Dust Emission Sources Research Articles

Spatiotemporal analysis of sand and dust emission point sources detected from satellite imagery in Syria, Jordan, and Iraq

This study utilized MODIS true color satellite imagery to analyse blowing sand and dust events dynamics in the Middle East from 2010 to 2021, focusing on Syria, Iraq, and Jordan. A total of 4923 dust point sources were detected, with a significant concentration (~90 %) located within the Tigris-Euphrates Basin (Nearest Neighbor Ratio = 0.41, р < 0.001). Land cover analysis revealed that bare land, comprising most of the study area, was the predominant source of dust emissions. Wetlands, though only constituting about 1 % of the area, showed the highest frequency of dust sources per unit area, highlighting their role as critical dust emission hotspots. The study emphasizes the impact of drought and anthropogenic factors, such as poor land management, on blowing dust intensity. It suggests the necessity of strategic land management practices, including re-vegetation of arid areas, reducing soil exposure, and implementing wind erosion control measures. To effectively address the transboundary nature of dust emissions, the findings underscore the importance of fostering regional cooperation through mechanisms such as shared environmental monitoring and data exchange platforms, joint management of cross-border natural resources, and collaborative policy making.

A new approach to dust source mapping using visual interpretation and object-oriented segmentation of satellite imagery

The emission of dust particles, mainly from arid and semi-arid lands, as a result of climate change and human activities, is known to be a global issue. Identifying dust emission sources is the first key step in dealing with the hazardous consequences of this rising phenomenon. This study is an attempt to address one of the major challenges in mapping dust emission sources. Accordingly, an innovative approach based on visual interpretation of multi-temporal MODIS-Terra/Aqua imagery and object-oriented image segmentation techniques has been developed and implemented in the study areas of the Tigris and Euphrates basin and eastern Iran. This approach takes advantage of land surface characteristics (i.e., dust drivers), including geomorphology, soil, land use/cover, and land surface radiation, to attribute dust emission hotspots to their corresponding areas using multi-source remote sensing data. The results show that the multi-resolution segmentation algorithm with optimized parameters can identify homogeneous segments corresponding to dust emission sources in the study areas with an average spatial agreement of ∼92% compared to the reference areas. Our findings emphasize the robustness and generalizability of the proposed approach, and its capabilities can be used in a complementary way with visual interpretation of satellite images to map dust sources with high spatial accuracy.

Characteristics of dust emission over desert steppe

Desert steppe is widely distributed in wind erosion regions, and is also an important potential dust emission source in the regions. Recognition of dust emission characteristics of desert steppe is the foundation for accurate simulation of dust emission in wind erosion regions; however, few related studies have been conducted in desert steppe areas. In this study, we selected four sites in a region of desert steppe to conducting dust emission observations, analyzing the characteristics of horizontal saltation flux and vertical dust flux, identifying the suitable models for desert steppe, and examining the relationship between saltation bombardment efficiency and wind friction speed (u*). The results revealed the following: the supply of saltation particles in most desert steppe is unlimited, the intensity of saltation is reasonably high, and the modified Owen-type model is suitable for predicting sediment transport above desert steppe. Dust emission intensity in desert steppe is lower than that in other land use types under similar wind speeds. Schemes based on saltation bombardment theory (i.e., the MB95, Shao93, and Kok12 schemes) were found suitable for predicting vertical dust flux above desert steppe, the Kok12 dust emission scheme performed slightly better than the other two schemes. Saltation bombardment is the main mechanism for dust emission when u*s exceeds a threshold u*s (u*ts), but aerodynamic entrainment also plays an important role in dust emission, especially when u*s < u*ts. The saltation bombardment efficiency of desert steppe is less than that of other land use types. The trend of change in saltation bombardment efficiency with wind speed varies at different sites. Soil properties affect the dependence of saltation bombardment efficiency on u*. Desert steppe is an important dust emission source in certain regions, and improved understanding of dust emission in desert steppe areas is required.

A broken debris cascade as a possible source of hot dust emission in transitioning planet-forming disks

Context. Planet-forming disks go from gas-rich, massive disks made of dust and gas into planetary systems containing only small amounts dust. This dust is produced by collisions between smaller planetary objects, such as planetesimals, asteroids, and comets. Traditionally, we talk about protoplanetary (age ~1 Myr), transitional (~5-10 Myr), and debris disks (~10-hundreds of Myr) even though the overlap between these phases may be relevant. Aims. We aim to show that in the transition phase of a disk, when the gas surface densities are reduced but not yet negligible, a seemingly small amount of collisional activity may lead to the production of dust on a level that is observationally relevant by creating regions characterised by an optical depth of 1 or above. In particular, we aim to show that the hot dust emission component of transitional disks may in fact be debris dust that has been produced in such collisions. Methods. We developed an analytical model to derive the conditions in which observationally relevant amounts of dust can be produced. We focussed on the effect of the gas surface density during the transition phase of a disk from fully gas-dominated to the gas-poor debris stage. Results. We show that the decrease in the gas surface density has an important effect. It allows for smaller planetesimals to become collisional, initiating a cascade. At the same time, small particles are not destroyed by collisions. This interrupted cascade is critical in terms of preserving the produced dust for significant time intervals, allowing for a seemingly minor amount of planetesimal collisions to be effective in producing detectable amounts of dust. Conclusions. The warm emission of low amounts of dust in many transitional planet-forming disks might be caused entirely by second-generation dust, exposing planetary material at a much earlier time than the age that debris disks have traditionally been characterised by.

Geoecological monitoring during mining operations

In recent decades environmental quality assessment has become a fundamentally important task in the operation of mining enterprises. This assessment becomes an integral part of the strategy for determining maximum permissible loads for mining regions and is aimed at reducing geoecological risk in them. Technological processes of mining and processing plants generate emissions of various pollutants into the atmospheric air, lead to violation of adjacent territories. Monitoring, primarily of atmospheric air and soils, is necessary to ensure the ecological balance of such territories. Lebedinsky Mining and Processing Plant is one of the most significant sources of gas and dust emissions from massive explosions in quarries during ore extraction, which form a large dust and gas cloud, creating a risk of deterioration of the life of the population in the surrounding area. The article examines the main pollutants in soils and in the atmospheric air during mass explosions, and determines the areole of their distribution from the work site. The forecast of an increase in the concentrations of detected harmful substances for the next 50 years is given. A methodology for conducting geoecological monitoring during mining operations is proposed. The research results may be useful in assessing geoecological risks and developing measures to reduce them.

Investigating nuisance dust complaints: Combining high frequency dust deposition records and source identification using integrated microanalytical techniques

While ducted dust emissions from industry are usually well regulated and controlled, fugitive dust emissions can be difficult to quantify or differentiate from off-site emissions, particularly where fugitive emissions are transient or intermittent. In this study, sources of nuisance dust were investigated using a novel dust deposition sampling methodology, followed by chemical and mineralogical analysis using optical microscopy, x-ray diffraction (XRD), scanning electron microscopy with energy dispersive x-ray spectrometry (SEM-EDS), and isotope ratio mass spectrometry analysis. Dust deposition over 24 h was collected on horizontally orientated 300 mm square glass panels at 6 sites in the region of interest. This method captured very small (<10 mg) masses of dust and could distinguish very small variations in dust deposition at different sites and on different days. Comparison samples collected from potential dust sources at a nearby lime manufacturing facility, and other potential fugitive dust sources in the region were differentiated using XRD mineralogy, visual appearance by optical microscopy and SEM-EDS analysis of individual particles. Comparison of selected dust samples to reference samples indicated most dust deposition at the study sites consisted of soil or sand. However, dust deposition at two sites was sometimes composed of a material that was similar in composition to lime that had been rehydrated to portlandite, but not yet fully carbonated to calcite. Subsequent analysis of δ13C and δ18O for selected dust samples from these two sites were consistent with rapid and recent carbonation of small particles in an alkaline environment, which could have occurred during the atmospheric release and transport of lime, and ruled out fugitive dust emission from lime stockpiles existing on site. Combining the information obtained from high frequency record of dust deposition with targeted mineralogical, isotopic and morphological examinations provided new insight into the source of fugitive dust emissions in this area.

Water, dust, and environmental justice: The case of agricultural water diversions

AbstractWater diversions for agriculture reduce ecosystem services provided by saline lakes around the world. Exposed lakebed surfaces are major sources of dust emissions that may exacerbate existing environmental inequities. This paper studies the effects of water diversions and their impacts on particulate pollution arising from reduced inflows to the Salton Sea in California via a spatially explicit particle transport model and changing lakebed exposure. We demonstrate that lakebed dust emissions increased ambient and concentrations and worsened environmental inequalities, with historically disadvantaged communities receiving a disproportionate increase in pollution. Water diversion decisions are often determined by political processes; our findings demonstrate the need for distributional analysis of such decisions to ensure equitable compensation.

Dust storms from the Taklamakan Desert significantly darken snow surface on surrounding mountains

Abstract. The Taklamakan Desert (TD) is a major source of mineral dust emissions into the atmosphere. These dust particles have the ability to darken the surface of snow on the surrounding high mountains after deposition, significantly impacting the regional radiation balance. However, previous field measurements have been unable to capture the effects of severe dust storms accurately, and their representation on regional scales has been inadequate. In this study, we propose a modified remote-sensing approach that combines data from the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite and simulations from the Snow, Ice, and Aerosol Radiative (SNICAR) model. This approach allows us to detect and analyze the substantial snow darkening resulting from dust storm deposition. We focus on three typical dust events originating from the Taklamakan Desert and observe significant snow darkening over an area of ∼ 2160, ∼ 610, and ∼ 640 km2 in the Tien Shan, Kunlun, and Qilian mountains, respectively. Our findings reveal that the impact of dust storms extends beyond the local high mountains, reaching mountains located approximately 1000 km away from the source. Furthermore, we observe that dust storms not only darken the snowpack during the spring but also in the summer and autumn seasons, leading to increased absorption of solar radiation. Specifically, the snow albedo reduction (radiative forcing) triggered by severe dust deposition is up to 0.028–0.079 (11–31.5 W m−2), 0.088–0.136 (31–49 W m−2), and 0.092–0.153 (22–38 W m−2) across the Tien Shan, Kunlun, and Qilian mountains, respectively. This further contributes to the aging of the snow, as evidenced by the growth of snow grain size. Comparatively, the impact of persistent but relatively slow dust deposition over several months during non-event periods is significantly lower than that of individual dust events. This highlights the necessity of giving more attention to the influence of extreme events on the regional radiation balance. This study provides a deeper understanding of how a single dust event can affect the extensive snowpack and demonstrates the potential of employing satellite remote sensing to monitor large-scale snow darkening.

Impact of COVID-19 Lockdown on Inhaled Toxic Elements in PM2.5 in Beijing: Composition Characterization and Source-Specific Health Risks Assessment

In early 2020, China experienced a mass outbreak of a novel coronavirus disease (COVID-19). With an aim to evaluate the impact of emission variations on toxic element species in PM2.5 and the health risks associated with inhalation exposure during COVID-19, we collected PM2.5 filter samples in Beijing from January 1 to February 28, 2020. Positive matrix factorization (PMF) and a health risk (HR) assessment model were used to assess the health risks of the toxic elements and critical risk sources. The total concentration of eight toxic elements (Se, Cd, Pb, Zn, As, Cu, Ni, and Cr) in Beijing showed a trend of first increasing and then decreasing: full lockdown (322.9 ng m−3) &gt; pre-lockdown (264.2 ng m−3) &gt; partial lockdown (245.3 ng m−3). During the lockdown period, stringent control measures resulted in significant reductions (6−20%) in Zn, Pb, Cd, and Ni levels, while concentrations of Se, As, Cu, and Cr were unexpectedly elevated (14−348%). A total of five sources was identified: traffic emission, coal combustion, dust emission, industrial emission and mixed source of biomass burning and firework combustion. Total carcinogenic risk (TCR) of the selected toxic elements exceeded the US EPA limits for children and adults. As and Cr (IV) were the main contributors to non-carcinogenic and carcinogenic risks, respectively. For source-resolved risks, coal combustion was the main contributor to HI (43%), while industrial emissions were the main cause of TCR (45%). Additionally, increased contributions from coal combustion, biomass burning, and firework combustion during the full lockdown elevated the HI and TCR values.

Forming localized dust concentrations in a dust ring: DM Tau case study

Context. Previous high-angular-resolution 225 GHz (~1.3 mm) continuum observations of the transitional disk DM Tau have resolved an outer ring at 20–120 au radii that is weakly azimuthally asymmetric. Aims. We aim to examine dust growth and filtration in the outer ring of DM Tau. Methods. We performed ~0″.06 (~8.7 au) resolution Karl G. Jansky Very Large Array (JVLA) 40–48 GHz (~7 mm; Q band) continuum observations, along with complementary observations at lower frequencies. In addition, we analyzed the archival JVLA observations undertaken since 2010. Results. Intriguingly, the Q band image resolved the azimuthally highly asymmetric, knotty dust emission sources close to the inner edge of the outer ring. Fitting the 8–700 GHz spectral energy distribution (SED) with two dust components indicates that the maximum grain size (amax) in these knotty dust emission sources is likely ≳300 µm, whereas it is ≳50 µm in the rest of the ring. These results may be explained by a trapping of inwardly migrating “grown” dust close to the ring inner edge. The exact mechanism for developing the azimuthal asymmetry has not yet been identified, which may be due to planet-disk interaction that might also be responsible for the creation of the dust cavity and pressure bump. Otherwise, it may be due to the fluid instabilities and vortex formation as a result of shear motions. Finally, we remark that the asymmetries in DM Tau are difficult to diagnose from the ≳225 GHz observations, owing to a high optical depth at the ring. In other words, the apparent symmetric or asymmetric morphology of the transitional disks may be related to the optical depths of those disks at the observing frequency.

Assessment of the meshed screens operability to reduce dust emissions of bulk cargo from the ports open warehouses

Currently, the coal terminals of sea and river ports have a significant negative impact on the environment through their activities. The operation of the terminals technological equipment leads to high concentrations of dust in the air and dust emissions of bulk cargo. The main sources of dust emissions and dust removal are open coal storage warehouses. Recently, dust screens have been used to combat dusting in open coal warehouses and port terminals. However, the processes of wind flows interaction with stacks of port open slads and meshed screens have not been studied enough. In this regard, the purpose of this work is to evaluate in laboratory conditions the operability of meshed screens to reduce the dustiness of the air and the dust emission of bulk cargo during its storage in port open warehouses. During laboratory studies, models of open warehouses stacks are carried out at a certain scale, which allows you to use the full-scale bulk cargo and real meshed screens. The main results of these studies are the following conclusions: meshed screens are workable and effective devices for reducing the speed of wind flow inside the perimeter of the screen; the shape of the stack cross-section does not affect the screen performance; the level of the meshed screen performance to reduce the air dustiness and the amount of dust emission from the warehouses stacks with the different shape of the cross-section depends on the direction and speed of the wind flow. The use of soft meshed screens located along the perimeter of the open coal warehouse stack makes it possible to reduce air dustiness and dust emission at a wind speed of 5 m/s by an average of 1.8 times, and at a wind speed of 10 m/s by an average of 2.5 times.

3D numerical simulation of airflow structure and dust emissions from an open storage pile behind a dynamic solid fence-deflector

Open storage yards at industrial sites represent a significant fugitive dust emission source. Granular material subjected to wind erosion may emit significant dust into the atmosphere. Several windbreaks and fences with different shapes have been proposed to control and reduce those emissions. Solid fences are commonly erected around the open yard (i.e., open bays) to prevent and reduce those emissions, even though they have some limitations. The present study aims to enhance the effectiveness of solid fences by coupling them with dynamic wind deflectors. Computational fluid dynamics was employed to simulate the flow and shear stresses on storage pile surfaces using the numerical Reynolds-averaged Navier–Stokes equations and the k-ω SST turbulence model. At the same time, dust emission was estimated using an Environmental Protection Agency (EPA) method, which estimates the emission potential of a material based on the wind friction velocity and the material's threshold friction velocity. The numerical model was validated against experimental data from an EPA study. In addition, this study investigated the efficiency of various dynamic wind deflectors with different heights and inclination angles. The results showed that most of the investigated dynamic fence-deflector models reduced the velocity magnitude, vortices, and turbulence intensity, lessening the impact of shear stresses compared to single solid fences and consequently reducing the emission of dust from the exposed surfaces (i.e., a primary measure of impact reduction). More specifically, the deflector of width (Ydef) 2 m with an inclination of (∅def) 65° was the most effective, where the shear stress on the pile surface and the emission factor were reduced by 29.16% and 21.79%, respectively, compared to the single fence of the same height. Finally, adding dynamic wind deflectors enhances the performance of solid fences, and it is a more effective and less expensive solution than replacing single fences with other windbreak models.

Effects of multiple factors on particle size selectivity under artificial extreme rainfall events on simulated Gobi surface

Understanding multiple-factor effects on particle size selectivity by extreme rainfall events in Ala-Shan Gobi desert is of great significance for better estimation of potential Asian dust emission sources. Artificial rainfall simulation experiments were used to investigate the particle size selectivity characteristics by extreme rainfall events under different rainfall intensities (20 mm h−1 and 40 mm h−1), slope gradients (3° and 15°) and gravel coverages (0, 30%, and 60%). Moreover, the relations of clay content (Clc), silt content (Sic), fine particle (< 50 μm) content (Fic) and enrichment ratio of fine particles (ER<50) with multiple factors were regressed and validated. Results show that rainfall intensity significantly (P < 0.05) affect runoff and sediment yield processes, but slope gradient was a dominant factor that changed particle size distribution (PSD). The selectivity of fine particles was higher at low rainfall intensity (20 mm h−1), gentle slope (3°) and moderate gravel coverage (30%), with ER<50 reaching 6.14, which dominate the potential Asian dust emission sources. The interaction were discussed and classified into ‘Synergy’ and ‘Trade-off’. Clc and Fic showed negative exponential relationship with rainfall intensity and slope gradient, but positive exponential relationship with gravel coverage. While Sic and ER<50 showed negative power function relationship with rainfall intensity, slope gradient and gravel coverage. These findings could help to understand the effects of multiple factors on potential sources of Asian dust emission under extreme rainfall events in Gobi region of northwestern China and provide basic science reference for the prediction of dust emission in this region.

Technical Solutions to Reduce the Amount of Dust Particle Breakthrough when Cleaning Emissions from the Production of Reinforced Concrete Products Using Dust Collectors with Counter Swirling Flows

Introduction. The production of reinforced concrete products, being the basis of modern industrial construction, is a very significant source of dust emissions. Traditional cleaning methods are often unable to ensure the compliance with air quality requirements, and replacing them with more modern ones requires significant capital and operational costs. One of the most promising ways to solve the problem is the use of a new class of inertial dust collectors with counter swirling flows, combining constructive simplicity and low operating costs with sufficiently high work efficiency. The aim of the work was to analyze the factors influencing the magnitude of the breakthrough coefficient of fine dust particles, as well as the development of constructive solutions aimed at reducing it. Materials and Methods. An analytical review of technical solutions aimed at reducing the breakthrough magnitude was carried out, on the basis of which the designs of the lower input of dust collectors with counter swirling flows were developed. Methods of computational experiment and field measurements were used to confirm the effectiveness of the developed structures. Results. By means of numerical experiments, the information about the aerodynamic flow pattern in the separation chamber of the CSF dust collector was obtained, and the breakthrough magnitude of dust particles was estimated. The solutions were developed for the design of the lower coaxial input of the swirling flow of dust collectors on the counter swirling flows, taking into account the features of dust pollution generated during the operation of technological equipment of reinforced concrete production. Discussion and Conclusion. The presence of a displacement of the axis of the secondary swirling flow from the axis of symmetry of the separation chamber was established. The consequence of this was the non-coaxiality of the primary and secondary flows, which led to a decrease in the intensity of the twist, the formation of parasitic vortices, and, as a consequence, an increase in the value of the breakthrough coefficient. This effect was especially pronounced with a large proportion of fine dust particles, characteristic of dust pollution formed during the production of reinforced concrete products. The proposed design of the coaxial input of the secondary swirling flow reduced the magnitude of this eccentricity, which made it possible to achieve a significant reduction in the breakthrough magnitude of fine particles characteristic of dust emissions of reinforced concrete industries. The results obtained can be effectively used both in the production of reinforced concrete products and in other branches of construction production, which is characterized by intensive formation of fine dust emissions.

High-time resolution PM2.5 source apportionment assisted by spectrum-based characteristics analysis

Characteristics extraction and anomaly analysis based on frequency spectrum can provide crucial support for source apportionment of PM2.5 pollution. In this study, an effective source apportionment framework combining the Fast Fourier Transform (FFT)- and Continuous Wavelet Transform (CWT)-based spectral analyses and Positive Matrix Factorization (PMF) receptor model is developed for spectrum characteristics extraction and source contribution assessment. The developed framework is applied to Beijing during the winter heating period with 1-h time resolution. The spectrum characteristics of anomaly frequency, location, duration and intensity of PM2.5 pollution can be captured to gain an in-depth understanding of source-oriented information and provide necessary indicators for reliable PMF source apportionment. The combined analysis demonstrates that the secondary inorganic aerosols make relatively high contributions (50.59 %) to PM2.5 pollution during the winter heating period in Beijing, followed by biomass burning, vehicle emission, coal combustion, road dust, industrial process and firework emission sources accounting for 15.01 %, 11.00 %, 10.70 %, 5.31 %, 3.88 %, and 3.51 %, respectively. The source apportionment result suggests that combining frequency spectrum characteristics with source apportionment can provide consistent rationales for understanding the temporal evolution of PM2.5 pollution, identifying the potential source types and quantifying the related contributions.

Linking atmospheric emission and deposition to accumulation of soil cadmium in the Middle-Lower Yangtze Plain, China

Cadmium (Cd) is one of the most toxic heavy metals in the environment. Atmospheric deposition has been found to be the main source of Cd pollution of soil on a large scale in China, and identification of the relationships between anthropogenic emission, atmospheric deposition, and Cd accumulation in soil is important for developing ways to mitigate Cd non-point pollution. In this study, the relationship between atmospheric emission, atmospheric deposition, and soil Cd accumulation in the Middle-Lower Yangtze Plain in China was investigated using datasets of atmospheric emission, deposition, and soil accumulation from the literatures published between 2000 and 2020. The results showed that the soil Cd accumulation rate in the study area exceeded the national average (4.0 μg kg–1 yr–1) and continued to accumulate in recent decades, although the average accumulation rate decreased from 9.45 μg kg–1 yr–1 (2000–2010 period) to 8.86 μg kg–1 yr–1 (2010–2020 period). The contribution of atmospheric deposition flux to Cd increment in the soil was in the range of 22–29%, with the atmospheric deposition flux decreasing from 0.54 mg m–2 yr–1 (2000–2010) to 0.48 mg m–2 yr–1 (2010–2020), both values being greater than the national average. Atmospheric Cd deposition and emission were highly correlated in a provincial administrative region, which is close to a ratio of 1.0. Emission factors may be in a state of dynamic change due to the influences of new Cd emission control technologies and environmental policies. As the main sources of Cd emissions, dust, and smoke emissions per ton of non-ferrous metal production decreased by 64.7% between the 2000–2010 and 2010–2020 periods. Although new environmental policies have been instigated, atmospheric emission of Cd is still excessive. It was hoped that the findings of this work would provide a scientific basis for the rational control of atmospheric emissions and Cd pollution of soil.

Satellites reveal Earth's seasonally shifting dust emission sources

Establishing mineral dust impacts on Earth's systems requires numerical models of the dust cycle. Differences between dust optical depth (DOD) measurements and modelling the cycle of dust emission, atmospheric transport, and deposition of dust indicate large model uncertainty due partially to unrealistic model assumptions about dust emission frequency. Calibrating dust cycle models to DOD measurements typically in North Africa, are routinely used to reduce dust model magnitude. This calibration forces modelled dust emissions to match atmospheric DOD but may hide the correct magnitude and frequency of dust emission events at source, compensating biases in other modelled processes of the dust cycle. Therefore, it is essential to improve physically based dust emission modules.Here we use a global collation of satellite observations from previous studies of dust emission point source (DPS) dichotomous frequency data. We show that these DPS data have little-to-no relation with MODIS DOD frequency. We calibrate the albedo-based dust emission model using the frequency distribution of those DPS data. The global dust emission uncertainty constrained by DPS data (±3.8 kg m−2 y−1) provides a benchmark for dust emission model development. Our calibrated model results reveal much less global dust emission (29.1 ± 14.9 Tg y−1) than previous estimates, and show seasonally shifting dust emission predominance within and between hemispheres, as opposed to a persistent North African dust emission primacy widely interpreted from DOD measurements.Earth's largest dust emissions, proceed seasonally from East Asian deserts in boreal spring, to Middle Eastern and North African deserts in boreal summer and then Australian shrublands in boreal autumn-winter. This new analysis of dust emissions, from global sources of varying geochemical properties, have far-reaching implications for current and future dust-climate effects. For more reliable coupled representation of dust-climate projections, our findings suggest the need to re-evaluate dust cycle modelling and benefit from the albedo-based parameterisation.

On the Association between Fine Dust Concentrations from Sand Dunes and Environmental Factors in the Taklimakan Desert

Dust in sand dunes is an effective and important source of dust emission. The Taklimakan Desert (TD) is one of the main sources of global dust: the sand dunes account for approximately 85% of the total area of the TD. However, the dust concentration, emission characteristics, and physical factors of different parts of the sand dunes in the TD during the day and night, as well as dust and non-dust days, remain unclear. In this study, dust observations were collected over a 3 month period in the TD to investigate the physical processes by which dust moves across a surface and generates PM10 and PM2.5 from the top and bottom of sand dunes. The results showed that the daily average maximum concentrations of particulate matter with diameters below 2.5 and 10 µm (PM2.5 and PM10) in the dune during the observation period reach ~90 and ~190 µg·m−3, respectively. Dust emission generated in the saltation process (maximum emission of PM10 was 3–5 mg·m−2·s−1) in the TD dunes was larger than that in other areas and had a good correlation with u* (friction velocity), where u* = 0.4 m·s−1 was the threshold of sand dune dust emission. The wind speed at the top of dunes was larger than that at the bottom, which was conducive to the accumulation of PM10 at the top of the dune. Furthermore, the MLH (mixed layer height) decreased after sunset and the turbulence weakens, which was conducive to the retention of dust in the air. Moreover, the dust made the solar radiation at the top of the dune −15 W·m−2 (average) lower than at the bottom. These results provided a new understanding of dune emissions in the TD and could be used for dust modeling in regional and global models.

Doppler Boosted Dust Emission and Cosmic Infrared Background-Galaxy Cross-Correlations: A New Probe of Cosmology and Astrophysics.

We identify a new cosmological signal, the Doppler-boosted cosmic infrared background (DB CIB), arising from the peculiar motion of the galaxies whose thermal dust emission source the cosmic infrared background (CIB). This new observable is an independent probe of the cosmic velocity field, highly analogous to the well-known kinematic Sunyaev-Zel'dovich (KSZ) effect. Interestingly, DB CIB does not suffer from the "KSZ optical depth degeneracy," making it immune from the complex astrophysics of galaxy formation. We forecast that the DB CIB effect is detectable in the cross-correlation of CCAT-Prime and DESI-like experiments. We show that it also acts as a new CMB foreground which can bias future KSZ cross-correlations, if not properly accounted for.

Methodology for assessing the dustiness of the air environment of the working areas of foundries

The content of harmful substances in the air is an important parameter of the working conditions of foundry workers. Due to the peculiarities of the technology, there are many sources of intense dust emission in the foundry. The distribution of dust concentrations in the atmosphere of the workshops was determined from the equation of the dust balance in the workshop room. The possibility of obtaining by calculation an objective picture of the distribution of dust in various sections of foundries is shown. Data from various studies were used to determine the density and dust at various sites of foundries. The results of the theoretical calculations show that in foundries, dust capture is an effective means of reducing the dustiness of the air of working areas.