Effects of sampling height and climatic conditions in aerobiological studies.

This study examined the effect of sampling height on the measurement of airborne particles (pollen grains) common in the sampling area in the outskirts of the city of Córdoba, Spain. The effect of certain meteorological parameters on variations in concentration at different heights were also examined. The study was carried out throughout 1991 and 1992 using two Hirst samplers placed at two different heights (1.5 and 15 m) at the Faculty of Science at the University of Córdoba. The statistical results indicated that there were significant differences in the concentrations obtained at different heights, the values at 1.5 m being generally higher with the exception of pollen belonging to the Urticaceae family. The pollen counts of this type were greater at the higher elevation, probably due to the small size of the pollen, especially in the Urtica membranacea species, and to the convective phenomena in this climatic zone in spring, the season in which this species blooms. When these height comparison studies were conducted, the importance of the effect of placing the sampler in relation to a nearby building was also observed. Higher pollen concentrations were detected when the lower sampler was located on the leeward side. The meteorological parameters studied had some influence on the vertical dispersion of the pollen, although the percentage of variation according to height was very small, probably due to the short duration of the study. However, a certain relation between the differences in concentration per height and the degree of atmospheric stability was observed.     

北京城区空气中花粉分析

目的探讨北京城区空气中花粉的种类、含量及逐月分布规律。方法采用重力沉降法的叶氏定点取样器，于1983—1986年及1999～2007年。对北京城区进行每日空气曝片花粉监测。结果1983。1986年空气曝片中花粉的种类分别属于34科35属2种，1999—2007年空气曝片中花粉的种类分别属于35科41属3种；其中云杉属的花粉颗粒最大（150μm×100μm），构属的花粉颗粒最小（13—15μm）。两个阶段20年间花粉含量月分布情况变化很大，1983—1986年峰值以8—9月份为最高，3～4月份为次高；1999—2007年以4月份为最高。8～9月份为次高。结论北京城区空气中常见的、含量高的花粉有10余种。蒿属花粉每年持续时间最长，含量最高；蓓草属花粉其次。近10年蓓草属花粉有增高的趋势．白蜡树及银杏树花粉大幅度增多。     

Airborne pollen calendar of Portugal: a 15-year survey (2002–2017)

IntroductionData about the occurrence of airborne pollen enables the creation of pollen calendars with an approximation of flowering periods for the most common allergenic plant species in a specific area. The aim of this work is to provide pollen calendar for each of the seven monitoring regions of Portugal based on 15 years of airborne sampling, in order to chart the seasonal behaviour of the main allergenic pollen types.Material and methodsAirborne pollen monitoring (2002–2017) was carried out by the Portuguese Aerobiology Network (RPA), using Hirst-type volumetric spore traps, following well-established guidelines.ResultsA total of 14 airborne pollen types were recorded at RPA monitoring stations, of which 64.2% belong to trees, 28.5% to herbs and 7.1% to weeds. The airborne pollen spectrum is dominated by important allergenic pollen types such as Poaceae, Quercus spp., Urticaceae and Cupressaceae. The average pollen index was 42.557 in mainland Portugal and 3.818 in the Islands. There was an increased trend in the airborne pollen levels over the years, namely in Coimbra, Évora and Porto, compared to the remaining regions.ConclusionThis report provides accessible information about the main allergenic airborne pollen types occurring in the course of the year. The pollen calendars charted for each Portuguese region showed that the occurrence of most allergenic taxa was centred from March to July. Pollen peak concentrations were detected earlier in the Centre and Lisbon and Tagus Valley regions, and later in the remaining regions.     

Flora, distribution of vegetation and pollen content of the air: significance for allergics

The wealth of the flora of a given region cannot be seen in its airborne pollen list. Actually, for some plants there is a low probability that their pollens are recorded in the pollen counts (entomogamous plants, in particular). Moreover, the light microscopy reduces the possibilities of determination. In France, The Aerobiological Network of Surveillance (RNSA) retains 92 taxa at different levels (gender, family, group of families), and among them allergenic as well as non allergenic taxa. From the 130 families of the France flora, 63 are taken into account in the pollen studies, 57 taxa being determined at the gender level. The comparison between the surface occupied by the tree species in the French departments of C?te-d'Or and Sa?ne-et-Loire, and the average airborne pollen concentrations showed that usually there is no correspondence between the abundance of a plant and the number of its pollen in the records. So the flora of a region does not give enough information allowing to know the taxonomic composition and the pollen quantities in the air, which is of particular importance for allergic people.     

上海中心城区气传花粉调查

目的明确上海市全年气传花粉的种类和数量及其分布特征。方法应用重力沉降法对上海市中心城区2009年11月至2010年10月间的气传花粉进行监测。结果全年共监测到2个花粉含量高峰,分别为3-5月和9-10月。全年气传花粉分布有明显的种属差异,树木类花粉占全部花粉计数的65.55%,莠草类及禾本科花粉占全部花粉计数的27.74%。春季以树木类花粉为主,主要为构属(45.64%)、悬铃木属(6.06%)和松科(7.86%);而秋季以莠草类及禾本科花粉为主,主要为葎草属(59.01%)、禾本科(18.45%)和蒿属(5.32%)。结论上海市中心城区气传花粉的分布呈现2个高峰;构属花粉和葎草属花粉分别是上海市中心城区春、秋两季最主要的气传花粉。这为花粉预报、确定主要致敏花粉奠定了基础。     

Male flowering index can predict the annual airborne pollen count of Cryptomeria japonica at different altitudes

Cryptomeria japonica D. Don (the so-called Sugi or Japanese cedar) is one of the most important coniferous afforestation species. Its afforestation area today has reached 4.5 million hectares, making up 45% of the afforestation area in Japan. Cryptomeria japonica pollinosis was first reported in 1964. The prevalence of this disease has increased yearly and now affects over 10% of the Japanease population. In order to establish an accurate prediction method of airborne pollen counts for C. japonica, research into the relationship between the amount of airborne pollen, the distribution of C. japonica forests and flowering conditions has become very important. In order to clarify differences in airborne pollen counts at different altitudes, four gravity samplers (Durham's type) were set up at four observation points that were located from the coast to the side of a mountain up to 780 m altitude in Toyama Prefecture, Japan. The male flowering index and distribution of C. japonica forests were determined in order to evaluate the quantity of male flowers. The relationship between airborne pollen counts, the distribution of C. japonica forests and the male flowering index at each observation point was examined. There was a high positive correlation between the male flowering index of C. japonica and airborne pollen counts. The male flowering indices, as well as the distribution of C. japonica forests at different altitudes, were closely associated with airborne pollen counts at different altitudinal observation points. The flowering index and the distribution of C. japonica forests are useful indicators for the accurate prediction airborne pollen counts of C. japonica.     

四川省成都市城区气传花粉监测

目的探索四川省成都市城区气传花粉的种类、数量及飘散规律。方法应用重力沉降法于2018年3月1日至2019年2月28日在四川省成都市城区进行为期1年的连续每日气传花粉曝片。结果共收集到花粉139520粒/1000 mm 2,能鉴定的花粉总计隶属36科、31属、2个种。其中构属花粉含量最高,达81754粒/1000 mm 2,占全年花粉总量的58.60%,其播粉期为3~4月,高峰期为3月下半月至4月上半月;其次是柏科花粉,达27518粒/1000 mm 2,占全年花粉总量的19.72%,其播粉期为1~3月,高峰期为1月下旬至3月上旬;大麻/葎草属占第三位,花粉含量5112粒/1000 mm 2,占全年花粉总量的3.66%,其播粉期为8~10月,高峰期为8月下旬至10月下旬。上述3种花粉为本地区优势气传花粉,合计占全年花粉总量的81.98%。含量超过1%的花粉还依次包括银杏、桦木属、松属、悬铃木属、枫杨属及蒿属花粉。全年花粉含量月分布呈现2个高峰,第一高峰为1~5月,主要气传花粉为构属、柏科、银杏、桦木属、松属、悬铃木属、枫杨属等树木花粉,占全年花粉总量的89.38%。第二高峰为8~10月,主要气传花粉为大麻/葎草属、蒿属等莠草花粉,占全年花粉总量的5.04%。结论本地区花粉季节有两个:春季为主要花粉季节,主要气传花粉为构属、柏科等树木花粉;夏秋季为次要花粉季节,主要花粉气传为大麻/葎草属、蒿属等莠草花粉。构属、柏科、大麻/葎草属花粉为本地区优势气传花粉,构属花粉为本地区绝对优势气传花粉。     

Aerobiological study of Chenopodiaceae and Amaranthaceae in the Mediterranean area of southwestern Spain.

The study area is characterized by a maritime Mediterranean climate, abundant presence of Chenopodiaceae in the vegetation, and a high incidence of pollinosis caused by the pollen of this family. A Hirst-type sampler was used to determine pollen concentrations in the air of the city of Huelva during 3 consecutive years (1995-1997). The total annual amount of Chenopodiaceae-Amaranthaceae pollen was between 10.59% and 6.28% of the pollen spectrum of the city, depending on the year. The annual pattern of variation in pollen concentration (5-day means) was very similar in the 3 years, and no statistically significant differences were found between years. This pattern is characterized by concentrations not exceeding 20 grains/m3 between April and the beginning of August, with an obvious seasonal variation in the second half of August and September, when the 5-day mean concentrations exceeded 40 grains/m3 and the daily maxima exceeded 100 grains/m3. This coincided with the flowering of most of the species in the group. The meteorological parameters with a statistically significant effect on daily pollen concentration during the pollen season (August 15 to September 20) included mean temperature and south wind (positive correlations) and relative humidity of the air (negative correlation). The highest intradiurnal concentrations were found between 10:00 a.m. and 5:00 p.m.     

Concentration of airborne pollen from Cupressaceae in Lisbon

The concentration of airborne pollen from Cupressaceae was regularly monitored++ in Lisbon during 1997 and 1999, and the phenology of flowering cypress was studied in several species of the genus from 1992 to February 2000. Both methods showed a peak of pollen abundance during the month of February, with the airborne pollen concentration decreasing strongly to March and April. The results obtained are in accordance with the literature for the Mediterranean area, but in Lisbon the peak started and finished earlier than in other Mediterranean towns already studied.     

Allergenic pollen in the subdesert areas of the Iberian peninsula.

The yearly distribution of Artemisia and Chenopodiaceae-Amaranthaceae, two of the most common types of pollen in a rural area located in the southeastern part of the Iberian peninsula, was studied over a 3-year period (1995-1997). The particular bioclimatic conditions of the area, such as its subdesert climate, extreme dryness and high mountain location (1,000 m above sea level), have led to the adaptation and abundance of these species in this area. They usually flower in the second half of the year, and are the main pollen types collected in the samples in that time period. The Artemisia pollen levels recorded are the highest in Spain, since there are several species in the area which flower at different times. Chenopodiaceae-Amaranthaceae pollen counts are also very high. The severity of both pollen types was also analyzed. The height of the sampler was taken into account because the quantities at human height can be considerably higher than those recorded at 20 m off the ground. It was concluded that both pollen types should be considered some of the main causes of allergy in this area.     

云南省曲靖市区气传花粉调查

目的为探明曲靖市区气传花粉飘散的种类、数量及季节分布特点,以指导本地区对花粉症的预防和脱敏治疗。方法采用全国统一的重力沉淀法,于2006年7月至2007年7月对曲靖市区进行一年曝片调查,对全年收集到的365张曝片进行显微鉴定和统计处理。结果全年共收到花粉56356粒,其中裸子植物33066粒,占58.7%。被子植物22552粒,占40%。蕨类植物738粒,占1.3%。裸子植物有9个科、属、种,被子植物有49个科、属、种,蕨类植物主要有三缝花和单缝花两个类型。全年有两个花粉高峰,分别为2-4月以松、柏、蔷薇、桑科为主的春季花粉高峰和9-11月以旱冬瓜、蒿属为主的秋季高峰,其他月份花粉数量相差不大。蕨类植物花粉数量不多,但常年均有飘散。结论与全国及云南其他各地比较,曲靖市空气中花粉飘散的数量最多、种类也多,且常年均有飘散,尤其是桑科、豆科、蒿属、柳属、杨属、旱冬瓜、油菜花粉的数量较其他地区更为突出。     

Behavior of Platanus hispanica pollen, an important spring aeroallergen in northwestern Spain.

BACKGROUND AND OBJECTIVE: Platanus hispanica trees are considered an important source of airborne pollen allergens in many cities of Western Europe. As the prevalence of sensitization to this species is 8% to 9% in northwestern Spain, our objective was to propose models predicting both the onset of the pollen season and the mean daily pollen concentrations. METHODS: Airborne P. hispanica pollen was monitored from 1993 through 2002 with 2 Hirst volumetric spore traps in Ourense and Santiago de Compostela in northwestern Spain.The pollination start dates were determined and the data were fitted to predictive regression models, which were tested for the year 2002. RESULTS: P. hispanica pollen is present in the atmosphere from March to April. The main pollination period is short with a mean duration of around 40 days. The mean maximum daily concentrations exceeded 100 pollen grains/m(3). As temperature is the parameter that most influences atmospheric pollen levels, this variable was chosen as the basis for models predicting both the onset of the pollen season and daily pollen concentrations. The predicted onset date was a few days later than the real start date in 2002. However, the model gave an accurate prediction of the mean daily pollen concentration. CONCLUSIONS: The mean daily concentrations of P. hispanica pollen are high, and given the allergenic potential of this species, it should be taken into account as one of the most important local spring allergens. The weather-related models proposed help us to predict P. hispanica pollen concentrations in the atmosphere.     

Relationship between airborne Cry j 1 and the onset time of the symptoms of Japanese cedar pollinosis patients.

BACKGROUND: Some patients with Japanese cedar (JC) pollinosis already show pollinosis symptoms before the first day of the pollen season as determined by microscopic pollen counts. METHODS: Airborne pollen allergen (Cry j 1) levels were measured by electron spin resonance radical immunoassay, a highly-sensitive method for Cry j 1 with a sensitivity 10-100-fold higher than conventional enzyme-linked immunosorbent assay. The symptom data from patients with JC pollinosis were collected from a mobile phone site, "pollen check sheet", and the onset times of the patients' symptoms were analyzed. RESULTS: The relationship between airborne Cry j 1 levels and the onset time of pollinosis symptoms was investigated. The symptoms of some patients began at the time airborne Cry j 1 levels fluctuated at 1 to 3 pg/m3 and symptom scores increased at the time of sudden increase in Cry j 1 levels. About 40% of patients began to show symptoms until the first day of the pollen season and the time nearly corresponds to the time of sudden increase in Cry j 1 levels. CONCLUSIONS: Pollinosis symptoms of some patients began at the time airborne Cry j 1 levels fluctuated at 1 to 3 pg/m3 and symptom scores increased at the time of sudden increase in Cry j 1 levels. The latter time nearly corresponds to the first day of the pollen season.     

2010-2011年青岛市气传花粉调查

目的调查青岛市气传花粉的种类、含量和季节分布特点并与25年前的资料进行对比分析,为本地区花粉症的诊断和防治提供依据。方法采用重力沉降法安装叶氏花粉采样器。自2010年3月1日至2011年2月28日,进行逐日空气曝片花粉监测,并进行野外考察。结果全年花粉总含量为4018粒,较1985年减少了9.18%。共鉴定出14个科、26个属、2个种,全部归属于29科28属2个种;比1985年增加了10个科、11个属、2个种,未见到蓖麻花粉。全年出现春季3-5月和夏秋季8-10月2个花粉分布高峰期,3-5月份松属、桦木属和悬铃木属等木本植物花粉为主,比1985年增加了26.19%。8-10月以草本植物花粉为主,比1985年减少了47.48%。与1985年对比,年花粉含量变化较大的气传花粉有12种。全年树木花粉增多,草本花粉减少,以蒿草、葎草和豚草花粉减少明显。结论青岛地区主要气传花粉为松属、蒿属、葎草属、桦木属、杨属、禾本科、豚草属、悬铃木属等,对青岛地区花粉症的防治具有重要意义。     

Analysis of new respiratory allergies in patients monosensitized to airborne allergens in the area north of Milan.

BACKGROUND: A recent study carried out in North of Milan, an area that was recently colonized both by birch and ragweed pollen, showed that subjects developing allergies to these "new" allergens were much older than those becoming allergic to "traditional" airborne allergens, which suggests that predisposition to develop respiratory allergies is probably allergen-specific, persists throughout life, and does not occur until the patient encounters the appropriate allergen for a sufficiently long period. OBJECTIVE: The present study aimed to test this hypothesis by following-up a large cohort of patients monosensitized to airborne allergens. METHODS: The prevalence and characteristics of new sensitizations to airborne allergens after >2 years of follow-up were retrospectively assessed in 726 patients monosensitized to grass, pellitory, mite, birch, ragweed, Alternaria, mugwort, or plantain living North of Milan. RESULTS: The overall prevalence of new sensitizations was 35% (256/726), with marked differences between the subgroups ranging from 11% in Alternaria-allergic subjects to 46% in grass-allergic subjects. Patients allergic to grass, birch, or pellitory pollen showed a significantly higher propensity to become sensitized to a second airborne allergen than subjects allergic to ragweed, Alternaria, and mite. Overall, the "new" allergens (birch and ragweed) caused 228/256 (89%) new sensitizations detected in the whole study group. Ragweed pollen induced 90% (38/42) of new sensitizations in birch pollen allergic patients, and birch pollen induced 80% (8/10) of new sensitizations in ragweed allergic patients. No difference in age at the first visit or in duration of the follow-up between patients developing and not developing new respiratory allergies was observed. CONCLUSION: This study shows that: 1) predisposition to develop respiratory allergies is allergen-specific and persists throughout life; 2) proneness to become allergic to certain airborne allergens might be associated with primary sensitization to specific airborne allergens; 3) in monosensitized adults, sensitization to another airborne allergen that has been always present in that particular geographical area is unlikely.     

宁波市气传花粉研究

目的明确宁波市城区全年气传花粉种类和数量及其分布特征。方法应用重力沉降法对宁波市城区2012年1月至12月气传花粉进行调查。4个重力花粉采样器分别放置于城区海曙区,以及郊区镇海区、鄞州区和北仑区。结果全年共有2个花粉含量高峰,分别为3至5月和8至10月。海曙区共收集花粉7880粒/1000 mm~2,可鉴定出11个科,24个属,3个种。其中,树木类花粉总计7436粒/1000 mm~2(94.37%),草本类花粉332粒/1000 mm~2(4.21%)。3月至5月共收集到花粉7248粒/1000 mm~2(91.98%),以树木类花粉为主,花粉量较多的依次为松属(27.69%)、桑属(17.79%)、柏科(16.42%)。8月至10月共收集到花粉342粒/1000 mm~2(4.34%),以草本类花粉为主,花粉量较多的依次蒿属(0.96%)、禾本科(0.81%)和大麻葎草属(0.63%)。镇海区共收集花粉4090粒/1000 mm~2,可鉴定出13个科,23个属,3个种;其中,树木类花粉2962粒/1000 mm~2(72.42%),草本类花粉988粒/1000 mm~2(24.16%),花粉含量较多的依次为松属(21.66%)、柏科(12.37%)和柳杉属(10.90%)。鄞州区共收集花粉2568粒/1000mm~2,可鉴定出12个科,20个属;其中,树木类花粉1900粒/1000 mm~2(73.99%),草本类花粉522粒/1000 mm~2(20.33%),花粉含量较多的依次为松属(21.48%)、柏科(17.76%)和柳杉属(7.32%)。北仑区共收集花粉2204粒/1000mm~2,可鉴定出9个科,21个属;其中,树木类花粉1580粒/1000 mm~2(71.69%),草本类花粉526粒/1000 mm~2(23.87%),花粉含量较多的依次为松属(19.42%)、柏科(13.25%)和柳杉属(10.8%)。结论宁波市城区气传花粉分布呈现2个高峰,松属、桑属、柏科和柳杉属是其主要气传花粉。研究为花粉预报、确定主要致敏花粉奠定了基础。     

Higher airborne pollen concentrations correlated with increased SARS-CoV-2 infection rates,as evidenced from 31 countries across the globe

Pollen exposure weakens the immunity against certain seasonal respiratory viruses by diminishing the antiviral interferon response. Here we investigate whether the same applies to the pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is sensitive to antiviral interferons, if infection waves coincide with high airborne pollen concentrations. Our original hypothesis was that more airborne pollen would lead to increases in infection rates. To examine this, we performed a cross-sectional and longitudinal data analysis on SARS-CoV-2 infection, airborne pollen, and meteorological factors. Our dataset is the most comprehensive, largest possible worldwide from 130 stations, across 31 countries and five continents. To explicitly investigate the effects of social contact, we additionally considered population density of each study area, as well as lockdown effects, in all possible combinations: without any lockdown, with mixed lockdown−no lockdown regime, and under complete lockdown. We found that airborne pollen, sometimes in synergy with humidity and temperature, explained, on average, 44% of the infection rate variability. Infection rates increased after higher pollen concentrations most frequently during the four previous days. Without lockdown, an increase of pollen abundance by 100 pollen/m³ resulted in a 4% average increase of infection rates. Lockdown halved infection rates under similar pollen concentrations. As there can be no preventive measures against airborne pollen exposure, we suggest wide dissemination of pollen−virus coexposure dire effect information to encourage high-risk individuals to wear particle filter masks during high springtime pollen concentrations.

Progress of COVID-19 is presumed to be often asymptomatic or associated with only mild to moderate symptoms, mainly fever and dry cough (1). However, in susceptible individuals, such as elderly persons with metabolic, cardiovascular, and/or pulmonary comorbidities (2), COVID-19 can exacerbate to severe pneumonia requiring oxygen supplementation and intensive care treatment. COVID-19−associated deaths are mainly due to severe acute respiratory syndrome (SARS), cytokine storm (3–5), or disseminated coagulopathy leading to multiorgan failure. According to World Health Organization (WHO) estimates, the overall case fatality rate is 3.4% (6, 7).SARS coronavirus 2 (SARS-CoV-2), the causative of COVID-19, is a novel member of the Betacoronaviridae family with presumed zoonotic origin (8). It is a positive-stranded RNA virus with a genome size of ∼30 kb (9). SARS-CoV, the agent of the SARS epidemic of 2002 and its closest related sibling, is highly susceptible to antiviral interferons (IFNs) and has developed immune suppression mechanisms on the basis of antagonizing host cell IFNs. The accessory proteins encoded by the genes ORF3b, ORF6, M, and N of SARS-CoV-2 are highly homologous to their SARS-CoV and Middle East respiratory syndrome counterparts, which are type I IFN antagonists (10). Another set of accessory proteins, encoded by the genes E, ORF3a, and ORF8b and common to both SARS-CoV and SARS-CoV-2, are activators of the NLRP3 inflammasome (11, 12) and have up to 95% interstrain amino acid sequence identity (9). Excessive inflammasome activation and subsequent pyroptosis is the underlying mechanism for the IL-1β dominated cytokine storm associated with SARS-CoV mediated multiorgan failure (4, 13).A recent, large cohort study from South Korea reported that asthma exacerbations in school-aged children are associated with coexposure to multiple seasonal environmental factors, that is, ozone, rhinovirus, and tree pollen (14). Another study recently reported that pollen grains of various plant taxa release as yet unidentified compounds that down-modulate the production of antiviral λ-IFNs in respiratory epithelial cells, and provided evidence from human and mouse models that pollen exposure leads to enhanced susceptibility to infection with two different respiratory viruses, human rhinovirus and respiratory syncytial virus (15). Also, some pollen types enhance the release of the IL-1 family cytokines IL-1β, IL-18, and IL-33 from epithelial cells in vitro, indicating a role for pollen in NLRP3 inflammasome activation (16, 17). Thus, two mechanisms of the innate immune response, inflammasome activation and antiviral IFN response, appear to be modulated toward the same direction by pollen and SARS-CoV-2.The first COVID-19 cases were officially reported for European countries at the middle to end of January 2020. On 12 March, the WHO officially announced the onset of a global COVID-19 pandemic, with over 33% of the world´s nations reporting local spreading of the infection. Around the same time, a large-scale warm spell across the bulk of the Northern Hemisphere initiated the first large seasonal peak in tree pollen emissions. The synchronized timing of the spreading of the infection and the higher pollen concentrations, in combination with the recently found potential of pollen to enhance susceptibility for respiratory viruses, prompted us to analyze whether, under certain weather conditions, a positive correlation between SARS-CoV-2 infections and airborne pollen could be observed. We therefore collected airborne pollen data from most pollen monitoring stations operating at that time, from a total of 31 countries and from all inhabited continents, including both the Northern and Southern Hemispheres, and investigated for relationships between daily pollen concentrations and SARS-CoV-2 infection rates, also taking meteorological and sociodemographic factors into account.Our results reveal that the simultaneous exposure to SARS-CoV-2 (via other infected human carriers) and airborne pollen may, under “favorable” weather conditions, promote viral infection. While it is meaningful to inform the public about this risk, the wording should be extremely well considered to avoid misunderstandings and to not cause panic. On the other hand, wide dissemination of the potential dire effects of virus−pollen coexposure ought to be urgently and clearly communicated: As we cannot avoid airborne pollen exposure, high-risk groups have to be informed to wear particle filter masks during the pollen season, especially in springtime.     

原市30年间2次气传花粉调查结果对比

目的调查研究太原市中心常见气传花粉的种类、含量、花粉飘散消长规律及分布特点。方法采用叶氏重力沉降法调查该地区2008年7月1日至2009年6月30日空气中花粉的种类和含量;将其调查结果与1977-1978年度花粉调查数据进行统计对比分析。结果本次调查共收集该地区空气中飘散花粉17192粒,全年气传花粉出现2次飘散高峰期,分别在3、4、5月份和8、9月份,新增气传花粉12种;收集到有害入侵植物豚草花粉。1977-1978调查年度空气中5种致敏花粉含量较高,占全年花粉总量的76.72%;2008-2009调查年度4种致敏花粉含量较高,占全年花粉总量的73.33%,蒿属花粉为优势气传致敏花粉（38.37%）。杨属、柳属花粉全年百分比含量较30年前明显降低。结论气候变暖可能是本次调查春季气传花粉高峰出现早、持续时间长的主要原因。外来入侵有害物种豚草花粉不容忽视。     

La sédimentation pollinique à l'intérieur et à l'extérieur d'une maison en région Rhône-Alpes durant la période de floraison de l’ambroisie

To better understand atmospheric pollen transport and to define the allergic risks incurred by an individual throughout the day, airborne pollen was counted continuously for several weeks, using a Cour pollen trap inside and outside a house in Saint-Priest, a town east of Lyon, France. The results of this preliminary study revealed a large variety of pollen inside the house. Approximately 60% of the taxa found in the environment close to the house were also present inside the house during the same period. Ragweed pollen, which is responsible for severe seasonal allergy, was the most prevalent taxon. These results underline the importance of pollen grains accumulating inside a house. It therefore seems advisable to investigate the factors responsible for the variations observed in the proportion of pollen grains transported into the interior of a house and to estimate the potential impact on pollen-allergic patients.     

Changing pollen types/concentrations/distribution in the United States: Fact or fiction?

The buildup of greenhouse gases in the atmosphere has resulted in global climate change that is having a significant effect on many allergenic plants through increases in plant productivity and pollen allergenicity and shifts in plant phenology. Based on experimental studies, increased atmospheric levels of carbon dioxide have directly increased plant productivity. This has affected the total amount of pollen produced in some species. Research has also shown increased levels of birch allergen at warmer temperatures. Warmer temperatures have resulted in earlier flowering for many spring-flowering species in many countries, recorded through visual observations of flowering and by airborne pollen. Increases in the cumulative season totals of various pollen types also have been recorded; some of these increases may be explained by changes in plant distribution.