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This study aims to analyze the trends, causes, and future prospects of aerosols in the Arctic region using ground-based observations, satellite data, and reanalysis model data. An analysis of aerosol remote sensing data from AERONET stations in the Arctic from 2000 to 2023 showed a long-term decrease in aerosol optical depth (AOD), aligning with emission regulations in Europe and North America and changes in atmospheric circulation patterns. However, the maximum AOD values observed at AERONET stations in Canada and Russia during the period of 2018-2023 were up to five times higher than the long-term average. This significant increase highlights the potential influence of regional variations and external inputs in Arctic aerosol loading, and emphasizes the need for further investigation into the underlying mechanisms driving these anomalies. Satellite observations confirmed that these highs were associated with regional factors, such as the transport of smoke aerosols from wildfires originating at lower latitudes. Notably, the increase in Arctic aerosols coincided with a decrease in mid-latitude and tropical regions, suggesting the influence of long-range atmospheric transport. From 2000 to 2023, wildfire activity has trended downward in tropical and mid-latitude regions, but upward in the Arctic. However, record wildfire activity in 2019 and 2021 was strongly associated with increased aerosols in the Arctic. This is likely a result of increased temperatures and drier conditions due to climate change, which have intensified the frequency and intensity of wildfires. In fact, mean air temperatures in the summers of 2019 and 2021 were about 5 K above the average of the past 19 years, favorable conditions for wildfires. And changes in barometric pressure and wind direction influenced regional-scale aerosol dispersion characteristics in the Arctic. In conclusion, the recent sudden increase in aerosols in the Arctic was found to be due to wildfire activity and climate change., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Aims: UV-C based air cleaners may reduce the transmission of infectious diseases. However, microbiological validation is necessary to quantify their efficiency. In this study, the stability of aerosolized bacteriophages for validation purposes was investigated in a test room, before an UV-C based air cleaner was exemplarily evaluated regarding the inactivation of airborne bacteriophages., Methods and Results: The bacteriophage Phi6 was selected as virus surrogate and aerosolized in a room of 30 m³ volume. The recovery of infectious bacteriophages was first analyzed under variation of the relative humidity (20-55% RH) and sampling time. The aerosol studies showed that a low humidity between 20% RH and 30% RH provides a high and stable recovery of bacteriophages Phi6 over 1 h. However, with increasing humidity, the number of infectious airborne bacteriophages Phi6 decreased significantly. At 50% RH, the recovery of Phi6 was 4 orders of magnitude lower compared to 20% RH. The validation of an UV-C based air cleaner was then demonstrated in the test room whereat the decline of infectious airborne bacteriophages was recorded over time. The non-enveloped bacteriophage MS2 was used as a reference. The validation results were significantly different for Phi6 when the humidity in the test room was either 40% RH or 30% RH whereas comparable results were obtained for MS2 at both humidities., Conclusion: A rising humidity in the test room caused a significant decline in the recovery of infectious airborne bacteriophages Phi6. The result of a quantitative validation of UV-C based air cleaners may therefore be affected by the respective humidity., (© The Author(s) 2024. Published by Oxford University Press on behalf of Applied Microbiology International.)

To monitor health risks associated with vaping, we introduce a multi-spectral optical sensor powered by machine learning for real-time characterization of electronic cigarette aerosols. The sensor can accurately measure the mass of particulate matter (PM) in specific particle size channels, providing essential information for estimating lung deposition of vaping aerosols. For the sensor's input, wavelength-specific optical attenuation signals are acquired for three separate wavelengths in the ultraviolet, red, and near-infrared range, and the inhalation pressure is collected from a pressure sensor. The sensor's outputs are PM mass in three size bins, specified as 100-300 nm, 300-600 nm, and 600-1000 nm. Reference measurements of electronic cigarette aerosols, obtained using a custom vaping machine and a scanning mobility particle sizer, provided the ground truth for size-binned PM mass. A lightweight two-layer feedforward neural network was trained using datasets acquired from a wide range of puffing conditions. The performance of the neural network was tested using unseen data collected using new combinations of puffing conditions. The model-predicted values matched closely with the ground truth, and the accuracy reached 81-87% for PM mass in three size bins. Given the sensor's straightforward optical configuration and the direct collection of signals from undiluted vaping aerosols, the achieved accuracy is notably significant and sufficiently reliable for point-of-interest sensing of vaping aerosols. To the best of our knowledge, this work represents the first instance where machine learning has been applied to directly characterize high-concentration undiluted electronic cigarette aerosols. Our sensor holds great promise in tracking electronic cigarette users' puff topography with quantification of size-binned PM mass, to support long-term personalized health and wellness.

The importance of aerosols (particles suspended in air) produced during dental procedures became more apparent than ever during the COVID-19 pandemic. Concerns over transmission of infection in these aerosols led to unprecedented disruption to dental services across the world, adversely impacting patients' oral health. This article discusses the evidence related to airborne transmission of infectious diseases and the relevance to dentistry. The production of bioaerosols (aerosols carrying biological material) during dental procedures is explored, as well as how the potential risks posed by these bioaerosols can be controlled. A better understanding of dental bioaerosols is needed to prevent similar disruption to dental services in future outbreaks, and to reduce the risk of infection of dental professionals when treating patients with active infections who require urgent or emergency dental care., Competing Interests: Conflict of interest The authors declare that there are no conflicts of interest. JRA is supported by a Wellcome Trust Clinical Research Training Fellowship from the Wellcome 4Ward North Clinical PhD Academy and JRA, RH, JD, and NJ have received funding for research in dental bioaerosols from: the Faculties of Dental Surgery of the Royal College of Surgeons of England and the Royal College of Surgeons of Edinburgh; the British Endodontic Society; VODEX Ltd; and AerosolShield Ltd. JRA, RH, JD, and NJ are supported by the NIHR Newcastle Biomedical Research Centre (BRC), which is a partnership between Newcastle Hospitals NHS Foundation Trust, Newcastle University, and Cumbria, Northumberland and Tyne and Wear NHS Foundation Trust and is funded by the National Institute for Health and Care Research (NIHR). The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Aerosol-cloud interactions play a vital role in climate change. This study leverages observations from the King-350 aircraft over the North China Plain on November 29, 2019, to examine aerosol and cloud microphysical characteristics of mixed-phase clouds. Through detailed vertical and spectral distributions, we investigate aerosol, cloud droplet, and ice crystal distributions in seeded clouds (SC) and natural precipitating clouds (NPC) within the same cloud system. From the vertical profile, SC and NPC have similar vertical distributions of aerosol and cloud droplets, with over 95 % of aerosols concentrated below 1600 m near the ground. Cloud droplets are more evenly distributed within the two clouds, cloud droplet number concentrations (N c ) in SC were three orders of magnitude higher than in NPC. Ice water content (IWC) and ice crystal number concentration (N i ) show distinct layer preferences-accumulating predominantly in SC's top layer and NPC's middle layer. From spectral distribution, a smaller proportion of cloud droplets (40-50 μm in diameter, the same hereafter) in SC compared to NPC. Rimed ice crystals and globular graupel (1325-1550 μm in diameter) were in SC, while plate and irregular ice crystals (300-450 μm) were in NPC with an order of magnitude higher than in SC. These microphysical differences highlight the complexity of cloud seeding efficacy, which varies based on cloud conditions and microphysical properties. In the first seeding, Ni increased by 1-2 orders of magnitude (125-300 μm) in the high Nc (N c  > 1.11 × 10 5  L -1 ) region. Seeding in low N c (N c  < 1.11 × 10 5  L -1 ) regions was hard to be effective, especially in low N c and low liquid water content (LWC) (LWC < 0.122 g/m 3 ) regions. In the second seeding, ice crystals (125-250 μm) produced by the first seeding enhance the seeding efficiency. The responded regions were more sensitive to subsequent seeding, resulting in stronger reactions or longer duration., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Aerosol generating procedures pose a risk for SARS-CoV-2 transmission, and comprise a large percentage of cases performed in otolaryngology. An optimal method to mitigate this hazard does not currently exist. This study examined methods to mitigate surgical aerosols from the operating room., Methods: Utilizing an intubation manikin (Nasco Healthcare) and particle counter (Sensirion SPS30), a series of electrocautery-induced aerosols containing particles 0.5-10 μm in diameter were measured. Three different mitigation strategies were tested: intraoral (Yankauer, suction Bovie pencil (SBP)), extraoral (smoke evacuator system (SES)), and their combinations., Results: SES was effective compared to controls, but inferior to intraoral mitigation strategies (p < 0.0001). Combining SES with any intraoral mitigation strategy did not enhance mitigation efficiency, and in some comparisons led to inferior performance (SBP vs SBP-SES, p < 0.05). Comparison of intraoral mitigation strategies found no statistically significant differences between techniques, although SBP was found to have the lowest overall level of particles., Conclusions: Intraoral suction techniques are recommended for aerosol mitigation. Extraoral SES use alone is insufficient for aerosol mitigation, and may be counterproductive when used with intraoral suction techniques. Further research is needed to determine the optimal mitigation strategy for intraoperative surgical aerosols., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Background: Intraoperative bronchospasm in pediatric patients supported through laryngeal mask airways (LMAs) is commonly treated with pressurized metered-dose inhaler (pMDI) albuterol. The aim of the study was to evaluate delivery of pMDI albuterol through LMAs under different conditions in a model of infant/child supported with a ventilator., Methods: We compared drug delivery efficiency of 4 actuations of albuterol pMDI (captured on a filter placed between the LMA and a test lung), drug deposition in the circuit (elbow) and in the LMA under different experimental conditions. Outcomes were expressed of percentage of nominal dose. We compared devices (valved holding chamber [VHC] and adapter), timing of administration (inspiration and expiration), tidal volumes (50 mL and 100 mL), mode of actuation (single and multiple), and LMA sizes (1, 1.5, and 2). Multiple regression analysis was used to evaluate the contribution of each to these components to the outcomes. P < .05 was considered statistically significant., Results: Results are expressed as median (interquartile range) of pooled data. Drug delivery efficiency was 0% (0-1.1) and 6.3% (3.2-14.7) for adapter and VHC, respectively. Elbow deposition was 25.8% (19.2-63.3) and 2.9% (1.4-6.4) for adapter and VHC, respectively. LMA deposition was 2.6% (1.3-4.6) and 4.6% (2.9-6.1) for adapter and VHC, respectively. Multiple regression analysis showed that device, timing of actuation, and LMA size explained 33%, 17%, and 8% of the observed variation in delivery efficiency (R 2 0.63), respectively. Multiple regression analysis showed that device and timing of actuation explained 52% and 16% of the observed variation, respectively (R 2 0.70). Multiple regression analysis poorly explained factors associated with LMA deposition (R 2 0.22)., Conclusions: Using a VHC, actuating the pMDI during exhalation, and using a small LMA size increased drug delivery efficiency. The adapter was an inefficient add-on device for aerosol delivery with a pMDI through an LMA that caused significant circuit deposition., (Copyright © 2024 by Daedalus Enterprises.)

The presence of pathogenic bacteria and antibiotic resistance genes (ARGs) in urban air poses a significant threat to public health. While prevailing research predominantly focuses on the airborne transmission of ARGs by bacteria, the potential influence of other vectors, such as bacteriophages, is often overlooked. This study aims to investigate the characteristics of phages and ARGs in aerosols originating from hospitals, public transit centers, wastewater treatment plants, and landfill sites. The average abundance of ARGs carried by phages in the public transit centers was 8.81 ppm, which was 2 to 3 times higher than that at the other three sites. Additionally, the abundance of ARGs across different risk levels at this site was also significantly higher than at the other three sites. The assembled phage communities bearing ARGs in public transit centers are chiefly governed by homogeneous selection processes, likely influenced by human movement. Furthermore, observations at public transit sites revealed that the average abundance ratio of virulent phages to their hosts was 1.01, and the correlation coefficient between their auxiliary metabolic genes and hosts' metabolic genes was 0.59, which were 20 times and 3 times higher, respectively, than those of temperate phages. This suggests that virulent phages may enhance their survival by altering host metabolism, thereby aiding the dispersion of ARGs and bacterial resistance. These revelations furnish fresh insights into phage-mediated ARG transmission, offering scientific substantiation for strategies aimed at preventing and controlling resistance within aerosols., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The frequency and intensity of forest fires are amplified by climate change. Substantial quantities of PM 1 emitted from forest fires can undergo gradual atmospheric dispersion and long-range transport, thus impacting air quality far from the source. However, the chemical composition and physical properties of PM emitted from forest fires and its changes during atmospheric transport remain uncertain. In this study, the evolution of organic carbon (OC), elemental carbon (EC), water-soluble ions, and water-soluble metals in the particulate phase of smoke emitted from the typical forest vegetation combustion in Southwest China before and after photo-oxidation was investigated in the laboratory. Two aging periods of 5 and 9 days were selected. The OC and TC mass concentrations tended to decrease after 9-days aged compared to fresh emissions. OP, OC2, and OC3 in PM 1 are expected to be potential indicators of fresh smoke, while OC3 and OC4 may serve as suitable markers for identifying aged carbon sources from the typical forest vegetation combustion in Southwest China. K + exhibited the highest abundant water-soluble ion in fresh PM 1 , whereas NO 3 - became the most abundant water-soluble ion in aged PM 1 . NH 4 emerged as the primary secondary inorganic aerosol emitted from typical forest vegetation combustion in Southwest China. Notably, a 5-day aging period proved insufficient for the complete formation of the secondary inorganic aerosols NH 3 emerged as the primary secondary inorganic aerosol emitted from typical forest vegetation combustion in Southwest China. Notably, a 5-day aging period proved insufficient for the complete formation of the secondary inorganic aerosols NH 4 NO 3 and (NH 4 ) 2 SO 4 . After aging, the mass concentration of the water-soluble metal Ni in PM 1 from typical forest vegetation combustion in Southwest China decreased, while the mean mass concentrations of all other water-soluble metals increased in varying degrees. These findings provide valuable data support and theoretical guidance for studying the atmospheric evolution of forest fire aerosols, as well as contribute to policy formulation and management of atmospheric environment safety and human health., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: The use of probiotic bacteria to improve lung health has been gaining interest. Although the oral delivery of probiotics and their effects are well documented, there is currently limited knowledge on the respiratory delivery of probiotics., Objectives: This study aimed to investigate whether nebulisation is suitable for delivering Lacticaseibacillus rhamnosus GG (LGG) into the lungs for the potential treatment of bacterial pulmonary infections., Methods: It compared the dose output and aerosol performance of a vibrating-mesh nebuliser (VMN) and a jet nebuliser (JN) in nebulising LGG suspended in de Man Rogosa Sharpe (MRS) broth, phosphate-buffered saline (PBS), or normal saline (0.9% w / v sodium chloride in water)., Results: The VMN consistently produced a higher output than the JN for all liquid media, indicating that VMN was more efficient. The fine-particle fractions of both nebulisers were comparable for a given medium. The highest fine-particle fraction was achieved with LGG suspended in MRS broth for both nebulisers (20.5 ± 2.8% for VMN; 18.7 ± 3.4% for JN). This suggests that the aerosol performance of nebulised probiotics may depend on the medium in which the probiotic bacteria were suspended., Conclusions: Therefore, this study demonstrated that the nebulisation efficiency of LGG depended on the nebuliser type and liquid medium of the probiotic suspension.

We employed an enhanced WRF-Chem to investigate the discrete mechanisms of aerosol-radiation-feedback (ARF), extinction-photochemistry (AEP), and heterogeneous-reactions (AHR) across different seasons in eastern China, aiming to assess the synergistic effects arising from the simultaneous operation of multiple processes on O 3 and PM 2.5 . Our findings demonstrated that ARF fostered the accumulation of pollutants and moisture, initiating two distinct feedback mechanisms concerning O 3 . The elevation in the NO/NO 2 ratio amplified O 3 consumption. Increased near-surface moisture diminished upper-level cloud formation, thereby enhancing photolysis rates and O 3 photochemical production. The pronounced impact of heightened NO/NO 2 on O 3 led to a decrease of 0.1-2.7 ppb. When decoupled from ARF, AEP led to a more significant reduction in photolysis rates, resulting in declines in both O 3 and PM 2.5 , except for an anomalous increase observed in summer, with O 3 increasing by 1.6 ppb and PM 2.5 by 2.5 μg m -3 . The heterogeneous absorption of hydroxides in spring, autumn, and winter predominantly governed the AHR-induced variation of O 3 , leading to a decrease in O 3 by 0.7-1 ppb. Conversely, O 3 variations in summer were primarily dictated by O 3 -sensitive chemistry, with heterogeneous absorption of NO y catalyzing a decrease of 2.4 ppb in O 3 . Furthermore, AHR accentuated PM 2.5 by facilitating the formation of fine sulfates and ammonium while impeding nitrate formation. In summer, the collective impact of ARF, AEP, and AHR (ALL) led to a substantial reduction of 6.2 ppb in O 3 , alleviating the secondary oxidation of PM 2.5 and leading to a decrease of 0.3 μg m -3 in PM 2.5 . Conversely, albeit aerosol substantially depleted O 3 by 0.4-4 ppb through their interactions except for summer, aerosol feedback on PM 2.5 was more pronounced, resulting in a significant increase of 1.7-6.1 μg m -3 in PM 2.5 . Our study underscored the seasonal disparities in the ramifications of multifaceted aerosol-ozone interplay on air quality., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Q fever, also known as query fever, is a zoonotic illness brought on by the Coxiella burnetii bacteria. This disease was first discovered in 1935 in Queensland, Australia. Worldwide, Q fever is a disease that requires notification, and certain nations classify it as a national health concern. A feature of C. burnetii is known as cell wall phase fluctuation. Serological testing is the main method used to diagnose Q fever illnesses. Inhalation is the primary method of C. burnetii transmission in both people and animals, with smaller amounts occurring through milk and milk product ingestion. The bacterial strain that is causing the infection determines how severe it is. Q fever is a significant zoonosis that can be dangerous for personnel working in veterinary laboratories, livestock breeding operations, and slaughterhouses due to its high human contagiousness. Coxiella burnetii is a biological weapon that can be sprayed on food, water, or even mail. It can also be employed as an aerosol. Antibiotics work well against this disease's acute form, but as the infection develops into a chronic form, treatment becomes more difficult and the illness frequently returns, which can result in a high death rate. Vaccination has been demonstrated to lower the incidence of animal infections, C. burnetii shedding, and abortion. Several hygienic precautions should be put in place during an outbreak to lessen the spread of disease to animals., Competing Interests: The authors declare that there is no conflict of interest.

This study aimed to establish a feasible dissolution method for inhalation aerosols. A method of collecting fine particles was investigated to capture aerosol particles less than 4 μm in diameter for dissolution tests. This dose collection method enabled the aerosol particles to be uniformly distributed on the glass fiber filter, thus considerably reducing particle agglomeration. Budesonide was used as a model drug. The aerodynamic particle size distribution (APSD) of the meter-dose inhaler (MDI) was compared by replacing actuators with different orifice sizes. Dissolution tests were conducted on fine particle doses collected using various actuators, and the dissolution profiles were modeled. The fine particle dose decreased with an increasing orifice size of the actuator. Actuators with different orifice sizes would affect the dissolution behavior of inhaled drugs. This finding was supported by similarity factor f 2 analysis, suggesting the dissolution method has a discriminative capacity. The results of various model fits showed that the dissolution profiles produced by the different actuators could be fitted well using the Weibull mathematical model. The method employed in this study could offer a potential avenue for exploring the relationship between the orifice size of the actuator and the dissolution behavior of inhaled corticosteroids. This dissolution method was simple, reproducible, and suitable for determining the dissolution of inhalation aerosols., (© 2024. The Author(s), under exclusive licence to American Association of Pharmaceutical Scientists.)

Micro-nano bubble (MNB) aeration is an emerging technology that considerably enhances the aeration efficiency of wastewater. This study evaluates, for the first time, aerosolization at the water-air interface during MNB aeration. Our results show that the concentration of culturable mixed microorganisms (i.e., bacteria, fungi, and intestinal bacteria) in the in situ MNB generation (MNBs-G) phase is 2170 CFU/m 3 , 1.38 and 1.58-fold higher than those in medium-bubble aeration (MBA; 1568 CFU/m 3 ) and small-bubble aeration (SBA; 1376 CFU/m 3 ) aerosols, respectively. Conversely, the concentration of culturable mixed microorganisms in the MNB persistent dissolved oxygen (MNBs-O) phase is only 914 CFU/m 3 . Microbiological analysis shows a lower abundance of bacterial pathogens in MNBs-G (34.12%) and MNBs-O (34.02%) phases than in MBA (39.63%) and SBA (38.87%) aerosols. Acinetobacter is prevalent in MNBs-G (14.76%) and MNBs-O (8.22%) aerosols, whereas Bacillus and Arcobacter are prevalent in MBA (23.96%) and SBA (6.92%) aerosols, respectively. The total concentrations of chemicals [i.e., total organic carbon, water-soluble ions, and metal(loid)s] in aerosols formed via MNB aeration (205.98-373.74 μg/m 3 ) are lower than those in MBA and SBA (398.69-594.92 μg/m 3 ). Compared to MBA and SBA, the MNBs-G phase exhibits higher emissions of 12 elements in aerosols (i.e., NO 3 - , NO 2 - , Ca 2+ , Na + , Zn, Cd, Fe, Mn, As, and Cr), whereas the MNBs-O phase generally shows lower emissions. These findings highlight the potential of optimized MNB aeration technology in considerably mitigating aerosol emissions and thereby advancing environmental sustainability in wastewater treatment.+ , Mg 2+ , Zn, Cd, Fe, Mn, As, and Cr), whereas the MNBs-O phase generally shows lower emissions. These findings highlight the potential of optimized MNB aeration technology in considerably mitigating aerosol emissions and thereby advancing environmental sustainability in wastewater treatment.

We report a large outbreak of severe acute respiratory syndrome coronavirus 2 in a residential living facility. Measurements of carbon dioxide levels, aerosol particle clearance, and airflow were used to identify and remediate areas with suboptimal ventilation. A simple intervention involving continuous operation of bathroom fans was effective in significantly improving ventilation in resident rooms., (Published by Elsevier Inc.)

While artificial 3D nanostructures can generate precise and flexible coloration, their real-time color changes during 3D nanoprinting remain unexplored owing to the inherent challenges of in situ transient measurements and observations. In this study, a 3D-printing system which supports the operando observation/measurement of the color dynamics of subwavelength metallic nanoarchitectures fabricated in real time is developed and evaluated. During 3D printing, the dimensions and geometries of the 3D nanostructures grow over time, producing a large library of optical spectra associated with real-time color changes. Only a timer is needed to define the expected colors from a single 3D print run. Fin-like nanostructures are used to toggle colors based on the polarization effect and produce color gradients. Based on structural coloration, nanoarchitectures are designed and printed to animate desired color patterns. Moreover, the resulting color dynamics can also serve as an operando identifier for real-time structural information during 3D nanoprinting. A single print run enables the efficient creation of a comprehensive library of desired colorations owing to the flexibility in time-dependent controllability and 3D geometries at the subwavelength scale. 3D nanoprinted plasmonic structures exhibiting time-varying colorations (4D printing of colors) uniquely redefines the coloring stategy, offering considerable potential for numerous applications., (© 2024 Wiley‐VCH GmbH.)

Experimental systems allowing aerosol exposure (AE) of cell cultures at the air-liquid-interface (ALI) are increasingly being used to assess the toxicity of inhaled contaminants as they are more biomimetic than standard methods using submerged cultures, however, they require detailed characterisation before use. An AE-ALI system combining aerosol generation with a CULTEX® exposure chamber was characterised with respect to particle deposition and the cellular effects of filtered air (typical control) exposures. The effect of system parameters (electrostatic precipitator voltage, air flowrate to cells and insert size) on deposition efficiency and spatial distribution were investigated using ICP-MS and laser ablation ICP-MS, for an aerosol of CeO 2 nanoparticles. Deposition varied with conditions, but appropriate choice of operating parameters produced broadly uniform deposition at suitable levels. The impact of air exposure duration on alveolar cells (A549) and primary small airway epithelial cells (SAECs) was explored with respect to LDH release and expression of selected genes. Results indicated that air exposures could have a significant impact on cells (e.g., cytotoxicity and expression of genes, including CXCL1, HMOX1, and SPP1) at relatively short durations (from 10 mins) and that SAECs were more sensitive. These findings indicate that detailed system characterisation is essential to ensure meaningful results., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Crown Copyright © 2024. Published by Elsevier Ltd. All rights reserved.)

The chemical components of the e-liquids and aerosols contained in electronic nicotine delivery systems (ENDSs), better known as vapes, were evaluated. The analytical technique used was gas chromatography-mass spectrometry, where the extraction and injection methods were established in this study. The work consisted of the analysis of twenty samples of disposable electronic cigarettes prefilled with new e-liquid, of a known brand, flavor, volume, and, in some of them, the percentage of nicotine and the number of puffs per device were indicated on the label. We detected the presence of many substances (at a qualitative and semi-quantitative level), and we achieved the quantification of benzene, toluene, and xylenes (BTX), dangerous substances that cause severe damage to health. Several of the e-liquids and aerosols present BTX concentrations above the permissible exposure limit (PEL), recommended by the Occupational Safety and Health Administration (OSHA): benzene in aerosol samples 80% > PEL, and toluene in aerosol samples 45% > PEL. The number of chemical compounds found in the samples increases from 13 to 167, the average being 52 compounds for the water extraction method, 42 compounds for the methanol extraction method of e-liquids, and 107 compounds for the direct aerosol analysis. It is a fact that many of those compounds, especially BTX, can cause serious effects on human health, affecting the respiratory, digestive, cardiovascular, pulmonary, and immune systems, as well as the brain. Therefore, the use of these devices should be considered with caution, since the substances and their chemical nature may pose significant health risks to both users and those exposed to secondhand emissions.

This study aims to determine the presence of norovirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and bocavirus in air samples from a tertiary care hospital in Bangkok, Thailand. Air samples were collected in water using the BioSampler and concentrated using speedVac centrifugation. Based on RT-qPCR, norovirus RNA and SARS-CoV-2 RNA were detected in 13/60 (21.7%) and 3/60 (5.0%) of samples, respectively. One air sample had a weak positivity for both norovirus and SARS-CoV-2 RNAs. Detection rate of norovirus genogroup (G) II (13.3%) was higher than norovirus GI (6.7%). One air sample (1.7%) tested positive for GI and GII. The norovirus GI RNA concentration was 6.0 × 10 2 genome copies/m 3 . The norovirus GII RNA concentrations ranged from 3.4 × 10 1 to 5.0 × 10 3 genome copies/m 3 . Based on RT-nested PCR, norovirus GII was detected in two (3.3%) samples. All samples tested negative for GI RNA and bocavirus DNA. By phylogenetic analysis, GII.17, which is closely related to the outbreak Kawasaki308/JPN/2015 strain, was found in the RT-nested PCR-positive samples. This study highlights the potential of aerosols for norovirus and SARS-CoV-2 transmission and probably cause gastrointestinal and respiratory illnesses, respectively., (© 2024. The Author(s).)

In Europe, respiratory protective devices must be certified before they can be marketed. Among the parameters of interest, inward leakage (IL) characterizes the tightness between the face seal and the face, to verify that the device is well-designed. European standard EN 13274-1 (2001) and International Organization for Standardization (ISO) standard ISO 16900-1 (2019) specify that IL should be measured using sodium chloride (NaCl) aerosol or sulfur hexafluoride (SF6) gas. For reusable masks made of nonporous materials, both test agents are considered equally acceptable. However, the few studies that have compared IL values measured with various aerosols and gases have come to divergent conclusions. This work then aimed to measure IL with the test agents recommended by the standards to determine whether they are really equivalent. Since krypton (Kr) is an interesting candidate for replacing SF6 in standard tests, IL was assessed with SF6 and Kr simultaneously, and with NaCl aerosol using various calculation methods. Tests were carried out on 5 models of full-face masks donned on a headform connected to a breathing machine simulating 3 sinusoidal breathing rates of various intensities. The respirator fit on the headform was evaluated using a controlled negative pressure method to determine a manikin fit factor. Four scenarios were then tested to represent very poor, bad, good, and excellent fit. Gas concentration was measured using a mass spectrometer, and IL was calculated for SF6 and Kr. A combination of 3 devices allowed the determination of the number-based concentration of particles with diameters between 20 nm and 2 µm, and IL was calculated for each of the 33 channels, as well as using a cumulative number concentration. In addition, to comply with standards, a conversion was carried out to calculate IL using a cumulative mass concentration. The results of this work evidenced that the IL values measured with NaCl were systematically lower than those determined with gases. IL was also shown to vary with particle size, with a maximum value exceeding that calculated with cumulative concentrations (in number or mass). As part of the revision of the standards, protocols for measuring inward leakage should be redefined. On the one hand, acceptability thresholds should be re-evaluated according to the nature of the test agent (gas or aerosol), as it is clear that the 2 options do not give the same results for a given configuration. On the other hand, the aerosol leakage measurement protocol needs to be reworked to enable the measurement of a well-defined, robust, and reproducible inward leakage value., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Occupational Hygiene Society. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Palytoxins are a group of highly potent and structurally complex marine toxins that rank among some of the most toxic substances known to science. Palytoxins are naturally synthesized by a variety of marine organisms, including Palythoa zoanthids, Ostreopsis dinoflagellates, and Trichodesmium cyanobacteria, and are widely distributed in tropical and temperate regions where they can bioaccumulate in marine life. The evolution of research on palytoxins has been an intricate exchange between interdisciplinary fields, drawing insights from chemistry, biology, medicine, and environmental science in efforts to better understand and mitigate the health risks associated with this family of toxins. In this review, we begin with a brief history covering the discovery of this group of toxins and the events that led to its isolation. We then focus on the chemical structure of these compounds and their proposed mechanism of action. Finally, we review in vitro, ex vivo, and in vivo studies related to their toxicity, with the aim to provide a broad overview of the current knowledge on palytoxin toxinology.

Per- and polyfluoroalkyl substances (PFAS), often referred to as "forever chemicals", are a class of man-made, extremely stable chemicals, which are widely used in industrial and commercial applications. Exposure to some PFAS is now known to be detrimental to human health. By virtue of PFAS long residence times, they are widely detected in the environment, including remote locations such as the Arctics, where the origin of the PFAS is poorly understood. It has been suggested that PFAS may be transported through contaminated waters, leading to accumulation in coastal areas, where they can be aerosolised via sea spray, thereby extending their geographical distribution far beyond their original source regions. The aim of this work is to investigate, for the first time, whether "forever chemicals" could be transported to areas considered to be pristine, far from coastal sites. This study was performed at the Amazonian Tall Tower Observatory (ATTO), a unique remote site situated in the middle of the Amazon rainforest, where a restricted PFAS, perfluorooctanoic acid (PFOA), was observed with concentrations reaching up to 2 pg/m 3 . A clear trend of increasing concentration with sampling height was observed and air masses from the south over Manaus had the highest concentrations. Atmospheric lifetime estimations, removal mechanisms supported by measurements at two heights (320 and 42 m above the rainforest), and concentration spikes indicated a long-range transport of PFOA to pristine Amazon rainforest. Potential sources, including industrial activities in urban areas, were explored, and historical fire management practices considered. This research presents the first measurements of PFAS in the atmosphere of Amazon rainforest. Remarkably, even in this remote natural environment, appreciable levels of PFAS can be detected. This study provides valuable insights into the long-range transport of the anthropogenic "forever chemical" into a remote natural ecosystem and should raise awareness of potential environmental implications., Competing Interests: Declaration of competing interest The authors declare they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Respiratory infectious diseases, notably recurring waves of COVID-19 during autumn and winter, have significantly impacted global health and strained public health systems. Home isolation has emerged as a crucial and economical strategy to mitigate these impacts. This study investigates aerosol transmission and infection risks in home isolation environments using the Lattice Boltzmann Method with Large Eddy Simulation (LBM-LES). We focused on the impact of door operations and various natural ventilation rates on aerosol transmission and exposure risk in adjacent rooms. Our findings reveal that, without ventilation, aerosol leakage through door gaps poses a minimal infection risk to adjacent rooms, with an average probability of less than 2 × 10 -5 . However, with adequate ventilation, the infection risk for individuals in adjacent rooms for over 3 h can reach 60 %-70 %. Brief door movements have limited impact on infection risk (p ≤ 0.05, d ≤ 0.20), with aerosol leakage mainly occurring through door gaps rather than door movements. To reduce cross-infection during home isolation, we recommend avoiding prolonged stays near downwind walls facing the door. This research provides insights into aerosol dynamics in home isolation scenarios, offering theoretical guidance for designing safe isolation spaces and practical advice for healthy family members to minimize infection risk., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Phages are known as a promising method to combat antimicrobial resistance (AMR) in the human and veterinary sector. Use of phage aerosols enormously increases the application field, although the impact on the infectivity of phages during nebulization needs to be evaluated. In this study S. infantis was treated on plates and chicken skin with nebulized phage particles of the Myoviridae type, identified by transmission electron microscopy, using a commercial nebulizer primarily used for H 2 O 2 disinfection. The reduction of bacterial number by aerosol applied phage particles was evaluated. It could clearly be shown that the phage particles were able to infect Salmonella after being nebulized using ultrasound technology. Further studies on other types of phages as well as other conditions must be performed to standardize the aerosolic application of phages., (Copyright 2024, Mary Ann Liebert, Inc., publishers.)

Advancement of the absorbent for CO 2 capture is essential in optimizing the performance and reducing the negative environmental effects associated with this technology. Despite ammonia's promise as an absorbent, the volatility limits its practical application and creates potential environmental pollution. Therein, we assess various additives (amino acids, carbonates, and alkanolamines) for ammonia-based solvents using multi-stage circulation absorber from the viewpoints of aerosol emission, ammonia emission, and CO 2 capture efficiency. Experimental findings reveal that ammonia volatilization can be inhibited by the protonation of free ammonia by carboxyl groups and the formation of hydrogen bonding between amino/hydroxyl groups and ammonia, with ammonia emission reduced by 21.7 %, aerosol emission reduced by 26.5 %, and CO 2 capture efficiency increased to a maximum of 87.8 % under the condition of adding histidine. Moreover, the experiment highlights a positive correlation between total ammonia emission and aerosol concentration/diameter. Additionally, tests combining source abatement with water wash exhibit up to 50.5 % aerosol removal efficiency and up to 76.6 % ammonia removal efficiency. To further mitigate emissions, a comprehensive approach is proposed, achieving an 84.4 % reduction in ammonia emission and a 61.9 % reduction in aerosol emission. Finally, a method for recycling ammonia for desulfurization is suggested., Competing Interests: Declaration of competing interest We declare that we do not have any commercial or associative interest that represents a conflict of interest in connection with the work submitted., (Copyright © 2024. Published by Elsevier B.V.)

Aerosol-transmitted viruses possess strong infectivity and can spread over long distances, earning the difficult-to-control title. They cause various human diseases and pose serious threats to human health. Mutations can increase the transmissibility and virulence of the strains, reducing the protection provided by vaccines and weakening the efficacy of antiviral drugs. In this study, we established a manually curated database (termed AVM) to store information on aerosol-transmitted viral mutations (VMs). The current version of the AVM contains 42,041 VMs (including 2613 immune escape mutations), 45 clinical information datasets, and 407 drugs/antibodies/vaccines. Additionally, we recorded 88 human diseases associated with viruses and found that the same virus can target multiple organs in the body, leading to diverse diseases. Furthermore, the AVM database offers a straightforward user interface for browsing, retrieving, and downloading information. This database is a comprehensive resource that can provide timely and valuable information on the transmission, treatment, and diseases caused by aerosol-transmitted viruses (http://www.bio-bigdata.center/AVM)., (© The Author(s) 2024. Published by Oxford University Press and Science Press on behalf of the Beijing Institute of Genomics, Chinese Academy of Sciences / China National Center for Bioinformation and Genetics Society of China.)

Aims: Intubated patients with methicillin-resistant Staphylococcus aureus pneumonia, fail optimized treatment with intravenous (IV) vancomycin (serum trough 15-20 μg/mL) in 38-79% of cases. Airway blood flow is diminished compared to alveoli and we hypothesized that vancomycin concentrations achieved in airway secretions are suboptimal and nonbactericidal. Targeted therapy by inhalation may overcome this deficit., Methods: Airway pharmacokinetics of optimized IV and inhaled vancomycin in infected clinically stable prolonged mechanically ventilated patients were measured. First, IV vancomycin was given until optimized concentrations were achieved (15-20 μg/mL), and, at the same time point, sputum vancomycin concentrations were measured. Then, sputum concentrations were re-assessed after 4 treatments of inhaled vancomycin (120 mg/2 mL) via a previously characterized nebulizing system that deposited 18 ± 2 mg in the lungs. Vancomycin post-distribution phase serum peak and trough concentrations were also obtained. Serum albumin was measured to assess binding to vancomycin., Results: Mean serum trough concentration was 18.4 ± 6.5 μg/mL. Sputum concentrations were affected by serum albumin. Only patients with severe hypoalbuminaemia had penetration of drug leading to therapeutic (15.7-17 μg/mL) sputum concentrations. Following inhaled vancomycin, sputum concentrations increased significantly to 199 ± 37.0 μg/mL (P = .002) exceeding minimum inhibitory concentration by 2 orders of magnitude., Conclusion: Despite optimized serum concentrations, patients with albumin near normal had suboptimal concentrations of vancomycin in their sputum. Inhaled therapy may be clinically important for successful treatment of ventilator-associated methicillin-resistant Staphylococcus aureus infection. Further studies of inhaled therapy are needed to define their role as adjunctive therapy in ventilator-associated pneumonia and as single therapy in tracheobronchitis., (© 2024 The Author(s). British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

Pulmonary delivery of antibiotics is an effective strategy in treating bacterial lung infection for cystic fibrosis patients, by achieving high local drug concentrations and reducing overall systemic exposure compared to systemic administration. However, the inherent anatomical lung defense mechanisms, formulation characteristics, and drug-device combination determine the treatment efficacy of the aerosol delivery approach. In this study, we prepared a new tobramycin (Tobi) dry powder aerosol using excipient enhanced growth (EEG) technology and evaluated the in vitro and in vivo aerosol performance. We further established a Pseudomonas aeruginosa-induced lung infection rat model using an in-house designed novel liquid aerosolizer device. Notably, novel liquid aerosolizer yields comparable lung infection profiles despite administering 3-times lower P. aeruginosa CFU per rat in comparison to the conventional intratracheal administration. Dry powder insufflator (e.g. Penn-Century DP-4) to administer small powder masses to experimental animals is no longer commercially available. To address this gap, we developed a novel rat air-jet dry powder insufflator (Rat AJ DPI) that can emit 68-70 % of the loaded mass for 2 mg and 5 mg of Tobi-EEG powder formulations, achieving a high rat lung deposition efficiency of 79 % and 86 %, respectively. Rat AJ DPI can achieve homogenous distribution of Tobi EEG powder formulations at both loaded mass (2 mg and 5 mg) over all five lung lobes in rats. We then demonstrated that Tobi EEG formulation delivered by Rat AJ DPI can significantly decrease CFU counts in both trachea and lung lobes at 2 mg (p < 0.05) and 5 mg (p < 0.001) loaded mass compared to the untreated P. aeruginosa-infected group. Tobi EEG powder formulation delivered by the novel Rat AJ DPI showed excellent efficiencies in substantially reducing the P. aeruginosa-induced lung infection in rats., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Michael Hindle, Worth Longest has patent EXCIPIENT ENHANCED GROWTH (EEG) OF NANOPARTICLE AEROSOLSTO ENABLE IMPROVED PULMONARY TARTETING AND RETENTION issued to Quench Medical. Michael Hindle, Worth Longest has patent DRY POWDER INHALER (DPI) DESIGN FOR PRODUCING AEROSOLS WITHHIGH FINE PARTICLE FRACTIONS issued to Quench Medical. Michael Hindle, Worth Longest, Dale Farkas has patent Dry powder inhalers and interfaces for improved aerosol delivery to children pending to Virginia Commonwealth University. Michael Hindle, Worth Longest, Dale Farkas has patent Devices, systems, and methods for dry powder therapies pending to Virginia Commonwealth University. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Water vapor condensation on hygroscopic aerosol particles plays an important role in cloud formation, climate change, secondary aerosol formation, and aerosol aging. Conventional understanding considers deliquescence of nanosized hygroscopic aerosol particles a nearly instantaneous solid to liquid phase transition. However, the nanoscale dynamics of water condensation and aerosol particle dissolution prior to and during deliquescence remain obscure due to a lack of high spatial and temporal resolution single particle measurements. Here we use real time in situ transmission electron microscopy (TEM) imaging of individual sodium chloride (NaCl) nanoparticles to demonstrate that water adsorption and aerosol particle dissolution prior to and during deliquescence is a multistep dynamic process. Water condensation and aerosol particle dissolution was investigated for lab generated NaCl aerosols and found to occur in three distinct stages as a function of increasing relative humidity (RH). First, a < 100 nm water layer adsorbed on the NaCl cubes and caused sharp corners to dissolve and truncate. The water layer grew to several hundred nanometers with increasing RH and was rapidly saturated with solute, as evidenced by halting of particle dissolution. Adjacent cube corners displayed second-scale curvature fluctuations with no net particle dissolution or water layer thickness change. We propose that droplet solute concentration fluctuations drove NaCl transport from regions of high local curvature to regions of low curvature. Finally, we observed coexistence of a liquid water droplet and aerosol particle immediately prior to deliquescence. Particles dissolved discretely along single crystallographic directions, separated by few second lag times with no dissolution. This work demonstrates that deliquescence of simple pure salt particles with sizes in the range of 100 nm to several microns is not an instantaneous phase transition and instead involves a range of complex dissolution and water condensation dynamics.

The shape of environmental aerosols contributes to the discrepancy in their dynamic behavior compared to spherical particles, which have received inadequate consideration. We reported deposition patterns of aerosols and aerosol-transmissible pathogens in real human respiratory systems, taking into account their actual shape, using a validated computational-based model. We found that the shape of the aerosols significantly influenced its deposits and accessibility within the respiratory system, significantly in the tracheobronchial region. As an example, we estimated that over 180 % of differences in deposits in the trachea and bronchi were attributable to pathogens shape, inferring the underlying pathogenicity difference of these regions. These findings, capturing the spatial heterogeneity of pathogens and aerosols deposition in human respiratory system, have major implication for understanding the evolution of aerosol-related disease., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Human norovirus is transmitted mainly via the faecal-oral route, but norovirus disease outbreaks have been reported in which airborne transmission has been suggested as the only explanation. We used murine norovirus (MNV) as a surrogate for human norovirus to determine the aerosolization of infectious norovirus in an experimental setup. A 3-l air chamber system was used for aerosolization of MNV. Virus in solution (6 log 10 TCID 50 /ml) was introduced into the nebulizer for generating aerosols and a RAW 264.7 cell dish without a lid was placed in the air chamber. Cell culture medium samples were taken from the dishes after the aerosol exposure time of 30 or 90 min, and the dishes were placed in a 37 °C, 5% CO 2 incubator and inspected with a light microscope for viral cytopathic effects (CPEs). We determined both the infectious MNV TCID 50 titre and used an RT-qPCR assay. During the experiments, virus infectivity remained stable for 30 and 90 min in the MNV solution in the nebulizer. Infectious MNV TCID 50 values/ml of 2.89 ± 0.29 and 3.20 ± 0.49 log 10 were measured in the chamber in RAW 264.7 cell dish media after the 30-min and 90-min exposure, respectively. The MNV RNA loads were 6.20 ± 0.24 and 6.93 ± 1.02 log 10 genome copies/ml, respectively. Later, a typical MNV CPE appeared in the aerosol-exposed RAW cell dishes. We demonstrated that MNV was aerosolized and that it remained infectious in the experimental setup used. Further studies required for understanding the behaviour of MNV in aerosols can thus be performed., (© 2024. The Author(s).)

This study investigated the impact of sweeteners on the release of heavy metals during the heating and atomization processes in electronic cigarettes. Based on a PG/VG base e-liquid with the addition of 2% and 5% neotame or sucralose, we quantitatively analyzed the impact of sweetener content on the levels of heavy metals such as Ni, Cr, and Fe in the e-liquid and aerosol after heating and atomization. Additionally, the heated e-liquid samples were used to culture SH-SY-5Y and Beas-2B cells, and their cytotoxic effects were assessed using the CCK-8 assay. The results indicated that the e-liquid with 5% sucralose had the highest average levels of heavy metals after heating and atomization, particularly nickel (13.36 ± 2.50 mg/kg in the e-liquid and 12,109 ± 3,229 ng/200 puffs in the aerosol), whereas the e-liquid with neotame had significantly lower average heavy metal content in comparison. Additionally, it was measured that the chloride ion concentration in the e-liquid with 5% sucralose reached 191 mg/kg after heating at 200°C for 1 h, indicating that heating sucralose generated chloride ions, Which might corrode metal parts components leading to heavy metal release. Cytotoxicity tests revealed that the base e-liquid without sweeteners exhibited the highest average cell viability after heating, at 64.80% ± 2.84% in SH-SY-5Y cells and 63.24% ± 0.86% in Beas-2B cells. Conversely, the e-liquid variant with 5% sucralose showed a significant reduction in average cell viability, reducing it to 50.74% ± 0.88% in SH-SY-5Y cells and 53.03% ± 0.76% in Beas-2B cells, highlighting its more pronounced cytotoxic effects compared to other tested e-liquids. In conclusion, sucralose in e-liquids should be limited preferably less than 2%, or replaced with neotame, a safer alternative, to minimize health risks., Competing Interests: XY, ZC, XR, ZC, GW, ZD, YF, TH were employed by IMiracle (Shenzhen) Innovation Technology Co., Ltd., (Copyright © 2024 Yan, Chen, Rong, Chen, Wu, Dong, Fu and Hai.)

Transmission of airborne infectious diseases poses great risk for public health and socio-economic stability, thus, there is a need for an effective control method targeting the spread and transmission of pathogenic aerosols. The existence of chemically-reductive trace air contaminants in animal agriculture may affect the oxidation inactivation process of pathogens. In this study, we report how the presence of such gasses impacts the effectiveness of using non-thermal plasma (NTP) within a packed-bed dielectric barrier discharge reactor to inactivate MS2 bacteriophage. Inactivation of the aerosolized bacteriophage is determined by the combination of viability and polymerase chain reaction assays. Using a plasma power source with a voltage of 20 kV and frequency of 350 Hz, after differentiating and excluding the physical removal effects of viral aerosols potentially caused by plasma, the baseline inactivation of MS2 aerosol in air has been determined based on an overall air flow rate of 200 Liters per minute and plasma discharge power of 1.8 W. When either ammonia or hydrogen sulfide gas is introduced into the airstream at a concentration of 1 part per million, the NTP virus inactivation efficiency is reduced to around 0.5-log from the 1-log baseline inactivation in air alone. Higher concentrations of those gasses will not further inhibit the effectiveness of plasma inactivation., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Co-author Herek L. Clack is co-founder and chief scientific officer at Taza Aya (www.taza-aya.com) If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Exposure assessments to metalworking fluids (MWF) is difficult considering the complex nature of MWF. This study describes a comprehensive exposure assessment to straight and water-based MWFs among workers from 20 workshops. Metal and organic carbon (OC) content in new and used MWF were determined. Full-shift air samples of inhalable particulate and gaseous fraction were collected and analysed gravimetrically and for metals, OC, and aldehydes. Exposure determinants were ascertained through observations and interviews with workers. Determinants associated with personal inhalable particulate and gaseous fractions were systematically identified using mixed models. Similar inhalable particle exposure was observed for straight and water-based MWFs (64-386 µg/m 3 ). The gaseous fraction was the most important contributor to the total mass fraction for both straight (322-2362 µg/m 3 ) and water-based MWFs (101-699 µg/m 3 ). The aerosolized particles exhibited low metal content irrespective of the MWF type; however, notable concentrations were observed in the sumps potentially reaching hazardous concentrations. Job activity clusters were important determinants for both exposure to particulate and gaseous fractions from straight MWF. Current machine enclosures remain an efficient determinant to reduce particulate MWF but were inefficient for the gaseous fraction. Properly managed water-based MWF meaning no recycling and no contamination from hydraulic fluids minimizes gaseous exposure. Workshop temperature also influenced the mass fractions. These findings suggest that exposures may be improved with control measures that reduce the gaseous fraction and proper management of MWF., (© 2024. The Author(s).)

High pathogenicity avian influenza viruses (HPAIVs) have caused major epizootics in recent years, with devastating consequences for poultry and wildlife worldwide. Domestic and wild ducks can be highly susceptible to HPAIVs, and infection leads to efficient viral replication and massive shedding (i.e., high titres for an extended time), contributing to widespread viral dissemination. Importantly, ducks are known to shed high amounts of virus in the earliest phase of infection, but the dynamics and impact of environmental contamination on the epidemiology of HPAIV outbreaks are poorly understood. In this study, we monitored mule ducks experimentally infected with two H5N8 clade 2.3.4.4b goose/Guangdong HPAIVs sampled in France in 2016-2017 and 2020-2021 epizootics. We investigated viral shedding dynamics in the oropharynx, cloaca, conjunctiva, and feathers; bird-to-bird viral transmission; and the role of the environment in viral spread and as a source of samples for early detection and surveillance. Our findings showed that viral shedding started before the onset of clinical signs, i.e., as early as 1 day post-inoculation (dpi) or post-contact exposure, peaked at 4 dpi, and lasted for up to 14 dpi. The detection of viral RNA in aerosols, dust, and water samples mirrored viral shedding dynamics, and viral isolation from these environmental samples was successful throughout the experiment. Our results confirm that mule ducks can shed high HPAIV titres through the four excretion routes tested (oropharyngeal, cloacal, conjunctival, and feather) while being asymptomatic and that environmental sampling could be a non-invasive tool for early viral RNA detection in HPAIV-infected farms., (© 2024. The Author(s).)

A study was conducted to measure aerosol particles emitted from laboratory coats (lab coats) under vibration, comparing them with a suit and a shirt. This study focused on particles ranging from 0.3 μm to >10 μm. Experimental results showed that lab coat vibration increased particles >5 μm while reducing submicron particles. The lab coat (old and used) exhibited greater particle concentration variations under vibration compared to those using the new lab coat or the shirt. Contrastingly, the suit under vibration did not significantly affect particle concentrations. These findings highlight the impact of lab coat vibration on aerosol particle concentrations in the surrounding air, which is important for work environments., Competing Interests: The author declares no conflicts of interest.

Background: A BCG booster vaccination administered via the respiratory mucosa may establish protective immune responses at the primary site of Mycobacterium tuberculosis infection. The primary objective of this trial was to compare the safety and immunogenicity of inhaled versus intramuscular administered ChAdOx1-85A., Methods: We conducted a single-centre, randomised, double-blind, controlled phase 1 study (Swiss National Clinical Trials Portal number SNCTP000002920). After a dose-escalation vaccination in nine BCG-vaccinated healthy adults, a dose of 1 × 10 10 vp of ChAdOx1-85A was administered to twenty BCG-vaccinated adults that were randomly allocated (1:1) into two groups: aerosol ChAdOx1-85A with intramuscular saline placebo or intramuscular ChAdOx1-85A with aerosol saline placebo, using block randomisation. A control group of ten BCG-naïve adults received aerosol ChAdOx1-85A at the same dose. Primary outcomes were solicited and unsolicited adverse events (AEs) up to day 16 post-vaccination and Serious AEs (SAEs) up to 24 weeks; secondary outcomes were cell-mediated and humoral immune responses in blood and bronchoalveolar lavage (BAL) samples., Findings: Both vaccination routes were well tolerated with no SAEs. Intramuscular ChAdOx1-85A was associated with more local AEs (mostly pain at the injection site) than aerosol ChAdOx1-85A. Systemic AEs occurred in all groups, mainly fatigue and headaches, without differences between groups. Respiratory AEs were not different between BCG-vaccinated groups. Aerosol ChAdOx1-85A vaccination induced Ag85A BAL and systemic cellular immune responses with compartmentalisation of the immune responses: aerosol ChAdOx1-85A induced stronger BAL cellular responses, particularly IFNγ/IL17+CD4+ T cells; intramuscular ChAdOx1-85A induced stronger systemic cellular and humoral responses., Interpretation: Inhaled ChAdOx1-85A was well-tolerated and induced lung mucosal and systemic Ag85A-specific T-cell responses. These data support further evaluation of aerosol ChAdOx1-85A and other viral vectors as a BCG-booster vaccination strategy., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

In recent years, a series of public health issues caused by the spread of antibiotic resistance have been widely concerned. The indoor air of livestock and poultry houses is considered to be one of the main sources of environmental contamination of ARGs. This study characterized the micro-organisms and ARGs in the air particulate matter of chicken houses using metagenomics. The study successfully detected 761 different subtypes of resistance genes including aminoglycosides, tetracyclines, MLSB etc., 4 types of mobile genetic elements, and various pathogenic microorganisms from the aerosols in the chicken coop environment. The results showed that the abundance of ARGs in the air of the chicken coop was at a relatively high level, correlation network analysis showed that multiple types of ARGs could promote the emergence of antibiotic-resistant bacteria., Competing Interests: DISCLOSURES The authors declare no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Rapidly increasing urbanization in recent decades has elevated the subway as the primary public transportation mode in metropolitan areas. Indoor air quality (IAQ) inside subways is an important factor that influences the health of commuters and subway workers. This review discusses the subway IAQ in different cities worldwide by comparing the sources and abundance of particulate matter (PM 2.5 and PM 10 ) in these environments. Factors that affect PM concentration and chemical composition were found to be associated with the subway internal structure, train frequency, passenger volume, and geographical location. Special attention was paid to air pollutants, such as transition metals, volatile/semi-volatile organic compounds (VOCs and SVOCs), and bioaerosols, due to their potential roles in indoor chemistry and causing adverse health impacts. In addition, given that the IAQ of subway systems is a public health issue worldwide, we calculated the Gini coefficient of urban subway exposure via meta-analysis. A value of 0.56 showed a significant inequity among different cities. Developed regions with higher per capita income tend to have higher exposure. By reviewing the current advances and challenges in subway IAQ with a focus on indoor chemistry and health impacts, future research is proposed toward a sustainable urban transportation systems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

In this contribution, we report the study of nuclear resonance magnetic spectroscopy techniques ( 1 H-NMR, 13 C-NMR, and 2D-NMR) efficiency in the characterisation of the functional composition of water-soluble organic compounds (WSOC) from atmospheric aerosols. The chosen site was our scientific and technical center of research (CRAPC) situated in Algerian Bou-Ismail city. where the concentrations of PM 10 were found to be between 15.66 and 142.19 µg.m -3 . As results, 1 H-NMR analysis showed the coexistence of biological material and emissions from urban and biomass burning. The dominant source was identified by quantitative integration of each 1H NMR spectral region. By using the HSQC technique, many peaks are revealed in biogenic samples including biomass burning. On the other hand, the identification of the source of various organic compounds and their functional composition is possible through specific NMR spectra, which can also be used to adjust the surrounding organic aerosol sources., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Yellow fever (YF), caused by the yellow fever virus (YFV), continually spreads and causes epidemics worldwide, posing a great threat to human health. The live-attenuated YF 17D vaccine (YF-17D) has been licensed for preventing YFV infection and administrated via the intramuscular (i.m.) route. In this study, we sought to determine the immunogenicity and protective efficacy of aerosolized YF-17D via the intratracheal (i.t.) route in mice. YF-17D stocks in liquids were successfully aerosolized into particles of 6 μm. Further in vitro phenotype results showed the aerosolization process did not abolish the infectivity of YF-17D. Meanwhile, a single i.t. immunization with aerosolized YF-17D induced robust humoral and cellular immune responses in A129 mice, which is comparable to that received i.p. immunization. Notably, the aerosolized YF-17D also triggered specific secretory IgA (SIgA) production in bronchoalveolar lavage. Additionally, all immunized animals survived a lethal dose of YFV challenge in mice. In conclusion, our results support further development of aerosolized YF-17D in the future.

Objectives: N95 or Type II filtering face pieces (FFP2) are often worn during work hours or on public transportation to prevent airborne infection. The aim of this randomized controlled crossover study is to assess the impact of FFP2 induced breathing resistance on pulmonary function, blood gas values and discomfort during walking and stair climbing., Methods: N = 16 healthy adults (24.8 ± 2.2 years; 10 females, ) participated. Interventions included (1) six minutes of walking in a 16-meter-long hallway (612 m) and (2) eight minutes of stair climbing in a two-story staircase (420 stairs), both with and without a FFP2 (> 48 h wash-out). Spiroergometric data (Ventilation, breathing frequency, tidal volume, oxygen uptake and carbon dioxide exhalation (primary outcome), end tidal carbon dioxide- and oxygen pressure) and self-reported response (Perceived exertion, dyspnoea and pain) were assessed during activities. Blood gas analysis (capillary carbon dioxide- (pCO 2 ) (primary outcome) and oxygen partial pressure (pO 2 ), pH, lactate and base excess) was measured immediately after cessation of activities. Manipulation effects (FFP2 versus no mask) were tested using repeated measures analyses of variance., Results: Analysis showed no effect of FFP2 on pCO 2 or other blood-gas parameters but on carbon dioxide exhalation during walking: (mean 1067, SD 209 ml/min) (mean 1908, SD 426 ml/min) (F(15) = 19.5; p < 0.001; η p 2  = 0.566) compared to no mask wearing (mean 1237, SD 173 ml/min; mean 1908, SD 426 ml/min). Ventilation was decreased and dyspnoea was increased by FFP2 during activities. FFP2 led to lower oxygen uptake and lower end tidal oxygen but higher end tidal carbon dioxide during stair climbing., Conclusions: FFP2 decreased ventilation based on slower breathing patterns and led to limitations in pulmonary gas exchange and increased subjective dyspnoea. However, invasive diagnostics revealed no signs of clinically relevant metabolic effects immediately after everyday physical activities., (© 2024. The Author(s).)

The risk of Legionella transmission in built environments remains a significant concern. Legionella can spread within buildings through aerosol transmission, prompting the exploration of airborne transmission pathways and proposing corresponding prevention and control measures based on building characteristics. To this end, a comprehensive literature review on the transmission risk of Legionella in built environments was performed. Four electronic databases (PubMed, Web of Science, Google Scholar, and CNKI) were searched from inception to March 2024 for publications reporting the risk of Legionella transmission in built environments. Relevant articles and gray literature reports were hand-searched, and 96 studies were finally included. Legionella pollution comes from various sources, mainly originates in a variety of built environments in which human beings remain for extended periods. The sources, outbreaks, national standards, regulations, and monitoring techniques for Legionella in buildings are reviewed, in addition to increases in Legionella transmission risk due to poor maintenance of water systems and long-distance transmission events caused by aerosol characteristics. Air and water sampling using various analytical methods helps identify Legionella in the environment, recognize sources in the built environments, and control outbreaks. By comparing the standard regulations of national organizations globally, the authors further highlight gaps and deficiencies in Legionella surveillance in China. Such advancements offer essential insights and references for understanding and addressing Legionella transmission risk in the built environment, with the potential to contribute to safeguarding public health and building environment safety., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Yao, Shen, Hao, Huang and Keng.)

Because of the increasing popularity of e-cigarettes, monitoring the e-cigarette market has become important for national health authorities to guarantee safety and quality. In the EU, the Tobacco Products Directive requires emission studies for e-cigarette products. The absence of industry guidelines for studying these emissions and the lack of proper validation in the literature led us to develop and validate a method using the total error approach for the determination of nicotine in e-cigarette aerosols. A commercial vaping device was used to generate aerosols, which were then collected on Cambridge filter pads and measured for nicotine concentration by UHPLC-DAD after extraction. The method was successfully validated by generating accuracy profiles, which show that the β-expectation tolerance intervals remained below the acceptance limits of ±20%. Within-run repeatability and intermediate precision were considered acceptable since the highest RSD value obtained was below 5%. The method was applied to 15 commercial e-liquids. A complete validation of a method for the analysis of e-cigarette emissions is presented, including several parameters that impact the accuracy and reproducibility. Similar systematic approaches for method development and validation could be used for other e-cigarette emission analysis methods to ensure the reliability of the measurements.

Airborne infection risk analysis is usually performed for enclosed spaces where susceptible individuals are exposed to infectious airborne respiratory droplets by inhalation. It is usually based on exponential, dose-response models of which a widely used variant is the Wells-Riley (WR) model. We revisit this infection-risk estimate and extend it to the population level. We use an epidemiological model where the mode of pathogen transmission, airborne or contact, is explicitly considered. We illustrate the link between epidemiological models and the WR and the Gammaitoni and Nucci models. We argue that airborne infection quanta are, up to an overall density, airborne infectious respiratory droplets modified by a parameter that depends on biological properties of the pathogen, physical properties of the droplet and behavioural properties of the individual. We calculate the time-dependent risk of being infected for two scenarios. We show how the epidemic infection risk depends on the viral latent period and the event time, the time infection occurs. Infection risk follows the dynamics of the infected population. As the latent period decreases, infection risk increases. The longer a susceptible is present in the epidemic, the higher its risk of infection for equal exposure time to the pathogen is., Competing Interests: We declare we have no competing interests., (© 2024 The Authors.)

Aerosol transmission remains a major challenge for control of respiratory viruses, particularly those causing recurrent epidemics, like influenza A virus (IAV). These viruses are rarely expelled alone, but instead are embedded in a consortium of microorganisms that populate the respiratory tract. The impact of microbial communities and inter-pathogen interactions upon stability of transmitted viruses is well-characterized for enteric pathogens, but is under-studied in the respiratory niche. Here, we assessed whether the presence of five different species of commensal respiratory bacteria could influence the persistence of IAV within phosphate-buffered saline and artificial saliva droplets deposited on surfaces at typical indoor air humidity, and within airborne aerosol particles. In droplets, presence of individual species or a mixed bacterial community resulted in 10- to 100-fold more infectious IAV remaining after 1 h, due to bacterial-mediated flattening of drying droplets and early efflorescence. Even when no efflorescence occurred at high humidity or the bacteria-induced changes in droplet morphology were abolished by aerosolization instead of deposition on a well plate, the bacteria remained protective. Staphylococcus aureus and Streptococcus pneumoniae were the most stabilizing compared to other commensals at equivalent density, indicating the composition of an individual's respiratory microbiota is a previously unconsidered factor influencing expelled virus persistence.IMPORTANCEIt is known that respiratory infections such as coronavirus disease 2019 and influenza are transmitted by release of virus-containing aerosols and larger droplets by an infected host. The survival time of viruses expelled into the environment can vary depending on temperature, room air humidity, UV exposure, air composition, and suspending fluid. However, few studies consider the fact that respiratory viruses are not alone in the respiratory tract-we are constantly colonized by a plethora of bacteria in our noses, mouth, and lower respiratory system. In the gut, enteric viruses are known to be stabilized against inactivation and environmental decay by gut bacteria. Despite the presence of a similarly complex bacterial microbiota in the respiratory tract, few studies have investigated whether viral stabilization could occur in this niche. Here, we address this question by investigating influenza A virus stabilization by a range of commensal bacteria in systems representing respiratory aerosols and droplets., Competing Interests: The authors declare no conflict of interest.

Background: Zinc fever is well described in medical literature, particularly in workers after handling zinc-containing materials at high temperatures e.g., in the welding of hot-dip galvanized steel sheets. It is not known whether zinc fever also occurs at low temperatures., Case Presentation: We present the case of a 33-year-old Caucasian atopic painter and varnisher with work-related dyspnea, sweating, as well as multiple occurrences of fever. He was sent to Institute for Prevention and Occupational medicine of the German Social Accident Insurance, Institute of the Ruhr-Universität Bochum (IPA) for the evaluation of isocyanate asthma, but an inhalative challenge with hexamethylene diisocyanate was negative. Since symptoms were closely related to the use of zinc coatings at room temperature without adequate protective measures, the diagnosis of zinc fever was made. After exposure cessation the worker immediately became symptom-free. The work as painter and varnisher may be associated with various exposures to hazardous substances. Besides solvents, epoxy compounds and isocyanates, which can cause obstructive respiratory diseases; additionally, zinc-containing agents should be considered as health hazards., Conclusions: This case demonstrates that zinc fever may occur also after application of zinc coatings by spray painting at low temperatures., (© 2024. The Author(s).)

Enclosed public spaces are hotspots for airborne disease transmission. To measure and maintain indoor air quality in terms of airborne transmission, an open source, low cost and distributed array of particulate matter sensors was developed and named Dynamic Aerosol Transport for Indoor Ventilation, or DATIV, system. This system can use multiple particulate matter sensors (PMSs) simultaneously and can be remotely controlled using a Raspberry Pi-based operating system. The data acquisition system can be easily operated using the GUI within any common browser installed on a remote device such as a PC or smartphone with a corresponding IP address. The software architecture and validation measurements are presented together with possible future developments.

Aerosols could significantly influence ecosystem carbon and water fluxes, potentially altering their interconnected dynamics, typically characterized by water-use efficiency (WUE). However, our understanding of the underlying ecophysiological mechanisms remains limited due to insufficient field observations. We conducted 4-yr measurements of leaf photosynthesis and transpiration, as well as 3-yr measurements of stem growth (SG) and sap flow of poplar trees exposed to natural aerosol fluctuation, to elucidate aerosol's impact on plant WUE. We found that aerosol improved sun leaf WUE mainly because a sharp decline in photosynthetically active radiation (PAR) inhibited its transpiration, while photosynthesis was less affected, as the negative effect induced by declined PAR was offset by the positive effect induced by low leaf vapor pressure deficit (VPD leaf ). Conversely, diffuse radiation fertilization (DRF) effect stimulated shade leaf photosynthesis with minimal impact on transpiration, leading to an improved WUE. The responses were further verified by a strong DRF on SG and a decrease in sap flow due to the suppresses in total radiation and VPD. Our field observations indicate that, contrary to the commonly assumed coupling response, carbon uptake and water use exhibited dissimilar reactions to aerosol pollution, ultimately enhancing WUE at the leaf and canopy level., (© 2024 The Authors. New Phytologist © 2024 New Phytologist Foundation.)

There is nothing like a global pandemic to motivate the need for improved respiratory treatments and mucosal vaccines. Stimulated by the COVID-19 pandemic, pulmonary aerosol drug delivery has seen a flourish of activity, building on the prior decades of innovation in particle engineering, inhaler device technologies, and clinical understanding. As such, the field has expanded into new directions and is working toward the efficient delivery of increasingly complex cargos to address a wider range of respiratory diseases. This review seeks to highlight recent innovations in approaches to personalize inhalation drug delivery, deliver complex cargos, and diversify the targets treated and prevented through pulmonary drug delivery. We aim to inform readers of the emerging efforts within the field and predict where future breakthroughs are expected to impact the treatment of respiratory diseases.