Main Dust Source Research Articles

Synoptic Conditions at Pressure Different Levels for the Dust Storm of May/ 2022 Over Iraq

This study examines the severe dust storm from May 12-16/2022,culminating on May 15, with a comprehensive analysis and explanation. The weather maps from the National Oceanic and Atmospheric Administration (NOAA) and the European Centre for Medium-Range Weather Forecasts (ECMWF) weather maps were used to identify systems and patterns that contributed to the storm's activity, continuity, and tracking as well as maps of pressure compounds and wind vectors in levels 1000 and 850 mbar that appear with the dust state for the same days accompanied by tracking patterns in the middle of the turbosphere 500 mbar to give a comprehensive analytical view of climate conditions at each level of pressure and higher systems supportive of their persistence on the surface. The northwesterly winds are the main factor that carries dust over long distances. The eastern desert in Syria, the Empty Quarter in the Kingdom of Saudi Arabia, the desert of western Iran, and the desert region of western Iraq are among the main sources of dust In its atmosphere. Based on weather maps of the surface and upper levels of storm days, the concentration of dust reached very high levels in Iraq's airspace and surrounding countries, including Egypt, Jordan, Lebanon, Palestine, and Syria. The intensity of the dust gradually decreased as the area was affected by wet westerly winds with relatively low temperatures and a relative increase in wind speeds due to the impact of the study area on the atmospheric decline centered around the Turkish island of Cyprus.

Spatial Source Contribution and Interannual Variation in Deposition of Dust Aerosols Over the Chinese Loess Plateau

AbstractThe Chinese Loess Plateau (CLP) in northern China is home to one of the most prominent loess records in the world, reflecting past eolian dust activity in East Asia. However, their interpretation is hampered by ambiguity in the origin of loess‐forming dust and an incomplete understanding of the circulation forcing dust accumulation. In this study, we used a novel modeling approach combining a dust emission model FLEXDUST with simulated back trajectories from FLEXPART to trace the dust back to where it was emitted. Over 21 years (1999–2019), we modeled back trajectories for fine (∼2 μm) and super‐coarse (∼20 μm) dust particles at six CLP sites during the peak dust storm season from March to May. FLEXPART source‐receptor relationships are combined with the dust emission inventory from FLEXDUST to create site‐dependent high‐resolution maps of the source contribution of deposited dust. The nearby dust emission areas were found to be the main source of dust to the CLP. Dust deposition across the CLP was found to predominantly occur via wet removal, with also some super‐coarse dust from distant emission regions being wet deposited following high‐level tropospheric transport. The high topography located on the downwind side of the emission area plays an essential role in forcing the emitted super‐coarse dust upward. On an interannual scale, the phase of the Arctic Oscillation in the preceding winter was found to have a strong association with the spring deposition rate on the CLP, while the strength of the East Asian Winter Monsoon was less influential.

A Comprehensive Machine and Deep Learning Approach for Aerosol Optical Depth Forecasting: New Evidence from the Arabian Peninsula

AbstractAccurate forecasting of environmental pollution indicators holds significant importance in diverse fields, including climate modeling, environmental monitoring, and public health. In this study, we investigate a wide range of machine learning and deep learning models to enhance Aerosol Optical Depth (AOD) predictions for the Arabian Peninsula (AP) region, one of the world’s main dust source regions. Additionally, we explore the impact of feature extraction and their different types on the forecasting performance of each of the proposed models. Preprocessing of the data involves inputting missing values, data deseasonalization, and data normalization. Subsequently, hyperparameter optimization is performed on each model using grid search. The empirical results of the basic, hybrid and combined models revealed that the convolutional long short-term memory and Bayesian ridge models significantly outperformed the other basic models. Moreover, for the combined models, specifically the weighted averaging scheme, exhibit remarkable predictive accuracy, outperforming individual models and demonstrating superior performance in longer-term forecasts. Our findings emphasize the efficacy of combining distinct models and highlight the potential of the convolutional long short-term memory and Bayesian ridge models for univariate time series forecasting, particularly in the context of AOD predictions. These accurate daily forecasts bear practical implications for policymakers in various areas such as tourism, transportation, and public health, enabling better planning and resource allocation.

Evaluation of CAS-ESM2 in simulating the spring dust activities in the Middle East

The assessment of Earth System Models (ESMs) in simulating long-term dust activities is a prerequisite for the applications of ESMs to the projection of future dust change. Middle East is the second largest dust source region in the world after North Africa, and our knowledge of the ESMs' ability in simulating regional dust cycle in this region is still limited. Here we examine the ability of the Chinese Academy of Sciences Earth System Model version 2 (CAS-ESM2) in simulating the spatiotemporal variations of dust activity over the Middle East region (30°E to 65°E, 10°N to 42°N). CAS-ESM2 simulations are compared with station observations, satellite observations, the Dust Constraints from joint Experimental-Modeling-Observational Analysis (DustCOMM) dataset, and the Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2). The results show that CAS-ESM2 captures the main dust sources extending from the south of the Persian Gulf to the Arabian Peninsula, Iraq, and Sudan. CAS-ESM2 also simulates similar patterns of dust optical depth (DOD) with referential data, although there is some uncertainty in DOD observation. Further analysis shows that the model is able to reproduce the temporal variations of dust event frequency with the temporal correlation coefficient between model and station observations reaching 0.39. Simulations of dust-relevant variables such as surface wind, precipitation, and soil moisture are also evaluated. The biases including weaker surface wind speed and larger soil moisture as well as their impacts on the dust emission and transport are also noted for future model improvements. Overall, CAS-ESM2 demonstrates a good ability to simulate the spatio-temporal variations of spring dust activity over the Middle East, yet some biases remain to be improved.

First assessment of changes in dust sources in the black forest during the Holocene: case study at Wildseemoor

A 600 cm peat sequence was extracted from the ombrotrophic peat bog Wildseemoor in the northern Black Forest, covering the last ca. 10,000 years thus allowing for identification of potential changes in dust input during the Holocene. Such information is critical to the understanding of past environmental change at the local to supra-regional scale and helps with interpreting, in particular, fire history and its links to both climate change and anthropogenic impacts. Dust composition change was investigated using X-ray fluorescence core scanning (XRF-CS) to establish bulk chemical composition of lithogenic input to the peatland, using element signatures, and in particular the ratios of Ca/Ti and Ti/Zr. Two main different sources of dust could be differentiated, a local and a distal (long-distance) dust source, which show variations through time. Distal dust input is elevated during the early Holocene (ca. 8,800 - 8,300 cal BP), as well as around 5,000 cal BP, 3,000 cal BP, 2,300 cal BP and the last ca. 200 years. Distal dust might originate from remobilized loess deposits in the Upper Rhine Graben or, periodically, more distant sources such as the Sahara or the Massif Central. Local dust input roughly correlates to peaks in charcoal influx after ca. 3,850 cal BP, potentially recording phases of increased anthropogenic influence in the surroundings of Wildseemoor. Additional research in nearby bogs (from the Black Forest and the Vosges), as well as more precise geochemical fingerprinting of the different dust sources, is needed to explore the regional extent and significance of Holocene environmental changes recorded at Wildseemoor.

Soil-geochemical assessment of salinization of the territory adjacent to the Kuchuk salt deposit (Altai Krai)

A soil geochemical analysis was conducted to assess the impact of the exploitation of the Lake Kuchuk salt deposit on the salinization of the soils in the adjacent areas. The specific characteristic of the soil forming in the Kulunda steppe is the wide distribution of salinization processes. Solonetzes soils are distributed in the impact zone of the deposit exploitation; therefore, as background soils, we considered also Solonetzes. Background soils are located at a considerable distance (2–10 km) from industrial facilities. The results of the chemical analysis of the soil-water extracts showed that the area of the most intense salinization is concentrated in the eastern and southeastern parts of the depression of the former lake. Nowadays, a salt evaporation pond and an open salt storage, which are the main industrial sources of sodium sulfate dust, occupy the bottom of the lake. The maximum salt content (over 1%) was found in these parts of the basin and is associated with the prevailing wind direction in the study area. With an increase in the hypsometric level of the surfaces and the distance from the open technological sources of dust, as well as on the opposite slope of the basin, there was a sharp (2–3 times) decrease in the salt content. The total salt content in the background soils ranged from 0.3 to 0.6%. The specificity of the chemistry of soil salinization in the impact zone was the dominance of sulfates and sodium in the composition of the soil-water extract, and thenardite, which is a dehydration product of mirabilite, in the composition of salt crust minerals and salt efflorescences. In the background Solonetzes, the participation of soda in the chemical composition became more noticeable, which is a natural halogen geochemical feature of the Kulunda steppe. In the surface salt crusts in the background areas, a greater variety of minerals were noted, among which there were typical minerals of the evaporite association (gypsum, halite, calcite, dolomite, mirabilite) and their rare species (konyaite, wedellit).

Quantitative analysis of the Martian atmospheric dust cycle: Transported mass, surface dust lifting and sedimentation rates

The atmospheric dust cycle on Mars plays a dominant role in the planetary radiative balance, atmospheric photochemistry escape, and redistribution of materials on the surface. Although this planetary dust cycle has been extensively modelled and characterized with both orbital and in situ observations, to date little is known about the total mass of dust that is circulated, the actual dust lifting and settling rates, and the main dust sources and sinks. Using orbital global and seasonal measurements of atmospheric dust opacity, a data reduction methodology that can describe the annual dust redistribution cycle on a planetary scale with 95% accuracy is presented. The method was applied to the 9.3 μm infrared observations of the Thermal Emission Spectrometer (TES) aboard the Mars Global Surveyor (MGS) during two full Martian Years (MY) 25 and 26, and partly MY 24 and MY 27, disregarding the global dust storm that occurred in MY 25. By comparison with terrestrial observations, a mass-to-extinction conversion factor of 1.9 ± 0.3 g m−2 is proposed, assuming a dust density of 2.6 g cm−3. The analysis shows an estimation of 400 1012 g of dust transported globally in the atmosphere for a typical Mars year, which is comparable to the minimum total annual mass of dust transported on Earth. The methodology proposed here is based on remote sensing and cannot disentangle completely local surface lifting and sedimentation rates from dust advection. However, this analysis provides upper bounds which can be compared with in-situ observations. The analysis of the dust sedimentation cycle suggests that the annual cycle might produce a dust layer of about 50–100 μm on the surface of some particular zones, as Valle Marineris or Meridiani Planum. This estimation agrees with in-situ observations of rovers on Mars. The potential dust sources are mainly located from latitudes of 20°S to 60°S. Our results find the 70% of the sources previously identified by the existing planetary circulation models. This kind of large-scale analysis can be applied to other remote sensing observations to refine these calculations and study the annual and geographical variability of the dust-mass transport on Mars.

Dust in Western Iran: the emergence of new sources in response to shrinking water bodies

We detected sources of dust in the Middle East that contribute to dust events in Western Iran in different seasons. By the analysis of the synoptic data, we identified 309 dusty days in Western Iran during the period 2000–2016. A dusty day is diagnosed if under low horizontal visibility (< 1 km), the dust in suspension is reported at least once a day in at least three synoptic stations. We identified dust sources in the Middle East based on the analysis of the MOD04L2 data from MODIS, the backward HYSPLIT trajectory model, and synoptic conditions. The most influential sources affecting Western Iran are located on the shore and northwest of Lake Tharthar, Hour-al-Azim Marsh, the shore of Razzaza, Habbaniyah Lakes, and West Hammar Marsh, which contributed to 110, 79, 59, 56, and 51 dusty days, respectively. The fluctuation of the surface water area largely contributes to the variability of dusty days in Western Iran. Indeed, the peak dust activity in Western Iran was during the period 2008–2012 in response to the substantial shrinkage of the main water bodies in Iraq. The main sources of dust influencing Western Iran are located in northern and eastern Saudi Arabia in spring, Deir ez-Zur in Syria’s Aleppo and Raqqa in summer, and Syria’s Homs and Al-Hasakah in winter and spring. Sources of dust in Western Iraq and in most parts of entire Iraq have, respectively, led to the formation of summer and spring dust events in Western Iran. Decreased precipitation in the Middle East from autumn 2007 to 2012 and the occurrence of severe droughts have also contributed to the shrinkage of lakes and wetlands, as well as the reduced agricultural productivity in the Middle East, all of which contributed to the intensification of dust activity in Western Iran in recent decades.

A super dust storm enhanced by radiative feedback

As the main dust source area in East Asia, the Gobi Desert (GD) exerts critical impacts on the radiation budget in downstream regions. Dust radiative feedback in the GD on the Mongolian cyclone, however, remains poorly understood. Herein, the dynamic dust source is coupled with the Weather Research and Forecasting model with Chemistry (WRF-Chem) for better dust simulations. Results show that the Mongolian cyclone dominates the dust event in May 2019. Dust radiative feedback results in downward momentum transport and cools northeast of Mongolia by affecting zonal winds and temperature advection. Lower-troposphere cooling and upper-atmosphere warming change the atmospheric vertical structure and enhance baroclinicity. Further, cold air deeply descends into the bottom of the warm air in a wedge shape and promotes the ascension of warm air to enhance the Mongolian cyclone. The strong dust is maintained and continues to cause high dust concentrations in northern China via westerlies. This study explores how dust radiative feedback over the GD can intensify the Mongolian cyclone and provides a scientific reference for related studies.

Intense Desert Dust Event in the Northern Adriatic (March 2020); Insights From the Numerical Model Application and Chemical Characterization Results

AbstractThe uncharacteristically extreme outbreak of particulate matter took place over the Balkan region from 27 to 30 March 2020. Observations at air quality stations in Croatia recorded hourly PM10 concentrations up to 412 μgm−3. The meteorological analysis shows that the increase in PM10 concentrations was primarily due to the advection of dust from the deserts east of the Caspian Sea. The anticyclone north of Croatia and the cyclone over Anatolia formed a strong pressure gradient driving transport from the east. Both back trajectories and satellite products pointed to the dry Aral Sea as the main source of dust. A dust plume influenced the PM10 increase observed in Croatia, starting at the easternmost air quality stations. The modeling study shows that the vertical extent of the dust plume was up to ∼2 km. However, the chemical and morphological (scanning electron microscope analysis) composition of PM10 at the sites in the northeastern Adriatic Sea showed mainly the presence of Saharan dust. Prior to the advection of the Asian dust, the transport of Saharan dust, driven by Sharav cyclone, was observed in the PM10 values at several stations in the Adriatic Sea and on the Croatian mainland on 26 March 2020. Modeling results showed that the Saharan dust transport occurred at altitudes below ∼8 km. The mixing of the Asian and Saharan dust plumes over the Balkans was favored by the subsidence due to anticyclonic high‐pressure conditions and is the most likely explanation for the observed PM chemical and morphological results.

Mongolia Contributed More than 42% of the Dust Concentrations in Northern China in March and April 2023

Dust storms are one of the most frequent meteorological disasters in China, endangering agricultural production, transportation, air quality, and the safety of people’s lives and property. Against the backdrop of climate change, Mongolia’s contribution to China’s dust cannot be ignored in recent years. In this study, we used the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem), along with dynamic dust sources and the HYSPLIT model, to analyze the contributions of different dust sources to dust concentrations in northern China in March and April 2023. The results show that the frequency of dust storms in 2023 was the highest observed in the past decade. Mongolia and the Taklimakan Desert were identified as two main dust sources contributing to northern China. Specifically, Mongolia contributed more than 42% of dust, while the Taklimakan Desert accounted for 26%. A cold high-pressure center, a cold front, and a Mongolian cyclone resulted in the transport of dust aerosols from Mongolia and the Taklimakan Desert to northern China, where they affected most parts of the region. Moreover, two machine learning methods [the XGBoost algorithm and the Synthetic Minority Oversampling Technique (SMOTE)] were used to forecast the dust storms in March 2023, based on ground observations and WRF-Chem simulations over East Asia. XGBoost-SMOTE performed well in predicting hourly PM10 concentrations in China in March 2023, with a mean absolute error of 33.8 µg m−3 and RMSE of 54.2 µg m−3.

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.

Investigation of mid-infrared long-term variability of dusty AGB stars using multi-epoch scan data of AKARI and WISE

Abstract Asymptotic giant branch (AGB) stars are one of the main sources of dust in the Universe. They form and supply dust triggered by stellar pulsations, but the details of the mechanism are still unknown. Among all AGB stars, dusty AGB stars are the most important in terms of dust supply because they contain the star with a high mass-loss rate. To investigate the relationship between the pulsation and the dust supply for such dusty AGB stars, long-term mid-infrared monitoring is necessary. In this study, we combine data from a infrared astronomical satellites AKARI and WISE to generate mid-infrared long-term observation data. This collected data enables us to investigate the variability of dusty AGB stars with a variability period of more than several hundred days (&amp;gt;250 d). Furthermore, we determine the mid-infrared variability amplitudes of 169 O-rich AGB stars and 28 OH/IR stars in our Galaxy, as well as data at other wavelengths. This study is the largest study on mid-infrared variability. Additionally, we discover a positive correlation between the variability amplitude A18μm in the 18μm band and the $\mathit {W3}-\mathit {W4}$ infrared color which is the measure of the dust supply. Also, we find that this relationship is independent of the variability period and mode. Finally, we calculate the radiative transfer of circumstellar dust from AGB stars. The result of our calculations showed that $A_{18\mu \rm {m}}$ is strongly affected by the luminosity change ratio of the central star. These experimental results imply that the luminosity change ratio has a strong influence on the dust supply of AGB star.

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.

Analysis and Prediction of the Meteorological Characteristics of Dust Concentrations in Open-Pit Mines

Based on the dust concentration data and meteorological environment data monitored at the open-pit mine site, the characteristics of dust concentration and the influence of temperature, humidity, wind speed, air pressure and other meteorological conditions on dust concentration were analyzed, and the causes of the change of dust concentration were clarified. Meanwhile, a dust concentration prediction model based on LSTM neural network is established. The results show that the dust concentration of the open-pit mine is high in March, November and the whole winter, and it is low in summer and autumn. The daily variation of humidity and temperature in different seasons showed the trend of “herringbone” and “inverted herringbone”, respectively. In addition, the wind speed was the highest in spring and the air pressure distribution was uniform, which basically maintained at 86–88 kPa. The peak humidity gradually deviates with each month and is obviously affected by seasonality. The higher the humidity, the lower the temperature and the higher the concentration of dust. In different seasons, the wind speed is the highest around 20:00 at night, and the dust is easy to disperse. The R2 values of PM2.5, PM10 and TSP concentrations predicted by LSTM model are 0.88, 0.87 and 0.87, respectively, which were smaller than the MAE, MAPE and RMSE values of other prediction models, and the prediction effect was better with lower error. The research results can provide a theoretical basis for dust distribution law, concentration prediction and dust removal measures of main dust sources in open-pit mines.

Spatiotemporal evolution of aeolian dust in China: An insight into the synoptic records of 1984–2020 and nationwide practices to combat desertification

AbstractAeolian dust is closely related to land degradation, desertification, and sand and dust storm weather, and is a significant factor influencing the Earth's biogeochemical cycles. Here we present an investigation of the recent synoptic features of atmospheric dust in China and analyze its spatiotemporal change based upon meteorological observation data and satellite products. It shows that aeolian dust frequency in China has decreased gradually from 1984 to 2020. The outbreak frequency of dust storms declined significantly by 97.7%, followed by severe dust storm, dust in suspension, and blowing dust with 88.8%, 75%, and 64.3% reduction, respectively. The main dust sources influencing China are the Mongolian Gobi Desert, the Taklimakan Desert, the Hexi Corridor, the Alxa Plateau Desert, the Qaidam basin Desert, and the northeast‐southwest stretching semiarid farming‐pasture ecotone. Atlantic multidecadal oscillation (AMO) and Pacific decadal oscillation (PDO) may play an important role in teleconnection with aeolian dust event occurrence in China. Their correlation coefficients are −0.6 and 0.37, respectively. For more than 40 years, China has made huge investments in ecological restoration projects, and enacted national policies and laws to mitigate desertification. Significant environmental improvement has consequently ensued in China in the early 21st century, and the aeolian dust events were reduced to a record minimum in 2020. In contrast to the growing nationwide greenness, China is now facing up to an incremental dust risk generated from extraterritorial source regions such as the Mongolian Gobi Desert and Central Asian desiccated salt lakes.

Improved indoor air quality during desert dust storms: The impact of the MEDEA exposure-reduction strategies

Desert dust storms (DDS) are natural events that impact not only populations close to the emission sources but also populations many kilometers away. Countries located across the main dust sources, including countries in the Eastern Mediterranean, are highly affected by DDS. In addition, climate change is expanding arid areas exacerbating DDS events. Currently, there are no intervention measures with proven, quantified exposure reduction to desert dust particles. As part of the wider “MEDEA” project, co-funded by LIFE 2016 Programme, we examined the effectiveness of an indoor exposure-reduction intervention (i.e., decrease home ventilation during DDS events and continuous use of air purifier during DDS and non-DDS days) across homes and/or classrooms of schoolchildren with asthma and adults with atrial fibrillation in Cyprus and Crete-Greece. Participants were randomized to a control or intervention groups, including an indoor intervention group with exposure reduction measures and the use of air purifiers. Particle sampling, PM10 and PM2.5, was conducted in participants' homes and/or classrooms, between 2019 and 2022, during DDS-free weeks and during DDS days for as long as the event lasted. In indoor and outdoor PM10 and PM2.5 samples, mass and content in main and trace elements was determined. Indoor PM2.5 and PM10 mass concentrations, adjusting for premise type and dust conditions, were significantly lower in the indoor intervention group compared to the control group (PM2.5-intervention/PM2.5-control = 0.57, 95% CI: 0.47, 0.70; PM10-intervention/PM10-control = 0.59, 95% CI: 0.49, 0.71). In addition, the PM2.5 and PM10 particles of outdoor origin were significantly lower in the intervention vs. the control group (PM2.5 infiltration intervention-to-control ratio: 0.49, 95% CI: 0.42, 0.58; PM10 infiltration intervention-to-control ratio: 0.68, 95% CI: 0.52, 0.89). Our findings suggest that the use of air purifiers alongside decreased ventilation measures is an effective protective measure that reduces significantly indoor exposure to particles during DDS and non-DDS in high-risk population groups.

Effects of dust sources on dust attenuation properties in IllustrisTNG galaxies at z ∼ 7

ABSTRACT Dust emission from high-redshift galaxies gives us a clue to the origin and evolution of dust in the early Universe. Previous studies have shown that different sources of dust (stellar dust production and dust growth in dense clouds) predict different ultraviolet (UV) extinction curves for galaxies at z ∼ 7 but that the observed attenuation curves depend strongly on the geometry of dust and star distributions. Thus, we perform radiative transfer calculations under the dust–star geometries computed by a cosmological hydrodynamic simulation (IllustrisTNG). This serves to investigate the dust attenuation curves predicted from ‘realistic’ geometries. We choose objects with stellar mass and star formation rate appropriate for Lyman break galaxies at z ∼ 7. We find that the attenuation curves are very different from the original extinction curves in most of the galaxies. This makes it difficult to constrain the dominant dust sources from the observed attenuation curves. We further include infrared dust emission in the analysis and plot the infrared excess (IRX)–UV spectral slope (β) diagram. We find that different sources of dust cause different IRX–β relations for the simulated galaxies. In particular, if dust growth is the main source of dust, a variation of dust-to-metal ratio causes a more extended sequence with smaller IRX in the IRX–β diagram. Thus, the comprehensive analysis of the abundance of dust and metals, the UV slope, and the dust emission could provide a clue to the dominant dust sources in the Universe.

Variability of Airborne Dust Fallout and Associated Trace Metals around Industrial Sites in Esfahan, Iran

AbstractThe seasonal and spatial variability of airborne dust deposits and associated trace metals such as Pb, Co, Ni, Cd, Mn in 15 sites surrounding a heavily industrialized region in south Esfahan (central Iran) are investigated. Total deposit rates (TDR) of dusts and trace metals are analyzed, contamination factor (CF) and pollution load index (PLI) are also calculated. Furthermore, correlation and cluster analysis are performed to identify the source of the pollution. The highest dust‐TDR (15.97 g m−2 per season), the highest concentration of trace metals, CF and PLI are recorded in summer because of the lack of precipitation, high temperature, and drought conditions in this season. Pb and Cd show the highest CF values. In the towns near the two major steel mills in the region (i.e., Esfahan Steel Company and Mobarekeh Steel Complex), the CF values for Pb and Cd are about 13 and 12, respectively (i.e., 13 and 12 times higher than the pre‐industrial values, respectively). The spatial distribution maps of the dust deposit rate, dust‐borne trace metals, and the obtained PLI of the trace metals in the study area reveal that the two major industries in the region are the main sources of dust and trace metal distribution.

Quantifying the contribution of dust sources in the arid area of northwest China using multivariate statistical techniques and Bayesian mixing models

In this study, topsoil samples and dust samples during dust storms were collected from the main dust source in northwest China, the geochemical elements were measured, and the contribution of dust sources was quantified using a discriminant function analysis (DFA) model and a MixSIAR model. Finally, the accuracy of the model was evaluated using an artificial mixture sample. The results showed that the dust sources and their contributions were significantly heterogeneous due to the natural and anthropogenic influences on the source-transport-sink process. DFA and MixSIAR models showed that the main dust sources in Dunhuang and Jiuquan were the Western Gobi and Western oasis, and Zhangye was mainly influenced by the Western Gobi, Western oasis, Middle Gobi, and Central oasis, with the influence of the Middle oasis being more pronounced. The Eastern Gobi, Eastern oasis, Badain Jaran desert, and Tengger desert have a greater influence on Jinchang, Wuwei, Baiyin, and Lanzhou. The contribution of each dust source in the Hexi region was found to show a significant distance effect. The accuracy of the models varied depending on the number of dust sources. The study provides new ideas for quantifying the contribution of dust source and for global dust storm control.