Human exposure to allergenic pollens: a comparison between urban and rural areas

Background

Pollinosis is found more frequently in urban areas than in rural environments. This could be partly related to the different types of pollen exposure in these dissimilar areas. The objective of this study was to compare the distribution of pollen in these environments across an urbanization gradient.

Methods

Daily pollen abundances were obtained in France using Hirst-type sensors. Sampling was conducted from January to June in 2003 and 2006 in a rural area, a semi-rural area and in two urban areas, which were characterized by several urbanization criteria.

Results

Total allergenic pollen abundance was higher in rural and semi-rural areas than in urban areas irrespective of the sampling year. Multivariate analyses showed that pollen exposures differed according to the type of area and were strongly explained by the urbanization gradient. Grass, ash, birch, alder, hornbeam, hazel and plantain pollen quantities exceeded the allergy threshold more often in rural settings than in urban areas. In urban areas, only plane pollen quantities exceeded the allergy threshold more often than in rural areas.

Conclusions

Allergenic pollen exposure is higher in rural areas than in urban areas, and the most abundant pollen in each area did not originated from the same taxa. This result should be taken into account in epidemiological studies comparing allergies in rural and urban areas to adapt the panel of pollen extracts for human environmental exposure. In addition, this study highlights that some ornamental trees produce a large number of allergenic pollens and provide new sources of aeroallergens.     

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.     

Biological activities of respirable dust from Eastern Canadian peat moss factories

Bacteria, moulds, endotoxin and quartz from respirable dust of agricultural and industrial buildings are typically incriminated for the respiratory health decline of exposed workers despite that dust being an undefined mixture and quantification methods of aerosolized bacteria, moulds or endotoxin not being standardized yet. We developed an in vitro alveolar epithelial cell system in which biological activities of peat moss factories’ dust might be correlated to bacteria, mould, endotoxin and quartz concentrations of the analyzed samples. Following exposure, interleukin-8 protein secretion, necrosis and apoptosis of the exposed A549 cells were monitored respectively with ELISA on cell supernatants, trypan blue exclusion and DNA fragmentation detection by flow cytometry. Respirable dust was collected with liquid impingers and respirable quartz with 10 mm Dorr-Oliver cyclones. We quantified mesophilic bacteria, mesophilic moulds and endotoxins from liquid impinger samples. No correlation was observed between biological activities of dust and bacteria, mould, endotoxin or quartz concentrations under our experimental conditions. Our speculation is that simple measurements, such as dust concentrations, may not be adequate indicators of the human respiratory health hazard for a given environment.     

Pollen allergenic potential nature of some trees species: A multidisciplinary approach using aerobiological, immunochemical and hospital admissions data

Trees are considered producers of allergenic pollen. The aims of this work were to characterize the aerobiology of the Platanus, Acer, Salix, Quercus, Betula and Populus pollen, linking it with monthly emergency hospital admissions and to identify the different reactivity levels in sensitized patients. This information would be of great importance to evaluate the convenience of changing the inventory of pollen producer trees related to the risk of allergenic reactions. The study was conducted in Porto, Portugal, from 2005 to 2007. Airborne pollen was sampled using a Hirst-type volumetric trap. The antigenic and allergenic properties of Acer negundo, Betula pendula, Platanus occidentalis, Populus hybrida, Quercus robur and Salix babylonica pollen, collected in public gardens or sidewalks, were investigated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunological techniques using polysensitized-patient sera. Monthly hospital admissions of asthma or dyspnea related with respiratory diseases were obtained from the Emergency Room database of Hospital Geral de Santo António. Tree pollen and hospital admissions were positively correlated. Tree pollen peaked in March which coincides with the hospital admissions maximum. The highest binding affinity was observed with A. negundo, S. babylonica and P. occidentalis pollen extracts and the lowest with P. hybrida. Consistently, Acer and Platanus maximum airborne pollen concentrations were observed during March attaining levels considered moderate to high risk for allergenic reactions. Prominent bands with approximately 71, 35, 31, 22, 19, 16, 14, 13 and 11 kDa were revealed. A 52 kDa band was shared by all analyzed sera. High levels of airborne pollen and emergency hospital admissions were related. High binding affinity of specific IgE to pollen extracts of the most abundant tree pollen present in the atmosphere was observed. Patient sera revealed multiple similar allergenic bands shared by the different extracts. This multidisciplinary approach is useful in day-to-day medical practice to help in diagnostic, therapeutic and allergy alerting system adjusting.     

Human pathogens and tetracycline-resistant bacteria in bioaerosols of swine confinement buildings and in nasal flora of hog producers

Swine confinement buildings in eastern Canada are enclosed and equipped with modern production systems to manage waste. Bioaerosols of these swine confinement buildings could be contaminated by human pathogens and antimicrobial resistant bacteria which could colonize exposed workers. We therefore wanted to analyze bioaerosols of swine confinement buildings and nasal flora of Canadian hog producers to evaluate possible colonization with human pathogens and tetracycline-resistant bacteria. Culturable and non-culturable human pathogens and tet genes were investigated in the bioaerosols of 18 barns. The nasal passages of 35 hog producers were sampled and total DNA was extracted from the calcium-alginate swabs to detect, by PCR, Campylobacter, C. perfringens, Enterococcus, E. coli, Y. enterocolitica, tetA/tetC, tetG and ribosomal protection protein genes. Airborne culturable C. perfringens, Enterococcus, E. coli, and Y. enterocolitica were present in the bioaerosols of 16, 17, 11 and 6 of the 18 facilities. Aerosolized total (culturable/non culturable) Campylobacter, C. perfringens, Enterococcus, E. coli and Y. enterocolitica were detected in 10, 6, 15, 18 and 2 barns, respectively. Tet genes were found in isolates of culturable human pathogens. TetA/tetC, tetG and ribosomal protection protein genes were detected in the bioaerosols of all 18 studied buildings. Campylobacter, C. perfringens, Enterococcus, E. coli, and Y. enterocolitica were found respectively in 4, 9, 17, 14 and one nasal flora of workers. One and 10 workers were positive for tetA/tetC and tetG genes, respectively. In swine confinement buildings, hog producers are exposed to aerosolized human pathogens and tetracycline-resistant bacteria that can contaminate the nasal flora.     

The association between asthma-related emergency department visits and pollen and mold spore concentrations in the Bronx, 2001–2008

Background: The incidence of asthma morbidity and mortality is highest among minority inner-city populations. Among New York City’s five boroughs, the Bronx has the highest rate of asthma-related hospitalizations and mortality. Outdoor air pollutants have been associated with increased asthma-related ED visits (AREDV) in this borough. Objective: To better understand the contribution of pollen and mold to asthma severity in the Bronx. Methods: The numbers of daily adult and pediatric AREDV and asthma-related hospitalizations (ARH) from 2001 to 2008 were obtained from two Bronx hospitals. AREDV and ARH data were acquired retrospectively through the Clinical Looking Glass data analysis software. Daily counts for tree, grass and weed pollen and mold spore counts from March 2001 to October 2008 were obtained from the Armonk counting station. All data were statistically analyzed and graphed as daily values. Results: There were a total of 42?065 AREDV and 10?132 ARH at both Bronx hospitals. There were spring and winter peaks of increased AREDV. Tree pollen counts significantly correlated with total AREDV (rho?=?0.3639, p?p?p?p?Conclusions: There exists a significant association between spring AREDV and ARH and tree pollen concentrations in a highly urbanized area such as the Bronx. Early anticipation of spring pollen peaks based on ongoing surveillance could potentially guide clinical practice and minimize asthma-related ED visits in the Bronx.     

Unexpected pollinosis or insufficient pollen records? Importance of regional monitoring

Particular climates and the occurrence of endemic flowering plant species potentially leads to special aerobiological situations through the word. After a 6-year study carried out in Murcia (SE Spain) some particularities were detected in the 'aerobiological behaviour' of airborne pollen. Among them, Artemisia was shown to be the most original, particularly because of its unique winter pollination period, not reported elsewhere outside of SE Spain, and due to the occurrence of endemic Artemisia species. This state of affairs is possibly responsible of the high incidence of Artemisia in Murcia (23.5%; European mean, 10%) and the high number of long-season pollinosis sufferers (15%). These results stress the importance of regional and local aerobiological studies for interpreting and predicting allergenic diseases in Mediterranean areas.