Showing papers on "Bioaerosol published in 2023"

An assessment of occupational exposure to bioaerosols in automated versus manual waste sorting plants

Abstract: Occupational exposure during waste sorting is associated with several health outcomes. This study obtained knowledge about the impact of work in fully automated waste sorting plants (AWSP; n = 3) vs manual waste sorting plants (MWSP; n = 3) on personal exposure (n = 71) to bioaerosols and exposure-related health effects. Personal full-shift air samples were collected using various filter-based active sampling devices that were placed in the workers’ breathing zone. Personal exposure to inhalable and thoracic dust, endotoxin and microorganisms varied considerably between and within types of waste sorting plants (WSP). Workers at AWSP were on average exposed to 0.34 mg/m3 inhalable dust, 0.15 mg/m3 thoracic dust, and 51 EU/m3 endotoxins (geometric mean (GM) levels), whereas GM exposure levels at MWSP were 0.66 mg/m3 for inhalable dust, 0.44 mg/m3 for thoracic dust, and 32 EU/m3 for endotoxins. Exposure to submicronic fungal fragments did not differ between types of plants and ranged from levels below the detection limit (limit of detection, LOD) to levels in the order of 106 fragments/m3. Higher levels of fungal fragments and fungal spores were found at AWSP compared to MWSP with a GM of 2.1 × 105 spores/m3and with a GM of 1.2 × 105 spores/m3, respectively. Actinobacterial spores were found in samples from AWSP only, with exposure levels ranging from 1.9 × 104 to 1.1 × 107 spores/m3. Exposure to microbial DNA varied within and between WSP and was on average in the order of 104 copies/m3 for fungi and 105 copies/m3 for bacteria. Health symptoms, such as sneezing, congested nose and runny nose were significantly more common among exposed workers compared to the unexposed control group.

Design and Simulation of Aerosol Inlet System for Particulate Matter with a Wide Size Range

Abstract: A novel aerodynamic lens-based inlet system was developed for a wide particle size range, and it could extend the size range of transmitted particulate matter (PM) to 50 nm–10 μm. The lens system adopted a seven-stage aerodynamic focusing orifice to extend the range of transmitted PM, and a relaxation system with a virtual impact function was introduced at the front of the aerodynamic lens. Through the innovative design, the system could concentrate the input samples as well as effectively enhance the focusing effect on large PM. Furthermore, an additional aerodynamic pre-focusing inlet system was innovatively added to the front of the sampling orifice of the traditional aerodynamic lens, and it could pre-focus large PM into the axis region before it entered the small orifice and then solve the previous problem with loss of large PM. Fluid simulations indicated that the inlet system could achieve 100% effective transmission and focusing for PM in the range of 0.18–10 μm. The characterization and verification results obtained from the improved single-particle aerosol mass spectrometer (SPAMS) were remarkably consistent with the theoretical values. The practical tests indicated that bioaerosol particles up to 10 μm could be detected. Compared with the observation for the same type of lens, the focusing performance of this novel lens system has better advantages in particle size range and transmission efficiency and therefore, it has broad application prospects in bioaerosol research, single-cell analysis, etc.

Aerobiological Monitoring in an Indoor Occupational Setting Using a Real-Time Bioaerosol Sampler

Abstract: Aerobiological monitoring is a crucial tool for human and environmental health. Real-time bioaerosol samplers are major innovative techniques for aerobiological monitoring. In this study, we evaluate the use of a real-time bioaerosol sampler to monitor the exposure in an indoor occupational environment. We used a WIBS-NEO sampler, continuously operating during working and non-working days. The fluorescent particles were 16.5% of the total, identifiable as bioparticles. There was a significant difference between working and non-working days regarding bioparticles (+19% on average), especially in the morning (+91% on average), the part of the day mostly associated to worker presence. In working days, there is a difference between working and non-working-hours, reinforced by a strong correlation between the time of occupation of the room and the number of particles identified as pollen and fungal spores (R2 = 0.741, p < 0.01). The bacterial component does not seem to be influenced by the presence of workers; however, it follows the general distribution of bioparticles. Our results indicate the reliability of the real-time instrument for the monitoring of different biocomponents, and the role of workers in the distribution of some types of bioaerosol particles, like pollen and fungal spores, which can have several health impacts, such as allergies.

Wood dust and asthma

Abstract: Purpose of the review Review recent developments on asthma associated with wood dust, given the increasing scale of wood handling and processing activities globally. Recent findings Work in wood industries is associated with a significantly increased risk of respiratory symptoms, rhinitis and asthma. This can be attributed to traditional processing techniques and newer technologies producing complex bioaerosol exposures, which may include chemicals. Meta-analysis studies indicate strong evidence for wood dusts as occupational sensitizers for asthma, but the underlying mechanisms remain poorly understood. The global prevalence of asthma in wood workers ranges between 6–18% and for rhinitis 16–33%. Exposure estimates show wide variation. Risk factors include atopy and exposure to certain wood species, elevated current and cumulative particulate exposures. Summary Future studies should focus on better characterization of wood dust allergens and other bioaerosol components, specific immunoglobulin E responses to different wood species, pathophysiological mechanisms underlying asthma, and modelling dose–response relationships using refined exposure metrics for dust particulate and other bioaerosol components. There is a need for improved health-based international exposure standards and effective workplace control measures to reduce exposures to wood dust particulate (hard and soft woods), endotoxin and β-glucan, to reduce the risks of asthma in wood workers.

Design and quantitative evaluation of ‘Aerosol Bio-Containment Device (ABCD)’ for reducing aerosol exposure during infectious aerosol-generating events

Abstract: The Coronavirus Disease 2019 (COVID-19) pandemic renewed interest in infectious aerosols and reducing risk of airborne respiratory pathogen transmission, prompting development of devices to protect healthcare workers during airway procedures. However, there are no standard methods for assessing the efficacy of particle containment with these protective devices. We designed and built an aerosol bio-containment device (ABCD) to contain and remove aerosol via an external suction system and tested the aerosol containment of the device in an environmental chamber using a novel, quantitative assessment method. The ABCD exhibited a strong ability to control aerosol exposure in experimental and computational fluid dynamic (CFD) simulated scenarios with appropriate suction use and maintenance of device seals. Using a log-risk-reduction framework, we assessed device containment efficacy and showed that, when combined with other protective equipment, the ABCD can significantly reduce airborne clinical exposure. We propose this type of quantitative analysis serves as a basis for rating efficacy of aerosol protective enclosures.

Particle motion determines the types of bioaerosol particles in the stratosphere

Abstract: Bioaerosol particles in the stratosphere are topics of interest for aerobiological and astrobiological studies. Although various studies have succeeded in sampling bioaerosol particles in the stratosphere, limited research has been conducted to evaluate how and why these bioaerosol particles can lift up to as high as the stratospheric level. This study tested different driving forces acting on particles in the stratosphere in order to simulate the motion of particles with various bioaerosol characteristics. The findings show that small pollen-sized particles can scarcely levitate in the stratosphere, although spore-sized and dust particles attached to microorganisms such as bacteria or fungus might be able to do so.

Microbial Air Quality in the Built Environment—Case Study of Darvas-La Roche Heritage Museum House, Oradea, Romania

Abstract: Problems in the degradation and biodegradation of cultural heritage objects exposed or stored in public buildings and museums and of construction materials are caused (between others) by the activity of microorganisms. Biodeterioration can be observed not only at the level of the building materials of museum buildings, but also at the level of materials from which art objects are made (natural or artificial) and is determined by factors such as the chemical composition and nature of the composition material, the microclimate characteristics and exposure objects, but also through the manner and frequency of surface cleaning and housekeeping in museums. Based on this, the present study offers, through classical methods, a qualitative and quantitative identification of microorganisms inside a heritage museum building located in a temperate climate country. The purpose of the work was to determine to what extent the bacteriological microflora inside can directly and indirectly contribute to the health quality of the building’s occupants as well as the degradation of its materials and structures. The results emphasize the presence of some fungi and bacteria, among them Alternaria spp., Aspergillus spp., Penicillium spp., Cladosporium spp., and Botrytis spp. All of the analyzed rooms have a high and very high degree of fungal contamination (between 524 and 3674 UFC/m3), which can represent a danger to both human health and the integrity of the exhibitions. This is more pronounced considering that some of species of fungi identified are associated with sick building syndrome, problems in humans due to harmful exposure to viruses, bacteria, and pathogens, which generate possible symptoms such as rhinorrhea, nasal congestion, hoarseness, coughing, sneezing, and irritability for the personnel and visitors.

Modeling the infection risk and emergency evacuation from bioaerosol leakage around an urban vaccine factory

Abstract: Mounting interest in modeling outdoor diffusion and transmission of bioaerosols due to the prevalence of COVID-19 in the urban environment has led to better knowledge of the issues concerning exposure risk and evacuation planning. In this study, the dispersion and deposition dynamics of bioaerosols around a vaccine factory were numerically investigated under various thermal conditions and leakage rates. To assess infection risk at the pedestrian level, the improved Wells-Riley equation was used. To predict the evacuation path, Dijkstra's algorithm, a derived greedy algorithm based on the improved Wells-Riley equation, was applied. The results show that, driven by buoyancy force, the deposition of bioaerosols can reach 80 m on the windward sidewall of high-rise buildings. Compared with stable thermal stratification, the infection risk of unstable thermal stratification in the upstream portion of the study area can increase by 5.53% and 9.92% under a low and high leakage rate, respectively. A greater leakage rate leads to higher infection risk but a similar distribution of high-risk regions. The present work provides a promising approach for infection risk assessment and evacuation planning for the emergency response to urban bioaerosol leakage.

Aerosolized airborne bacteria and viruses inhalation: Micro-bioaerosols deposition effects through upper nasal airway inhalation

Abstract: The study of bacterial and viral aerosols effects on the human respiratory system is essential to improve prevention, management, and treatment of respiratory diseases. Microbioaerosols may transmit in conversation even while wearing common N95 respiratory masks as “silent spreaders.” Because of the complexity when measuring this process, it is modeled in this chapter for a condition when breathing through the nose, indoors, and for three activity levels. Due to their tiny size, bacterial and viral aerosols can travel to the terminal airways of the respiratory system and form severe health hazards. This chapter investigates bioaerosol transport and deposition in the upper airways and their throughput to the lungs. The ANSYS 2021 R1 solver is used to simulate the bioaerosol transport through the respiratory system. Numerical results demonstrate that a lower percentage of the microbioaerosols are trapped in the upper airways when resting and in a light activity condition, so that at 6 L/min and 15 L/min flow rates the average lung contamination percentage is more than 87%. Thus, for all inlet flow rates of less than 30 L/min the average bacterial and viral contamination percentage in the upper respiratory tract is less than 50%, and more than 50% in the lungs. This chapter provides a model of bacterial and viral aerosol transport through the respiratory system to inform lung health risk assessment and prevention.

Aircraft surveys for air eDNA: probing biodiversity in the sky.

Abstract: Air is a medium for dispersal of environmental DNA (eDNA) carried in bioaerosols, yet the atmosphere is mostly unexplored as a source of genetic material encompassing all domains of life. In this study, we designed and deployed a robust, sterilizable hardware system for airborne nucleic acid capture featuring active filtration of a quantifiable, controllable volume of air and a high-integrity chamber to protect the sample from loss or contamination. We used our hardware system on an aircraft across multiple height transects over major aerosolization sources to collect air eDNA, coupled with high-throughput amplicon sequencing using multiple DNA metabarcoding markers targeting bacteria, plants, and vertebrates to test the hypothesis of large-scale genetic presence of these bioaerosols throughout the planetary boundary layer in the lower troposphere. Here, we demonstrate that the multi-taxa DNA assemblages inventoried up to 2,500 m using our airplane-mounted hardware system are reflective of major aerosolization sources in the survey area and show previously unreported airborne species detections (i.e., Allium sativum L). We also pioneer an aerial survey flight grid standardized for atmospheric sampling of genetic material and aeroallergens using a light aircraft and limited resources. Our results show that air eDNA from terrestrial bacteria, plants, and vertebrates is detectable up to high altitude using our airborne air sampler and demonstrate the usefulness of light aircraft in monitoring campaigns. However, our work also underscores the need for improved marker choices and reference databases for species in the air column, particularly eukaryotes. Taken together, our findings reveal strong connectivity or mixing of terrestrial-associated eDNA from ground level aerosolization sources and the atmosphere, and we recommend that parameters and indices considering lifting action, atmospheric instability, and potential for convection be incorporated in future surveys for air eDNA. Overall, this work establishes a foundation for light aircraft campaigns to comprehensively and economically inventory bioaerosol emissions and impacts at scale, enabling transformative future opportunities in airborne DNA technology.

Catalyst Droplet‐Based Puncturable Nanostructures with Mechano‐Bactericidal Properties Against Bioaerosols

Abstract: Bioaerosol contamination problems have led to the need for new technologies that effectively collect and inactivate airborne microorganisms. Typical nanomaterial‐based filter membranes are usually sterilized using photocatalysts, electrical stimulation, and thermal treatment, which are expensive and require additional devices and cumbersome manufacturing. In this study, a membrane with nanotopographical features is manufactured via a catalyst droplet‐based procedure to mechanically damage airborne bacteria. The catalyst droplets are used as templates for in situ novel puncturable nanopillar growth on the membrane surface. Numerical simulations and microscopic observations show that puncturable nanopillars with a thin and rough nano‐edge are advantageous for rupturing the bacterial cell compared to flat nanopillars without a thin edge. A puncturable nanostructured air filter (PNAF) is compared to a bare air filter and exhibits higher bioaerosol collection efficiencies (>98% and 89.3–95.7%, respectively). PNAF is tested under breathing conditions as part of a face mask, where it effectively captures and deactivates E. coli aerosols through a mechano‐bactericidal effect, resulting in the inhibition of bacterial proliferation and finally death. Thus, PNAF can be applied as an air purifier or face mask filter for bioaerosol collection presenting antibacterial effects without external stimulation.

117 Optimization of the Measurement Method for Airborne Endotoxins in Workplace Atmospheres: a Laboratory and Field Study

Abstract: Endotoxins are lipopolysaccharides present in the outer membrane of most Gram-negative bacteria. They can become airborne by working tasks, techniques and processes that generate aerosols from materials contaminated by these microorganisms and can cause harmful effects on the health of workers by inhalation. Since 2005, INRS has been proposing a method for measuring endotoxins, which use a 2 L/min closed-face cassette sampling and an analysis by chromogenic LAL assay, mainly following EN 14031 standard. However, the evolution of knowledge and the lack of some validation data led to new experimental investigations in order to optimize this method: optimization of the sampling (filters type) and the extraction protocol (liquid volume, duration, methodology) as well as the influence of sample storage have been studied. A bubbler-type generator was used to produce a bioaerosol from a mixture of three bacteria to obtain controlled concentrations of 50 to 10000 EU/m3. These laboratory tests confirmed a better recovery of endotoxins when extraction is carried out directly in the cassette and let possible to fix the volume (5 mL) and the duration (20 min) of elution. PVC filters appear to result in lower endotoxins recovery compared to fiberglass, PTFE or PC filters. Additional field tests were done in different workplaces as livestock farm (pig, cow), grain processing, composting and wastewater treatment plants. Comparison of filters results in these occupational environments as well as the influence of samples storage at room temperature during 8 days will be discussed.

Assessment of indoor bioaerosol exposure using direct-reading versus traditional methods - potential application to home health care.

Abstract: Home healthcare workers (HHCWs) can be occupationally exposed to bioaerosols in their clients' homes. However, choosing the appropriate method to measure bioaerosol exposures remains a challenge. Therefore, a systematic comparison of existing measurement approaches is essential. Bioaerosol measurements with a real-time, fluorescence-based Wideband Integrated Bioaerosol Sensor (WIBS) were compared to measurements with four traditional off-line methods (TOLMs). The TOLMS included optical microscopic counting of spore trap samples, microbial cultivation of impactor samples, qPCR, and next-generation sequencing (NGS) of filter samples. Measurements were conducted in an occupied apartment simulating the environments that HHCWs could encounter in their patients' homes. Descriptive statistics and Spearman's correlation test were computed to compare the real-time measurement to each TOLM. The results showed that the geometric mean number concentrations of the total fluorescent aerosol particles (TFAPs) detected with the WIBS were several orders of magnitude higher than those of total fungi or bacteria measured with the TOLMs. Among the TOLMs, concentrations obtained with qPCR and NGS were the closest to the WIBS detections. Correlations between the results obtained with the WIBS and TOLMs were not consistent. No correlation was found between the concentrations of fungi detected using microscopic counting and any of the WIBS fluorescent aerosol particle (FAP) types, either indoors or outdoors. In contrast, total concentrations detected with microbial cultivation correlated with the WIBS TFAP results, both indoors and outdoors. Outdoors, total concentration of culturable bacteria correlated with FAP type AC. In addition, fungal and bacterial concentrations obtained with qPCR correlated with FAP types AB and AC. For a continuous, high time resolution but broad scope, the real-time WIBS could be considered, whereas a TOLM would be the best choice for specific and more accurate microbial characterization. HHCWs' activities tend to re-aerosolize bioaerosols causing wide temporal variation in bioparticle concentrations. Thus, the advantage of using the real-time instrument is to capture those variations. This study lays a foundation for future exposure assessment studies targeting HHCWs.

Immunomagnetic separation coupled with flow cytometry for the analysis of Legionella pneumophila in aerosols.

Abstract: Abstract Legionella pneumophila are pathogenic bacteria that can be found in high concentrations in artificial water systems like evaporative cooling towers, which have been the source of frequent outbreaks in recent years. Since inhaled L. pneumophila can lead to Legionnaires’ disease, the development of suitable sampling and rapid analysis strategies for these bacteria in aerosols is therefore of great relevance. In this work, different concentrations of viable L. pneumophila Sg 1 were nebulized and sampled by the cyclone sampler Coriolis® µ under defined conditions in a bioaerosol chamber. To quantify intact Legionella cells, the collected bioaerosols were subsequently analyzed by immunomagnetic separation coupled with flow cytometry (IMS-FCM) on the platform rqmicro.COUNT. For analytical comparison, measurements with qPCR and cultivation were performed. Limits of detection (LOD) of 2.9 × 10 3 intact cells m −3 for IMS-FCM and 7.8 × 10 2 intact cells m −3 for qPCR indicating a comparable sensitivity as in culture (LOD = 1.5 × 10 3 culturable cells m −3 ). Over a working range of 10 3 − 10 6 cells mL −1 , the analysis of nebulized and collected aerosol samples with IMS-FCM and qPCR provides higher recovery rates and more consistent results than by cultivation. Overall, IMS-FCM is a suitable culture-independent method for quantification of L. pneumophila in bioaerosols and is promising for field application due to its simplicity in sample preparation. Graphical abstract

Review of automatic control tools for biological agent in the atmosphere above sea surface

Abstract: Object and purpose of research. Methods of biological aerosol research and technical means for their implementation. Subject matter and methods. Analysis of technical documentation for used and prospective equipment. Main results. The main parameters of foreign and domestic bioaerosol analysis devices based on the flow-optical method. Conclusion. Based on the results obtained, it can be concluded that the development of methods for the analysis of bioaerosol particles in the near future will be determined by the development of new radiation sources for the effective excitation of particle fluorescence, as well as the creation of new techniques to determine the independent quantitative and qualitative parameters of the studied particles. A typical example is the creation of a highly efficient system that combines several approaches, including destructive laser spectroscopy, which was not previously used in the flow-optical method.

Effects of Occupant’s Micro-environment on Bioaerosol Transport

Abstract: To effectively investigate the bioaerosol transmission and assess its adverse health effect from the fluid dynamics perspective, four vital processes, from bioaerosol release via respiratory behaviour, suspension in the air, to inhalation and deposition within the human respiratory system should be deeply understood.