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Dust dynamics influence planetary atmospheres. However, the settling velocity of dust—and thus its residence time in the atmosphere—is often mispredicted. Challenging, indirect experiments involving few ideal particles revealed that dust settling velocity deviates from Stokes' law under rarefied atmospheres. While useful, such experiments are inadequate to simulate more complex scenarios, including variable particles sizes and shapes. Here, we present direct measurements of settling velocity for spherical particles under Earth‐to‐Mars atmospheric pressures using time‐resolved particle image velocimetry (TR‐PIV), and validate their robustness with existing models. Our results demonstrate that TR‐PIV provides a relatively simple approach to quantifying dust settling velocity from direct observations of over 10,000 particles, enabling systematic investigations of dust settling under realistic scenarios. Such experiments will have significant implications for our understanding of Mars' past, present, and future ‐ from providing a tool to decipher its sedimentary record to enhancing predictive capabilities of atmospheric models. Plain Language Summary: Airborne dust strongly affects the environments and atmospheres of Earth and Mars. Knowing the speed at which dust settles is critical because it controls the time dust stays in the atmosphere. However, it is a difficult quantity to measure, and as a result, it is often poorly predicted by existing models. These models were built from experiments that did not match real‐world conditions and typically only considered few, idealized particles. Here, we propose a relatively simple approach to make direct measurements of dust settling under Earth‐to‐Mars atmospheric pressures. This technique, time‐resolved particle image velocimetry, allows us to directly measure the speed of over 10,000 particles. Using ideal particles, we show that our measurements align well with results from previously published models, validating the robustness of our procedure. The same experimental setup can be used to investigate dust settling under more realistic conditions, for example, varying the size distribution of dust particles, their shape, or dust concentration. Such measurements are a stepping stone toward accurate interpretations and predictions of dust dynamics on Earth and Mars. Key Points: Dust settling velocity controls residence time of dust in the atmosphere but is challenging to measure under low atmospheric densityWe measure dust settling velocity under Earth‐to‐Mars‐like conditions using time‐resolved particle image velocimetry (TR‐PIV)TR‐PIV enables systematic studies of dust settling on Mars and other bodies using realistic particles and varying dust concentrations [ABSTRACT FROM AUTHOR]

Resuspension of dust from carpet is an important source of human exposure to microorganisms. The microbial composition of dust can be measured using environmental DNA, such as with polymerase chain reaction (PCR) technologies. However, we need an improved understanding of collection losses and efficiencies to support accurate quantification of these exposures. The goal of this study was to characterize accuracy and precision of PCR-based analysis methods for microbial DNA in residential carpet dust. We spiked dust with known concentrations of bacterial cells Escherichia coli and Bacillus atrophaeus, as well as spores of the fungus Aspergillus fumigatus. We embedded the dust into nylon carpet of varying pile heights and recovered it by vacuuming using two different attachments. Overall reproducibility using quantitative PCR ranged from 13% to 36% coefficient of variation for this sampling procedure. Overall efficiencies associated with recovery of dust from the carpet via vacuuming and extraction of DNA from the dust ranged from 27% for A. fumigatus spores to 9% for E. coli cells. Failure to account for DNA recovery efficiencies could result in up to 11.2 times underestimation of exposure. Incorporating DNA recovery efficiencies into the analysis avoids underestimation of environmental exposures to microbes. [ABSTRACT FROM AUTHOR]

In the present study with a novel two-chamber setup (TCS) for dustiness investigations, the relationship between pressure differences as well as air velocities and the resulting dust emissions is investigated. The dust emissions of six particle size fractions of acetaminophen at pressure differences between 0 and 12 Pa are examined. The results show that both simulated and measured air velocities increase with increasing pressure difference. Dust emissions decrease significantly with increasing pressure difference and air velocity. Fine particles cause higher dust emissions than coarse particles. A high goodness of fit is obtained with exponential and quadratic functions to describe the relationship between pressure difference and dust emission, indicating that even moderate increases in pressure may lead to a reduction in the emission. Average air velocities within the TCS simulated with Computational Fluid Dynamics are between 0.09 and 0.37 m/s, whereas those measured experimentally are between 0.09 and 0.41 m/s, both ranges corresponding to the recommended values for effective particle separation in containment systems. These results underline the ability of the novel TCS to control pressure and airflow, which is essential for reliable dust emission measurements and thus provide support for further scientific and industrial applications. [ABSTRACT FROM AUTHOR]

This work analyses 10 years (from 2009 to 2018) of long‐range Saharan dust advections (SDAs) and their correlation with the precipitation and radiative budget over the Central Mediterranean region. The identification of the SDAs is based on back‐trajectories (BTs) of air mass and complementary measurements of the dust deposited at the site of Monte Martano in Central Italy. The associated synoptic circulation weather types (CWT), precipitation and radiation variables have been estimated by using ERA5 and CAMS reanalysis, satellite data and raingauge observations. It is found that the 50% of all SDAs occur under a CWT characterized by an upper level trough over the Western Mediterranean and a high‐pressure system over the Eastern Mediterranean. Strong southerly winds, large vertical integral of water vapour transport and a positive anomaly of 2 m temperature are associated with dust uplift and transport. The effect of dust on rainfall intensity puts forward the important modulation of the aerosol effects on the radiative budget with a latitudinal dependence. On dusty days, intense rainfall increases over the northern Central Mediterranean and light rainfall is suppressed in the southern Central Mediterranean, pointing out a relevant correlation between dust and the intensification of extreme events. Other than affecting rainfall intensity, the stronger surface heating over the southern Central Mediterranean, which is correlated to a higher dust optical depth, causes a local maximum of sea surface temperature (SST) and near‐surface temperature anomaly. [ABSTRACT FROM AUTHOR]

This paper considers extreme dusty conditions at workplaces in underground coal mine. These extreme conditions stem from various physical factors that affect employees' performance. The extreme effect of the dust can significantly contribute to permanent health damage or even the death of employees. In this study, we present and discuss the results of measurements of airborne dust and respiratory dust taken during wall cutting in a coal mine and propose effective measures to reduce the burden on the life and health of employees and the environment. [ABSTRACT FROM AUTHOR]

Dust emission fluxes during wind soil erosion are usually estimated using a dust concentration vertical gradient, by assuming a constant dust flux layer between the surface and the dust measurement levels. Here, we investigate the existence of this layer during erosion events recorded in Iceland and Jordan. Size‐resolved dust fluxes were estimated at three levels between 2 and 4 m using the eddy‐covariance method. Dust fluxes were found mainly constant only between the two upper levels in Iceland, the lower dust flux being often stronger and richer in coarse particles, while dust fluxes in Jordan were nearly constant across all levels. The wind dynamics could not explain the absence of a constant dust flux layer in Iceland. We show that the presence of stationary dust source patches in Iceland, related to surface humidity, created a non‐uniform dust layer near the surface, named dust roughness sublayer (DRSL), where individual plumes behind each patch interact but do not fully mix. The lowest dust measurement level was probably located within this sublayer while the upper ones were located above, such that there the emitted dust became spatially well‐mixed. This explains near the surface in Iceland, the more intermittent dust concentration, its low correlation with the dust concentrations above, and the richer dust flux in coarse particles due to their lower deposition contribution. Our findings highlight the importance of estimating dust fluxes above a dust blending height whose characteristics depend on the dust source patchiness caused by surface humidity or the presence of sparse non‐erosive elements. Plain Language Summary: During soil erosion by wind, dust flux from the surface is estimated at a few meters height, by assuming the existence of a constant dust flux layer between the surface and the dust measurement levels. Here, we investigated for the first time the existence of this layer during erosion events in Iceland and Jordan, by estimating the dust fluxes at three levels between 2 and 4 m height. In Iceland, the dust fluxes were constant only between the two upper levels. In Jordan, the dust fluxes remained constant across all levels. We demonstrates that the absence of a constant dust flux layer in Iceland is due to patches of stationary dust sources, which are related to surface humidity. These patches created a non‐uniform dust layer near the surface, known as the dust roughness sublayer. In this layer, individual plumes behind each patch interact but do not fully mix. The lowest dust measurement level was likely within this sublayer, while the upper measurements were located above it. Our findings highlight the importance of estimating dust fluxes above a dust blending height, which depends on the patchiness of the dust source caused by surface humidity or the presence of sparse non‐erosive elements. Key Points: Size‐resolved dust emission fluxes have been estimated for the first time at different heights during erosion events in Iceland and JordanUnlike in Jordan, the absence of a constant dust flux layer in Iceland is due to the dust source patchiness related to surface humidityOur results highlight the importance of estimating dust fluxes above a dust blending height that depends on the dust source patchiness [ABSTRACT FROM AUTHOR]

The Ulysses spacecraft was launched in 1990 and, after a Jupiter swing-by in 1992, became the first interplanetary spacecraft orbiting the Sun on a highly inclined trajectory with an inclination of 79∘. The spacecraft was equipped with an impact ionization dust detector which provided 17 years of in situ dust measurements in interplanetary space from 1990 to 2007. Cometary meteoroid streams (also referred to as trails) exist along the orbits of comets, forming fine structures of the interplanetary dust cloud. We use the Interplanetary Meteoroid Environment for eXploration (IMEX) dust streams in space model (Soja RH et al. 2015 Characteristics of the dust trail of 67P/Churyumov-Gerasimenko: an application of the IMEX model. Astron. Astrophys.583, A18. (doi:10.1051/0004-6361/201526184)) to predict cometary stream traverses by Ulysses and re-analyse the Ulysses dust dataset in order to identify impacts of cometary stream particles detected during such trail traverses. We identify 19 particles compatible with three Ulysses trail traverses on 12 March 1995, 25–27 April 2001 and 16–19 May 2001. The particle origin is compatible with up to five comets, i.e. 10P/Tempel 2, 146P/Shoemaker-LINEAR, 267P/LONEOS and possibly 45P/Honda-Mrkos-Pajdušáková and P/1999 RO28 (LONEOS). We find a dust spatial density in these trails of approximately 2−7⋅10−8m−3. The radii of the detected cometary stream particles derived from the dust instrument calibration are in the micrometre range. The in situ analysis of meteoroid trail particles in space, which can be traced back to their source bodies, opens a new opportunity for remote compositional analysis of comets and asteroids without the necessity to send a spacecraft to or even land on these celestial bodies, opening new opportunities for future space missions equipped with in situ dust analyzers. This article is part of the theme issue 'Dust in the Solar System and beyond'. [ABSTRACT FROM AUTHOR]

Abstract An edge-cloud computing collaborative dust concentration detection architecture is proposed for real-time operation of intelligent algorithms to reduce the warning delay. And, an end-to-end three-channel convolutional neural network (E2E-SCNN) method is proposed in the paper to facilitate intelligent monitoring and management of dust concentration in tobacco production workshops. This model, which includes three sub-networks-a local feature branch, a global feature branch, and a spatial feature branch, learns the detail texture, overall layout, and spatial distribution information of the input image respectively. A fusion of the three complementary features is performed at the end of the network for the final dust concentration regression prediction. The design, when compared with the single network structure that directly regresses the entire image, is shown to more fully represent the overall information of the image and enhance monitoring performance. A richly annotated image dataset of tobacco production workshops is constructed to verify the effectiveness of the proposed method. The prediction error of E2E-SCNN is compared with existing image estimation algorithms, dual-channel networks, and other methods on this dataset using indicators such as Mean Absolute Error (MAE) and $${R}^{2}$$ R 2 . It is shown by the results that excellent performance is achieved by the E2E-SCNN algorithm, significantly surpassing other comparison methods. The paper demonstrates that the accuracy and robustness of dust concentration prediction can be greatly improved by using a three-channel convolutional neural network spatial information monitoring framework. This achievement provides an effective means for dust supervision and governance during the tobacco production process and offers a technical route that can be referred to for image analysis tasks in other similar fields.

Spatially resolved images of debris discs are necessary to determine disc morphological properties and the scattering phase function (SPF) thatantifies the brightness of scattered light as a function of phase angle. Current high-contrast imaging instruments have successfully resolved several dozens of debris discs around other stars, but few studies have investigated trends in the scattered-light, resolved population of debris discs in a uniform and consistent manner. We have combined Karhunen-Loeve Image Projection (KLIP) with radiative-transfer disc forward modelling in order to obtain the highest-quality image reductions and constrain disc morphological properties of eight debris discs imaged by the Gemini Planet Imager at H -band with a consistent and uniformly applied approach. In describing the scattering properties of our models, we assume a common SPF informed from solar system dust scattering measurements and apply it to all systems. We identify a diverse range of dust density properties among the sample, including critical radius, radial width, and vertical width. We also identify radially narrow and vertically extended discs that may have resulted from substellar companion perturbations, along with a tentative positive trend in disc eccentricity with relative disc width. We also find that using a common SPF can achieve reasonable model fits for discs that are axisymmetric and asymmetric when fitting models to each side of the disc independently, suggesting that scattering behaviour from debris discs may be similar to Solar system dust. [ABSTRACT FROM AUTHOR]

This study proposes a system that can collect and analyze the brake particle matter generated from a vehicle and brake dynamometer. A dust cover is developed to collect brake particle matter, and the number of particle matter by size is measured using a portable aerosol spectrometer. Brake PM10 generated when the vehicle is driving on highways, country and city roads is collected and analyzed. Based on the vehicle driving data, the test mode for the brake dynamometer is developed using the relationship between brake energy and brake power. The same brake fine dust collection and measurement system as the vehicle is installed on the brake dynamometer, and brake PM10 generated according to the test mode for each road condition is collected and analyzed. As a result, the total number of brake PM10 collected from the vehicle and brake dynamometer shows about maximum of 20% error rate for each road condition. The Pearson correlation coefficient for the test results is 0.9988, and it means that the vehicle and brake dynamometer test results has a strong positive relationship. [ABSTRACT FROM AUTHOR]

Mineral dust aerosols are composed of a complex assemblage of various minerals depending on the region in which they originated. Given the different mineral composition of desert dust aerosols, different physicochemical properties and therefore varying climate effects are expected. Despite the known regional variations in mineral composition, chemical transport models typically assume that mineral dust aerosols have uniform composition. This study adds, for the first time, mineralogical information to the mineral dust emission scheme used in the chemical transport model COSMO–MUSCAT. We provide a detailed description of the implementation of the mineralogical database, GMINER (), together with a specific set of physical parameterizations in the model's mineral dust emission module, which led to a general improvement of the model performance when comparing the simulated mineral dust aerosols with measurements over the Sahara region for January–February 2022. The simulated mineral dust aerosol vertical distribution is tested by a comparison with aerosol lidar measurements from the lidar system PollyXT , located at Cape Verde. For a lofted mineral dust aerosol layer on 2 February at 05:00 UTC the lidar retrievals yield a dust mass concentration peak of 156 µgm-3 , while the model calculates the mineral dust peak at 136 µgm-3. The results highlight the possibility of using the model with resolved mineral dust composition for interpretation of the lidar measurements since a higher absorption in the UV–Vis wavelengths is correlated with particles having a higher hematite content. Additionally, the comparison with in situ mineralogical measurements of dust aerosol particles shows that more of them are needed for model evaluation. [ABSTRACT FROM AUTHOR]

This paper presents a new approach to determining the dimensions of particles that can be lifted to a coma by the sublimation flux of water ice. Due to the diverse colour of the cometary surfaces, in the presented calculations we take into account the influence of the reflectance coefficient (hemispherical albedo) on the size of particles lifted from the surface of the nucleus. A Cary 5000 spectrometer was used to measure hemispherical albedo. Spectroscopic measurements used dust particles that consisted of pure silicate or were a mixture of pure silicate and organic compounds such as charcoal, soot, and ash. In addition, these admixtures acted as a means of darkening the tested sample. Depending on the colour of the sample and the wavelength, the measured value of hemispherical albedo oscillated in the range from 4.93 per cent to 48.65 per cent. A thermodynamic model of cometary matter emission was developed based on the results of hemispherical albedo measurements. The performed numerical simulations show that the temperature decreases with the increase of the hemispherical albedo, which translates into the sublimation flux and the dynamics of the dust-ice particles present on the surface of the cometary nucleus. Taking into account the extreme values of the hemispherical albedo, the differences in the size of particles carried away from the surface of the nucleus are in the order of centimeters. [ABSTRACT FROM AUTHOR]

An edge-cloud computing collaborative dust concentration detection architecture is proposed for real-time operation of intelligent algorithms to reduce the warning delay. And, an end-to-end three-channel convolutional neural network (E2E-SCNN) method is proposed in the paper to facilitate intelligent monitoring and management of dust concentration in tobacco production workshops. This model, which includes three sub-networks-a local feature branch, a global feature branch, and a spatial feature branch, learns the detail texture, overall layout, and spatial distribution information of the input image respectively. A fusion of the three complementary features is performed at the end of the network for the final dust concentration regression prediction. The design, when compared with the single network structure that directly regresses the entire image, is shown to more fully represent the overall information of the image and enhance monitoring performance. A richly annotated image dataset of tobacco production workshops is constructed to verify the effectiveness of the proposed method. The prediction error of E2E-SCNN is compared with existing image estimation algorithms, dual-channel networks, and other methods on this dataset using indicators such as Mean Absolute Error (MAE) and R 2 . It is shown by the results that excellent performance is achieved by the E2E-SCNN algorithm, significantly surpassing other comparison methods. The paper demonstrates that the accuracy and robustness of dust concentration prediction can be greatly improved by using a three-channel convolutional neural network spatial information monitoring framework. This achievement provides an effective means for dust supervision and governance during the tobacco production process and offers a technical route that can be referred to for image analysis tasks in other similar fields. [ABSTRACT FROM AUTHOR]

X-ray photons from energetic sources such as gamma-ray bursts (GRBs) can be scattered on dust clouds in the Milky Way, creating a time-evolving halo around the GRB position. X-ray observations of such haloes allow the measurement of dust cloud distances in the Galaxy on which the scattering occurs. We present the first systematic comparison of the distances to scattering regions derived from GRB haloes with the 3D dust distribution derived from recently published optical-to-near infrared extinction maps. GRB haloes were observed around seven sources by the Swift XRT and the XMM–Newton EPIC instruments, namely GRB 031203, GRB 050713A, GRB 050724, GRB 061019, GRB 070129, GRB 160623A, and GRB 221009A. We used four 3D extinction maps that exploit photometric data from different surveys and apply diverse algorithms for the 3D mapping of extinction, and compared the X-ray halo-derived distances with the local maxima in the 3D extinction density distribution. We found that in all GRBs, we can find at least one local maximum in the 3D dust extinction map that is in agreement with the dust distance measured from X-ray rings. For GRBs with multiple X-ray rings, the dust distance measurements coincide with at least three maxima in the extinction map for GRB 160623A, and five maxima for GRB 221009A. The agreement of these independent distance measurements shows that the methods used to create dust extinction maps may potentially be optimized by the X-ray halo observations from GRBs. [ABSTRACT FROM AUTHOR]

Over the past decades, northern China has been suffering from persistent air pollution caused by both fine and coarse atmospheric particles. Although there are plenty of theoretical and observational studies on aerosols in northern China, most of them only consider total aerosol concentrations and focus on heavy pollution episodes; the long-term vertical distributions of dust (coarse) and anthropogenic aerosols (fine) and their relationships with the mixing layer height (MLH) have not been revealed. In this study, the dust and anthropogenic aerosols' mass concentration and the MLH were retrieved by polarization Raman lidar over Beijing from May 2019 to February 2022. We found that large amounts of anthropogenic aerosols accumulate at the top of the mixing layer, which is most noticeable in summer, with monthly mean mass concentration up to 57 µ g m -3. It is mainly influenced by the southward transport in the upper air, where the atmosphere is relatively stable and moist, favoring hygroscopic growth of particles. Dust mass concentration is discontinuous in the vertical direction, not only on the ground but also in lofted layers that reach up to several kilometers. The heights of these lofted dust layers exhibited apparent seasonal dependence, with the height of the main dust layer gradually ascending from 1.1 km to about 2.5 km from April to June and below 3 km from October to December. In addition, there is a significant negative correlation between bottom anthropogenic aerosols' mass concentration and the MLH, and an inverse function fit is more suitable to characterize this relationship, while the relationship between bottom dust mass concentration and the MLH is insignificant. These results will enhance our understanding of the sophisticated interactions between dust and anthropogenic aerosols, the MLH, and regional transport in northern China. It will also help to refine atmospheric chemistry models and improve surface prediction capabilities. [ABSTRACT FROM AUTHOR]

Inhalation of organic powders may lead to various diseases such as asthma-like syndrome and hypersensitivity pneumonia. The study aim to evaluate respiratory health effects by respiratory function measurements, respiratory survey, ambient dust concentration, and toxic gas in workers of a tea packaging factory. 69 employees from different departments of the tea packaging factory were included. A group of 53 office workers of a separate establishment was included as a control. Sputum production in the morning was significantly higher in the tea packaging workers (p=0.013). Among the respiratory function values, only FEV1/FVC was lower in this group than in the control group. There was a significant decrease in FEF75% value among smokers in the study group compared to non-smokers. Respiratory effects observed in some food processing industry workers are also seen in the tea packaging industry. Effective dust control will positively affect the health of the workers. More studies are needed to better identify potential risks. [ABSTRACT FROM AUTHOR]

The mineralogical composition of airborne dust particles is an important but often neglected parameter for several physiochemical processes, such as atmospheric radiative transfer and ocean biochemistry. We present the development of the METAL-WRF module for the simulation of the composition of desert dust minerals in atmospheric aerosols. The new development is based on the GOCART-AFWA dust module of WRF-Chem. A new wet deposition scheme has been implemented in the dust module alongside the existing dry deposition scheme. The new model includes separate prognostic fields for nine (9) minerals: illite, kaolinite, smectite, calcite, quartz, feldspar, hematite, gypsum, and phosphorus, derived from the GMINER30 database and also iron derived from the FERRUM30 database. Two regional model sensitivity studies are presented for dust events that occurred in August and December 2017, which include a comparison of the model versus elemental dust composition measurements performed in the North Atlantic (at Izaña Observatory, Tenerife Island) and in the eastern Mediterranean (at Agia Marina Xyliatos station, Cyprus Island). The results indicate the important role of dust minerals, as dominant aerosols, for the greater region of North Africa, South Europe, the North Atlantic, and the Middle East, including the dry and wet depositions away from desert sources. Overall, METAL-WRF was found to be capable of reproducing the relative abundances of the different dust minerals in the atmosphere. In particular, the concentration of iron (Fe), which is an important element for ocean biochemistry and solar absorption, was modeled in good agreement with the corresponding measurements at Izaña Observatory (22% overestimation) and at Agia Marina Xyliatos site (4% overestimation). Further model developments, including the implementation of newer surface mineralogical datasets, e.g., from the NASA-EMIT satellite mission, can be implemented in the model to improve its accuracy. [ABSTRACT FROM AUTHOR]

Fundamental to our understanding of planetary bulk compositions is the relationship between their masses and radii, two properties that are often not simultaneously known for most exoplanets. However, while many previous studies have modeled the two-dimensional relationship between planetary mass and radii, this approach largely ignores the dependencies on other properties that may have influenced the formation and evolution of the planets. In this work, we extend the existing nonparametric and probabilistic framework of MRExo to jointly model distributions beyond two dimensions. Our updated framework can now simultaneously model up to four observables, while also incorporating asymmetric measurement uncertainties and upper limits in the data. We showcase the potential of this multidimensional approach to three science cases: (i) a four-dimensional joint fit to planetary mass, radius, insolation, and stellar mass, hinting of changes in planetary bulk density across insolation and stellar mass; (ii) a three-dimensional fit to the California Kepler Survey sample showing how the planet radius valley evolves across different stellar masses; and (iii) a two-dimensional fit to a sample of Class-II protoplanetary disks in Lupus while incorporating the upper limits in dust mass measurements. In addition, we employ bootstrap and Monte Carlo sampling to quantify the impact of the finite sample size as well as measurement uncertainties on the predicted quantities. We update our existing open-source user-friendly MRExo Python package with these changes, which allows users to apply this highly flexible framework to a variety of data sets beyond what we have shown here. [ABSTRACT FROM AUTHOR]

Background. Di-(2-ethylhexyl) phthalate (DEHP), which is ubiquitous in indoor environments, was the predominant phthalate measured in house dust in the Canadian CHILD Cohort and was found to be associated with a large increased risk of childhood asthma. Objective. To inform interventions by identifying sources of DEHP in dust and assessing behaviors related to DEHP concentrations in house dust. Methods. DEHP levels were measured in 726 dust samples collected at ~3 months of age in CHILD as well as in ~50 homes at two time points (June and November) in the CHILD pilot study. DEHP metabolites were measured in urine for a subset of the ~3-month-old infants. Housing characteristics were assessed at the time of dust and urine collection. Numerous factors from these surveys were investigated as potential sources of DEHP using univariate analyses and multivariable regressions. Correlations between DEHP in dust and urinary metabolites and between repeat dust samples were examined to study the relationship between dust measurement and DEHP exposure. Results. Overall, DEHP dust concentrations were higher for lower-income families. Homes with vinyl flooring in the kitchen and bathroom showed higher levels of DEHP than those without vinyl flooring. The quantity of vinyl furniture and the presence of mold were associated with higher DEHP concentrations, while the use of mattress covers reduced concentration. No other significant associations were found. DEHP concentrations in dust were consistent over 6 months, although the correlation between dust and DEHP metabolites in urine was low. Conclusion. DEHP in house dust persisted over multiple months, contributed to infant internal exposure, and was associated with specific housing characteristics. These findings may inform the public on their choice of building materials and products, as well as future policies, aimed at reducing the health risk associated with exposures in the indoor environment especially for children. [ABSTRACT FROM AUTHOR]

Over the past decades, Beijing has been suffering from persistent air pollution caused by both fine and coarse atmospheric particles. Although there are plenty of theoretical and observational studies on aerosols in Beijing, most of them only consider total aerosol concentrations and focus on heavy pollution episodes, the long‒term vertical distributions of dust (coarse) and anthropogenic aerosols (fine) and their relationships with mixing layer height (MLH) have not been revealed. In this study, the dust and anthropogenic aerosols mass concentration, and MLH were retrieved by polarization Raman lidar over Beijing from May 2019 to February 2022. We found large amounts of anthropogenic aerosols accumulate at the top of the mixing layer, which is most noticeable in summer, with monthly mean mass concentration up to 57 µg/m3. It is mainly influenced by the southward transport in the upper air, where the atmosphere is relatively stable and moist, favoring hygroscopic growth of particles. Dust mass concentration is discontinuous in the vertical direction. Not only on the ground but also in lofted layers that reach up to several kilometers. The heights of these lofted dust layers exhibited apparent seasonal dependence, with the height of the main dust layer gradually ascending from 1.1 km to about 2.5 km from April to June and below 3 km from October to December. In addition, there is a significant negative correlation between bottom anthropogenic aerosols mass concentration and MLH, and an inverse function fit is more suitable to characterize this relationship, while the relationship between bottom dust mass concentration and MLH is insignificant. These results will enhance our understanding of the sophisticated interactions between dust and anthropogenic aerosols, MLH, and regional transport in northern China. It will also help to refine atmospheric chemistry models and improve surface prediction capabilities. [ABSTRACT FROM AUTHOR]

Dust extinction is one of the fundamental measurements of dust grain sizes, compositions, and shapes. Most of the wavelength-dependent variations seen in Milky Way extinction are strongly correlated with the single parameter R (V) = A (V)/ E (B − V). Existing R (V)-dependent extinction relationships use a mixture of spectroscopic and photometry observations, and hence do not fully capture all the important dust features or continuum variations. Using four existing samples of spectroscopically measured dust extinction curves, we consistently measure the R (V)-dependent extinction relationship spectroscopically from the far-ultraviolet (FUV) to mid-infrared for the first time. Linear fits of A (λ)/ A (V) dependent on R (V) are done using a method that fully accounts for their significant and correlated uncertainties. These linear parameters are fit with analytic wavelength-dependent functions to determine the smooth R (V) (2.3–5.6) and wavelength (912 Å–32 μ m) dependent extinction relationship. This relationship shows that the FUV rise, 2175 Å bump, and the three broad optical features are dependent on R (V), but the 10 and 20 μ m features are not. Existing literature relationships show significant deviations compared to this relationship especially in the FUV and infrared (IR). Extinction curves that clearly deviate from this relationship illustrate that this relationship only describes the average behavior versus R (V). We find tentative evidence that the relationship may not be linear with R (V)−1 especially in the ultraviolet (UV). For the first time, this relationship provides measurements of dust extinction that spectroscopically resolve the continuum and features in the UV, optical, and IR as a function of R (V), enabling detailed studies of dust grain properties and full spectroscopic accounting for the effects of dust extinction on astrophysical objects. [ABSTRACT FROM AUTHOR]

Asphalt mixes comprise aggregates, additives and bitumen. The aggregates are of varying sizes, and the finest category, referred to as sands, encompasses the so-called filler particles present in the mixture, which are smaller than 0.063 mm. As part of the H2020 CAPRI project, the authors present a prototype for measuring filler flow, through vibration analysis. The vibrations are generated by the filler particles crashing to a slim steel bar capable of withstanding the challenging conditions of temperature and pressure within the aspiration pipe of an industrial baghouse. This paper presents a prototype developed to address the need for quantifying the amount of filler in cold aggregates, considering the unavailability of commercially viable sensors suitable for the conditions encountered during asphalt mix production. In laboratory settings, the prototype simulates the aspiration process of a baghouse in an asphalt plant, accurately reproducing particle concentration and mass flow conditions. The experiments performed demonstrate that an accelerometer positioned outside the pipe can replicate the filler flow within the pipe, even when the filler aspiration conditions differ. The obtained results enable extrapolation from the laboratory model to a real-world baghouse model, making it applicable to various aspiration processes, particularly those involving baghouses. Moreover, this paper provides open access to all the data and results used, as part of our commitment to the CAPRI project, with the principles of open science. [ABSTRACT FROM AUTHOR]

In the present study, dust concentrations of PM 2.5 and PM 10 were analysed for nine animal welfare barns on seven pig farms in Baden-Württemberg, comparatively for summer and winter. In two farms, two identical barns were investigated, all other barns were structurally different. The dust measurements were carried out at three measuring positions (M1, M2, M3) in the barn, as well as in winter and in summer. The measurements showed differences in dust concentrations in all barns. The comparison of dust concentrations within the farms showed, with one exception, higher dust concentrations in winter than in summer (for PM 2.5 and PM 10; significant for two farms). Further, differences for both fractions were shown in the interaction between measurement positions and season. The inter-farm comparison of the data showed, among others, a significant impact of the measurement position on the concentration of PM 2.5 (p = 0.0048) and PM 10 (p = 0.0131) as well as a highly significant impact of the outdoor temperature (p < 0.0001) on both dust fractions. Additionally, the number of animals (p = 0.0008) and the number of daily feedings (p < 0.0001) were identified as influencing factors on the dust concentration of PM 2.5. This study highlights the relevance of further studies on dust exposure in freely ventilated pig barns with straw bedding. [ABSTRACT FROM AUTHOR]

The Comet Interceptor space mission, selected by ESA in June 2019 as the first F-Class mission, will study a dynamically new comet or an interstellar object by a unique multi-point 'snapshot' measurement. The mission design will allow to complement previous single spacecraft's fly-by cometary observations. The Dust Impact Sensor and Counter (DISC), devoted to the dust coma characterization, is part of the payload selected for Comet Interceptor. It will be mounted on-board two of the three spacecraft, as part of the Dust-Fields-Plasma (DFP) suite, dedicated to understand further: 1) dust in the coma; 2) magnetic field; 3) plasma and energetic neutral atoms. DISC architecture originates from the Impact Sensor subsystems, part of the Grain Impact Analyzer and Dust Accumulator (GIADA) that successfully flew on-board the ESA/Rosetta spacecraft. DISC main scientific objectives are: 1) to define the dust mass distribution for particles in the mass range 10−15 − 10−8 kg ejected from the cometary nucleus; 2) to count dust particles with mass > 10−15 kg; 3) to constrain dust particle density/structure. In this paper, we describe DISC design, aims, methods, feasibility and performances evaluations, carried out by real and simulated dust impacts and by retrieving the number of particles, and their corresponding momentum, using the Comet Interceptor's Engineering Dust Coma Model. [ABSTRACT FROM AUTHOR]

Peak ambient dust levels in the San Joaquin Valley (SJV) are often coincident with peak agricultural harvest seasons, particularly for nut orchards. Federal reference methods (FRMs), consisting of mass-based sampling techniques, are designed to measure and analyze ambient dust concentrations. However, FRMs generally require meticulous attention to sampling details, tedious labor and logistics, and time-consuming dispersion calculations. This study used opacity-based techniques – the U.S. Environmental Protection Agency (EPA) Method 9 and the Digital Compliance Opacity Technique (DCOT) - to quickly measure relative dust intensity at different harvester settings and to evaluate visible dust emission reductions using a new/low-dust nut harvester. Results indicate that old/conventional harvester at standard settings (3 mph ground speed and 900 rpm blower speed) produced visible dusts with opacities ranging from 23.3% to 29.0%. The dust plume generated from new/low-dust harvesters at similar settings registered lower opacity readings, with an average of 13.94%. The lowest average dust opacity (7.8%) was achieved when the separation fan was turned off. The present results validated the previous FRM emission findings that an old/conventional harvester has the highest PM emissions, but with a potential to achieve 50% reduction by adopting new/low-dust harvesters. Compared to an old harvester, the relative intensity of dusts was reduced by 40%−51% for low-dust harvesters operated at lower ground speeds. Further dust reductions could be achieved by lowering the fan speed (58%) and operating at no fan/blower setting (66.4%). Both visible emission evaluation (VEE) techniques were able to provide rapid quantitative feedback on the effects of operational changes on emitted harvest dusts. At this stage, opacity-based techniques can potentially be adapted as a screening tool for identifying best management practices (BMP) in reducing harvest dusts, rather than to solely rely on FRM mass-based techniques. Implications: U.S. EPA VEE techniques are established, robust methods of dust measurement systems that can be adopted to evaluate visible dust mitigation strategies in the SJV, alongside the existing FRM protocols. The use of Method 9 and DCOT, as both non-disruptive and rapid dust measurement tools, can bring immediate impact concerning the goal of the almond industry to significantly reduce its PM emissions in the next coming years. [ABSTRACT FROM AUTHOR]

Preliminary study of the total dust exposure in the textile industry of Semarang city is 233 μg/Nm3, which exceeds the quality standard. The high concentration of dust is influenced by increased productivity, so that it has the potential as a source of pollutants that can affect the respiratory system of workers. The purpose of this study was to determine the relationship between dust exposure and respiratory disorders symptoms in workers. The method used is a cross-sectional study with a sample size of 161 people and 6 points of dust measurement locations. The Modified Medical Research Council (MMRC) standardized questionnaire was used to collect data. The data were analyzed using the SPSS 24 with Chi square and Binary logistic regression tests to determine the relationship. The results showed that the average dust concentration exceeded the quality standard, namely 4 location points for PM2.5, 1 location point for PM10, and 2 location points for total dust. The average exposure to respirable dust is 3.93 μg/m³, which exceeds the quality standard. A total of 57% of workers experienced symptoms of respiratory disorders with the results of bivariate statistical analysis of 5 significant variables, namely PM2.5 (p = 0.021), PM10 (p = 0.002), total dust (p = 0.000), respirable dust (p = 0.002), and working period (p = 0.037). Meanwhile, the results of the binary logistic regression test had 2 significant variables, namely total dust (p = 0.000) and respirable dust (p = 0.006). The conclusion of this study is that total dust and respirable dust that exceed the quality standard have a higher risk of causing respiratory disorders symptoms with a probability of 71.6% and dust may be minimized by adding a pneumablo to each machine. [ABSTRACT FROM AUTHOR]

Two three-dimensional reanalysis datasets of atmospheric composition, the Copernicus Atmosphere Monitoring Service reanalysis (CAMSRA) and the Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), are analyzed for the years 2003--2018 with respect to dust transport into the Arctic. The reanalyses agree on that the largest mass transport of dust into the Arctic occurs across western Russia during spring and early summer, but substantial transport events occasionally also occur across other geographical areas during all seasons. In many aspects, however, the reanalyses show considerable differences: the mass transport in MERRA-2 is substantially larger, more spread out, and occurs at higher altitudes than in CAMSRA, while the transport in CAMSRA is to a higher degree focused to well-defined events in space and time; the integrated mass transport of the 10 most intense 36-hour dust events in CAMSRA constitutes 6 % of the total integrated dust transport 2003--2018, whereas the corresponding value for MERRA-2 is only 1 %. Furthermore, we compare the reanalyses with surface measurements of dust in the Arctic and dust extinction retrievals from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) satellite data. This comparison indicates that CAMSRA underestimates the dust transport into the Arctic and that MERRA-2 likely overestimates it. The discrepancy between CAMSRA and MERRA-2 can partially be explained by the assimilation process where too little dust is assimilated in CAMSRA while in MERRA-2, the assimilation process increases the dust concentration in remote areas. Despite the profound differences between the reanalyses regarding dust transport into the Arctic, this study still brings new insights into the spatio-temporal distribution of the transport. We estimate the annual dust transport into the Arctic to be within the range 1.5--31 Tg, where the comparison with observations indicates that the lower end of the interval is less likely. [ABSTRACT FROM AUTHOR]

Accurate disk mass measurements are necessary to constrain disk evolution and the timescale of planet formation, but such measurements are difficult to make and are very dependent on assumptions. Here, we look at the assumption that the disk is optically thin at radio wavelengths and the effect of this assumption on measurements of disk dust mass. We model the optical to radio spectral energy distributions of 41 protoplanetary disks located in the young (∼1–3 Myr old) Lupus star-forming region, including 0.89 1.33 and 3 mm flux densities when available. We measure disk dust masses that are ∼1.5–6 times higher than when using the commonly adopted disk dust mass equation under the assumption of optically thin emission in the (sub)millimeter range. The cause of this discrepancy is that most disks are optically thick at millimeter wavelengths, even up to 3 mm, demonstrating that observations at longer wavelengths are needed to trace the fully optically thin emission of disks. [ABSTRACT FROM AUTHOR]

We aim to reveal properties of evolution stages in AGB phase; Mira, OH/IR stars, and non-variable OH/IR stars. We presented results of our VLBI observations of four stars; NSV17351, OH39.7+1.5, IRC–30363, and AW Tau. We used the VERA VLBI array to observe 22 GHz H2O masers. Parallaxes of the four sources were obtained to be 0.247±0.035 mas (4.05±0.59 kpc), 0.54±0.03 mas (1.85±0.10 kpc), 0.562±0.201 mas (1.78±0.73 kpc), and 0.449±0.032 mas (2.23±0.16 kpc). Determination of pulsation period of NSV17351 was done for the first time. We revealed the position and kinematics of NSV17351 in our Galaxy and found that NSV17351 is located in an interarm region. A new period-magnitude relationship was indicated in the infrared region. Various other properties based on the distance measurements are also discussed. We have to emphasize that the VLBI astrometry is effective and the only way for parallax measurements of dust obscured OH/IR stars. [ABSTRACT FROM AUTHOR]

The Lidar on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission, makes robust measurements of dust and has generated a record that is significant both seasonally and interannually. We exploit this record to determine the properties of dust emanating from different source types during sand and dust storms (SDS). We use the relevant browsed images to describe the characteristics of the SDS layers qualitatively and the average properties quantitatively. In particular, we examine dust optical depths, dust layer frequencies, and layer heights during three sandstorms. The data are screened by using standard CALIPSO quality-assurance flags, cloud aerosol discrimination (CAD) scores, overlying features, and layer properties. To evaluate the effects of the SDS origin, phenomena such as morphology, vertical extent, and size of the dust layers, we compare probability distribution functions of the layer integrated volume depolarization ratios, geometric depths, and integrated attenuated color ratios as a function of source type. This study includes 17 individual dust storm cases observed near the city of Kuwait from three categories of sources: single source, combined sources, and unspecified sources. The strongest dust storms occurred in the summer months. The dust layers reached the highest altitudes for the combined cases. The layer top altitudes were approximately 3 km for the SDS from unspecified and single sources whereas the layer top altitudes averaged 4.1 km for the SDS from combined sources. Particles from single and combined sources recorded depolarization ratios of 0.22 and 0.23, respectively, whereas the depolarization ratios of SDS particles from unspecified sources were noticeably lower at 0.17. SDS from single sources resulted in the highest average AOD (0.66) whereas the SDS from combined sources and unspecified sources resulted in AODs of 0.41 and 0.28, respectively. Winter dust layers were disorganized, especially at night when the boundary layer was weak. The most well-organized layers close to the ground were observed in the daytime during the summer months. [ABSTRACT FROM AUTHOR]

In a typical laboratory nanodusty plasma, nanometer-sized solid dust particles can be generated from the polymerization of reactive plasma species. The interplay between the plasma and the dust gives rise to behavior that is vastly different from that of pristine plasmas. Two of the key parameters in nanodusty plasma physics are, among other things, the dust particle size and the dust density. In this work, we introduce a novel method for the determination of these two quantities from the measurement of the free electron density using microwave cavity resonance spectroscopy and laser light extinction measurements. When comparing these two measurements to theory, one can determine the best-fitting dust particle size and dust density. Generally, cyclic behavior of the dust particle size and dust density was observed, of which the trends were relatively insensitive to varying the most stringent input assumptions. Finally, this method has been used to explore the behavior of the dust particle size and dust density for varying plasma powers. [ABSTRACT FROM AUTHOR]

Chainsaw operation is associated with several hazards, including exposure to wood dust, a risk factor which requires serious attention due to health impacts such as respiratory disease. This study aims to investigate the effect of saw chain type and wood species on the mass concentration of airborne wood dust during chainsaw cross-cutting operations. Real-time inhalable and respirable dust measurements in the breathing zone of the chainsaw operator were carried out using a desktop aerosol monitor. Three types of cutter shape (semi chisel, full chisel, and chamfer chisel) and four types of wood species (oak, beech, spruce, and fir) were used in the experiments. The split-plot ANOVA results showed that both respirable and inhalable mass concentrations of wood dust were affected exclusively by wood species. No statistically significant differences were found among particular levels of cutter shape. The highest average mass concentrations of airborne dust were generated by the combination of oak wood and a full chisel cutter. [ABSTRACT FROM AUTHOR]

This article presents measurements of the emission of salt dust discharged into the atmosphere in the Wieliczka Salt Mine. Industrial tests have been carried out cyclically since 2004. The research methodology included six measurements of the salt dust's mass increments on the filters, including three before the inlet to the desalination installation and three measurements at the emitter outlet. In order to limit errors resulting from the diversity of concentrations in the mixture of dosed brine, three series of measurements are carried out each time. The proposed research methodology uses the Aspirator Stationary (AS-50) gravimetric aspirator for measurements with a designed probe adjusted to the characteristics of the dedusting installation used. The conducted tests allowed calculation of the efficiency of the scrubber and confirm the usefulness of the measuring probe used. Moreover, long-term and cyclical measurements make it possible to observe the effectiveness of the installation and salt production using the wet system from brine obtained in the mine. The proposed method is an innovative solution for monitoring salt-dust emissions in mining applications. [ABSTRACT FROM AUTHOR]

This review considers the use of filters to sample air in mining workplace environments for dust concentration measurement and subsequent analysis of hazardous contaminants, especially respirable crystalline silica (RCS) on filters compatible with wearable personal dust monitors (PDM). The review summarizes filter vendors, sizes, costs, chemical and physical properties, and information available on filter modeling, laboratory testing, and field performance. Filter media testing and selection should consider the characteristics required for mass by gravimetry in addition to RCS quantification by Fourier-transform infrared (FTIR) or Raman spectroscopic analysis. For mass determination, the filters need to have high filtration efficiency (≥99% for the most penetrable particle sizes) and a reasonable pressure drop (up to 16.7 kPa) to accommodate high dust loading. Additional requirements include: negligible uptake of water vapor and gaseous volatile compounds; adequate particle adhesion as a function of particle loading; sufficient particle loading capacity to form a stable particle deposit layer during sampling in wet and dusty environments; mechanical strength to withstand vibrations and pressure drops across the filter; and appropriate filter mass compatible with the tapered element oscillating microbalance. FTIR and Raman measurements require filters to be free of spectral interference. Furthermore, because the irradiated area does not completely cover the sample deposit, particles should be uniformly deposited on the filter. [ABSTRACT FROM AUTHOR]

To study the influence of particle size polydispersity (σ D) on the flame propagation and temperature distribution of magnesium dust clouds, an open-space dust explosion measurement system equipped the two-color pyrometer technique were used to explore the flame propagation behaviors and temperature distribution characteristics of magnesium dust clouds with different σ D. Furthermore, the correlation analysis was applied to assess the correlation degree between the flame propagation velocity and various particle size parameters. The results showed that the flame structure, temperature distribution and propagation velocity were related to the σ D. Flames in magnesium dust clouds with low σ D spread around spherically, while those with high σ D burned more intensely at the bottom part with an irregular structure. The flame temperature increased with the mass fraction of small particles, due to their higher diffusion and heat transfer efficiency. With the increase of σ D value, the combustion rate of magnesium dust increased, so that the flame propagation velocity accelerated. The results of Pearson analysis verified that σ D had a significant effect on the flame propagation velocity, which was more suitable than the Sauter mean diameter (D 3,2) to describe the explosion characteristics. [Display omitted] • Freely propagation flames in Mg dust clouds with different σ D were presented. • Temperature distributions of Mg dust clouds were mapped with the pyrometer. • Effects of σ D on flame structure and temperature of Mg dust cloud were analyzed. • Correlation analysis for typical particle size parameters and flame speed was taken. [ABSTRACT FROM AUTHOR]

[Display omitted] To further investigate the production and diffusion laws of tunnel blasting dust, this study utilizes a railway tunnel for field measurements and numerical simulations. On-site dust levels are monitored every 10 s using a dust meter. A one-dimensional uniform turbulent diffusion theory is applied to formulate a relationship between dust concentration and space–time variables. The Origin software is employed to fit the on-site dust concentration data. The mass of the tunnel blasting dust at the measurement point is determined using the fitting formula. Characteristics of the blasting dust from the tunnel's surrounding rock are obtained from the on-site analysis of particle size and composition. Employing on-site dust monitoring data and dust characteristics, a three-stage(shock wave generation, pre-ventilation, and post-ventilation) numerical simulation is conducted. On-site monitoring of dust concentrations revealed a characteristic 'M'-shaped temporal profile at the measurement point, and the peak dust concentration reached approximately 2100 mg/m3. Numerical inversion analysis of the three-stage dust diffusion revealed the total dust mass during tunnel blasting to be approximately 178.1 kg. Numerical simulations further indicated that particles measuring below 10 μm were predominantly dispersed throughout the tunnel after 1800 s. This investigation offers a methodology for calculating the total mass of tunnel blasting dust and for its numerical simulation, providing a data reference for dust mitigation strategies. [ABSTRACT FROM AUTHOR]

• Numerical simulation of dust deposition on PV arrays by CFD; • Dust deposition process and its behavior on PV arrays are studied; • Considering the effect of row spacing of PV modules on dust deposition characteristics. Dust deposition on the surfaces of Photovoltaic (PV) arrays during their operation markedly affects their power generation efficiency. Previous research has overlooked the impact of the row spacing of PV modules on the actual dust deposition on PV arrays. This study investigates the dust deposition process and its behavior on PV arrays considering variations in row spacings, inlet wind speeds, dust particle sizes, and dust particle counts. By employing commercial Computational Fluid Dynamics (CFD) software, incorporating the SST k - ω turbulence model and discrete particle model, numerical simulations were performed to analyze the airflow field, dust particle trajectories, dust deposition patterns, and deposition rates on the PV array through grid-independent verification and numerical validation. At the same time, we performed a comparative analysis of the deposition rate considering the rebound of dust particles on the PV module surface versus the case where rebound is not considered. Results revealed that the maximum dust deposition rates at different inlet wind speeds were 6.84 %, 8.84 %, 11.0 %, and 14.6 %, corresponding to dust sizes of 50 μm, 100 μm, 120 μm, and 300 μm, respectively. Smaller dust particles exhibited lower deposition rates, while larger particles were influenced more by mass inertia and gravity, leading to predominant deposition on the front row of PV modules. Larger dust particles are more likely to deposit primarily on the front row of PV modules in a PV array. The tilt angles of 30°, 45°, and 60° were chosen to study the effects of different tilt angles on the dust deposition of PV arrays, and the results show that the dust deposition rate decreases as the tilt angle increases, and it is worth noting that the larger the tilt angle, the larger the dust deposition rate is when the dust particles are especially small as 5 μm. When wind speeds are low and dust particles are small, the dust deposition rate gradually rises as the row spacing increases. However, at higher wind speeds with small dust particles, the row spacing has minimal impact on the dust deposition rate. Conversely, with larger dust particles, increasing the row spacing results in a lower dust deposition rate. These findings underscore the significance of optimizing PV array design for enhanced power generation efficiency. [ABSTRACT FROM AUTHOR]

We investigate the role of secondary electron and ion emission from impact of gas molecules on the Cassini Langmuir probe (RPWS-LP or LP) measurements in the ionosphere of Saturn. We add a model of the emission currents, based on laboratory measurements and data from comet 1P/Halley, to the equations used to derive plasma parameters from LP bias voltage sweeps. Reanalysing several hundred sweeps from the Cassini Grand Finale orbits, we find reasonable explanations for three open conundrums from previous LP studies of the Saturn ionosphere. We find an explanation for the observed positive charging of the Cassini spacecraft, the possibly overestimated ionospheric electron temperatures, and the excess ion current reported. For the sweeps analysed in detail, we do not find (indirect or direct) evidence of dust having a significant charge-carrying role in Saturn's ionosphere. We also produce an estimate of H2O number density from the last six revolutions of Cassini through Saturn's ionosphere in greater detail than reported by the Ion and Neutral Mass Spectrometer. Our analysis reveals an ionosphere that is highly structured in latitude across all six final revolutions, with mixing ratios varying with two orders of magnitude in latitude and one order of magnitude between revolutions and altitude. The result is generally consistent with an empirical photochemistry model balancing the production of H+ ions with the H+ loss through charge transfer with e.g. H2O, CH4, and CO2, for which water vapour appears as the likeliest dominant source of the signal in terms of yield and concentration. [ABSTRACT FROM AUTHOR]

Dust particles larger than 20 µ m in diameter have been regularly observed to remain airborne during long-range transport. In this work, we modify the parameterization of the mineral dust cycle in the GOCART-AFWA dust scheme of WRFV4.2.1 to also include such coarse and giant particles, and we further discuss the underlying misrepresented physical mechanisms which hamper the model in reproducing adequately the transport of the coarse and giant mineral particles. The initial particle size distribution is constrained by observations over desert dust sources. Furthermore, the Stokes drag coefficient has been updated to account for realistic dust particle sizes (Re < 10 5). The new code was applied to simulate dust transport over Cabo Verde in August 2015 (AER-D campaign). Model results are evaluated against airborne dust measurements and the CALIPSO-LIVAS pure dust product. The results show that the modeled lifetimes of the coarser particles are shorter than those observed. Several sensitivity runs are performed by reducing artificially the particles' settling velocities in order to compensate underrepresented mechanisms, such as the non-spherical aerodynamics, in the relevant parameterization schemes. Our simulations reveal that particles with diameters of 5.5–17 and 40–100 µ m are better represented under the assumption of an 80 % reduction in the settling velocity (UR80), while particles with sizes ranging between 17 and 40 µ m are better represented in a 60 % reduction in settling velocity (UR60) scenario. The overall statistical analysis indicates that the best agreement with airborne in situ measurements downwind (Cabo Verde) is achieved with a 40 % reduction in settling velocity (UR40). Moreover, the UR80 experiment improves the representation of the vertical structure of the dust layers as those are captured by the CALIPSO-LIVAS vertically resolved pure dust observations. The current study highlights the necessity of upgrading the existing model parameterization schemes of the dust life-cycle components towards improving the assessment of the dust-related impacts within the Earth–atmosphere system. [ABSTRACT FROM AUTHOR]

Grain dust represents a significant health risk to grain farmers and workers. Exposure to grain dust can diminish lung function as well as cause respiratory diseases. Grain storage facilities are considered agricultural confined spaces with high concentrations of grain dust. On-farm research for dust sample measurements is time consuming and cost prohibitive. The objective of this research was to design, build, and test a grain dust simulator (GDS) to simulate the dusty environments of grain storage bins in a laboratory setting whereby different types of grain dusts with various environmental conditions (airflow, temperature, and humidity) could be studied. The GDS, a 1/10th scale bin model, was designed with similar ventilation and auger systems as an on-farm grain bin with a diameter of 15.24 m and a capacity of 1762 m3. Dust concentration data collected from farms in Ohio, USA were used to guide the development of the GDS. Feasibility and performance tests verified that the GDS designed can be used as a testing platform for simulating the dusty environment in grain bins and development of effective respiratory protection for farmers under various on-farm conditions. • Grain dust simulator designed, built and tested. • Design simulates the respirable dust environment in on-farm grain bins. • Simulator a testing platform for dust mitigation strategies. • Also, simulator a testing platform for respirable protection equipment. [ABSTRACT FROM AUTHOR]

Determining the controls on aeolian dust emissions from major sources is necessary for reliable quantification of atmospheric aerosol concentrations and fluxes. However, ground‐based measurements of dust emissions at‐source are rare and of generally short duration, failing to capture the annual cycle. Here, we provide new insights into dust dynamics by measuring aerosol concentrations and meteorological conditions for a full year (July 2015–June 2016) at Etosha Pan, Namibia, a globally significant dust source. Surface deployed field instrumentation provided 10‐min averaged data on meteorological conditions, aerosol concentration (mg/m3), and horizontal dust flux (g/m2/min10). A Doppler lidar provided additional data for some of the period. 51 significant dust events were identified in response to strong E‐ENE winds. We demonstrate that these events occurred throughout the year and were not restricted to the austral winter, as previously indicated by satellite observations. Peak horizontal flux occurred in the spring (November) due to strengthening erosive winds and highly desiccating conditions increasing surface erodibility. We identify a strong seasonal differentiation in the meteorological mechanisms controlling dust uplift; low‐level jets on dry winter mornings (61% of all events), and cold pool outflows in humid summer evenings (39% of events). Significantly, we demonstrate a very strong bias toward the contribution of low frequency and high magnitude events, with nearly 31% of annual horizontal dust flux generated by only 6 individual events. Our study demonstrates how longer‐term (≈1 year), ground‐based, and at‐source field measurements can radically improve interpretations of dust event dynamics and controls at major source locations. Plain Language Summary: Atmospheric dust is important because it affects climate, human health, and nutrient distribution. Most atmospheric dust is sourced from dry lake beds in deserts and much of our understanding of dust emission comes from satellite observations. Few field studies have measured dust emission from such sources for more than a few months and so our understanding of the processes that govern dust emission is partial. We measured dust concentrations and associated meteorological conditions for a full year at Etosha Pan in Namibia, a major source of dust globally. We found that dust emission occurred throughout the year, not just in winter as had previously been thought. Our data showed that the meteorological mechanisms controlling dust emission changed seasonally. In dry winter mornings dust was eroded by jets of fast‐moving winds soon after sunrise. In summer, emission occurred in the late evenings due to high‐speed winds associated with the development of convective storms. Further, dust emission was dominated by high magnitude and low frequency events. Our field data demonstrate the seasonal complexity in the controlling mechanisms of dust emission which need to be accounted for in calculations of atmospheric dust loading. Key Points: Ground‐based data show aeolian dust emissions occur throughout the year, not restricted to winter as indicated by satellite observationsEmissions are largely driven by low‐level jets in the dry winter, and by cold pool outflows in the more humid summerThe magnitude of emissions is dominated by only a few events, with six events accounting for nearly 31% of all horizontal dust flux [ABSTRACT FROM AUTHOR]

East Asia is the second-largest mineral dust source in the world, after the Sahara. When dispersed in the atmosphere, mineral dust can alter the Earth's radiation budget by changing the atmosphere's absorption and scattering properties. Therefore, the mineralogical composition of dust is key to understanding the impact of mineral dust on the atmosphere. This paper presents new information on mineralogical dust during East Asian dust events that were obtained from laboratory dust measurements combined with satellite remote sensing dust detections from the Infrared Atmospheric Sounding Interferometer (IASI). However, the mineral dust in this region is lifted above the continent in the lower troposphere, posing constraints due to the large variability in the Land Surface Emissivity (LSE). First, a new methodology was developed to correct the LSE from a mean monthly emissivity dataset. The results show an adjustment in the IASI spectra by acquiring aerosol information. Then, the experimental extinction coefficients of pure minerals were linearly combined to reproduce a Gobi dust spectrum, which allowed for the determination of the mineralogical mass weights. In addition, from the IASI radiances, a spectral dust optical thickness was calculated, displaying features identical to the optical thickness of the Gobi dust measured in the laboratory. The linear combination of pure minerals spectra was also applied to the IASI optical thickness, providing mineralogical mass weights. Finally, the method was applied after LSE optimization, and mineralogical evolution maps were obtained for two dust events in two different seasons and years, May 2017 and March 2021. The mean dust weights originating from the Gobi Desert, Taklamakan Desert, and Horqin Sandy Land are close to the mass weights in the literature. In addition, the spatial variability was linked to possible dust sources, and it was examined with a backward trajectory model. Moreover, a comparison between two IASI instruments on METOP-A and -B proved the method's applicability to different METOP platforms. Due to all of the above, the applied method is a powerful tool for exploiting dust mineralogy and dust sources using both laboratory optical properties and IASI detections. [ABSTRACT FROM AUTHOR]

ALMA observations have revealed the presence of dust in the first generations of galaxies in the Universe. However, the dust temperature T d remains mostly unconstrained due to the few available FIR continuum data at redshift |$z$| > 5. This introduces large uncertainties in several properties of high- |$z$| galaxies, namely their dust masses, infrared luminosities, and obscured fraction of star formation. Using a new method based on simultaneous [C  |$\scriptstyle \rm II$| ] 158-μm line and underlying dust continuum measurements, we derive T d in the continuum and [C  |$\scriptstyle \rm II$| ] detected |$z$| ≈ 7 galaxies in the ALMA Large Project REBELS sample. We find 39 < T d < 58 K, and dust masses in the narrow range M d = (0.9−3.6) × 107 M⊙. These results allow us to extend for the first time the reported T d(⁠|$z$|⁠) relation into the Epoch of Reionization. We produce a new physical model that explains the increasing T d(⁠|$z$|⁠) trend with the decrease of gas depletion time, t dep = M g/SFR, induced by the higher cosmological accretion rate at early times; this hypothesis yields T d ∝ (1 + |$z$|⁠)0.4. The model also explains the observed T d scatter at a fixed redshift. We find that dust is warmer in obscured sources, as a larger obscuration results in more efficient dust heating. For UV-transparent (obscured) galaxies, T d only depends on the gas column density (metallicity), |$T_{\rm d} \propto N_{\rm H}^{1/6}$| (T d ∝  Z −1/6). REBELS galaxies are on average relatively transparent, with effective gas column densities around N H ≃ (0.03−1) × 1021 cm−2. We predict that other high- |$z$| galaxies (e.g. MACS0416-Y1, A2744-YD4), with estimated T d ≫ 60 K, are significantly obscured, low-metallicity systems. In fact, T d is higher in metal-poor systems due to their smaller dust content, which for fixed L IR results in warmer temperatures. [ABSTRACT FROM AUTHOR]

• Description of an impact sensor for the detection, in real-time, of micron-sized micrometoroids and space debris. • Analysis of results collected upon 5 years on the SAC-D mission on a polar orbit and comparison with models. • Most the space debris detected appear to result from peculiar events, instead of a steady supply. • Attempt to correlate these events with natural environment, with space activity. • Implications are important for the knowledge of the space debris environment. Micrometeoroids and orbital debris (M&D) are an important component of the space environment. High velocity interaction with spacecraft could be of serious concern for the operation of long-lived space structures and for manned operations in space. Since the beginning of space exploration, dedicated experiments designed to sample the low Earth orbit orbital debris and meteoroid environment have been used in low Earth orbits. Upon the SAC-D mission, an experiment package from CNES, CARMEN was deployed. One of the experiments, SODAD-2 was devoted to the detection of micrometeoroid and space debris. The capacitor type sensors allow the detection of particles larger than 1 µm in diameter. This was the first dust measurement on a sun-synchronous orbit. The behaviour of the experiment was nominal and impact flux data recorded are compared with similar experiments and with current flux models. Most of the impacts appear to be not random and some of them could be associated with peculiar events, having generated particles at a higher altitude. The same trend was observed on a similar experiment flown on the ISS. [ABSTRACT FROM AUTHOR]

We analyse FIR dust continuum measurements for 14 galaxies (redshift z ≈ 7) in the ALMA Reionization Era Bright Emission Line Survey (REBELS) Large Program to derive their physical properties. Our model uses three input data, i.e. (a) the UV spectral slope, β, (b) the observed UV continuum flux at 1500 Å, F 1500, (c) the observed continuum flux at |$\approx 158\, \mu$| m, F 158, and considers Milky Way (MW) and SMC extinction curves, along with different dust geometries. We find that REBELS galaxies have 28−90.5 per cent of their star formation obscured; the total (UV+IR) star formation rates are in the range |$31.5 \lt {\rm SFR}/({\rm M}_\odot \, {\rm yr}^{-1}) \lt 129.5$|⁠. The sample-averaged dust mass and temperature are |$(1.3\pm 1.1)\times 10^7 \, \mathrm{M}_\odot$| and 52 ± 11 K, respectively. However, in some galaxies dust is particularly abundant (REBELS-14, |$M^{\prime }_{\rm d} \approx 3.4 \times 10^7 \, \mathrm{M}_\odot$|⁠), or hot (REBELS-18, |$T^{\prime }_{\rm d} \approx 67$| K). The dust distribution is compact (<0.3 kpc for 70 per cent of the galaxies). The inferred dust yield per supernova is |$0.1 \le y_{\rm d}/\, \mathrm{M}_\odot \le 3.3$|⁠ , with 70 per cent of the galaxies requiring |$y_{\rm d} \lt 0.25 \, \mathrm{M}_\odot$|⁠. Three galaxies (REBELS-12, 14, 39) require |$y_{\rm d} \gt 1 \, \mathrm{M}_\odot$|⁠ , which is likely inconsistent with pure SN production, and might require dust growth via accretion of heavy elements from the interstellar medium. With the SFR predicted by the model and a MW extinction curve, REBELS galaxies detected in [C  ii ] nicely follow the local L CII−SFR relation, and are approximately located on the Kennicutt–Schmidt relation. The sample-averaged gas depletion time is |$0.11\, y_{\rm P}^{-2}$| Gyr, where y P is the ratio of the gas-to-stellar distribution radius. For some systems, a solution simultaneously matching the observed (β, F 1500, F 158) values cannot be found. This occurs when the index Im  = (F 158/ F 1500)/(β − βint), where βint is the intrinsic UV slope, exceeds |$I_m^{*}\approx 1120$| for an MW curve. For these objects, we argue that the FIR and UV emitting regions are not co-spatial, questioning the use of the IRX–β relation. [ABSTRACT FROM AUTHOR]

Interstellar dust extinction curves provide valuable information about dust properties, including the composition and size of the dust grains, and are essential to correct observations for the effects of interstellar dust. In this work, we measure a representative sample of near-infrared (NIR; 0.8â€"5.5 ÎĽ m) spectroscopic extinction curves for the first time, enabling us to investigate the extinction at wavelengths where it is usually only measured in broad photometric bands. We use IRTF/SpeX spectra of a sample of reddened and comparison stars to measure 15 extinction curves with the pair method. Our sample spans A (V) values from 0.78 to 5.65 and R (V) values from 2.43 to 5.33. We confirm that the NIR extinction curves are well fit by a power law, with indices and amplitudes differing from sight line to sight line. Our average diffuse NIR extinction curve can be represented by a single power law with index α = 1.7, but because of the sight line-to-sight line variations, the shape of any average curve will depend on the parental sample. We find that most of the variation in our sample can be linked to the ratio of total-to-selective extinction R (V), a rough measurement of the average dust grain size. Two sight lines in our sample clearly show the ice extinction feature at 3 ÎĽ m, which can be fitted by a modified Drude profile. We find tentative ice detections with slightly over 3 σ significance in two other sight lines. In our average diffuse extinction curve, we measure a 3 σ upper limit of A (ice)/ A (V) = 0.0021 for this ice feature. [ABSTRACT FROM AUTHOR]

From 1 March to 30 April and from 1 August to 30 September 2021, comparative studies of PM2.5 and PM10 concentrations were carried out in Gdynia. For intercalibration, a device was used that operates based on non-reference methodologies and without proven equivalence to the reference methodology (SEZO AM, WIRAN), and an EDM 180 analyzer (GRIMM) with certificates and approvals (US-EPA, UK-MCERTS, CN-CMA) was used. The aim of this research is to determine whether the SEZO AM device could be used in port areas for continuous PM2.5 and PM10 concentrations measurements. Two campaigns of two months allowed us to see a good agreement of the results achieved with both methods. The concordance of the results obtained from the SEZO AM and the EDM 180 methods amounted to between 78% and 94% for the PM2.5 and between 70% and 75% for the PM10. The comparison of two SEZO AM devices to a higher-class TSI OPS3330 reference in a measurement dust chamber showed a fit between 79% and 86% for the PM2.5 and between 81% and 86% for the PM10. This indicates the possibility of using this analyzer to measure the concentrations of PM2.5 and PM10 in the port atmosphere in which they were carried out. The preliminary analysis of meteorological parameters shows that the main potential impact on the concentration of the analyzed dust fractions measured by the SEZO AM method was relative humidity. The determination of the correction factor for the PM2.5 and PM10 concentrations and adding an inlet external cover contributed to a two-fold reduction in the analysis error and good concordance of the results, at a level of 93% for PM2.5 and 91% for PM10, without discarding any data. [ABSTRACT FROM AUTHOR]

The method of the ongoing assessment of the reclaim quality originating from the mechanical reclamation is described in this paper. In the process, the triboelectric system of measuring amounts of dust in the dedusting part of a reclamation device was applied. Based on the online measurements of the amounts of dust generated in the spent sand-reclamation process and the post-process determinations of the ignition losses and granular structures of the removed dust, the proper work parameters of the experimental reclaimer were selected. The allowable value of the ignition losses as well as the main fraction of the reclaimed matrix being similar to fresh sand was assumed as the main criteria of the positive assessment of the process. Within the presented investigations, a periodically operating device for rotormechanical reclamation was developed. The possibility of changing the intensity and time of the reclamation treatment as well as the triboelectric system of the dust-amount measuring were applied in this device. Tests were performed for the spent moulding sand with phenol-resol resin Carbophen 5692 hardened by CO2. This sand represents the moulding sand group with a less harmful influence on the surroundings for which the recovery of the quartz matrix utilising the reclamation requires stricter control of the parameters of the reclamation process and reclaim quality. [ABSTRACT FROM AUTHOR]