Air Phase Research Articles

Establishing quantitative relationships between changes in nasal spray in vitro metrics and drug delivery to the posterior nasal region

Nasal sprays are typically characterized using in vitro spray metrics such as spray cone angle and droplet size distribution. It is currently not clear how these in vitro metrics correlate with regional nasal deposition, and these relationships could help explain the impact of product differences. In this study, the effects of changes in spray cone angle, spray velocity, spray ovality and droplet size distribution on regional nasal deposition were analyzed using a validated computational fluid dynamics model in recently developed adult characteristic nasal airway anatomies. The impact of the spray on the surrounding air phase was included. Results indicated that changes in spray cone angle largely influenced the nasal posterior deposition (PD) of the drug. Changes in the plume ovality and characteristic droplet size moderately influenced PD, but the results were dependent on the insertion conditions and nasal geometry. Changes in spray velocity and uniformity constant of the droplet size distribution had only minimal influence on PD. The rank order of metrics having the greatest to least impact on PD was cone angle ≫ plume ovality ≫ characteristic droplet size ≫ velocity ≫ size distribution uniformity constant. Overall, results from this study established quantitative relationships for predicting expected changes in PD.

Direct Electro-oxidation of H2S gas in a membrane electrode assembly cell (MEA): A proof of concept

This work focuses on the treatment in gas phase of air polluted with hydrogen sulphide in an electrochemical cell equipped with a MEA and demonstrates that it is a feasible option, in which this pollutant can be efficiently transformed into solid sulphur and sulfuric oxide. This later species can be successfully retained by reactive absorption into a sodium hydroxide solution producing a sodium sulphate solution, while the elemental sulphur obtained is dragged from the electrochemical reactor to a solid trap. This product has a pale-yellow colour and the XRD diffraction analysis shows that it has a S8 crystallization type. An increase in the current density applied produces an increase in the percentages of hydrogen sulphide removal (37.47, 50.67 and 65.33 % at 20, 50 and 100 mA cm−2) from the gas fed and influences on the speciation, favouring the formation of sulphur and the oxidation of water to oxygen over the formation of sulphur trioxide. The gas flowrate increment gives lower H2S elimination percentages (72.73, 50.67 and 51.69 % at 4, 7 and 10 mL min−1) and favours the dragging of sulphur which seems to be very positive to avoid its further oxidation to sulfuric oxide. Electrochemical characterization indicates that direct electro-oxidation of H2S gas takes place in the anode surface and that MEA does not undergo any relevant deterioration during performance of continuous operation tests. The maximum Coulombic efficiency for SO3 production was 60 % at 7 mL min−1 and 20 mA cm−2, while for the S0 production was 9.5 % at 10 mL min−1 at 50 mA cm−2. Energy consumption for H2S removal ranges from 18 to 87 Wh gS-1.

The Effect of Air Turbulence on Vortex Beams in Nonlinear Propagation.

Vortex beams with orthogonality can be widely used in atmospheric applications. We numerically analyzed the statistical regularities of vortex beams propagating through a lens or an axicon with different series of turbulent air phase screens. The simulative results revealed that the distortion of the transverse intensity was sensitive to the location and the structure constant of the turbulence screen. In addition, the axicon can be regarded as a very useful optical device, since it can not only suppress the turbulence but also maintain a stable beam pattern. We further confirmed that a vortex beam with a large topological charge can suppress the influence of air turbulence. Our outcomes are valuable for many applications in the atmospheric air, especially for optical communication and remote sensing.

A predictive model of frost formation on leaf surface and estimation of frost amount

The massive frost that occurs each year in autumn and spring across subtropical and temperate regions cause severe damage to horticultural crops, therefore, the research for frost formation and estimation of frost amount are important for monitoring and regulation of frost damage. In this study, a predictive model of frost formation on leaf surface with the interaction of wet air phase and frost phase was established by Euler multiphase flow model. According to the variation of phase volume fraction, the evolution process of frost under non-stationary conditions was simulated using Fluent calculations based on leaf surface frosting mechanism. In addition, the influence of different surface temperatures, air velocities and humidity on frost amount were investigated deeply during simulation by building frost amount measurement device combined with microscopic image processing. The results showed that the frost amount increased mainly with decreased surface temperature under time-varying conditions, and reduce the velocity or increase humidity also has a beneficial effect. The estimation of frost thickness fell within confidence intervals up to 90%, with overall deviations in frost mass ranging from −8.4% to 23.8%. Eventually, the model was demonstrated that it could provide an acceptable prediction of frost formation and estimate of frost amount.

Oxygen intake and giant thermo-chemical expansion of ceramics in the non-stoichiometric CaBaFe4O7+δ ferrite

The high-precision coulometric titration measurements were used in order to find the temperature and oxygen pressure dependent variations of oxygen homogeneous fields in CaBaFe4O7+δ1 (CBF7) and CaBaFe4O8–δ2 (CBF8) ferrites and to demonstrate a miscibility gap separating bordering compositions CaBaFe4O7.1 and CaBaFe4O7.8. The spinodal mechanism of the structural transition between CBF7 and CBF8 is proposed to be responsible for the excellent mechanical robustness and unusually large thermal expansion coefficient (156∙10−6 К−1 at 400 – 600 °C) of ceramic samples formed during the heating and oxidation of the CBF7 phase in air.

Experiment on bubble characteristics of turbulent bubbly jets in pipe crossflow

Air-water bubbly jets in crossflow are commonly encountered in various practical applications such as artificial aeration in oceans and submarine pipelines. This study reveals the bubble characteristics for bubbly jets in pipe crossflow by conducting a series of physical experiments. It was found that the horizontal distance from nozzle exit to where bubble centerline touches the top pipe wall can be expressed as a function of the Reynolds and Weber numbers of the ambient pipe flow, and the Reynolds numbers of both the air and water phases of bubbly jets. The centerline gas void fraction and bubble size increase with distances after bubbles touch the top wall, mainly because bubbles are prone to gathering to the centerline to form larger bubbles. Afterwards, the (horizontal) bubble velocity decreases mainly due to the resistance force from the top wall. Good agreement has been achieved between horizontal bubble velocity and the 1/7th power law for water velocity in the pipe, and a correlation was proposed for predicting bubble rise velocity. Furthermore, turbulence characteristics of bubbles (e.g., root-mean-square of bubble fluctuating velocity, bubble turbulence intensity) were investigated for the bubbly jets.

Influence of the Gelatin Amount on the Indicators of a Defrosted Fermented Milk Dessert Texture

BACKGROUND: The expansion of the range and improvement of the quality are urgent tasks in the ice cream industry. Fermented milk desserts consumed defrosted and combining the properties of ice cream and fermented products can be considered new products. The selection of stabilizergelling agents and determination of their mass fraction are important stages in the development of the fermented milk dessert technology. Among them, gelatin is the most effective and convenient.
 AIM: The object of this study is to examine the effect of the gelatin amount on the structure and texture of defrosted fermented milk desserts.
 MATERIALS AND METHODS: Samples of desserts with a mass fraction of gelatin from 1,3 to 1,9% are the objects of this study. Rheological research methods for estimating the dynamic viscosity and indicators of consistency were used. The dispersion of the air phase of frozen samples and after storing at the temperature of 42С for 4 hours has been estimated.
 RESULTS: The dispersion of the air phase and texture characteristics, such as hardness, adhesiveness, adhesive force, apparent modulus, and recoverable deformation, were examined during the research. The research results show that increasing the gelatin amount did not influence the viscosity but decreased the overrun. Increasing the gelatin amount did not influence the average size of air bubbles after 4 h of storage. The influence of the gelatin amount on the texture indicators of the defrosted dessert was estimated. Adhesiveness and adhesive force with the increase in the gelatin amount by 0.3% were reduced by 16% and 912%, respectively. The obtained results have practical importance in the production and sale of defrosted fermented milk desserts.

Numerical Simulation on Air-Liquid Transient Flow and Regression Model on Air-Liquid Ratio of Air Induction Nozzle

Air induction nozzle (AIN) has a special Venturi structure that has been widely used in the field of reducing the probability of drift of pesticide droplets and realizing precise application. The present research mainly adopts the method of comparative test and analyzes the difference between AIN and standard fan nozzle. However, the research on internal flow characteristics and air–liquid ratio (ALR) of AIN is very limited. In order to detect the air-liquid transient flow distribution and the influence of the geometric parameter structure of Venturi on the air–liquid ratio in the air induction nozzle, numerical simulation and air-liquid ratio prediction model of AIN combined with TD (Turbo Drop series) type Venturi tubes and ST110 (standard nozzle series) type fan nozzles are used. Based on the VOF (volume of fluid) model and Realizable k-ε turbulence control method, the TD-ST combined AIN is simulated numerically using open input and exit boundary conditions. The results show that the transient flow characteristic of the combined AIN is determined by the geometric structure of the Venturi tube, and the internal velocity and pressure change significantly at the Venturi angle. Under the same ST110 fan nozzle, the size of the larger TD Venturi tube will decrease the air phase content in the air–liquid flow. TD03-ST06 combined AIN has a maximum volume flow of 0.0092 (L/min) under 0.6 MPa. The air–liquid ratio regression model is established by designing the intake volume measurement system. According to this model, the influence law of tube size and spray parameters on the air–liquid ratio can be clarified. After variance analysis, it is proved that this model is suitable for air–liquid ratio prediction of TD-ST combined AIN. This study clarifies the air–liquid coupling law inside AIN and provides some reference for the quantitative analysis of the relationship between the geometric parameters, spray parameters, and the air–liquid ratio.

Quasi-Steady Simulation of Glaze Ice Accretion and Heat Transfer in the Supercooled Large Droplet Regime in Atmospheric Turbulent Air Flow

Abstract To avoid the use of a computationally intensive full unsteady simulation while providing an accurate solution, a quasi-steady simulation has been performed to study glaze and mixed ice accretion in the supercooled large droplet (SLD) regime in turbulent flow of atmospheric air. We have attempted to find the minimum time-step necessary to adequately simulate the icing process on an airfoil surface. Based on node displacement, a mesh morphing scheme has been adopted in the computations to account for the moving boundaries that are caused by the continuous ice buildup. We have modeled ice accretion on an airfoil surface for a time period of 232 s using several time steps. At each time-step we solved the steady-state conservation equations for the air and droplet phases and then used the results as initial conditions for the next time position. The magnitude of the time-step ranged from a least accurate two-shot simulation (where the time-step is 116 s) to a most accurate 2320-shot simulation (where the time-step is 0.1 s). In-between these two extreme time steps, we have performed a three-shot simulation (where the time-step is 77.33 s), a four-shot simulation (where the time-step is 58 s), a six-shot simulation (where the time-step is 38.67 s), a 46-shot simulation (where the time-step is 5 s), and a 232-shot simulation (where the time-step is 1 s). We have done so to find out the degree of accuracy (or inaccuracy) of the multishot simulation approach and to find out the appropriate time-step needed for a successful and valid quasi-steady simulation. A valid quasi-steady simulation needs to use a time-step that is small enough to reproduce the full time-dependent solution within a very small error band. We have found that both the 1 s and the 0.1 s time steps produce virtually identical results. This is the primary litmus test that proves the validity of the quasi-steady-state assumption. The results adopted in this paper are thus all based on the more conservative 0.1 s time-step. In the process of performing the simulations, remeshing was required in order to maintain the grid density in zones of high curvature to be able to capture the full physics in those zones. After successfully modeling glaze ice accretion over the airfoil surface using the 0.1 s quasi-steady simulation approach, the effects of supercooled large droplets (SLDs) impacting the surface have been examined and presented in terms of the variation of the local collection efficiency, the water film thickness, and the heat transfer rate. Examination of the variation of the angle that the ice horn makes with the airfoil chord line demonstrated a 20% improvement in angle prediction when the time-step is reduced from 116 s to 0.1 s. The analysis also reveals a 12% or 8.5% increase in the maximum collection efficiency, βmax, depending on whether the value of the liquid water content (LWC) has been doubled from 0.5 g/m3 to 1 g/m3, or the value of the freestream velocity has been doubled from 75 m/s to 150 m/s, respectively. Because of the need to monitor the local collection efficiency and convective heat fluxes at each shot (regardless of the number of shots employed), the approach adopted here was found to be effective in successively and successfully reproducing the curvature of the glaze ice horn.

Laser-Induced Graphene Arrays-Based Three-Phase Interface Enzyme Electrode for Reliable Bioassays

Electrochemical oxidase biosensors have been widely applied in healthcare, environmental measurements and the biomedical field. However, the low and fluctuant oxygen levels in solution and the high anodic detection potentially restrict the assay accuracy. To address these problems, in this work, we constructed a three-phase interface enzyme electrode by sequentially immobilizing H2O2 electrocatalysts and an oxidase layer on a superhydrophobic laser-induced graphene (LIG) array substrate. The LIG-based enzyme electrode possesses a solid-liquid-air three-phase interface where constant and sufficient oxygen can be supplied from the air phase to the enzymatic reaction zone, which enhances and stabilizes the oxidase kinetics. We discovered that the enzymatic reaction rate is 21.2-fold improved over that of a solid-liquid diphase system where oxygen is supplied from the liquid phase, leading to a 60-times wider linear detection range. Moreover, the three-phase enzyme electrode can employ a cathodic measuring principle for oxidase catalytic product H2O2 detection, which could minimize interferences arising from oxidizable molecules in biofluids and increase the detection selectivity. This work provides a simple and promising approach to the design and construction of high-performance bioassay systems.

An improved human skin explant culture method for testing and assessing personal care products.

Cultured human skin models have been widely used in the evaluation of dermato-cosmetic products as alternatives to animal testing and expensive clinical testing. The most common in vitro skin culture approach is to maintain skin biopsies in an airlifted condition at the interface of the supporting culture medium and the air phase. This type of ex vivo skin explant culture is not, however, adequate for the testing of cleansing products, such as shampoos and body washes. One major deficiency is that cleansing products would not remain confined on top of the epidermis and have a high chance of running off toward the dermal side, thus compromising the experimental procedure and data interpretation. Here, we describe an improved ex vivo method for culturing full-thickness human skin for the effective testing and evaluation of skin care products by topical application. This newly developed ex vivo human skin culture method has the ability to maintain healthy skin tissues for up to 14 days in culture. Importantly, the model provides a quick and safe way to evaluate skin care products at different time points after single or repetitive topical applications using a combined regimen of leave-on and wash-off. We found that the results obtained using the new skin culture method are reproducible and consistent with the data collected from clinical testing. Our new ex vivo skin explant method offers a highly efficient and cost-effective system for the evaluation and testing of a variety of personal care products and new formulations.

Enhancing the Air Conditioning Unit Performance via Energy Storage of Different Inorganic Phase Change Materials with Hybrid Nanoparticles

Air conditioning unit performance, coupled with new configurations of phase change material as thermal energy storage, is investigated in hot climates. During the daytime, the warm exterior air temperature is cooled when flowing over the phase change material structure that was previously solidified by the night ambient air. A theoretical transient model is constructed and solved numerically for the proposed design in plate and cylinder configurations. This model is studied at different inlet hot ambient air temperatures and phase change material types (SP24E and SP26E) without and with inclusion of hybrid nanoparticles. The results affirm that the discharging and charging duration for the cylinder is minimal compared to the plate configuration. Raising the inflow air temperature lowers the exit air temperature and air conditioning coefficient of performance and power-saving but shortens the cooling time. Using phase change material with a relatively low melting temperature increases the melting time and exit air temperature but reduces the charging time. Mixing hybrid nanoparticles with phase change material has a short-term positive influence on air conditioning performance. The maximum power saving for 2 h of working is 16.4% for the cylinder, while for 10 h of working, it is 6.4% for the plate.

Agglomeration and dispersion characteristics of particles in simultaneous crystallization of NaCl and Na2SO4 in liquid and air phase

Simultaneous crystallization of multiple salt occurs during evaporative crystallization of industrial high-salt wastewater, making it difficult to separate multiple salt components due to agglomeration, thus forming solid waste. To investigate the main stages of simultaneous crystallization agglomeration phenomenon and the possibility of recovering pure components, agglomeration and dispersion of particles in simultaneous crystallization of NaCl and Na2SO4 under different crystallization orders in liquid and air phase are investigated in this paper. The results show that crystal agglomeration occurs mainly in the air phase, and the simultaneous crystallization of NaCl and Na2SO4 in liquid rarely results in agglomeration, and there are great differences in crystal morphology and size between NaCl and Na2SO4, which can be considered for separation of the two by physical means.

An insight on the experimental volumetric behaviour of gassy soils

Induced Partial Saturation (IPS) is one of the most innovative and promising countermeasures to mitigate soil liquefaction risk. Mechanical benefits of air/gas bubbles occluded within the pore water have been studied in the last decade through undrained cyclic tests on quasi-saturated (gassy) soils, demonstrating that the increased pore fluid compressibility prevents liquefaction triggering. The greater compressibility of the air bubbles rules the volumetric strains of gassy soils during seismic shaking reducing the build up of the pore water pressure. Mele et al., (2022) verified that, at the laboratory scale, due to lower frequencies of the applied cyclic loads, a non-negligible amount of soil volumetric strains is due to dissolution of air bubbles in the water (εv,diss). The outcomes of some simple compression tests carried out on a two-phase medium made of air/water confirm that such amount cannot be correctly computed with the Henry’s law, which considers the dissolution process of air into water in the hypothesis of continuous air phase. Experimental evidences highlighted that εv,diss is mainly ruled by the continuity of air phase (linked to the chosen experimental procedure), and it exceeds the theoretical previsions when air phase is discontinuous with single bubbles occluded in the fluid phase.

Exploring controls on perfluorocarboxylic acid (PFCA) gas-particle partitioning using a model with observational constraints.

The atmospheric fate of perfluorocarboxylic acids (PFCAs) has attracted much attention in recent decades due to the role of the atmosphere in global transport of these persistent chemicals. There is a gap in our understanding of gas-particle partitioning, limited by availability of reliable atmospheric measurements, partitioning properties, and models of gas-particle interactions. The gas-particle equilibrium phase partitioning of C2-C16 PFCAs in the atmosphere were modeled here by taking account of both deprotonation and phase partitioning equilibria among air, aerosol liquid water, and particulate water-insoluble organic matter using a range of available PFCA partitioning properties. We systematically varied water and organic matter content to simulate the full range of atmospheric conditions. Except in severe organic matter pollution episodes, shorter-chain PFCAs are predicted to mainly partition between air and aqueous phase, while for PFCAs with carbon chains longer than 12, organic matter is more likely to be the dominant particle phase reservoir. The model framework underestimated the particle fraction of C2-C8 PFCAs compared with several ambient observations, with larger discrepancies observed for longer-chain PFCAs. The discrepancy could result from externally mixed dust components, non-ideality of aerosol liquid water, surfactant descriptions at phase boundaries, and missed interactions between organic matter and charged PFCA molecules. Reliable measurements of ambient PFCAs with high time resolution and the measurement of uptake parameters by particle-relevant components will be beneficial to more reliable environmental fate modeling of ambient PFCAs.

Microscopy in the Study of Asbestos-Containing Joint Compound and Patching Products, Including Spackling

Drywall (wallboard, plasterboard, gypsum board) became the common construction material for interior walls in buildings in the later 1940s. Joint compound (mud, spackling, taping compound, joint treatment material) and patching products such as spackle or spackling were used to seal the seams between the boards and cover cracks and nail indentations. Most joint compounds from the 1940s into the later 1970s contained chrysotile asbestos in various formulations. Analyses by microscopy determined the chrysotile asbestos content of samples of Bondex, Georgia-Pacific, and Reardon products to be 1–5%, 3–8%, and 1–2% asbestos, respectively. Information compiled from several sources, including corporate responses to the U.S. EPA Asbestos Information Act of 1988 and other documents, suggest that asbestos-containing joint compounds and patching products from the 1930s into the late 1970s contained chrysotile in the range of 0.5% to 23%, with one company having a few formulations with asbestos levels as high as 45.2%. Although there were no documents showing that amphibole asbestos was intentionally added to joint compounds, there is some evidence of amphibole asbestos fibers in certain joint compound products, probably as accessory minerals with added chrysotile, talc, or limestone. No amphibole asbestos fibers were found in a Georgia-Pacific joint compound product tested using the acid/base digestion preparation procedure. During simulation testing, the asbestos level in the breathing zone of a worker during the mixing of Bondex Joint Compound ranged from 6.9 to 12 asbestos fibers per cubic centimeter of air (F/cc) (phase contrast microscopy modified by transmission light microscopy). The level was below detection during application. During sanding, the asbestos level in the breathing zone of the worker ranged from 1.9 to 5.5 asbestos F/cc. The simulations showed results that were within the ranges reported in the scientific literature for airborne asbestos levels caused by dry mixing and sanding of asbestos-containing joint compound. The sale of joint compound and spackling sold for consumer use with intentionally added asbestos was banned by the Consumer Product Safety Commission in 1977.

Effects of Emulsifier Type and Ingredient on the Foam Stability of Meringue

Food foams provide texture and structure for many food products, such as meringues. Meringues, a fundamental of culinary arts, commonly consist of whipped egg white and sugar and have about most of the air phase. These types of composition allow for making different products with the same ingredients; thus, meringue design is essential to investigate foam stability and ability. This study aims to examine the foam stability of meringue using the different components such as protein as emulsifiers (egg white and gelatin) and the composition of sugars (icing and granule) on the foam stability and formation of meringue. Using gelatin as an emulsifier showed the foam more stable than egg white (>24 h), and adding the icing sugar with gelatin made the foam texture smoother. On the other hand, foam formation was faster when using emulsifier egg white, but stability was less than gelatin. The more stable foam produced by the combination of emulsifier and sugar ingredients would provide a better texture of meringue after baking, a smooth surface, no hole, and a more crunchy sweet taste. It was concluded that the composition of the ingredients and type of emulsifier would affect the stability and ability of foam, resulting in the character of the meringue after baking.

Quality Evaluation Research of Low-Calorie Milk Ice Cream

A modern approach to nutrition requires the creation and further development of new types of ice cream that are more beneficial for health in comparison with the traditional ones. The solution to this issue lies in the creation of the low-calorie ice cream. It gets its distinctive properties and features due to the reduction of fat and sugar content along with the mixing of various functional components. The aim of the research was to study the effects of milk processing products and plant ingredients on the quality of low-calorie milk ice cream. The organoleptic, physical, chemical and microbiological indicators of low-calorie milk ice cream were examined. It was established that according to taste profiles, experimental samples of ice cream had good indicators of smell and color in the absence of extraneous odors. According to physical, chemical and microbiological indicators, samples of low-calorie milk ice cream met the requirements of the State Standard of Ukraine (DSTU) 4733:2007.Studies of the microstructure of low-calorie milk ice cream have shown that there is a tendency to increase the dispersion of the air phase in its samples. It is proven that the new low-calorie ice cream components possess properties of the moisture-binding components. The amount of sugar was reduced by a third comparing to the traditional composition of ice cream precisely due to the utilization of the components. The composition of low-calorie milk ice cream in which the protein and vegetable components was substantiated, and the organoleptic, physical, chemical and microbiological parameters were studied. The expediency of the protein and plant components usage in low-calorie milk ice cream recipes has been proven. Key words: low-calorie milk ice cream, quality, organoleptic indicators, physical and chemical indicators, microbiological indicators, microstructure, whey processing products.

Prediction of Dispersion Rate of Airborne Nanoparticles in a Gas-Liquid Dual-Microchannel Separated by a Porous Membrane: A Numerical Study.

Recently, there has been increasing attention toward inhaled nanoparticles (NPs) to develop inhalation therapies for diseases associated with the pulmonary system and investigate the toxic effects of hazardous environmental particles on human lung health. Taking advantage of microfluidic technology for cell culture applications, lung-on-a-chip devices with great potential in replicating the lung air-blood barrier (ABB) have opened new research insights in preclinical pathology and therapeutic studies associated with aerosol NPs. However, the air interface in such devices has been largely disregarded, leaving a gap in understanding the NPs' dynamics in lung-on-a-chip devices. Here, we develop a numerical parametric study to provide insights into the dynamic behavior of the airborne NPs in a gas-liquid dual-channel lung-on-a-chip device with a porous membrane separating the channels. We develop a finite element multi-physics model to investigate particle tracing in both air and medium phases to replicate the in vivo conditions. Our model considers the impact of fluid flow and geometrical properties on the distribution, deposition, and translocation of NPs with diameters ranging from 10 nm to 900 nm. Our findings suggest that, compared to the aqueous solution of NPs, the aerosol injection of NPs offers more efficient deposition on the substrate of the air channel and higher translocation to the media channel. Comparative studies against accessible data, as well as an experimental study, verify the accuracy of the present numerical analysis. We propose a strategy to optimize the affecting parameters to control the injection and delivery of aerosol particles into the lung-on-chip device depending on the objectives of biomedical investigations and provide optimized values for some specific cases. Therefore, our study can assist scientists and researchers in complementing their experimental investigation in future preclinical studies on pulmonary pathology associated with inhaled hazardous and toxic environmental particles, as well as therapeutic studies for developing inhalation drug delivery.

Distribution characteristics, air-water exchange, ozone formation potential and health risk assessments of VOCs emitted from typical coking wastewater treatment process

Coking industry has been considered as important source of volatile organic compounds (VOCs) emissions. However, few studies have emphasized the occurrence and adverse effects of VOCs from coking wastewater treatment processes. In this research, pollution profiles of both air and water phase VOCs in a typical coking wastewater treatment plant were investigated in terms of distribution characteristics, air-water exchange, ozone formation potential (OFP) and associated human health risks. Thirty VOCs were detected in the air phase, in which benzene and naphthalene were found to be the major VOCs with total contribution of 87.81 %. Nineteen VOCs were detected in the water phase, in which benzene, naphthalene and toluene contribute most to total VOCs with total contribution of 75.1 %. The regulating tank (RT) was the major source of VOCs, and the emission rate of total VOCs from all unites was 2711.03 g/d with annual emission of 0.99 t. The emission factor was estimated to be 1.36 g VOCs/m3 wastewater. The air-water exchange was assessed using the Fugacity model, and water-to-air volatilization was predominant based on the net flux of air-water exchange. OFP evaluated by emission factor indicated that the total OFP in RT was the highest (1.52 g O3/m3 wastewater), and toluene contributed 41.8 % of the total OFP, followed by naphthalene accounting for 38.7 % The total carcinogenic risks were in the range of 8.60 × 10−6 to 2.18 × 10−3, in which the RT exceeded the significant risk threshold (>1 × 10−4). The non-carcinogenic risks of hazard quotient value in RT also exceeded the risk threshold (>1), and naphthalene was the major contributor accounting for 79.02 %. These results not only provided comprehensive knowledge on pollution profiles and environmental risks of VOCs during coking wastewater treatment processes, but also facilitated the implement of VOCs regulation and occupational health protection strategies in coking industries.