Search Results (366)

Pollen monitoring is an integral part of aerobiology. The analysis of pollen content in the air, which is its core routine work, requires reliable devices. The continuous evolution of technology prompted us to give an update on current techniques used in pollen monitoring to provide a historical overview and an outlook into the future. Standard works in aerobiology and the most important literature were incorporated to summarize the development of pollen monitoring technology. We span a range from the first description of pollen monitoring in the 1870s, the invention of simple devices by early researchers, onwards to the development of the first volumetric samplers, such as the Rotorod- or Hirst-type traps. While volumetric devices are widely used in the USA and in Europe today, automatic and near-real-time pollen monitoring play an increasing role and offer new possibilities. In contrast to volumetric methods, most of these still require validation and standardization. Other methods, like the analysis of environmental DNA (eDNA) and the modeling of historical pollen data for pollination forecasts, are outlined. Aerobiology and pollen monitoring will continue to benefit from technological advances and be re-shaped in the next decades. Full article

Bioaerosols play significant roles in ecological interactions, climate change, and public health. Their diverse origins contribute to a dynamic atmospheric microbiome with considerable spatiotemporal variability, which are generally categorized as natural and anthropogenic sources. Accurate monitoring and source apportionment are critical for assessing environmental impacts and health risks. This review systematically summarizes the characteristics of bioaerosol sources and emphasizes emission risks from intensive human activities. This study also elucidates source apportionment strategies of bioaerosols and analyzes the technological evolution from traditional culture-based methods to advanced molecular and real-time physicochemical systems. In addition, the shift of bioaerosol monitoring technologies towards high-sensitivity, culture-independent, and online monitoring is emphasized in this review. An outlook on future research priorities is provided in the end. We emphasize the pressing need to establish localized characteristic databases, develop integrated real-time monitoring systems coupling rapid screening with deep biological analysis, and optimize the application of machine learning and AI algorithms to enhance the precision of multi-source contribution modeling in complex environments. Full article

Bioaerosol emissions from biological treatment processes like composting, livestock operations, and wastewater plants pose notable occupational and environmental health risks. Biofiltration is a common mitigation measure for gaseous pollutants, but its effectiveness in controlling bioaerosols is less studied. This review synthesizes current evidence on biofiltration for the removal of bioaerosols. Findings indicate that biofiltration can significantly reduce emissions from waste-related biological processes, although results vary widely and depend heavily on design and operational factors. In composting, agricultural, and wastewater treatment contexts, fungal bioaerosols are consistently removed with high efficiency, often over 90%. Conversely, bacterial removal shows greater variability, from negligible to above 90%, influenced primarily by airflow rate, bed depth, and media stability. Systems with residence times of tens of seconds and bed depths of at least 1 m tend to reliably reduce bacterial counts, whereas undersized, high-flow systems experience marked efficiency losses. The choice of packing material is also crucial; mature, stable media maintain performance, whereas nutrient-rich or unstable substrates can lead to fungal emissions, turning the biofilter into a secondary source. Data on endotoxin removal are limited and remain insufficient for firm design recommendations. Overall, biofiltration’s effectiveness depends on complex interactions among physical retention, biological stability, and design. These insights emphasize the need for future research to focus on standardized, performance-based design criteria supported by consistent reporting and full-scale validation. Full article

Bioaerosols released during wildland and prescribed fires may influence ecosystems, air quality, and microbial dispersal, yet their transport and deposition remain poorly understood. This study combined infrared uncrewed aircraft system (UAS) observations of a prescribed burn with the coupled fire–atmosphere model WRF-SFIRE and a Lagrangian particle model in order to evaluate how uncertainties in simulated fire behavior affect predicted bioaerosol (bacterial cell) transport and deposition. A reconstruction of the observed spatiotemporal evolution of the fire was derived from thermal UAS measurements acquired during the burn and incorporated into a WRF-SFIRE simulation, in which the modeled fire spread was constrained to follow this reconstructed progression. This benchmark run was compared with two unconstrained, fully coupled simulations that used a low and a high estimate of fuel moisture content (FMC) to represent typical uncertainty in fire rate of spread (ROS) prediction. Despite substantial differences in fire intensity and plume dynamics among the simulations, the resulting bioaerosol transport pathways and deposition patterns were broadly consistent across cases. The horizontal transport of the bioaerosols was dominated by the ambient Easterly wind and the bioaerosols were lofted by fire-affected updrafts—some exceeding 10 m/s—within the buoyant plume structure resolved in WRF-SFIRE. Deposition hot-spots appeared in consistent locations in the three simulations, especially regions where topography forced up-slope transport. Although the most intense fire produced slightly greater local deposition—likely due to a combination of stronger fire-induced downdrafts and overturning from penetration into strong vertical wind shear above the boundary layer—differences were small relative to the overall deposition footprint. These results suggested that, for burns of this scale, bioaerosol transport and deposition predictions are relatively robust to realistic uncertainties in fire-behavior modeling. This finding indicates that coupled fire–atmosphere and particle-transport modeling frameworks could be employed to quantitatively forecast microbial transport and deposition during future controlled burn experiments. Full article

Air quality management in zoological gardens plays a crucial role in their sustainable development. However, air quality in these settings remains understudied. In addition, previous research has largely focused on airborne microbial contamination merely in animal enclosures. This exploratory study provides preliminary insights into airborne fungal contamination alongside microclimate conditions in the visitor and worker areas of animal premises in the Zagreb Zoo. The study was performed in the Monkey House, Tropical House, Rainy Africa, and Bird House, as well as outdoors in fall. Fungi were identified based on macroscopic and microscopic examinations. Total culturable fungal concentration in indoor air ranged between 50 and 4.25 × 10³ CFU/m³, and in outdoor air between 1.00 × 10² and 1.50 × 10³ CFU/m³. Molds of eight genera and yeasts were isolated from the air. Both indoors and outdoors, the predominant genera were Cladosporium and Penicillium, and also genus Aspergillus indoors. Cladosporium spp. and Penicillium spp. concentrations, as well as total fungal concentration in the air, were on average, highest in Rainy Africa and Bird House, while the highest average Aspergillus spp. concentration was found in the Tropical House. Levels of Cladosporium spp., Penicillium spp., and Aspergillus spp. concentrations were associated with microclimate conditions. Study results suggest that the airborne fungal contamination may depend on the animals housed in the premises, and the design and management of the premises. Although total fungal concentration determined may not necessarily pose a health risk for exposed people, the qualitative composition of fungi signifies the importance of implementing good practices in zoo premises, including optimal microclimate conditions and effective ventilation. The results obtained also indicate the need for air quality monitoring, which concurs with zoo sustainability goals. Full article

Conventional antimicrobial air filters often conflate physical interception with true biochemical inactivation, posing secondary aerosolization risks during maintenance. This study developed a lactoferricin B-functionalized polypropylene (LfCF) filter to provide a dual-action mechanism: electrostatic capture and robust contact-killing against bioaerosols. To rigorously decouple these mechanisms, a polyallylamine binder-only (PP+PAA) control was incorporated. Dynamic penetration assays at 10 cm/s revealed that the 2.0 mg LfCF achieved significantly lower viable penetration rates for Escherichia coli (41.2%) and λ phage (46.0%) compared to the PP+PAA control (75.1% and 76.3%). This substantial gap demonstrates instantaneous sublethal injury upon aerodynamic impaction, defined here as “dynamic inactivation.” Crucially, time-dependent elution assays confirmed a >2 log reduction in viable counts for both retained E. coli and λ phage on LfCFs within 60 min, definitively validating its genuine contact-killing capability. Furthermore, the amphipathic lactoferricin B peptide maintained exceptional biocidal efficacy even under high-humidity conditions (70% RH), overcoming the electrostatic shielding typical of traditional biopolymers, without increasing aerodynamic pressure drop. Finally, field validation in a dental clinic demonstrated an 83.3% reduction in airborne viable bioaerosols. As a passive, self-sterilizing engineering control, the LfCF offers a highly reliable intervention for mitigating occupational bioaerosol exposures. Full article

The expansion of tropical specialty livestock farming raises urgent concerns about airborne pathogen and antibiotic resistance dissemination. Ostrich farming, characterized by high-density stocking and feed exposure, yet their microbial ecology remain poorly characterized. This study analyzed 48 bioaerosols samples from an ostrich farm in Hainan, China, across dry and rainy seasons using 16S rRNA sequencing and metagenomics. The bacterial community were dominated by Firmicutes, Proteobacteria, and Actinobacteria, followed by Staphylococcus, Bacillus, and Acinetobacter as predominant genera, with particle size significantly shaping their structure. Large particles (>7.0 μm) carried higher species richness, while medium particles (2.1–3.3 μm) exhibited the highest diversity and evenness. Notably, small particles (0.65–1.1 μm), which can penetrate deep into the lungs, were enriched with Brevibacillus and Corynebacterium. Metagenomic analysis identified 638 antibiotic resistance genes (ARGs), dominated by efflux pump-associated determinants. The detection of clinically relevant ARGs (e.g., mcr-1 and bla_TEM) reflects the genetic potential of the airborne resistome, rather than confirmed resistance phenotypes or active horizontal gene transfer. Functional analysis revealed a strong potential for organic matter degradation, driven by abundant carbohydrate-active enzymes (CAZymes) and their corresponding CAZyme genes, as well as a nitrogen cycle dominated by assimilation and reduction pathways, while genes for nitrogen fixation and nitrification were absent. Our findings demonstrate that ostrich farming enhanced airborne microbial diversity and functional potential, facilitating the ARG dissemination and nitrogen transformation. This study provides critical insights into the ecological and health risks of bioaerosols in tropical livestock farms, informing environmental monitoring and risk management strategies. Full article

The study aimed to assess the microbiological quality of the air in three barns that differed in size, housing system, and number of animals in the context of sustainable and safe food production. Air samples were collected four times a year (spring, summer, autumn, and winter) to account for seasonal variations. The abundance of selected microorganisms (mesophilic aerobic bacteria, mold fungi, actinomycetes, Staphylococcus spp. and E. coli) was determined using the impact method and appropriate microbiological media. Simultaneously, the air temperature, relative humidity, and real-time resistive sensor readings for current bioaerosols were measured in the tested rooms. Byre (III) had the lowest mean resistive sensor reading for bioaerosols, while barn (II) had the highest. The mean temperature was lowest in barn (I) and highest in barn (II). The mean relative air humidity was lowest in barn (III) and highest in barn (I). The 60 m² barn had the highest number of microorganisms. Factors conducive to the proliferation of microorganisms in the barn included the use of deep litter, which was removed once a quarter. Additionally, storing manure in close proximity to the barn contributed to an increase in the number of microorganisms in the livestock facility. No excessive air pollution with bacteria or mold fungi was found in any of the studied barns. Overall, the study demonstrates that barn management practices, litter type, microclimatic conditions, and ventilation significantly influence airborne microbial concentrations. These findings provide practical insights for improving environmental hygiene and animal welfare in barns and promoting sustainable development in dairy cattle farming. Full article

Understanding the dynamics of atmospheric ions, the carriers of electrons and ions in the global electric circuit (GEC), is necessary to fully understand Earth’s atmospheric electricity. Because atmospheric ions are too small to be influenced by gravity, the gravitational settling of aerosol particle in fair weather has not been considered as a driving force in the GEC model. However, the attachment of these particles to other coarse particles can cause them to move in gravity’s direction. In this study, the influence of the gravitational settling of various bioaerosol particles with electrostatic force on the GEC is calculated. The results show the importance of considering bioaerosol particles in the GEC model, and that pollen grains can carry the order of 0.1% of ions and electrons carried by atmospheric ions due to their weight and charging efficiencies. Also, the reduction in atmospheric conductivity in the presence of bioaerosol particles was calculated. Bioaerosol particles can reduce atmospheric conductivity by an order of $0.01\%$ due to pollen and by an order of $0.1\%$ due to microbes. Full article

Rapid urbanization and significant lifestyle changes have become the risk drivers for the epidemiology of diseases. With urban transitions, substantial persistence of pollutants in the environment has been observed. Epidemiological studies indicate a strong relationship between air pollution and exacerbation of asthma and other allergic diseases due to particulate matter (PM). PMs in bioaerosols and aeroallergens induce the immune response, eliciting systemic inflammation. Continuous exposure to PM_2.5 along with gases like nitrogen oxide aggravate oxidative stress and inflammatory responses. Other pollutants elevate blood glucose, inducing poor sleep patterns which in turn induce low-grade chronic inflammation. This in turn acts as a trigger for adipocyte dysfunction and reduced energy expenditure. Taken together, air pollution, allergy, and obesity constitute a jigsaw with missing pieces. Transient Receptor Protein (TRP) channels have important roles in allergic rhinitis, systemic inflammation, adipogenesis, and obesity development, underscoring a potential role as a common mechanistic link. The goal of this review is to summarize and comprehend the intricate network connecting these “modern-day hyperendemic diseases” and the plausible role played by TRP in shaping their epidemiology. Bioactive compounds in dietary spices also modulate TRP channels. Thus, spices position themselves as potential regulators at the interface of environmental sensing, inflammation, and metabolism, indicating spice-based interventions may represent an adjunct strategy to alleviate the pollution-induced allergy and obesity risk. Full article

Microbiological contamination in public buildings is closely linked to human presence, such as airborne bacteria, fungi, and particulate matter, which strongly influence indoor air quality (IAQ). This study examined the distribution of microorganisms in a museum building in relation to time of day, air-handling unit (AHU) type, and ventilation operating mode. Exhibition rooms without natural light relied entirely on a central heating, ventilation and air conditioning (HVAC) system. Microbiological contamination was assessed using Koch’s passive sedimentation method over a 24 h cycle for two AHUs (I and III) and selected rooms, while CO₂ levels were monitored as indicators of occupancy and ventilation demand in line with EN 16798-1:2019 and ASHRAE 62.1-2022. Although the demand-controlled ventilation system increased the outdoor air fraction from 40% to 70–100% during peak visitor density, localized increases in microbial contamination occurred. AHU I showed higher loads of Staphylococcus sp. and fungi, while AHU III exhibited pronounced fungal peaks influenced by elevated humidity from an open water reservoir. Psychrophilic bacteria reached 140–230 CFU·m⁻³, mesophilic bacteria 230–320 CFU·m⁻³, and fungi up to 740 CFU·m⁻³. Most CFU values remained below commonly referenced upper limits (<1000 CFU·m⁻³), but several peaks exceeded lower recommended thresholds, indicating a need for improvements. Enhanced filtration, humidity control, increased airflow during high occupancy, and reducing moisture sources in AHUs may mitigate microbial growth and improve IAQ in public buildings. Full article

Airborne organic dust has rarely been subject to immunotoxicological analysis. A pilot study was undertaken to link exposure metrics (respirable crystalline silica (RCS), bacteria, fungi, endotoxins (END), peptidoglycans (PGN), (1 → 3)-β-D-glucans (GLU)) with in vitro cytotoxicity and cytokine responses based on analysis of airborne organic dust samples collected during a single work shift at six different facilities. The A549 and BEAS-2B cell lines were used to assess cytotoxicity and proinflammatory cytokine release. The general linear model (GLM) and taxonomic linear ordering were used to identify key determinants and rank facilities by the hazard level they pose. The highest cytotoxicity of organic dust was observed at the sewage treatment plant, while the lowest was at the poultry farm. The most hazardous agents present in organic dust included RCS, aerobic bacteria, fungi, PGN, and GLU. They significantly affected cytokine release, particularly of IL-6 and IL-8. The use of a synthetic measure showed that inhalable organic dust from the composting plant presented the highest potential to induce adverse effects on human health, while the lowest one was characterized by the biomass-fired power plant samples. The open-ended statistical method can significantly increase awareness of occupational hazards and promote more responsible protection for exposed workers. Full article

Fungal bioaerosols play a critical ecological and health role in intensive poultry production systems. However, their dynamic characteristics and community succession patterns in confined cage environments during winter remain poorly understood. This study investigated a typical confined broiler house in Hebei Province, China, during winter. A combined approach of Andersen six-stage sampling, colony counting, and Internal Transcribed Spacer (ITS) high-throughput sequencing was employed to comprehensively analyze the concentration, particle size distribution, diversity, and community composition of fungal bioaerosols across three key growth stages: 7 days (brooding phase), 21 days (growing phase), and 35 days (finishing phase). The results revealed a significant increasing trend in fungal aerosol concentration as the rearing cycle progressed, increasing from 1125 ± 125 CFU/m³ at day 7 to 3872 ± 565 CFU/m³ at day 35 (p < 0.001), reaching high-risk exposure levels in the later stages. Small-sized fungal bioaerosols (<4.7 μm) were dominant across all stages (54.35–65.50%), with the highest proportion observed at day 21, indicating their potential for deep respiratory deposition and long-distance airborne transmission. The number of Operational Taxonomic Units (OTUs), along with Chao1 and Shannon indices, increased significantly with bird age (p < 0.001), demonstrating a clear community succession from early-stage yeast-dominated forms (e.g., Diutina, Blumeria) to mid- and late-stage assemblages dominated by filamentous fungi (e.g., Aspergillus, Cladosporium, Alternaria). Notably, several zoonotic pathogenic genera were detected throughout all rearing stages, highlighting the potential risks of airborne fungi to animal health, occupational exposure, and environmental safety under winter ventilation restrictions. This study characterizes a stage-dependent pattern of increasing airborne fungal concentrations accompanied by shifts in particle size distribution and community composition under winter confined conditions. The findings provide a crucial scientific basis for optimizing winter ventilation and environmental management strategies, improving environmental control technologies, establishing airborne biosafety standards, and developing targeted fungal monitoring and prevention technologies. Full article

Air quality management in greenhouses is critical to safeguarding plant health and occupational safety, yet conventional filtration methods often fall short in performance and sustainability. These enclosed environments are prone to the accumulation of bioaerosols, including fungi, bacteria, pollen, and dust particles, which can compromise crop productivity and pose health risks to workers. This review explores recent advancements in air filtration technologies for controlled environments such as greenhouses, where airborne particulate matter, bioaerosols, and volatile organic compounds (VOCs) present ongoing challenges. Special focus is given to the development of filtration media based on electrospun nanofibers, which offer high surface area, tunable porosity, and low airflow resistance. The use of biodegradable polymers in these systems to support environmental sustainability is examined, along with electrospinning techniques that enable precise control over fiber morphology and functionalization. Antimicrobial enhancements are discussed, including inorganic agents such as metal nanoparticles and bio-based options like essential oils. Essential oils, known for their broad-spectrum antimicrobial properties, are assessed for their potential in long-term, controlled-release applications through nanofiber encapsulation. Overall, this paper highlights the potential of integrating sustainable materials, innovative fiber fabrication techniques, and nature-derived antimicrobials to advance air filtration performance while meeting ecological and health-related standards. Full article

This study evaluates the performance of two real-time fluorescence-based bioaerosol sensors, the WIBS-NEO and IBAC-2, operating in urban Dublin, Ireland, and assesses the influence of different meteorological and pollution parameters on their outputs. This was done by comparing particle sensor data to meteorological variables and air quality metrics. Over the 41-day campaign, Urticaceae pollen and Cladosporium spores were the dominant bioaerosols recorded, comprising 78% and 66% of total pollen and fungal spore concentrations, respectively. Correlation analyses revealed several significant variables: fluorescent BC-type particles (>8 μm) detected by WIBS-NEO strongly correlated with pollen concentrations (r = 0.84 after excluding high-wind days). For fungal spores, PM₁₀ and grass minimum temperature were the most significant parameters related to variability. Anthropogenic pollutants, particularly NO_X and combustion-related aerosols, were found to correlate with fluorescence signals, especially for smaller particles (<2 μm), underscoring urban detection challenges. Wind trajectory analysis identified the likely source of Urticaceae pollen as northerly green spaces (e.g., Phoenix Park), while Cladosporium spores showed multidirectional transport. Multiple linear regression (MLR) analysis achieved strong correlation (${\mathrm{R}}^2$ = 0.82 for pollen, 0.78 for fungal spores), highlighting the value of incorporating multiple environmental variables to investigate the complex relationships between urban environmental conditions and bioaerosol sensor outputs. Both instruments exhibited operational limitations under the study conditions. The WIBS-NEO outperformed the IBAC-2 in biological discrimination due to its multi-channel single particle fluorescence capabilities. However, operational limitations emerged during higher wind speeds, comparable to moderate breezes (>16.6 km/h), which affected sampling comparability when compared with traditional methods. This study investigates how meteorological conditions and air quality influence bioaerosol detection in an urban environment. The use of MLR techniques to examine the complex relationships between environmental variables and fluorescent sensor outputs may help inform future bioaerosol modelling efforts. Full article