expecting peak performance. Potential Olympic athletes should be screened for the possibility of pollen allergy and have medical programs with permitted medication tailored to meet their needs. This may involve preventative therapy with medication, such as intranasal corticosteroid sprays or immunotherapy programs, if symptoms are particularly severe. The newer nonsedating antihistamines are the treatment of choice for acute intermittent symptoms. Appropriate management will ensure that the allergic athlete will safely perform to maximum ability with permitted medication during the Spring 2000 Olympic Games in Sydney. (J Allergy Clin Immunol 2000;106:260-6.)

A late Pleistocene vegetational and climatic history of part oxygen isotope stage 5, Ararata, south Taranaki, New Zealand

A late Pleistocene palynological record of vegetation and climate is investigated from a 5m lignite section within terrestrial cover beds of the Ngarino Marine Terrace on Ararata Road, near Hawera, south Taranaki, New Zealand. The pollen assemblages are dominated throughout by high levels of pollen derived from gymnosperm trees. A lower zone (AR1) is characterised by high levels of pollen of Prumnopitys taxifolia, Libocedrus, shrubs and grass, interpreted to represent a stadial phase with climate cooler and drier compared with present. A middle zone (AR2) is characterised by high levels of pollen of P. taxifolia, Dacrydium cupressinum, Metrosideros and spores of Cyathea dealbata-type and of the bryophyte Bryosporis anisopolaris Mildenhall and Bussell. Pollen values for Libocedrus and grass are low. These assemblages are similar to Holocene pollen spectra in the region but differ in containing high levels of Dracophyllum-type and Restionaceae pollen, and Gleichenia spores. The zone also lacks any significant levels of Ascarina lucida pollen, typical of interglacial maxima in this region, and is considered to represent an interstadial phase with climate approaching that of the present. The third zone (AR3) is characterised by high values for P. taxifolia, Nothofagus, shrub, and grass pollen with decreases in abundance of D. cupressinum and Metrosideros pollen, and C. dealbata-type spores in particular. This zone is considered to represent a transitional cooling phase leading into a stadial period. Climate was initially cooler and drier than present but may have become wetter later. The Ngarino Terrace marine deposits that underlie the section provide a maximum age constraint of c. 210,000 yr, while tephra within the lignite are estimated to age 70,000–110,000 yr, and amino acid racemisation dating of a wood sample in the lignite provides an age estimate of c. 80,000 ± 20,000 yr. The lower pollen zone (AR1) is correlated with stadial oxygen isotope substage 5d, the middle zone (AR2) is correlated with interstadial substage 5c, and the upper zone (AR3) is correlated with early stadial substage 5b. Climate during oxygen isotope substage 5c is inferred closely to have approached interglacial conditions similar to those of the present day. Libocedrus, Nothofagus menziesii, Halocarpus, Dracophyllum-type, and Gleichenia are some taxa which were growing near the Ararata Road Site at various times during oxygen isotope stage 5, but which are either not found in Taranaki today or are mainly restricted to higher altitudes or local areas in Taranaki.