Search Results (24)

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

Background: Submarines represent extremely confined environments where breathing air is continuously recirculated for extended periods with minimal renewal, generating complex multipollutant atmospheres. Objectives: This critical narrative review aims to (i) summarize sources and composition of submarine indoor air, (ii) evaluate respiratory and cardiovascular risks for crews, and (iii) assess current purification technologies. Methods: A narrative review was conducted following PRISMA recommendations applicable to non-systematic reviews. The PubMed search covered all years from inception to September 2025, complemented by backward citation tracking and technical reports. Results: Eligible studies consistently report elevated levels of CO₂, VOCs, NO_X, CO, PM_2.5, and bioaerosols aboard submarines. Evidence from submariner cohorts and toxicological studies indicates risks of airway irritation, impaired mucociliary defenses, endothelial dysfunction, cardiovascular stress, and neurobehavioral alterations. Conclusions: Submarine indoor air quality is a credible determinant of crew health. Existing filtration systems mitigate some risks but do not address multipollutant mixtures adequately. Improved real-time monitoring, advanced filtration, CFD-guided airflow optimization, and longitudinal medical surveillance are necessary. Full article

Molds are frequent indoor contaminants, where they can colonize many materials. The subsequent aerosolization of fungal spores from moldy surfaces can strongly impact indoor air quality and the health of occupants. The investigation of fungal contamination of habitations is a key point in evaluating sanitary risks and understanding the relationship that may exist between the fungal presence on surfaces and air contamination. However, to date there is no “gold standard” of sampling indoor air for such investigations. Among various air sampling methods, impingement can be used for capturing fungal spores, as it enables real-time sampling and preserves analytical follow-up. Its efficiency varies depending on several factors, such as spore hydrophobicity, sampling conditions, etc. Sampling devices may also impact the results, with recovery rates sometimes lower than filtration-based methods. The Coriolis µ air sampler, an impingement-based device, utilizes centrifugal force to concentrate airborne particles into a liquid medium, offering flexibility for molecular analysis. Several studies have used this device for air sampling, demonstrating its application in detecting pollen, fungal spores, bacteria, and viruses, but it is most often used in laboratory conditions. The present case study, conducted in a moldy house, aims to investigate the efficiency of this device in sampling fungal spores for DNA analysis in indoor environments. The results obtained suggest that the use of this device requires an optimized methodology to enhance its efficiency and reliability in bioaerosol research. Full article

Novel and practical methods are always sought across all disciplines; within bioaerosol research, portable, lightweight, and low-cost sampling pumps are few and far between. Fungal spores, key components of bioaerosols, have attracted attention due to their negative effects on human populations, agricultural systems, and ubiquitous nature. In terms of spatial scales, fungal spores across vertical gradients are frequently overlooked and in cases where atmospheric samples are collected, they are often a large distance away from the ground, occurring hundreds or thousands of meters into the atmosphere, which also requires substantial expenses for specialist apparatus. Here, we have utilized a drone and low-cost equipment to produce a new sampling method that can efficiently collect fungal spores and bridge the gap between ground sampling and atmospheric sampling, and sample in areas such as forest canopies or at building rooftop heights, in which planes, helicopters, or other UAVs may not be able to safely or practically maneuver. Additionally, we have created a novel approach to utilizing a drone for bioaerosol sampling during rain events, which, to our knowledge, is the first of its kind, opening up the possibilities for much needed comparisons of fungal spores in varying weather conditions. Full article

Studies on bioaerosol bacterial biodiversity have relevance in both ecological and health contexts, and molecular methods, such as 16S rRNA gene-based barcoded sequencing, provide efficient tools for the analysis of airborne bacterial communities. Standardized methods for sampling and analysis of bioaerosol DNA are lacking, thus hampering the comparison of results from studies implementing different devices and procedures. Three samplers that use gelatin filtration, swirling aerosol collection, and condensation growth tubes for collecting bioaerosol at an aeration tank of a wastewater treatment plant in Trieste (Italy) were used to determine the bacterial biodiversity. Wastewater samples were collected directly from the untreated sewage to obtain a true representation of the microbiological community present in the plant. Different samplers and collection media provide an indication of the different grades of biodiversity, with condensation growth tubes and DNA/RNA shield^TM capturing the richer bacterial genera. Overall, in terms of relative abundance, the air samples have a lower number of bacterial genera (64 OTUs) than the wastewater ones (75 OTUs). Using the metabarcoding approach to aerosol samples, we provide the first preliminary step toward the understanding of a significant diversity between different air sampling systems, enabling the scientific community to orient research towards the most informative sampling strategy. Full article

In the wake of the COVID-19 pandemic, the scientific community has been galvanized to unravel the enigmatic role of bioaerosols in the transmission of infectious agents. This literature review, anchored in the extensive Web of Science Core Collection database covering the period from 1990 to 2023, utilizes a bibliometric approach to chart the dynamic landscape of bioaerosol research. It meticulously documents the paradigm shifts and burgeoning areas of inquiry that have emerged in the aftermath of the pandemic. This review meticulously maps out the sources and detection strategies of pathogens in a variety of ecosystems. It clearly shows that impaction and filtration sampling methods, followed by colony counting and PCR-based detection techniques, were predominantly used in the scientific works within the previous three decades. It synthesizes the progress and limitations inherent in a range of models for predicting aerosol-mediated pathogen spread and provides a comparative analysis of eDNA technology and traditional analytical techniques for bioaerosols. The accuracy of these detection methods and forecasting models is paramount for the early recognition of transmission risks, which, in turn, paves the way for prompt and effective disease mitigation strategies. By providing a thorough analysis of the historical progression and current state of bioaerosol research, this review illuminates the path ahead, identifying the critical research needs that will drive the field’s advancement in the years to come. Full article

The USA is the third-leading cotton-producing country worldwide and cotton farming is common in the state of Georgia. Cotton harvest can be a significant contributor to airborne microbial exposures to farmers and nearby rural communities. The use of respirators or masks is one of the viable options for reducing organic dust and bioaerosol exposures among farmers. Unfortunately, the OSHA Respiratory Protection Standard (29 CFR Part 1910.134) does not apply to agricultural workplaces and the filtration efficiency of N95 respirators was never field-tested against airborne microorganisms and antibiotic resistance genes (ARGs) during cotton harvesting. This study addressed these two information gaps. Airborne culturable microorganisms were sampled using an SAS Super 100 Air Sampler in three cotton farms during cotton harvesting, and colonies were counted and converted to airborne concentrations. Genomic DNA was extracted from air samples using a PowerSoil^® DNA Isolation Kit. A series of comparative critical threshold (2^−ΔΔCT) real-time PCR was used to quantify targeted bacterial (16S rRNA) genes and major ARGs. Two N95 facepiece respirator models (cup-shaped and pleated) were evaluated for their protection against culturable bacteria and fungi, total microbial load in terms of surface ATP levels, and ARGs using a field experimental setup. Overall, culturable microbial exposure levels ranged between 10³ and 10⁴ CFU/m³ during cotton harvesting, which was lower when compared with bioaerosol loads reported earlier during other types of grain harvesting. The findings suggested that cotton harvesting works can release antibiotic resistance genes in farm air and the highest abundance was observed for phenicol. Field experimental data suggested that tested N95 respirators did not provide desirable >95% protections against culturable microorganisms, the total microbial load, and ARGs during cotton harvesting. Full article

Emerging infectious diseases that we are witnessing in the modern age are among the leading public health concerns. They most often occur in the form of epidemics or pandemics, and they have not been sufficiently researched. Owing to the current coronavirus disease 2019 (COVID-19) pandemic, the World Health Organization has published various recommendations to prevent the spread of this communicable disease, including a recommendation to wear protective facial masks. Therefore, this study aimed to determine the filtration effectiveness of bacteria, yeasts, and molds on three different commonly and commercially available masks used in children’s educational institutions. In addition, the bacterial content of indoor air bioaerosols was identified. The genera Staphylococcus and Micrococcus were dominant in all samples, whereas bacteria of the genera Bacillus, Acinetobacter, and Corynebacterium were identified at a significantly smaller number. Bacterial, yeast, and mold filtering effectiveness increased from the single-layer cloth mask, which proved to be the least effective, to the surgical mask, to the filtering facepiece type 2 (FFP2) mask. Furthermore, surveys are needed to study the effectiveness of protective measures. Full article

The Earth’s atmosphere plays a critical role in transporting and dispersing biological aerosols. Nevertheless, the amount of microbial biomass in suspension in the air is so low that it is extremely difficult to monitor the changes over time in these communities. Real-time genomic studies can provide a sensitive and rapid method for monitoring changes in the composition of bioaerosols. However, the low abundance of deoxyribose nucleic acid (DNA) and proteins in the atmosphere, which is of the order of the contamination produced by operators and instruments, poses a challenge for the sampling process and the analyte extraction. In this study, we designed an optimized, portable, closed bioaerosol sampler based on membrane filters using commercial off-the-shelf components, demonstrating its end-to-end operation. This sampler can operate autonomously outdoors for a prolonged time, capturing ambient bioaerosols and avoiding user contamination. We first performed a comparative analysis in a controlled environment to select the optimal active membrane filter based on its ability to capture and extract DNA. We have designed a bioaerosol chamber for this purpose and tested three commercial DNA extraction kits. The bioaerosol sampler was tested outdoors in a representative environment and run for 24 h at 150 L/min. Our methodology suggests that a 0.22-µm polyether sulfone (PES) membrane filter can recover up to 4 ng of DNA in this period, sufficient for genomic applications. This system, along with the robust extraction protocol, can be automated for continuous environmental monitoring to gain insights into the time evolution of microbial communities within the air. Full article

Carbon nanotubes (CNTs) have extraordinary properties and are used for applications in various fields of engineering and research. Due to their unique combination of properties, such as good electrical and thermal conductivity and mechanical strength, there is an increasing demand to produce CNTs with enhanced and customized properties. CNTs are produced using different synthesis methods and have extraordinary properties individually at the nanotube scale. However, it is challenging to achieve these properties when CNTs are used to form macroscopic sheets, tapes, and yarns. To further improve the properties of macroscale forms of CNTs, various types of nanoparticles and microfibers can be integrated into the CNT materials. The nanoparticles and microfibers can be chosen to selectively enhance the properties of CNT materials at the macroscopic level. In this paper, we propose a technique to manufacture carbon hybrid materials (CHMs) by combining CNT non-woven fabric (in the form of sheets or tapes) with microfibers to form CNT-CF hybrid materials with new/improved properties. CHMs are formed by integrating or adding nanoparticles, microparticles, or fibers into the CNT sheet. The additive materials can be incorporated into the synthesis process from the inlet or the outlet of the reactor system. This paper focuses on CHMs produced using the gas phase pyrolysis method with microparticles/fibers integrated at the outlet of the reactor and continuous microfiber tapes integrated into the CNT sheet at the outlet using a tape feeding machine. After synthesis, characterizations such as microscopy and thermogravimetric analysis were used to study the morphology and composition of the CNTs, and examples for potential applications are discussed in this paper. Full article

A crucial environmental public health risk is air pollution caused by organic contaminants, bio-aerosols, and fine particulate matter (PM_2.5–10). A multi-purpose photocatalyst filter with photocatalytic nitrogen-doped titanium dioxide (PNT) incorporated into non-woven polymer fibers (NWPF) with wide applications is focused on in detail in this work. Loading of PNT on NWPF is carried out by the simple dip coating method. Para-xylene is selected as the target pollutant for the removal of organic contaminants. Higher removal efficiency of p-xylene (94.2%) is achieved under fluorescent daylight. The filtration efficiency of PNT is also evaluated to capture PM_2.5–10, which is increased with higher loading content of PNT. At a high air flow rate, the filtration efficiency of the photocatalyst PNT/NWPF is 97.33%, whereas the efficiency of the pristine NWPF is 91.1%. Moreover, the PNT/NWPF filter exhibits excellent antibacterial activity (99.9%) under visible light irradiation, but the pristine NWPF filter has negligible destruction effects on pathogens. These results clearly indicate that a PNT-coated NWPF filter would be an outstanding multi-purpose material for indoor air purification systems. Full article

Background: Standardized methods for testing Viral Filtration Efficiency (VFE) of tissues and devices are lacking and few studies are available on aerosolizing, sampling and assessing infectivity of SARS-CoV-2 in controlled laboratory settings. NanoAg-coated endonasal filters appear a promising aid for lowering viable virus inhalation in both adult and younger populations (e.g., adolescents). Objective: to provide an adequate method for testing SARS-CoV-2 bioaerosol VFE of bio-gel Ag nanoparticles endonasal filters, by a model system, assessing residual infectivity as cytopathic effect and viral proliferation on in vitro cell cultures. Methods: A SARS-CoV-2 aerosol transmission chamber fed by a BLAM aerosol generator produces challenges (from very high viral loads (10⁵ PFU/mL) to lower ones) for endonasal filters positioned in a Y shape sampling port connected to a Biosampler. An aerosol generator, chamber and sampler are contained in a class II cabinet in a BSL3 facility. Residual infectivity is assessed from aliquots of liquid collecting bioaerosol, sampled without and with endonasal filters. Cytopathic effect as plaque formation and viral proliferation assessed by qRT-PCR on Vero E6 cells are determined up to 7 days post inoculum. Results: Each experimental setting is replicated three times and basic statistics are calculated. Efficiency of aerosolization is determined as difference between viral load in the nebulizer and in the Biosampler at the first day of experiment. Efficiency of virus filtration is calculated as RNA viral load ratio in collected bioaerosol with and without endonasal filters at the day of the experiment. Presence of infectious virus is assessed by plaque forming unit assay and RNA viral load variations. Conclusions: A procedure and apparatus for assessing SARS-CoV-2 VFE for endonasal filters is proposed. The apparatus can be implemented for more sophisticated studies on contaminated aerosols. Full article

Particulate matter (PM) represents an air quality management challenge for confined swine production systems. Due to the limited space and ventilation rate, PM can reach relatively high concentrations in swine barns. PM in swine barns possesses different physical, chemical, and biological characteristics than that in the atmosphere and other indoor environments. As a result, it exerts different environmental and health effects and creates some unique challenges regarding PM measurement and mitigation. Numerous research efforts have been made, generating massive data and information. However, relevant review reports are sporadic. This study aims to provide an updated comprehensive review of swine barn PM, focusing on publications since 1990. It covers various topics including PM characteristics, sources, measurement methods, and in-barn mitigation technologies. As PM in swine barns is primarily of biological origins, bioaerosols are reviewed in great detail. Relevant topics include bacterial/fungal counts, viruses, microbial community composition, antibiotic-resistant bacteria, antibiotic resistance genes, endotoxins, and (1→3)-β-D-glucans. For each topic, existing knowledge is summarized and discussed and knowledge gaps are identified. Overall, PM in swine barns is complicated in chemical and biological composition and highly variable in mass concentrations, size, and microbial abundance. Feed, feces, and skins constitute the major PM sources. Regarding in-barn PM mitigation, four technologies (oil/water sprinkling, ionization, alternation of feed and feeders, and recirculating air filtration) are dominant. However, none of them have been widely used in commercial barns. A collective discussion of major knowledge gaps and future research needs is offered at the end of the report. Full article

In this paper, the use of HVAC systems and non-HVAC control measures to reduce virus-laden bioaerosol exposure in a highly occupied indoor space is investigated. A simulation tool was used to model the fate and transport of bioaerosols in an indoor space in the hotel industry (bar or pub) with three types of HVAC system (central air handling system (CAHS), dedicated outdoor air system (DOAS), and wall unit system (WUS)). Non-HVAC control measures such as portable air cleaners (PAC) and local exhaust fans were considered. Occupant exposure was evaluated for 1 μm bioaerosols, which transport SARS-CoV-2, for 3 h/day of continuous source and exposure. The combined effects of ventilation (400 l/s of outdoor air), recirculated air filtration (90% efficacy), and a PAC with a capacity up to 900 m³/h mitigated the (normalized) integrated exposure of the occupant by 0.66 to 0.51 (CAHS) and 0.43 to 0.36 (DOAS). In the case of WUS, the normalized integrated exposure was reduced by up to 0.2 when the PAC with a capacity of up to 900 m³/h was used. The corresponding electricity consumed increased by 297.4 kWh/year (CAHS) and 482.7 kWh/year (DOAS), while for the WUS it increased by 197.1 kWh/year. Full article

The coronavirus disease (COVID-19) pandemic is a global health threat and has posed a challenge for society and social care services as well as healthcare systems. Due to the risks involved in being exposed to the virus, public health actions such as wearing masks and physical distancing are necessary to reduce its spread. However, using non-validated masks is a serious issue as such masks may provide inadequate protection against airborne bioaerosol transmission, resulting in the spread of the virus. Therefore, it is necessary to evaluate the filtering performances of the masks against bioaerosols as well as particulate matter (PM). Here, we evaluated the filtering performances of sixteen different masks (four brands each of woven, antidroplet, KF80, and KF94 masks) commercially available in Korea with high market shares. As a simulation of being exposed to bioaerosols and to the yellow dust commonly found in Korea, the filtration efficiency levels of the masks were tested against airborne bacteria-containing droplets and against fine dusts of different ranges of particle sizes. Their filtration efficiency levels against the droplets showed strong positive correlations, specifically Pearson correlation coefficient r values of 0.917, 0.905, and 0.894, with their efficiency levels against PM1.0, PM2.5, and PM10, respectively. The results of this study should be useful for choosing appropriate masks, including those that meet filtering performance requirements. Full article