Aerobiologia最新文献

Ramularia leaf spot is a major economic disease of barley caused by the dothidiomycete fungus Ramularia collo-cygni. The fungus has a complex life cycle which includes extensive late season spore release events and a seed-borne phase. Predicting disease epidemics during the growing season remains a difficult challenge. To better understand the interaction between spore movement and disease epidemics, spore samplers were set up in Germany (two sites over 4 years), Poland (seven sites over 2 years) and the UK (two sites over 9 years), where the disease has been observed. Spore concentrations were determined using a real time PCR assay, and meteorological data were obtained from co-located automatic stations. Spore release events were seen to peak in June on mainland Europe and July in the UK. The pattern of spore release was broadly similar across countries with earlier peaks in mainland Europe. A relationship was observed in the UK between July spore levels and disease in following winter barley crops. Rainfall and temperature were proposed as significant drivers of spore release in these months. The major environmental parameter associated with spore release across the two UK sites was crop surface wetness, although some site-specific interactions were noted for rainfall and wind movement. Regression analysis of spore patterns and disease epidemics indicates a relationship between spore levels 75–105 days pre harvest and final disease levels in UK winter barley crops. This relationship was not observed in spring barley. The implications on risk forecasts are discussed.

We present the first implementation of the monitoring of airborne fungal spores in real-time using digital holography. To obtain observations of Alternaria spp. spores representative of their airborne stage, we collected events measured in the air during crop harvesting in a contaminated potato field, using a Swisens Poleno device. The classification algorithm used by MeteoSwiss for operational pollen monitoring was extended by training the system using this additional dataset. The quality of the retrieved concentrations is evaluated by comparison with parallel measurements made with a manual Hirst-type trap. Correlations between the two measurements are high, especially over the main dispersion period of Alternaria spp., demonstrating the potential for automatic real-time monitoring of fungal spores.

Studies have shown that the aquatic algae can cause allergy in humans. However, there are relatively few studies of airborne and soil algae on skin allergenicity. Therefore, we aimed to assess the skin allergenicity potential of airborne and soil algae isolated from Malaysia. Six algal species namely Scenedesmus sp., Stichococcus sp., Chlorococcum sp., Chlorella sp., Ulothrix sp. and Hapalosiphon sp. isolated from air and soil samples were screened based on the expression of IL-18 by NCTC 2544 keratinocytes in vitro assay. The mechanism of Stichococcus sp., Hapalosiphon sp. and Scenedesmus sp. in inducing skin allergenicity was further elucidated using Balb/c mouse model. Both proliferation of T-lymphocytes at local lymph nodes and expression of various acute inflammatory cytokines were assessed. The in vitro study showed that all algal extracts (1 mg/mL) except Ulothrix sp. were potential contact sensitisers and induced the expression of IL-18 by 0.369–5.227 pg/mg (IL-18/unit protein) in NCTC 2544 cells. The in vivo study revealed that Scenedesmus sp., Hapalosiphon sp. and Stichococcus sp. were able to induce skin sensitisation in mice with a stimulation index (SI) greater than 1.6 in the local lymph node assay (LLNA) suggesting these three algae species can cause allergic contact dermatitis (ACD). In addition, they are able to stimulate the expression of acute inflammatory cytokines such as GM-CSF, IL-1α and TNF-α. It was concluded that airborne and soil algae are potential contact allergens and can cause allergic contact dermatitis.

This study assessed the concentration characteristics of culturable airborne microbes in 60 family homes with children aged 1–15 years in Hangzhou, southeast China. The concentration of culturable airborne microbes ranged from 314 colony-forming units (CFU)/m³ to 2903 CFU/m³, with a mean value of 873 CFU/m³. The mean fungal concentration (653 CFU/m³) was significantly higher than the mean bacterial concentration of the atmosphere (220 CFU/m³), and the proportion of airborne fungi (73.9%) was significantly higher than that of airborne bacteria (26.1%). Microbial concentrations in family homes with a male child were significantly higher than those in homes with a female child, and there was a negative correlation between microbial concentration and living area per capita in family homes. The mean microbial concentration was highest in summer, followed by spring and autumn, and lowest in winter. This study provides an exposure database of airborne microbes in family homes in southeast China, suggesting that child gender and human occupancy in family homes significantly influence the microbial concentration in the air.

Airborne particles, bacteria and fungi consist main determinants of indoor air quality. In this study, these characteristics were investigated in two exhibition halls of the Historical Museum of Crete, in comparison with the outdoor environment. In Zacharias Portalakis (ZP) hall, three air purifiers were operating during museum opening hours, as opposed to El Greco (EG) hall. A significant part of ultrafine (< 1 μm) particles was efficiently removed by the air purifiers in ZP hall. Airborne coarse particles PN_2.5–10 were associated with human occupancy in both halls, indicating transportation from visitors and resuspension as possible sources. Average airborne bacterial concentration was also lower in ZP than in EG hall, assessed by both molecular and culture-dependent methods. The bacterial and fungal communities of both indoor halls were distinct from the outdoor counterpart. Micrococcus and Staphylococcus, in terms of bacteria, and Alternaria and Malassezia, in terms of fungi, were the most abundant genera indoors, most of them being human-related. Hierarchical clustering of indoor samples indicated that EG hall bacteria were similar to ZP hall bacteria collected on the same day, but varied between different sampling dates. This observation, together with the bacterial beta-diversity analysis, implied that both indoor halls probably shared common bacterial source(s), while the respective fungal pattern of the two indoor halls was found significantly separated. The outdoor air contribution in EG and ZP hall bacterial profile presented a comparable fluctuation pattern; this was not observed for fungi, probably indicating the complexity of potential sources for different fungal taxa.

The USA National Phenology Network (USA-NPN) hosts the largest volunteer-contributed collection of plant phenology observations in the USA. The potential contributions of these spatially and temporally explicit observations of flowers and pollen cones to the field of aerobiology remain largely unexplored. Here, we introduce this freely available dataset and demonstrate its prospective applications for modeling airborne pollen in a case study. Specifically, we compare the timing of 4265 observations of flowering for oak (Quercus) trees in the eastern USA to winter–spring temperatures. We then use this relationship to predict the day of peak flowering at 15 pollen monitoring stations in 15 years and compare the predicted day of peak flowering to the peak day of measured pollen (n = 111 station-years). There was a strong association between winter–spring temperature and the presence of open flowers (r² = 0.66, p < 0.0001) and the predicted peak flowering was strongly correlated with peak airborne pollen concentrations (r² = 0.81, p < 0.0001). These results demonstrate the potential for the USA-NPN’s phenological observations to underpin source-based models of airborne pollen. We also highlight opportunities for leveraging and enhancing this near real-time dataset for aerobiological applications.

In recent years, significant efforts have been made to study changes in the levels of air pollutants at regional and urban scales, and changes in bioaerosols during air pollution events have attracted increasing attention. In this study, the bacterial structure of PM_2.5 was analysed under different environmental conditions during hazy and non-hazy periods in Guilin. A total of 32 PM_2.5 samples were collected in December 2020 and July 2021, and the microbial community structures were analysed using high-throughput sequencing methods. The results show that air pollution and climate change alter the species distribution and community diversity of bacteria in PM_2.5, particularly Sphingomonas and Pseudomonas. The structure of the bacterial community composition is related to diurnal variation, vertical height, and urban area and their interactions with various environmental factors. This is a comprehensive study that characterises the variability of bacteria associated with PM_2.5 in a variety of environments, highlighting the impacts of environmental effects on the atmospheric microbial community. The results will contribute to our understanding of haze trends in China, particularly the relationship between bioaerosol communities and the urban environment.

Up-to-date reporting of atmospheric pollen contents is essential to assist doctors and allergy sufferers alike to undertake treatment or preventative measures. We have evaluated the extent of the digitally accessible knowledge (DAK) created by the Spanish network of pollen monitoring stations and analyzed the gaps in three main DAK factors: data completeness, data obsolescence, and data publication. Data from 118 distinct stations were discovered, of which one in four seemed to have discontinued publication of updated data either continuously or seasonally. While two-thirds of the sites published data through their own local portals, only about one-half also contributed daily data to the two main aggregators in the country (SEAIC and REA), which in turn were the only outlets available for one-tenth of the sites. The analysis revealed the probable existence of completely obscure sites recording, but not reporting, data. Recovering or surfacing dormant or silent sites may significantly improve the DAK about pollen in Spain.

Fungal aerosols deteriorate library collections and can impact human health, mainly via respiratory diseases. Their spread is influenced by factors such as temperature and relative humidity. This study aims to assess the concentration of fungal aerosols in the interior environment of the Popular Library of Gaira in the District of Santa Marta, Colombia, using a two-stage cascade impactor utilizing Sabouraud dextrose agar on Petri dishes for the collection of samples. The sampler was positioned at 1.5 m above ground level, operated with a flow rate of 28.3 l/min for 4 min and thermo-hygrometric conditions were also recorded. Concentrations in the air of up to 1197.0 CFU/m³ were reported, with a mean value close to 150 CFU/m³. Higher values during the morning samples were noted. Seven genera of fungi were found, Aspergillus and Curvularia were the most abundant. The temperature was between 30.80 and 33.51 °C, and the relative humidity was between 62.61 and 64.80%. Statistical analysis showed a significant correlation between the fungal aerosol concentration and relative humidity, where an increase of 10% in moisture could double the fungal aerosol concentration. We concluded that potentially favorable conditions exist indoors for the growth and survival of the following fungi: Aspergillus, Penicillium, Cladosporium, and Curvularia, and to a lesser extent for Chrysonilia, Cunninghamella, and Paecylomices. Relative humidity was seen to be the factor that affects the concentration of aerosols fungal in the library most significantly.

Pollen grains are released from plants and rupture, releasing pollen grain fragments referred to as subpollen particles (SPPs). This study is a laboratory evaluation of live oak, Quercus virginiana, to determine the environmental conditions needed to emit SPPs and measure the concentration of SPPs produced. To represent conventional SPP release, live oak branches were exposed to high relative humidity (> 95%), followed by reduced relative humidity (73.5%-76.3%) and wind (up to 1.8 m s⁻¹). In contrast, wind-driven SPP release experiments were conducted by exposing branches to constant relative humidity while cycling fans used to simulate winds. Wind-driven experiments produced maximum SPP concentrations as high as 3.3 × 10² ± 2.7 × 10² SPPs per cm³. The maximum SPP emissions during conventional SPP release experiments were as high as 7.3 × 10¹ ± 3.4 × 10¹ SPPs per cm³. The total number of SPPs emitted during conventional SPP release experiments was not significantly different from the SPP emissions during wind-driven SPP release experiments at a 5% significance level. The concentration of SPPs generated from pollen grains was used to calculate SPP emission factors. SPP emission factors were determined to be between 1.6 × 10⁴ and 9.0 × 10⁴ SPPs per pollen grain and between 4.7 × 10¹² and 2.2 × 10¹⁵ SPPs per m². These results indicate that SPPs represent a significant source of cloud-forming aerosol and have the ability to impact respiratory health.