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Viscosity, or the thickness, of aerosols plays a key role in atmospheric processes like ice formation, water absorption, and heterogeneous kinetics. However, the viscosity of sea spray aerosols (SSA) has not been widely studied. This research explored the relationship between particle size and viscosity of authentic SSA particles through particle bounce, atomic force microscopy analysis, and predictive viscosity modeling from molecular composition. The study found that 40 nm SSA particles had estimated viscosities around 104 Pa·s and bounce fractions three times higher than 100 and 200 nm particles with less than 102 Pa·s at a relative humidity (RH) of 60%. Additional studies revealed the Kelvin effect and particle density, influenced by particle size, have a greater impact on size-dependent bounce fractions than changes in RH across impactor stages. While changes in the level of surfactants can impact particle bounce, the increased viscosity in smaller SSA is attributed to the formation of gel-like phase states caused by cation-organic cross-links between divalent calcium ions and organic anions enriched in the smaller particles. This work shows the smallest gel-like SSA particles observed in the field are highly viscous, which has implications for cloud formation, secondary aerosol growth, and pollutant transport in coastal environments.

Our purpose was to test the hypothesis that ultrasonic cigarettes (u-cigarettes), which operate at relatively low temperatures, produce aerosols that are less harmful than heated-coil pod-style electronic cigarettes (e-cigarettes). The major chemicals in SURGE u-cigarette fluids and aerosols were quantified, their cytotoxicity and cellular effects were assessed, and a Margin of Exposure risk assessment was performed on chemicals in SURGE fluids. Four SURGE u-cigarette flavor variants (Blueberry Ice, Watermelon Ice, Green Mint, and Polar Mint) were evaluated. Flavor chemicals were quantified in fluids and aerosols using gas chromatography/mass spectrometry. Cytotoxicity and cell dynamics were assessed using the MTT assay, live-cell imaging, and fluorescence microscopy. WS-23 (a coolant) and total flavor chemical concentrations in SURGE were similar to e-cigarettes, while SURGE nicotine concentrations (13-19 mg/mL) were lower than many fourth generation e-cigarettes. Transfer efficiencies of dominant chemicals to aerosols in SURGE ranged from 44-100%. SURGE fluids and aerosols had four dominant flavor chemicals (>1 mg/mL). Toxic aldehydes were usually higher in SURGE aerosols than in SURGE fluids. SURGE fluids and aerosols had aldehyde concentrations significantly higher than pod-style e-cigarettes. Chemical constituents, solvent ratios, and aldehydes varied among SURGE flavor variants. SURGE fluids and aerosols inhibited cell growth and mitochondrial reductases, produced attenuated and round cells, and depolymerized actin filaments, effects that depended on pod flavor, chemical constituents, and concentration. The MOEs for nicotine, WS-23, and propylene glycol were

Abstract: Ships brighten low marine clouds from emissions of sulfur and aerosols, resulting in visible “ship tracks”. In 2020, new shipping regulations mandated an ∼80% reduction in the allowed fuel sulfur content. Recent observations indicate that visible ship tracks have decreased. Model simulations indicate that since 2020 shipping regulations have induced a net radiative forcing of +0.12 Wm−2. Analysis of recent temperature anomalies indicates Northern Hemisphere surface temperature anomalies in 2022–2023 are correlated with observed cloud radiative forcing and the cloud radiative forcing is spatially correlated with the simulated radiative forcing from the 2020 shipping emission changes. Shipping emissions changes could be accelerating global warming. To better constrain these estimates, better access to ship position data and understanding of ship aerosol emissions are needed. Understanding the risks and benefits of emissions reductions and the difficultly in robust attribution highlights the large uncertainty in attributing proposed deliberate climate intervention.

Environmentally persistent free radicals (EPFRs) play an important role in aerosol effects on air quality and public health, but their atmospheric abundance and sources are poorly understood. We measured EPFRs contained in PM2.5 collected in Fairbanks, Alaska, in winter 2022. We find that EPFR concentrations were enhanced during surface-based inversion and correlate strongly with incomplete combustion markers, including carbon monoxide and elemental carbon (R2 > 0.75). EPFRs exhibit moderately good correlations with PAHs, biomass burning organic aerosols, and potassium (R2 > 0.4). We also observe strong correlations of EPFRs with hydrocarbon-like organic aerosols, Fe and Ti (R2 > 0.6), and single-particle mass spectrometry measurements reveal internal mixing of PAHs, with potassium and iron. These results suggest that residential wood burning and vehicle tailpipes are major sources of EPFRs and nontailpipe emissions, such as brake wear and road dust, may contribute to the stabilization of EPFRs. Exposure to the observed EPFR concentrations (18 ± 12 pmol m-3) would be equivalent to smoking ∼0.4-1 cigarette daily. Very strong correlations (R2 > 0.8) of EPFR with hydroxyl radical formation in surrogate lung fluid indicate that exposure to EPFRs may induce oxidative stress in the human respiratory tract.

Photothermal spectroscopy, and more specifically photothermal interferometry (PTI), is a highly sensitive technique for measuring gas and aerosol concentrations. Numerous implementations of different PTI configurations have demonstrated the versatility of the technique. This theoretical study presents a comprehensive analysis and an optimization of the PTI optical path length (OPL) amplitude using characteristic times. We investigate how the OPL amplitude depends on the dimensions and orientations of the interferometer laser beam and the continuous-wave excitation laser beam. This analysis quantifies the impact of advection on the OPL amplitude based on the relative orientation of the two laser beams and the gas flow direction. It is analytically shown that the possibilities for photothermal OPL amplitude optimization are limited when thermal diffusion is dominant. Theoretically, advection has the potential to double or cancel the OPL amplitude, depending on the specific configurations. In summary, we provide an in-depth understanding of the design and parameter considerations required when tailoring and optimizing a PTI sensor for different fields of applications. [ABSTRACT FROM AUTHOR]

The production of e-cigarette aerosols through vaping processes is known to cause the formation of various free radicals and reactive oxygen species (ROS). Despite the well-known oxidative potential and cytotoxicity of fresh vaping emissions, the effects of chemical aging on exhaled vaping aerosols by indoor atmospheric oxidants are yet to be elucidated. Terpenes are commonly found in e-liquids as flavor additives. In the presence of indoor ozone (O3), e-cigarette aerosols that contain terpene flavorings can undergo chemical transformations, further producing ROS and reactive carbonyl species. Here, we simulated the aging process of the e-cigarette emissions in a 2 m3 FEP film chamber with 100 ppbv of O3 exposure for an hour. The aged vaping aerosols, along with fresh aerosols, were collected to detect the presence of ROS. The aged particles exhibited 2- to 11-fold greater oxidative potential, and further analysis showed that these particles formed a greater number of radicals in aqueous conditions. The aging process induced the formation of various alkyl hydroperoxides (ROOH), and through iodometric quantification, we saw that our aged vaping particles contained significantly greater amounts of these hydroperoxides than their fresh counterparts. Bronchial epithelial cells exposed to aged vaping aerosols exhibited an upregulation of the oxidative stress genes, HMOX-1 and GSTP1, indicating the potential for inhalation toxicity. This work highlights the indirect danger of vaping in environments with high ground-level O3, which can chemically transform e-cigarette aerosols into new particles that can induce greater oxidative damage than fresh e-cigarette aerosols. Given that the toxicological characteristics of e-cigarettes are mainly associated with the inhalation of fresh aerosols in current studies, our work may provide a perspective that characterizes vaping exposure under secondhand or thirdhand conditions as a significant health risk.

The reaction of peracetic acid (PAA) and Fe(II) has recently gained attention due to its utility in wastewater treatment and its role in cloud chemistry. Aerosol-cloud interactions, partly mediated by aqueous hydroxyl radical (OH) chemistry, represent one of the largest uncertainties in the climate system. Ambiguities remain regarding the sources of OH in the cloud droplets. Our research group recently proposed that the dark and light-driven reaction of Fe(II) with peracids may be a key contributor to OH formation, producing a large burst of OH when aerosol particles take up water as they grow to become cloud droplets, in which reactants are consumed within 2 min. In this work, we quantify the OH production from the reaction of Fe(II) and PAA across a range of physical and chemical conditions. We show a strong dependence of OH formation on ultraviolet (UV) wavelength, with maximum OH formation at λ = 304 ± 5 nm, and demonstrate that the OH burst phenomenon is unique to Fe(II) and peracids. Using kinetics modeling and density functional theory calculations, we suggest the reaction proceeds through the formation of an [Fe(II)-(PAA)2(H2O)2] complex, followed by the formation of a Fe(IV) complex, which can also be photoactivated to produce additional OH. Determining the characteristics of OH production from this reaction advances our knowledge of the sources of OH in cloudwater and provides a framework to optimize this reaction for OH output for wastewater treatment purposes.

Within aerosol-rich environments, efficient simulation of frequency-modulated continuous wave (FMCW) laser detector echo characteristics is crucial. Conventional methods often need more efficiency. To address this, we propose a photon matrix-based approach for simulating intricate photon scattering processes, enhancing simulation accuracy. This study focuses on short-range FMCW laser detection under aerosol interference, assessing performance via signal-to-noise ratio (SNR). We analyze the impact of amplitude modulation coefficient and photon count on SNR. Surprisingly, the photon count minimally affects SNR, while the amplitude modulation coefficient significantly influences it. These findings shed light on optimizing FMCW laser detection in aerosol-laden environments. Attention to the amplitude modulation coefficient can notably enhance SNR and overall detection efficiency. [ABSTRACT FROM AUTHOR]

We develop a model for the thermodynamics and evaporation dynamics of aerosol droplets of a liquid, such as water, surrounded by gas. When the temperature and the chemical potential (or equivalently the humidity) are such that the vapor phase is in the thermodynamic equilibrium state, then, of course, droplets of the pure liquid evaporate over a relatively short time. However, if the droplets also contain nanoparticles or any other non-volatile solute, then the droplets can become thermodynamically stable. We show that the equilibrium droplet size depends strongly on the amount and solubility of the nanoparticles within, i.e., on the nature of the particle interactions with the liquid and, of course, also on the vapor temperature and chemical potential. We develop a simple thermodynamic model for such droplets and compare predictions with results from a lattice density functional theory that takes as input the same particle interaction properties, finding very good agreement. We also use dynamical density functional theory to study the evaporation/condensation dynamics of liquid from/to droplets as they equilibrate with the vapor, thereby demonstrating droplet stability. [ABSTRACT FROM AUTHOR]

ObjectivesThe effects of electronic cigarettes (e-cigarettes) on the larynx are relatively unknown. This study examined the short-term effects of e-cigarette inhalation on cellular and inflammatory responses within the mouse laryngeal glottic and subglottic regions after exposure to pod-based devices (JUUL).MethodsMale C57BL6/J mice (8-9 weeks) were assigned to control (n = 9), JUUL flavors Mint (JMi; n = 10) or Mango (JMa; n = 10). JUUL mice were exposed to 2 h/day for 1, 5, and 10 days using the inExpose inhalation system. Control mice were in room air. Vocal fold (VF) epithelial thickness, cell proliferation, subglandular area and composition, inflammatory cell infiltration, and surface topography were evaluated in the harvested larynges. Mouse body weight and urinary nicotine biomarkers were also measured. Chemical analysis of JUUL aerosols was conducted using selective ion flow tube mass spectrometry.ResultsJUUL-exposed mice had reduced body weight after day 5. Urinary nicotine biomarker levels indicated successful JUUL exposure and metabolism. Quantitative analysis of JUUL aerosol indicated that chemical constituents differ between JMi and JMa flavors. VF epithelial thickness, cellular proliferation, glandular area, and surface topography remained unchanged after JUUL exposures. Acidic mucus content increased after 1 day of JMi exposure. VF macrophage and T-cell levels slightly increased after 10 days of JMi exposures.ConclusionsShort-term e-cigarette exposures cause minimal flavor- and region-specific cellular and inflammatory changes in the mouse larynx. This work provides a foundation for long-term studies to determine if these responses are altered with multiple e-cigarette components and concentrations.Level of evidenceN/A Laryngoscope, 134:1316-1326, 2024.

Aerosols play a very important role in climate change with large uncertainties. Using the multimodel results from CMIP6, we analyzed the aerosol effective radiative forcing (ERF) and aerosol-induced surface air temperature (SAT) change in China in the present day (PD; 11-yr mean of 2004–14) relative to the preindustrial (PI) time (11-yr mean of 1850–60). With the increase in the anthropogenic emissions, the simulated surface PM2.5 concentration and aerosol optical depth (AOD) averaged over eastern China (EC; 18°–44°N, 103°–122°E) increased by 21.43 ± 7.58 μg m−3 and 0.47 ± 0.33, respectively, from PI to PD. The simulated aerosol ERFs in EC were −4.91 ± 2.56 and −5.35 ± 2.40 W m−2 from equilibrium and transient simulations, respectively. The simulated change in SAT caused by the increases in aerosols was −1.37° ± 0.38°C in EC from PI to PD. The simulated values of equilibrium and transient climate sensitivity to aerosols (CSA; aerosol-induced SAT change per unit aerosol ERF) in EC were 0.236° and 0.222°C (W m−2)−1, respectively. By using the observed AOD from MODIS to constrain aerosol ERF, the constrained aerosol equilibrium and transient ERFs over EC were −4.66 and −4.93 W m−2, respectively, which were smaller in magnitude than the simulated values directly from the models. By using the observed SAT from the Climatic Research Unit temperature version 5 to constrain aerosol-induced cooling, the surface cooling caused by aerosols was magnified to −1.47°C. The adjusted CSA after the constraint was calculated by dividing adjusted aerosol-induced SAT change by adjusted aerosol ERF. Adjusted equilibrium and transient CSA values in EC were 0.32° and 0.34°C (W m−2)−1, respectively. [ABSTRACT FROM AUTHOR]

The Medium-Resolution Spectral Imager-II (MERSI-II) instrument aboard China's Fengyun-3D satellite shares similarities with NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) sensor, enabling the retrieval of global aerosol optical depth (AOD). However, no officially released operational MERSI-II aerosol products currently exist over the ocean. This study focuses on adapting the MODIS dark target (DT) ocean algorithm to the MERSI-II sensor. A retrieval test is conducted on the 2019 MERSI-II data over the global ocean, and the retrieved AODs are validated against ground-based measurements from the automatic Aerosol Robotic Network (AERONET) and the shipborne Maritime Aerosol Network (MAN). The operational MODIS DT aerosol products are also used for comparison purposes. The results show that MERSI-II AOD granule retrievals are in good agreement with MODIS products, boasting high correlation coefficients (R) of up to 0.96 and consistent spatial distribution trends. Furthermore, the MERSI-II retrievals perform well in comparison to AERONET and MAN measurements, with high R-values (>0.86). However, the low-value retrievals from MERSI-II tend to be slightly overestimated compared to MODIS, despite both AODs displaying a positive bias. Notably, the monthly gridded AODs over the high latitudes of the northern and southern hemispheres suggest that MERSI-II exhibits greater stability in space and time, effectively reducing unrealistically high-value noise in the MODIS products. These results illustrate that the MERSI-II retrievals meet specific accuracy requirements by maintaining the algorithmic framework and most of the algorithmic assumptions, providing a crucial data supplement for aerosol studies and climate change. [ABSTRACT FROM AUTHOR]

The biases generated by state-of-the-art climate models in simulating dust optical depth (DOD) remain to be detailed. Here, a site-scale DOD dataset in March–August over northern China (NC) during 1980–2001 was reconstructed using the empirical relationship between MODIS-retrieved DOD and dust-event frequencies during 2001–21. Then, through the combined use of MODIS-based and reconstructed DOD, we evaluated the reproducibility of DOD from 10 models participating in phase 6 of the Coupled Model Intercomparison Project (CMIP6) for the historical period (1980–2001 and 2002–14) and under different Shared Socioeconomic Pathways (SSPs) during 2015–21. The results demonstrate that CMIP6 models and multimodel ensemble mean (MEM) are capable of capturing the spatial pattern of DOD, but with considerable uncertainty and intermodel variability in magnitude. Regionally averaged DOD is underestimated by 56.09% during 1980–2001 and overestimated by 30.97% during 2002–14 in MEM over NC. Simultaneously, the intermodel standard deviations are greater than MEM during 2002–14, suggesting large discrepancies among individual models. Very few models accurately capture the trends in DOD, which can mainly be attributed to the different trends in simulated wind speed (WS), soil moisture, and vegetation cover, and their contributions to dust evolution. Under four SSPs, despite the best correlation between SSP1-2.6-modeled and MODIS DOD over Gobi Desert (GD), overestimation of DOD is still observed. More models under SSP1-2.6 capture the positive DOD trend, mainly attributable to positive changes in simulated WS over GD. [ABSTRACT FROM AUTHOR]

Aerosol drug administration has a long history as an important part of the treatment for different respiratory disorders in both adult and paediatric patients. The nebulization process permits the drug delivery directly to the upper and lower airways tracts, allowing increased local effectiveness, and avoids systemic side effects. The aerosol therapy is mainly used in pneumology for lower respiratory tract disorders, a series of drugs having a proven efficacy. Few publications present the efficacy and safety of ENT nebulization, despite its worldwide utilization. Topical drug delivery to the nasal cavities and paranasal sinuses via aerosols appears to be an interesting, but also a challenging alternative. The transport and deposition of drugs and aerosol particles into the sinuses is debatable due to several factors: sinuses are poorly perfused and virtually non-ventilated cavities; they are protected by the efficient particle filtration function of the nasal cavities. The review evaluates the efficacy and safety of aerosol therapy in rhinologic pathology. [ABSTRACT FROM AUTHOR]

Heterogeneous filters can significantly improve capture rate and filtration penetration distance for applications involving particles with a distribution of sizes. An efficient computational approach is proposed for prediction of particle penetration and capture efficiency in heterogeneous filters of arbitrary structure. The proposed computational approach was validated against experimental, theoretical, and detailed computational data for filters with various fiber orientations and diameters. The proposed method was then used to compare relative effectiveness and demonstrate the advantages of different types of heterogeneous filters for filtration of an incident flow containing particles of multiple sizes, both for layered filters and for filters with volumetric heterogeneity. Copyright © 2024 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

Particle resuspension is an omnipresent source of aerosols into the environment as the necessary detachment force to return particles to the atmosphere can arise from a variety of environmental and anthropogenic mechanisms. Despite the significance of resuspension, the phenomenon is often neglected in aerosol dispersion models as there is limited understanding on the magnitude of the effect and its influencing factors. We provide a route toward determining the role of particle-specific characteristics, such as morphology, on resuspension efficiency with the aim of introducing greater complexity to resuspension models. A combination of two unique instruments is introduced, a quadrupole electrodynamic trap to fabricate particles and a small-scale 3D printed wind tunnel. Together they provide a method for manufacturing and resuspending particles of a reproducible spherical and non-spherical shape without the need for large or costly equipment. Experiments resuspending spherical glass standards and raspberry-shaped dried sodium chloride particles, alongside anemometer flow field analysis, were implemented to validate the approach and provide insight into potential limitations, including the necessity to increase non-spherical particle resuspension rates to evaluate the impacts of morphology in the future. This provides the foundation for future experiments with increasing deviations from idealized conditions and prospective step-wise resuspension model developments. [ABSTRACT FROM AUTHOR]

An accurate quantification of organic nitrate (RONO2) is important owing to its contribution to organic aerosol (OA) and its impacts on NOx cycling and ozone formation. Here, we calibrate and evaluate the response of the Aerodyne aerosol mass spectrometer (AMS) to synthetic monoterpene- and isoprene-derived RONO2 standards. The dominant fraction of nitrogen is detected as NO2+ and NO+ ions in the AMS with the NOx ratio (NO2+/NO+) being substantially lower than that of ammonium nitrate (NH4NO3). The NOx ratio also varies among the RONO2 standards, possibly driven by the proximity of other functional groups to the nitrate group and/or the position to which the nitrate group is attached (aliphatic vs. cyclic). The best match of the nitrogen-containing moiety mass concentrations of particulate RONO2 (pRONO2) between the AMS and a condensation particle counter (CPC) is observed when the CPC-derived concentrations are calculated using a molecular weight of 46 g mol−1 (NO2) rather than commonly assumed 62 g mol−1 (NO3). This result is consistent with the thermal decomposition on the AMS vaporizer predominantly breaking the O–N bond rather than the R–O bond of R–O–NO2 species. The estimation of pRONO2 mass concentration by the AMS depends on the identity of the measured nitrogen-containing moiety of pRONO2, which for the AMS has been historically assumed as NO3 (62 g mol−1) instead of NO2 (46 g mol−1) as found in this study. Therefore, actual pRONO2 mass concentrations as well as their contribution to OA could be higher than previously reported in literature by 35%, further highlighting the prevalence of pRONO2 in ambient environments. Copyright © 2024 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

The decline in air quality is thought to be due to rapid land use/land cover (LULC) changes near metropolitan areas that are undergoing rapid urbanisation. Here, we quantify the characteristics and relationship between the aerosol optical depth (AOD) index and LULC changes in Hangzhou, China, since the 21st century using multispectral satellite remote sensing data. The regional study results show that the correlation between the operational AOD observations (MOD04_3K) at 3 km resolution and the in situ AOD measurements available in Hangzhou ranges from 0.48 to 0.80, and their root mean square error (RMSE) < 0.30. During the past two decades, Hangzhou has been in the stage of rapid urbanisation, and the area of construction land has increased significantly, mainly converted from cultivated land and forests. The correlation coefficients between the AOD and the changes of cultivated land, forest land, grassland and construction land in Hangzhou were 0.36, 0.86, 0.61 and 0.63, respectively, indicating a strong correlation except for the cultivated land. Finally, the temporal evolution of the correlation coefficients between the cultivated land and building land are positively correlated with AOD, while from the trend of the correlation curve, grassland, woodland and AOD show negative correlations. [ABSTRACT FROM AUTHOR]

COVID-19, caused by SARS-CoV-2 infection, led to a pandemic of acute respiratory illness that is ongoing. High-flow nasal cannula (HFNC) is a commonly used form of respiratory support during acute respiratory distress and is used to treat patients with COVID-19 in many centers. Due to the novel nature of COVID-19 at the onset of the pandemic, evidence to support the use and best practices of HFNC for treating patients with COVID-19 was lacking. This is a review of key peer-reviewed manuscripts from 2022-2023 discussing the efficacy and best practices for using HFNC for patients with COVID-19. Efficacy of HFNC for COVID-19, the use of the respiratory oxygenation index to guide HFNC for COVID-19, and concerns of generated/fugitive aerosols when using HFNC for COVID-19 are emphasized. [ABSTRACT FROM AUTHOR]

Algal blooms of Karenia brevis produce brevetoxins that lead to the natural phenomenon of red tide. Beyond monitoring the red tide concentration and forecasting future outbreaks, uncertainty exists in the field when examining these toxins in relation to the physiology of people. Contaminated air that results from outbreaks of K. brevis leads to inhalation of aerosolized brevetoxins, which directly impact the human respiratory system. This scoping review focused on the respiratory effects of red tide and was conducted by using a comparative method between 2 researchers. Relevant abstracts were collected, and full-text articles were reviewed by using PubMed, Science Direct, CINAHL Complete, and BioMed Central databases. Thirty articles were included in the final analysis and categorized by study design, location, and number and age of participants, and were also divided into assessment by respiratory effects, exposure, measurements of K. brevis, and asthma. The research indicates that respiratory health issues exist and can be compounded with exposure to red tide, specifically upper respiratory symptoms. Both symptomatic issues and pulmonary function tests were of concern when individuals were subjected to brevetoxin exposure. Even low levels of K. brevis resulted in negative respiratory health effects. Red tide is common in many areas of the world. The toxins released can cause adverse respiratory effects. This article provides a comprehensive summary of the scholarly literature focused on the respiratory system and red tide produced by K. brevis. [ABSTRACT FROM AUTHOR]

Purpose: The spread of airborne diseases, including coronaviruses, remains a widespread public health concern. Published studies outline the use of protective barriers to limit the spread of pathogenic particles and droplets resulting from coughing, sneezing, and talking. The findings suggest a role for these barriers during aerosol-generating procedures, such as flexible endoscopic evaluation of swallowing (FEES). However, the question remains of whether doffing a protective barrier will create a concentrated cloud of particles that will increase health professionals' exposure. Method: We simulated four clinical scenarios of coughing and sneezing, talking, eating and drinking, and delivering supplemental oxygen to test whether doffing the FEES Box protective barrier would result in a particle cloud. Result: For all scenarios simulated, doffing the FEES Box did not result in a significant increase in mean particle count. Further, the manner of FEES Box removal did not significantly influence mean particle counts on a consistent basis. Conclusion: These results suggest that doffing the FEES Box does not increase exposure to airborne particles. Although more research is needed to confirm these findings, FEES Box usage should be considered during aerosol-generating procedures, to protect and reassure healthcare professionals who work with patients with COVID-19 or other airborne diseases. [ABSTRACT FROM AUTHOR]

Compared to independent drought or extreme heat events, compound drought and heat events (CDHEs) can pose more adverse impacts on ecosystems and human society. As the anthropogenic influence on CDHEs in China remains largely unquantified, we analyse both observed and simulated changes in the occurrence of CDHEs over China from 1961 to 2014, and perform detection and attribution analyses utilizing an optimal fingerprinting method, based on observations, reanalysis data and numerical experiments from seven Coupled Model Intercomparison Project Phase 6 (CMIP6) models. Upward trends are found in observed CDHEs during 1961–2014 over the majority of China, especially in the last two decades. The increase in CDHEs is largely attributed to human influence. Anthropogenic forcing is detectable in the observed CDHEs changes in the whole China and its eastern region. Furthermore, a three‐signal analysis indicates that greenhouse gases play a key role in increasing CDHEs over China, while natural forcing has a negligible effect. Anthropogenic aerosol emissions also play a detectable role in offsetting the greenhouse gas‐induced increase of CDHEs over China. [ABSTRACT FROM AUTHOR]

The infrared window region (780–1,250 cm−1, 12.8 to 8.0 μm) is of great importance to Earth's climate due to its high transparency and thermal energy. We present here a new investigation of the transparency of this spectral region based on observations by interferometers of downwelling surface radiance at two DOE Atmospheric Radiation Measurement program sites. We focus on the dominant source of absorption in this region, the water vapor continuum, and derive updated values of spectral absorption coefficients for both the self and foreign continua. Our results show that the self continuum is too strong in the previous version of Mlawer‐Tobin_Clough‐Kneizys‐Davies (MT_CKD) water vapor continuum model, a result that is consistent with other recent analyses, while the foreign continuum is too weak in MT_CKD. In general, the weaker self continuum derived in this study results in an overall increase in atmospheric transparency in the window, although in atmospheres with low amounts of water vapor the transparency may slightly decrease due to the increase in foreign continuum absorption. These continuum changes lead to a significant decrease in downwelling longwave flux at the surface for moist atmospheres and a modest increase in outgoing longwave radiation. The increased fraction of surface‐leaving radiation that escapes to space leads to a notable increase (∼5–10%) in climate feedback, implying that climate simulations that use the new infrared window continuum will show somewhat less warming than before. This study also points out the possibly important role that aerosol absorption may play in the longwave radiative budget. Plain Language Summary: The spectral region in the infrared from 780 to 1,250 cm−1 (12.8–8.0 μm) is referred to as a window due to its transparency; in this region, thermal radiation emitted by the surface can pass relatively unimpeded through the atmosphere, allowing Earth to cool. The limited amount of atmospheric absorption that does occur in this region is primarily due to water vapor, in particular an absorption mechanism termed the water vapor continuum. The strength of water vapor continuum absorption in the infrared window therefore has important consequences for Earth's climate. This study provides a new evaluation of water vapor continuum absorption in the infrared window from an analysis of spectrally resolved measurements of downwelling surface radiances. Our results indicate that for most atmospheres the strength of water vapor continuum absorption is less than had been previously thought due to reduced absorption related to the interactions of water vapor molecules with other water vapor molecules, that is, the water vapor self continuum. The derived water vapor continuum changes allow the Earth to cool ∼5–10% better than had previously been thought, and climate simulations that use the revised infrared window continuum will show somewhat less warming than before. Key Points: Analysis of ground‐based radiance observations indicates that the infrared window region is more transparent than had been thought.The derived water vapor self continuum is 10%–30% weaker than previously thought, while the foreign continuum is substantially stronger.The revised H2O continuum results in a 5%–10% increase in climate feedback and a large change to the radiative budget for moist atmospheres. [ABSTRACT FROM AUTHOR]

ABSTRACT Introduction Materials and Methods Results and Discussion Conclusion The COVID‐19 pandemic had extensive influence on dental education. UK dental schools were compelled to respond with substantial adaptations to clinical training approaches and environments to mitigate educational impact.The Surveying Pandemic Education Response in Higher Education Dental Schools (SPEARHEAD) study aimed to retrospectively evaluate the diverse responses of UK dental schools to the COVID‐19 pandemic. All UK dental schools were invited to participate in semi‐structured interviews to ascertain institutional responses, with transcripts subjected to thematic framework analysis.Ten UK dental schools contributed to the study and three main themes were identified: student education, environment, and procedures and equipment. The most common approach to student education was the reduction of student numbers in clinical areas; however, this increased supervisory demands. While there was widespread acknowledgement of the need for enhanced ventilation, implementing the necessary modifications was frequently constrained by building configurations and financial implications. Numerous procedural adjustments were implemented, accompanied by widespread adoption of enhanced personal protective equipment. Fallow periods were common, although differing durations underscored the need for data‐driven guidance. Many schools transitioned towards electric speed‐controlled handpieces, but the need to reflect real‐world scenarios often led to a reversion to air turbines.UK dental schools showed initiative, resilience, and ingenuity in safeguarding students from enduring irretrievable educational setbacks amidst the challenges posed by the COVID‐19 pandemic. Validating a data‐driven strategy for addressing future threats would facilitate a unified response, minimising the educational repercussions and bolstering the resilience of dental training. [ABSTRACT FROM AUTHOR]

Purpose: The COVID-19 pandemic has affected lives and dental treatment. Aerosols and droplets generated during dental treatment present a risk of infection for dental care workers. However, detailed elucidation of the conditions under which those are generated has yet to be presented, and no clear countermeasures for protection have been established. The present study aimed to clarify the process of generation of aerosol and droplets in dental treatment, as well as their dynamics for establishment of effective countermeasures and protection strategies. Methods: Images were obtained using a high-speed camera of aerosol and droplets generated during dental treatments performed on a mannequin. The effects of intraoral vacuum and extraoral vacuum to reduce those, as well as splash range with different body position were examined. Quantitative evaluations of aerosol and droplets were also performed using water-sensitive paper. Results: Aerosol and droplets quantities were significantly reduced by use of both intraoral and extraoral vacuums as compared to no vacuum in both image analysis and findings obtained with water-sensitive paper (p < 0.05). Additionally, the intensity of aerosol and droplets when using the intraoral and extraoral vacuum devices with a body position of 45 degrees was a significantly less as compared to the other settings (p < 0.001). Conclusions: The present study demonstrated the effectiveness of visualization of the aerosol and droplets generated by dental tools using a high-speed camera. Use of an extraoral vacuum resulted in a reduction of those generated during simulated dental treatment, and also contributed to diffusion prevention to protect the operator and assistant. Nevertheless, it is necessary to be careful because the use of extraoral vacuums may reverse the spread of aerosol and droplets depending on the position of patient. [ABSTRACT FROM AUTHOR]

The relative amount of scattering and absorbing aerosols is essential in determining the aerosol radiative and climate effects. Using reanalysis datasets and climate simulations, here, we show that changes in the relative amount of scattering and absorbing aerosols in the Northern Hemisphere (NH) high latitudes, manifested as long-term decreasing trends in aerosol single-scattering albedo (SSA), have played an important role in driving the widening and weakening trends of the NH Hadley circulation (HC) since the early 1980s. Decreasing SSA in the NH middle and high latitudes can notably warm the troposphere there, thus reducing the equator-to-pole temperature gradient, increasing static stability in mid-latitude regions, and leading to the widening and weakening trends of NH HC. Further analysis of the Coupled Model Intercomparison Project Phase 6 (CMIP6) aerosol forcing-only simulations also supports the importance of SSA trends in perturbing NH HC through the above mechanism. [ABSTRACT FROM AUTHOR]

The ability of anthropogenic aerosols to freeze supercooled cloud droplets remains debated. In this work, we present observational evidence for the glaciation of supercooled liquid-water clouds at industrial aerosol hot spots at temperatures between −10° and −24°C. Compared with the nearby liquid-water clouds, shortwave reflectance was reduced by 14% and longwave radiance was increased by 4% in the glaciation-affected regions. There was an 8% reduction in cloud cover and an 18% reduction in cloud optical thickness. Additionally, daily glaciation-induced snowfall accumulations reached 15 millimeters. Glaciation events downwind of industrial aerosol hot spots indicate that anthropogenic aerosols likely serve as ice-nucleating particles. However, rare glaciation events downwind of nuclear power plants indicate that factors other than aerosol emissions may also play a role in the observed glaciation events. [ABSTRACT FROM AUTHOR]

The spatial structure of atmospheric aerosol over Baikal in summer is studied on a regular basis with the use of ground-based LOSA-M2 lidar measurements at the Boyarsky scientific station of the Institute of Physical Material Science, Siberian Branch, Russian Academy of Sciences (51.83°N, 106.06°E, 456 m a.s.l.), Republic of Buryatia, Russia. The lake is located in a basin surrounded by mountain ranges on all side; its water volume is large. The lidar data are analysed along with the regional meteorological situation and meteorological parameters of the atmosphere. The daily dynamics of aerosol distribution over the atmospheric is examined for the period from 2015 to 2023 accounting the effect of different air masses in the region. Three main typical air circulation types are identified for the coastal zone of southern Baikal in summer, which determine the atmospheric aerosol generation and transport. The first and most common type relates to breeze circulation, where the main changes in the spatial structure of aerosol occur in the 2–3-km layer and are determined by changes in the transport direction within a breeze cell during the day. The main feature of this type is a decrease in the altitude of an air layer which contains most of aerosol in the lower atmosphere up to 1 km. The second type refers to southwestern transport under the presence of an anticyclone over the region. The maximal altitude of the aerosol layers attains 7 km in this case. The most complex and dynamic changes in the daily spatial structure of atmospheric aerosol occurred under transport of cyclones and associated atmospheric fronts over Lake Baikal. Under this third type, the altitude of the aerosol layers decreases throughout the day within the altitude range from the surface to 3–4 km. [ABSTRACT FROM AUTHOR]

The current quantitative retrieval of Aerosol Optical Depth (AOD) typically uses Top-of-atmosphere (TOA) reflectance data obtained by the scale and offset terms of radiometric calibration. Errors can be introduced during the conversion of Digital Number (DN) values to TOA reflectance, restraining the accurate retrieval of AOD. Particularly when surface reflectance is high, conversion errors can significantly distort the retrieval of Aerosol Optical Depth (AOD), given the minimal impact of aerosols on the radiation detected by satellite sensors. To counteract this, we introduce an innovative retrieval algorithm that harnesses a Generative Adversarial Network (GANN), a deep learning (DL) model, to accurately derive AOD from the scaled digital number (DN) values of multi-spectral satellite imagery. The DL technology enables the use of scaled DN values for AOD retrieval, bypassing the conversion errors associated with TOA reflectance since it relies on a sample learning approach instead of radiative transfer calculations. To ensure the number and representativeness of training samples, a total of 37,103 samples from different underlying surfaces from 2014 to 2018 were obtained using a space-time matching strategy. Our K-cross validation demonstrates that employing DN values for AOD retrieval promises to yield higher accuracy compared to using TOA reflectance. Independent 2019 data were used to estimate GANN, MCD19A2 and MOD04_3K aerosol products. Our model showed superior performance compared to the other products in terms of a higher correlation (R = 0.8184) with AERONET AOD and obtaining more reliable retrievals (7601). The sensitivity experiment suggests that GANN exhibits limitations in areas characterized by high aerosol loads and heterogeneity. Our study can give a novel insight into AOD retrieval based on multi-spectral satellite and DL models. [ABSTRACT FROM AUTHOR]

The effect of atmospheric aerosols on the earth's radiation budget is primarily through their direct effects. Understanding aerosols' morphology and elemental composition is crucial in this context. For two years, from January 2017 to December 2018, aerosol samples (PM 10) were collected on quartz filter papers using a high-volume sampler (PM 10) in Chennai, a semi-urban coastal environment located at 12.81°N, 80.03°E. These filter papers were stored under ambient laboratory conditions and were subsequently subjected to ultrasonication using ethanol as the solvent to separate the aerosols from the filters. The extracted samples were then analyzed using scanning electron microscopy (SEM) for the morphology and energy dispersive X-ray analysis (EDX) for elemental composition. The EDX analysis of the samples revealed the presence of various elements such as carbon (C), oxygen (O), aluminum (Al), silicon (Si), sulfur (S), potassium (K), iron (Fe), magnesium (Mg), calcium (Ca), vanadium (V), bismuth (Bi), sodium (Na), chlorine (Cl), phosphorus (P), and technetium (Tc). High concentrations of carbon, oxygen, and aluminum–silicate particles indicated the presence of carbonaceous aerosols and wind-blown dust particles. Concentration-weighted trajectory (CWT) analysis was carried out to assess the transport pathways of aerosols in the region. CALIPSO overpasses during the study period were selected, and the Vertical Feature Mask (VFM) identifiers for different aerosol types were compared with the local experimental results. The findings show that CALIPSO possess a reasonably effective capability in detecting and characterizing the local aerosol types. CALIPSO detected Dusty marine, Clean marine, Elevated smoke and Polluted dust in the study area across all four seasons. These findings closely match the characteristics of such aerosol types obtained from SEM/EDX analysis, HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectory) modeling, and the Angstrom exponent derived from sunphotometer readings. [ABSTRACT FROM AUTHOR]

The uncertainty regarding the correlation between sea spray aerosol (SSA) formation and sea surface temperature (SST) hinders the accurate estimation of SSA's impact on global climate. Here, we developed a temperature-controlled plunging SSA simulation tank to investigate the impact of SST on SSA formation from two perspectives: SSA particle size distribution and organic enrichment. Our findings show that SSA particle size decreases with decreasing SST, as exhibited by an increase in SSA within Aitken mode and a decrease in SSA within accumulation and coarse modes. SST can significantly enhance organic enrichment in SSA particles, while the multiplicative increases vary from 2 to 10 times depending on the organic matter species and the SSA particle size. Based on our experimental results, it is predicted that SST reduction may lead to a significantly higher contribution of Aitken modal SSA-derived CCN in cold waters (0 °C) than in warm waters (30 °C). Additionally, we incorporate SST for the first time in estimating the global flux of dissolved organic carbon (DOC) emitted via SSA, yielding a value ranging from 23.45 to 55.78 Tg C yr−1. Compared to previous works, our study reveals the crucial role of SST in influencing both cloud formation and the atmospheric organic burden of SSA. [ABSTRACT FROM AUTHOR]

Background: Using infection control barriers (ICBs) on light curing units (LCUs) became mandatory to achieve proper infection control measures without jeopardizing the integrity of the restorations, especially at deeper layers. This study explored the effect of two ICBs on the irradiance of the LCU, as well as the degree of conversion (DC) and flexural strength (FS) of two types of bulk-fill composites. Water vapor permeability (WVP) of both barriers was also assessed to evaluate the capability of such barriers to prevent transmission of blood and saliva droplets and aerosols. Methods: Two bulk-fill composites (X-tra fil and Tetric N- ceram) and two ICBs (Pinnacle Cure sleeve and Sanita wrapping film) were used in this study. Light irradiance was recorded per experimental condition using spectroradiometer. For DC and FS, specimens of 4 mm thickness were prepared. Each specimen was composed of two separable upper and lower layers of thickness 2 mm. DC and FS were measured using Infra-red spectroscopy and three-point loading test respectively. WVP was investigated using the cup method. Means and standard deviations were calculated, and the data were statistically analyzed using factorial analysis of variance test (α = 0.05). Results: Light irradiance showed highest values using no ICBs and lowest values using Pinnacle curing sleeve. Both bulk-fill composites showed higher DC mean values without ICBs and when using Sanita wrapping film for both upper and lower layers of the specimens compared to Pinnacle curing sleeve. The upper layers of composite specimens showed higher DC compared to lower layers for all experimental conditions. Both ICBs had no adverse effect on FS of both composites' upper layers. Pinnacle sleeve significantly reduced FS of both composites' lower layers. X-tra fil showed higher DC and FS compared to Tetric N-Ceram for all experimental conditions. Regarding WVP; the wrapping film showed higher WVP compared to the curing sleeve. Conclusions: Sanita wrapping film can be used as a successful ICB, without jeopardizing the concept of bulk-fill composites. Pinnacle cure sleeve can be considered an effective ICB, however its influence on properties and serviceability of bulk-fill composites remains questionable. [ABSTRACT FROM AUTHOR]

Aerosols constitute important substance components of the Earth's atmosphere and have a profound influence on climate dynamics, radiative properties, and biogeochemical processes. Here we introduce updated emission schemes for dust, sea-salt, and marine primary organic aerosols (MPOA), as well as augmented secondary organic aerosol (SOA) formation pathways within the Community Earth System Model (CESM; version 2.1.3). The modified dust emission scheme shifts the original hotspot-like dust emission to a more continuous distribution, improving the dust aerosol optical depth (DAOD) simulations at stations in north Africa and central Asia. This update also reduces dust residence time from 4.1 to 1.6 d, enhancing concentration simulations downwind of dust source regions. For sea-salt emissions, we incorporate an updated sea surface temperature (SST) modulation and introduce a relative-humidity-dependent correction factor for sea-salt particle size, with SST having a significantly larger impact on sea-salt emissions (16.1 %) compared to the minor effect of humidity (-0.3 %). We then extend our modelling to incorporate emissions of marine primary organic aerosols (MPOA) as mixed externally with sea-salt aerosols, coupled offline with the ocean component Parallel Ocean Program (POP2). The results underscore the substantial influence of phytoplankton diversity on MPOA emissions, with 148 % variability simulated among different phytoplankton types, highlighting the role of biological variability in aerosol modelling. Furthermore, we refine the model's chemical mechanisms by including the irreversible aqueous uptake of dicarbonyl compounds as a new pathway for SOA formation, contributing an additional 37 % to surface SOA concentrations. These improvements enrich the ability of the CESM to use intricate linkages between different components of the Earth system, thereby enabling a more comprehensive description of natural aerosol emissions, chemical processes, and their impacts. [ABSTRACT FROM AUTHOR]

A modeling protocol (defined by a series of climate model simulations with specified model output) is introduced. Studies using these simulations are designed to improve the understanding of climate impacts using a strategy for climate intervention (CI) known as marine cloud brightening (MCB) in specific regions; therefore, the protocol is called MCB-REG (where REG stands for region). The model simulations are not intended to assess consequences of a realistic MCB deployment intended to achieve specific climate targets but instead to expose responses to interventions in six regions with pervasive cloud systems that are often considered candidates for such a deployment. A calibration step involving simulations with fixed sea surface temperatures (SSTs) is first used to identify a common forcing, and then coupled simulations with forcing in individual regions and combinations of regions are used to examine climate impacts. Synthetic estimates constructed by superposing responses from simulations with forcing in individual regions are considered a means of approximating the climate impacts produced when MCB interventions are introduced in multiple regions. A few results comparing simulations from three modern climate models (CESM2, E3SMv2, and UKESM1) are used to illustrate the similarities and differences between model behavior and the utility of estimates of MCB climate responses that were synthesized by summing responses introduced in individual regions. Cloud responses to aerosol injections differ substantially between models (CESM2 clouds appear much more susceptible to aerosol emissions than the other models), but patterns in precipitation and surface temperature responses were similar when forcing is imposed with similar amplitudes in the same regions. A previously identified La Niña-like response to forcing introduced in the Southeast Pacific is evident in this study, but the amplitude of the response was shown to markedly differ across the three models. Other common response patterns were also found and are discussed. Forcing in the Southeast Atlantic consistently (across all three models) produces weaker global cooling than that in other regions, and the Southeast Pacific and South Pacific show the strongest cooling. This indicates that the efficiency of a given intervention depends on not only the susceptibility of the clouds to aerosol perturbations, but also the strength of the underlying radiative feedbacks and ocean responses operating within each region. These responses were generally robust across models, but more studies and an examination of responses with ensembles would be beneficial. [ABSTRACT FROM AUTHOR]

Geolocation and co-registration methodologies are essential for the accurate interpretation of observations from spaceborne remote sensors. In preparations for the Earth Cloud Aerosol and Radiation Explorer (EarthCARE), here, we refine the definition of these techniques and present various examples of geolocation assessments. The geolocation methods build upon earlier work; however, they introduce several improvements that have increased the reliability of the geolocation accuracy. The EarthCARE active-sensor geolocation methods use coastlines and significant elevation gradients in both statistical and numerical ways. The effectiveness of the proposed geolocation methods was tested using the extensive record of CloudSat and CALIPSO observations. The EarthCARE active-sensor geolocation methods were effective in identifying and correcting a short period of CloudSat observations when the star tracker was not operating properly. In addition, the geolocation methods were able to reproduce the excellent geolocation record of the CloudSat and CALIPSO missions. [ABSTRACT FROM AUTHOR]

Simple Summary: This article stems from my research project on the role of Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC) in the treatment of peritoneal carcinoma originating from colorectal cancer. Our aim was to assess the existing literature regarding the impact, benefits, and risks associated with PIPAC for patients. The results are encouraging and suggest that PIPAC is a safe option for patients. However, monitoring the progression of peritoneal carcinomatosis and evaluating the effects of PIPAC can be challenging. These findings reinforce the need for a randomized study to better define the role of PIPAC in treating colorectal peritoneal carcinomatosis. By clarifying the implications of this innovative therapy, this research aims to provide valuable insights for clinicians, patients, and policymakers, ultimately enhancing patient care and treatment outcomes. Introduction: Pressurized intraperitoneal aerosol chemotherapy (PIPAC) consists of the administration of aerosolized chemotherapy into the abdominal cavity of patients suffering from peritoneal carcinomatosis. Our aim was to review the evidence supporting PIPAC in patients with peritoneal carcinomatosis from colorectal cancer. Methods: A systematic review was performed in accordance with the 2020 PRISMA guideline. MEDLINE and CENTRAL were searched using combinations of terms including "Peritoneal carcinomatosis", "Peritoneal metastasis", "PIPAC", "Pressurized intraperitoneal aerosol chemotherapy" and "Colorectal cancer". Original studies, in English, including patients treated with PIPAC for colorectal peritoneal carcinomatosis, were considered eligible. Case reports, non-English or French language articles and secondary analyses were excluded. Results: A total of 385 articles were screened and 374 articles were excluded, leaving 11 publications for inclusion in the qualitative analysis. The included studies totalized 949 patients who received PIPAC for peritoneal carcinomatosis due to colorectal cancer. The median peritoneal carcinomatosis index (PCI) ranged from 10 to 31. In all studies, the complete PIPAC protocol was achieved with an average of two to three 3 PIPAC sessions per patient. Oxaliplatin (OX) was used as a chemotherapeutic agent in all studies and could be associated with intravenous 5-FU and leucovorin. Most post-operative adverse events were recorded as mild to moderate with no intraoperative complications. Only four studies reported a decrease in the average PCI score for 50% of the patients. Median overall survival ranged from 8 to 37.8 months. Quality of life indicators were stable between PIPAC-OX cycles with a small but not statistically significant trend of improvement of most functional scales. Conclusions: PIPAC for peritoneal carcinomatosis from colorectal origin is feasible, safe and tolerable. Its impact on survival outcomes or quality of life remains to be demonstrated by randomized trials. [ABSTRACT FROM AUTHOR]

Background: The CRC-PIPAC-II study prospectively assessed bidirectional therapy (BT) consisting of first-line palliative systemic therapy and electrostatic precipitation oxaliplatin-based pressurized intraperitoneal aerosol chemotherapy (ePIPAC-OX) in patients with unresectable colorectal peritoneal metastases (CPM). This study describes the exploration of patient-reported outcomes (PROs). Methods: In this phase II trial, 20 patients with isolated CPM were treated with up to three cycles of BT, each cycle consisting of two to three courses of systemic therapy, followed by ePIPAC-OX (92 mg/m2). Patients were asked to complete the EuroQoL EQ-5D-5L, EORTC QLQ-C30, and EORTC QLQ-CR29 questionnaires at baseline, during the first cycle of BT, and one and four weeks after each consecutive BT cycle. PRO scores were calculated and compared between baseline and each subsequent time point using linear-mixed modeling (LMM). PROs were categorized into symptom scales and function scales. Symptom scales ranged from 0 to 100, with 100 representing the maximum symptom load. Function scales ranged from 0 to 100, with 100 representing optimal functioning. Results: Twenty patients underwent a total of 52 cycles of bidirectional therapy. Most PROs (29 of 37, 78%) were not significantly affected during trial treatment. In total, only eight PROs (22%) were significantly affected during trial treatment: Six PROs (index value, global health status, emotional functioning, C30, appetite, and insomnia) showed transient improvement at different time points. Two PROs transiently deteriorated: pain initially improved during the first BT cycle [− 16, p < 0.001] yet worsened temporarily one week after the first two BT cycles (+ 20, p < 0.001; + 17, p = 0.004; respectively). Abdominal pain worsened temporarily one week after the first BT cycle (+ 16, p = 0.004), before improving again four weeks after treatment ended (− 10, p = 0.004). All significant effects on Pros were clinically significant and all deteriorations in PROs were of temporary nature. Discussion: Patients undergoing BT for unresectable CPM had significant, but reversible alterations in several PROs. Most affected PROs concerned improvements and only two PROs showed deteriorations. Both deteriorated PROs returned to baseline after trial treatment and were of a temporary nature. These outcomes help to design future studies on the role of ePIPAC in the palliative setting. [ABSTRACT FROM AUTHOR]

Objective: To review the efficacy, symptoms, inflammatory factors and pulmonary function of different doses of budesonide aerosol inhalation in the treatment of patients with asthma. Methods: The Chinese and English literature databases were searched with "Effects of different doses of budesonide aerosol inhalation on the efficacy, lung function, inflammation, symptoms and adverse reactions in patients with asthma" as the search direction, and a Meta-analysis was performed. Results: Compared with the low dose group, the efficacy, PEF and FEV1 were significantly increased and the clinical symptom score, TNF-α and IL-4 were significantly decreased in the high dose group (p < 0.05). There was no significant difference in IFN-γ level and the incidence of adverse reactions between the two groups (p > 0.05). Conclusion: High-dose budesonide aerosol inhalation therapy can improve the efficacy and lung function of patients, reduce inflammation and clinical symptoms, and does not increase the risk of adverse reactions, which is worthy of clinical promotion. [ABSTRACT FROM AUTHOR]

Some firms and marketers of electronic cigarettes (e-cigarettes; a type of electronic nicotine delivery system (ENDS)) and refill liquids (e-liquids) have made claims about the safety of ingredients used in their products based on the term "GRAS or Generally Recognized As Safe" (GRAS). However, GRAS is a provision within the definition of a food additive under section 201(s) (21 U.S.C. 321(s)) of the U.S. Federal Food Drug and Cosmetic Act (FD&C Act). Food additives and GRAS substances are by the FD&C Act definition intended for use in food, thus safety is based on oral consumption; the term GRAS cannot serve as an indicator of the toxicity of e-cigarette ingredients when aerosolized and inhaled (ie, vaped). There is no legal or scientific support for labeling e-cigarette product ingredients as "GRAS." This review discusses our concerns with the GRAS provision being applied to e-cigarette products and provides examples of chemical compounds that have been used as food ingredients but have been shown to lead to adverse health effects when inhaled. The review provides scientific insight into the toxicological evaluation of e-liquid ingredients and their aerosols to help determine the potential respiratory risks associated with their use in e-cigarettes. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the airborne exposure to aerosols according to the particle size distribution of three different spray types (nano-nozzled spray gun, low-temperature steam spray, and fogger) and compare the concentrations of inhaled aerosols between children and adults. Airborne aerosols released from three products were observed using size-segregated particle measurements, and particle concentrations deposited in the respiratory tracts of adults and children were estimated using multi-path particle dosimetry lung deposition models. All types of sprayers generated the most nanoparticles (~100 nm). Due to their higher respiratory rate than adults, a larger number of particles <1.0 μm deposited in the children's respiratory tracts was higher. The sequences of the total number of particles in the respiratory regions after spraying nano-nozzled spray gun and fogger were alveolar (AL)>tracheobronchial (TB)>head airway (HA) in adults and AL>HA>TB in children. Meanwhile, the trend of low-temperature steam spray was AL>TB>HA in adults and AL>TB>HA in children. [ABSTRACT FROM AUTHOR]

Cooking oil fumes (COFs) are widely acknowledged as substantial contributors to indoor air pollution, having detrimental effects on human health. Despite the existence of commercialized in vitro aerosol exposure platforms, assessment risks of aerosol pollutants are primarily evaluated based on multiwell plate experiments by trapping and redissolving aerosols to conduct comprehensive in vitro immersion exposure manner. Therefore, an innovative real-time exposure system for COF aerosol was constructed, featuring a self-designed microfluidic chip as its focal component. The chip was used to assess toxicological effects of in vitro exposure to COF aerosol on cells cultured at the gas–liquid interface. Meanwhile, we used transcriptomics to analyze genes that exhibited differential expression in cells induced by COF aerosol. The findings indicated that the MAPK signaling pathway, known for its involvement in inflammatory response and oxidative stress, played a crucial role in the biological effects induced by COF aerosol. Biomarkers associated with inflammatory response and oxidative stress exhibited corresponding alterations. Furthermore, the concentration of COF aerosol exposure and post-exposure duration exert decisive effects on these biomarkers. Thus, the study suggests that COF can induce oxidative stress and inflammatory response in BEAS-2B cells, potentially exerting a discernible impact on human health. [ABSTRACT FROM AUTHOR]

Brake wear particles (BWPs) are a major particulate matter (PM) emission of vehicles and they will be regulated under EURO-7 emission standards. To comply with EURO-7, some BWP emission reduction devices have been recently developed. However, most of the studies tested the devices in laboratory conditions, not actual vehicle conditions. In this study, a dust collector composed of a suction device and an electrostatic precipitator (EP) was developed to reduce BWP emission and it was tested on laboratory and actual vehicle. The collection efficiency (CE) of EP was studied under laboratory conditions using a brake dynamometer. More than 95% of BWPs were removed when the EP exhibited a corona charge imparted using a carbon brush. CE would not be changed in laboratory and actual vehicle conditions. The suction efficiency (SE) of the suction device was tested in laboratory and actual vehicle conditions. In the laboratory, the SE decreased from a maximum of 88–62% as the disk rotational speed increased. Although it was possible to maintain the EP CE above 95%, the SE was approximately 70%; the overall BWP reduction efficiency remained in the 60% range. SE had a dominant effect on total reduction efficiency. For actual vehicle testing, the reduction efficiency was 75%, higher than the value measured in laboratory conditions. Therefore, BWP emission reduction device must be tested in actual vehicles to estimate their efficiency in the real-world. Copyright © 2024 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

The small size and contactless environment of aerosol droplets results in unique surface compositions compared to macroscopic solutions. The large surface-area-to-volume ratio possessed by aerosol droplets can lead to a difference in the partitioning of surface-active molecules between macroscopic solutions and droplets, even when the total composition remains unchanged. Additionally, suspended aerosol droplets can become supersaturated and supercooled, affecting the droplet's surface tension. The importance of the surface tension of aerosol droplets has garnered much attention in the past years in diverse contexts including aerosol-assisted materials synthesis, respiratory aerosol dynamics, and atmospheric aerosol processes. To understand the implications of surface-area-to-volume ratio, supercooling, and supersaturation on aerosol surface tension a variety of new tools and techniques have been developed to measure the surface tension directly in the droplet phase. In this review, we will introduce the techniques used in the field to measure the surface tension of aerosol droplets, provide insight into the strengths of various techniques, and describe the types of measurements that these techniques have been used to make. Finally, we provide an outlook on the types of measurements that should be prioritized now that we have an arsenal of measurement techniques available. Copyright © 2024 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

This study thoroughly examines the impact of aerosols on atmospheric heating rates over the North Atlantic Ocean, with a specific focus on developing African easterly waves (AEWs). The analysis leverages data from the National Aeronautics and Space Administration (NASA) DC-8 aircraft, dropsonde profiles, lidar observations, and satellite-based precipitation data obtained during NASA's Convective Processes Experiment – Cabo Verde (CPEX-CV) field campaign, as well as the Modern-Era Retrospective Analysis for Research and Applications version 2 (MERRA-2) and Copernicus Atmosphere Monitoring Service (CAMS) reanalyses. Using a four-stream radiative transfer model, the research specifically focuses on days characterized by Saharan dust coinciding with a developing AEW and contrasts its findings with a notable dust-only event in June 2020. The findings reveal notable differences in shortwave (SW) heating rates of over 1.5 K d−1 between reanalysis and observations, underlining the persistent challenges in accurately representing aerosol effects in the atmosphere, even after assimilating observational data. These discrepancies were present on days with both background and high dust concentrations, emphasizing the challenges in accurately representing aerosol radiative effects in models and highlighting the urgent need for improved aerosol representation in reanalysis datasets. Differences in heating rates were analyzed in a case study of two developing AEWs, one leading to a Category 4 hurricane (Fiona) and another leading to a short-lived tropical storm (TS; Hermine). [ABSTRACT FROM AUTHOR]

Particle size is one of the key factors influencing how aerosol particles affect their climate and health effects. Therefore, a better understanding of particle size distributions from various sources is crucial. In urban environments, aerosols are produced in a large number of varying processes and conditions. This study intended to develop the source apportionment of urban aerosols by utilising a novel approach to positive matrix factorisation (PMF). The particle source profiles were detected in particle number size distribution data measured simultaneously in a street canyon and at a nearby urban background station between February 2015 and June 2019 in Helsinki, southern Finland. The novelty of the method is combining the data from both sites and finding profiles for the unified data. Five aerosol sources were found. Four of them were detected at both of the stations: slightly aged traffic (TRA2), secondary combustion aerosol (SCA), secondary aerosol (SecA), and long-range-transported aerosol (LRT). One of the sources, fresh traffic (TRA1) was only detected at a street canyon. The factors were identified based on available auxiliary data. Additionally, the trends of the found factors were studied, and statistically significant decreasing trends were found for TRA1 and SecA. A statistically significant increasing trend was found for TRA2. This work implies that traffic-related aerosols remain important in urban environments and that aerosol sources can be detected using only particle number size distribution data as input in the PMF method. [ABSTRACT FROM AUTHOR]

BACKGROUND: Environmental microorganisms are major contributors to the development and spread of disease. Chemical disinfection can inhibit pathogens and play a preventive role against diseases. In agriculture, prolonging the floating time of chemical pesticides in the air has a positive effect on the control of airborne diseases. However, the interaction of chemical pesticides with airborne pathogens is not yet known. RESULTS: Here, triazole fungicide was transformed into stable smoke aerosols in order to assess the feasibility of employing phase transition release pesticides for air disinfection. The phase transition had a minimal impact on hexaconazole (Hexa) and myclobutanil (Mycl), with their smoke formation rates remaining consistently >90%. In microscopic morphology, triadimenol (Tria) and epoxiconazole (Epox) are solid, and tebuconazole (Tebu), Hexa, Mycl and difenoconazole (Dife) are liquid. Liquid smoke has advantages over solid smoke in the inhibition of environmental pathogens. The floatability and spatial distribution of fungicide aerosol were optimized by the combination of smoke particles with different properties, so that the fungicide aerosol could meet the conditions of practical application. In practical applications, smoke exhibits a gentler deposition process at the target interface compared to spray, along with a more homogeneous distribution of fungicides. Moreover, fungicide smoke demonstrates superior control efficacy and leaves behind lower residual amounts on fruit. CONCLUSION: In conclusion, the implementation of fungicide phase transition as a smoke aerosol offers a viable approach to effectively suppress pathogen aerosols and enhance the control of airborne diseases. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The western North Pacific Subtropical High (WNPSH) significantly influences East Asian weather. In the Northwest Pacific where sea‐salt aerosols (SSAs) are abundant and the large‐scale environment is dominated by the dry subsidence of the WNPSH during summer, inhomogeneous SSAs form as a product of the environment. However, the extent to which inhomogeneous SSAs affect the WNPSH remains unclear. This study investigates the radiative effects of SSAs through numerical simulations, revealing a novel mechanism for the strengthening of the WNPSH. The results demonstrate that inhomogeneous SSAs enhance the WNPSH by generating diabatic cooling in the upper troposphere and associated unstable subsidence motion. Further considering the radiative hysteresis effects of inhomogeneous SSAs, the WNPSH further strengthens under the combined dynamic and thermodynamic influences associated with upper‐level radiative cooling. Inhomogeneous SSAs not only enhance the WNPSH but also influence the location where the central area of high pressure intensifies. Plain Language Summary: Variations in the western North Pacific Subtropical High (WNPSH), including changes in its intensity and position, significantly impact weather patterns in East Asia, particularly during the summer months. At high relative humidity (RH) levels, sea‐salt aerosols (SSAs) appear as homogeneous droplets; however, in moderate RH environments (45%–70%), SSAs exist in inhomogeneous states characterized by water coatings on their core particles. The dry subsiding airflow of the WNPSH creates extensive areas of moderate RH over the western Pacific Ocean. Despite this, the potential effects of SSAs on the WNPSH through radiative processes have not been previously considered. This study demonstrates that inhomogeneous SSAs induce cooling in the upper troposphere, which contributes to an overall strengthening of the WNPSH. Additionally, these aerosols influence the position where the primary area of high pressure intensifies. This newly identified mechanism by which inhomogeneous SSAs strengthen the WNPSH offers a unique perspective for understanding the evolution of the WNPSH. Key Points: Inhomogeneous sea‐salt aerosols (SSAs) contribute to strengthening the western North Pacific Subtropical High (WNPSH)Inhomogeneous SSAs also influence the position where the main body of the high pressure intensifiesDirect radiative effects of inhomogeneous SSAs offer a distinctive perspective for exploring the dynamics of the WNPSH [ABSTRACT FROM AUTHOR]

Fog and low stratus clouds (FLS) form as a result of complex interactions of multiple factors in the atmosphere and at the land surface and impact both the anthropogenic and natural environments. Here, we analyze the role of synoptic conditions and aerosol loading on FLS occurrence and persistence in the Po valley in northern Italy. By applying k‐means clustering to reanalysis data, we find that FLS formation in the Po valley is either based on radiative processes or moisture advection from the Mediterranean sea. Satellite‐based data on FLS persistence shows longer persistence of radiatively formed FLS events, likely due to air mass stagnation and a temperature inversion. Ground‐based aerosol optical depth observations further reveal that FLS event duration is significantly higher under high aerosol loading. The results underline the combined effect of topography, moisture advection and aerosol loading on the FLS life cycle in the Po valley. Plain Language Summary: Fog and low stratus clouds (FLS) are influenced by various drivers in the atmosphere and near the ground. Here, the impact of the large‐scale weather situation and aerosols is analyzed over the Po valley in northern Italy. Using reanalysis and satellite data we find that FLS events driven by nighttime cooling under stable conditions can persist longer than FLS events formed as a result of moisture transport. Investigating ground‐based observations of aerosols, particles on which moisture can condensate and fog and cloud droplets form, we find that FLS event duration is higher when a higher amount of aerosols is present. These results can help when predicting the duration of FLS events, which is particularly important for traffic safety. Key Points: Fog and low stratus (FLS) cloud formation in the Po valley is primarily controlled by radiative processes or moisture advectionFLS persistence from the satellite perspective is highest for radiatively formed FLS events likely due to a stable boundary layerFLS persistence is significantly higher under high aerosol loading [ABSTRACT FROM AUTHOR]

A straightforward nebulized spray system is designed to explore the hydrogenation of carbon dioxide (CO2) within water microdroplets surrounded by different gases such as carbon dioxide, nitrogen, oxygen, and compressed air. The collected droplets are analyzed using water‐suppressed nuclear magnetic resonance (NMR). Formate anion (HCOO−), acetate anion (CH3COO−), ethylene glycol (HOCH2CH2OH), and methane (CH4) are detected when water is nebulized. This pattern persisted when the water is saturated with CO2, indicating that CO2 in the nebulizing gas triggers the formation of these small organics. In a pure CO2 atmosphere, the formate anion concentration is determined to be ≈70 µm, referenced to dimethyl sulfoxide, which has been introduced as an internal standard in the collected water droplets. This study highlights the power of water microdroplets to initiate unexpected chemistry for the transformation of CO2 to small organic compounds. [ABSTRACT FROM AUTHOR]

The influence of entrainment, a key process characterized by the entrainment rate in cumulus parameterization, on aerosol‐cloud interactions has been widely recognized. However, despite qualitative links established between entrainment and aerosol loading, a quantitative relationship based on observational evidence remains elusive. This study utilizes aircraft observations of cumulus clouds during two field campaigns to determine the quantitative relationship between entrainment rate and aerosol loading. In both campaigns, the entrainment rate is negatively correlated with aerosol loading. It is speculated that increased aerosol loading enhances cloud edge droplet evaporation, which leads to increased buoyancy and vertical velocity within the cloud, thereby reducing the entrainment rate. Further analysis shows that the response of entrainment rate to aerosol perturbations is more significant in smaller cumulus clouds with weak buoyancy and less pronounced under opposite conditions. These findings shed new light on improving the description of aerosol‐cloud interactions in cumulus parameterizations. Plain Language Summary: Clouds play a crucial role in regulating Earth's climate, and understanding how they form and evolve is important for accurate weather and climate predictions. One key process affecting cloud development is entrainment, where drier air from outside the cloud mixes into the cloud, influencing its growth. Scientists know that aerosols can impact entrainment, but the exact relationship hasn't been clear. This study uses observations from research aircraft flown through cumulus clouds to quantify the relationship between entrainment and aerosol. The results show that aerosol concentration is negatively correlated with entrainment rate, meaning less dry air mixes into the cloud. We speculate that this happens because the increased aerosols enhance the evaporation of cloud droplets at the cloud edges, making the cloud more buoyant and less likely to mix with the surrounding air. Interestingly, this decline in entrainment rate to aerosol is stronger in smaller and weaker clouds. These findings provide valuable insights into how aerosols influence cloud development and can help improve the representation of aerosol‐cloud interactions in climate models, leading to more accurate climate projections. Key Points: The relationship between cumulus entrainment rate and aerosol loading is quantified based on observation for the first timeThe plausible physical mechanism linking entrainment rate to aerosol loading has been elucidatedA steeper decline in entrainment rate with increasing aerosol loading is observed in small and weakly buoyant cumulus clouds [ABSTRACT FROM AUTHOR]