Major Dust Source Research Articles

Short-term exposure to desert dust and sandstorms and all-cause and cause-specific mortality and morbidity: A systematic review and meta-analysis.

Desert dust and sandstorms raise concerns about their adverse effects on human health. Over the last decade, special attention has been given to mineral dust particles from desert sand. However, evidence from previous literature reviews has yielded inconclusive results regarding their health effects. We aim to systematically synthesize evidence on the short-term health effects of desert dust exposure from major dust source areas. The bibliographic search was conducted using the MEDLINE (PubMed), Scopus, and Web of Science databases to investigate the health effects of short-term exposure to desert dust in human populations, using time series or case-crossover study designs. Study selection and reporting followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We evaluated the risk of bias (RoB) for individual studies and the certainty of evidence (CoE) for environmental exposures, as developed by a group of experts convened by the World Health Organization (WHO). Publication bias was examined using funnel plots and Begg's asymmetry test. A total of 71 studies were included in the review, covering data from 1993 to 2024. Most studies focused on Asian and African desert dust, with fewer studies from Arabian, American, and Australian regions. We found a significant increase in the risk for all-cause mortality (Relative Risk, RR=1.0121, 95%CI=[1.0045, 1.0199]). In addition, the mortality risk associated with particulate matter less than 10μm (PM10) was slightly higher on dust days compared to non-dust days, while for particulate matter less than 2.5μm (PM2.5), the risk was higher on non-dust days. We also observed a significant increase in the risk for cardiovascular mortality (RR=1.0252, 95% CI=[1.0100, 1.0407]) during dust days compared to non-dust days, but not for respiratory mortality (RR=1.0001, 95% CI=[0.9773, 1.0277]). The risk also increased for cardiovascular (RR=1.0094, 95% CI=[1.0014, 1.0174]) and respiratory morbidity (RR=1.0693, 95% CI=[1.0188, 1.1224]). Exposure to desert dust and sandstorms is linked to increased risks of all-cause and cardiovascular mortality, as well as respiratory morbidity. The overall evidence quality for each exposure-outcome combination was assessed as moderate, although data limitations prevent the establishment of specific air quality thresholds for desert dust particles. This review highlights the need for targeted public health interventions in affected regions.

Transboundary hydropolitical conflicts and their impact on river morphology and environmental degradation in the Hirmand Basin, West Asia

The Hirmand Transboundary River Basin (HTRB), shared by Afghanistan, Iran, and Pakistan, is a hydrologically critical and politically sensitive region. This basin sustains livelihoods, ecosystems, and agriculture in a region plagued by climatic variability and geopolitical tensions. The Hirmand River, which forms the heart of this basin, faces severe morphological and discharge changes due to upstream water management, climatic shifts, and land use changes, directly impacting downstream ecosystems and human populations. This study examines the morphological changes in the Hirmand River and disentangles natural and human-induced drivers behind these shifts. Using the TWINS framework, the study assesses cooperation and conflict in hydropolitical relations, alongside the environmental repercussions of upstream activities on downstream ecosystems. Landsat imagery analysis (1987–2022) via Google Earth Engine reveals significant morphological changes, with 43% of river arcs shifting by 500–1200 m and an annual width reduction of three meters, even during wet periods. Further, prolonged droughts and upstream water diversions have desiccated the Hamoun Lake, obliterating ecosystems, displacing residents, and transforming exposed lakebeds into major dust sources. The TWINS analysis highlights hydropolitical dynamics as the predominant driver of these changes, outweighing climatic influences, and underscores the need for cooperative frameworks to address escalating environmental and social challenges in the basin.

Holocene dust activity in inland Asia driven by both the mid-latitude Westerlies and the East Asian winter monsoon

Inland Asia is a major global source of dust and the dust transport from this region has global implications. However, the processes and forcing mechanisms of dust activity in inland Asia during the Holocene are still debated due to the lack of high-quality records with accurate dating, unambiguous dust signals, and a high resolution. Here we present a well-dated record of dust activity based on the Ti content of the sediments of Shuanghu Lake, in the southern Altai Mountains, with a ∼ 15-yr-resolution and covering the entire Holocene. This record shows a gradual decrease in dust intensity during ∼11.7–6 thousand years ago (ka), followed by a persistent increase since ∼6 ka. Frequent dust events are also evident, lasting hundreds of years, and are superimposed on the millennial-scale trend, corresponding to the nine North Atlantic Bond events. We propose that the millennial-scale trend of dust activity was primarily influenced by variations in the mid-latitude Westerlies, while the dust events on the centennial scale were driven primarily by a strengthened East Asian winter monsoon. Overall, this study provides a reliable, high-resolution record of Holocene dust activity in inland Asia, and it updates the previous view that dust activity in this region was solely controlled by the mid-latitude Westerlies or the Siberian High. Our findings contribute to an improved understanding of global dust transport with implications for predicting future dust activity in this region.

Where is the Dust Source of 2023 Several Severe Dust Events in China?

Abstract Northern China was hit by 13 unprecedented mega dust events in spring 2023. However, a comprehensive understanding of the relative contributions of potential dust sources to dust concentrations in China remains elusive, threatening air quality, damaging ecosystems, and further complicating dust forecasting and warning efforts. The impact of five major Asian dust sources on China and its downstream regions has been accurately quantified using the Weather Research and Forecasting Model coupled with Chemistry (WRF-Chem). Notably, dust particles originating from Mongolia play a crucial role in downstream air pollution. Approximately 56% (82.7 μg m−3) of the dust in North China originated from Mongolia, while Mongolia contributed nearly 51% (15.9 μg m−3) of the dust in the Korean Peninsula and surroundings. In southwest China, the prevalence of dust was predominantly attributable to sources within Inner Mongolia, China (46%). Due to geographical constraints, dust in the Tibetan Plateau mainly originated from dust sources in Xinjiang, China. Topographic blocking by the Tibetan Plateau and limitations on local dust emissions are further unfavorable to the long-distance transport of dust from South Asia to downstream regions. We also highlight the importance of variation in surface soil parameters in driving frequent dust events in spring 2023. Our findings emphasize the urgent need for collaborative research and policymaking to effectively address international dust disaster mitigation.

The dominant factor in extreme dust events over the Gobi Desert is shifting from extreme winds to extreme droughts

Gobi Desert (GD) is one of the major global dust sources, where dust events are frequent. Based on satellite observations, we compiled extreme dust events (EDEs) over the GD during spring since 2000. Among all 43 extreme events, EDEs on 4–10 April 2001 (EDE 2001) and 14–19 March 2021 (EDE 2021) are the most pronounced, due to the longest duration and the most intense strength, while the generation mechanisms underlying these two EDEs are different. EDE 2001 is associated with extreme westerlies, which are caused by an abnormal low-pressure due to the extreme Eurasian teleconnection (EU). However, EDE 2021 is attributable to extreme droughts, which are caused by an abnormal high-pressure due to the extreme Arctic Oscillation (AO) and West Pacific teleconnection (WP). Moreover, the trends in EU, AO, and WP combined with the analysis of all EDEs indicate a shift in the dominant factor of EDEs over the GD from extreme winds to extreme droughts. Therefore, regional droughts should be given more importance in future EDE forecasts.

The Wind‐Blown Sand Experiment in the Empty Quarter Desert: Roughness Length and Saltation Characteristics

AbstractThe Empty Quarter Desert, one of Earth's major dust sources, frequently experiences dust storms due to wind erosion. Despite its significance as a primary dust source on a global scale, in‐situ observations from this region had not been reported until very recently. In summer 2022, the WInd‐blown Sand Experiment (WISE) Phase‐1 was initiated in the Empty Quarter Desert of the United Arab Emirates, and continued until 7 February 2023. Utilizing a diverse array of instruments, we measured winds, temperature, humidity, radiation fluxes, saltation, and the physical and optical properties of dust aerosols, atmospheric electric fields, and soil characteristics. A total of 38 distinct sand‐saltation events were recorded from September 2022 to February 2023, with activity peaking between 13:00 and 14:00 local time. Key findings include the identification of dominant wind patterns, and the measurement of the average aerodynamic roughness length (z0) at 0.8 ± 0.6 mm, and the thermal roughness length (zh) at 0.3 ± 0.5 mm—the first estimation of zh for this area. In‐situ observations revealed that dust particle concentrations near the surface increased 1.7‐fold on days with saltation compared to days without it. Moreover, we determined a wind‐speed threshold for initiating saltation at 7.70 m s−1. This comprehensive data set significantly advances our understanding of atmospheric‐soil interactions and sand movement dynamics, providing invaluable insights for ongoing research into desert environments and the global dust cycle.

Managing Dust in Academic Libraries

Abstract The study investigates dust management at the Albert Ilemobade library, The Federal University of Technology Akure. Dust deposition and accumulation poses a major challenge for the university library as all the units, sections, and divisions are affected. Dust not only adversely affects all materials, equipment, and facilities including books, audiovisual collections, and computers, but also constitutes a health hazard to library personnel and users. Major sources of dust include visitor activities and infiltration through openings like windows and doors. Dust mats, special computer enclosures, dusters, dust blowers, and respiratory masks were made available for dust protection and management in the library. The library lacked equipment like High Efficiency Particulate Arresting (HEPA) filters and dust collection, and suppressions systems. Lack of awareness and training, inadequate funding, and lack of equipment were identified as the challenges to dust management in the library.

Advancing respirable coal mine dust source apportionment: a preliminary laboratory exploration of optical microscopy as a novel monitoring tool

Exposure to respirable coal mine dust (RCMD) can cause chronic and debilitating lung diseases. Real-time monitoring capabilities are sought which can enable a better understanding of dust components and sources. In many underground mines, RCMD includes three primary components which can be loosely associated with three major dust sources: coal dust from the coal seam itself, silicates from the surrounding rock strata, and carbonates from the inert ‘rock dust’ products that are applied to mitigate explosion hazards. A monitor which can reliably partition RCMD between these three components could thus allow source apportionment. And tracking silicates, specifically, could be valuable since the most serious health risks are typically associated with this component-particularly if abundant in crystalline silica. Envisioning a monitoring concept based on field microscopy, and following up on prior research using polarized light, the aim of the current study was to build and test a model to classify respirable-sized particles as either coal, silicates, or carbonates. For model development, composite dust samples were generated in the laboratory by successively depositing dust from high-purity materials onto a sticky transparent substrate, and imaging after each deposition event such that the identity of each particle was known a priori. Model testing followed a similar approach, except that real geologic materials were used as the source for each dust component. Results showed that the model had an overall accuracy of 86.5%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$86.5\\%$$\\end{document}, indicating that a field-microscopy based monitor could support RCMD source apportionment and silicates tracking in some coal mines.

Impacts of Climate Change and Human Activity on Lakes around the Depression of Great Lakes in Mongolia

The western region of Mongolia is characterized by an arid climate and a fragile ecological environment. It is a sensitive zone in response to global climate change and one of the major sources of dust globally. This region is home to numerous lakes, and their dynamic changes not only reflect global climate variations but also have implications for the global ecological environment quality. In this study, Landsat images were used as the data source, and Google Earth Engine (GEE) was employed to extract lakes with an area larger than 1 km2 from 1992 to 2021. The spatiotemporal characteristics of lake water area (LWA) changes were analyzed, and a structural equation model was applied to attribute the lake changes. The results indicate an overall trend of increasing lake area followed by a decrease in the study area. Specifically, lakes in the provinces of Khovd and Gobi-Altai exhibited a decreasing trend followed by an increasing trend, while lakes in the provinces of Uvs and Zavkhan showed an increasing trend followed by a decreasing trend. Three typical types of lakes, namely, alpine lakes, throughflow lakes, and terminal lakes, all exhibited a trend of increasing area followed by a decrease. The analysis of driving forces behind lake area changes reveals that climate change and human activities primarily exert indirect influences on the lake area changes in each province. Specifically, climate change and human activities lead to changes in soil moisture, which have a significant explanatory power for lake area changes. Regarding the typical types of lakes, climate change serves as the primary driving force for alpine lakes, while human activities are the main driving forces for throughflow lakes and terminal lakes.

Contribution of black carbon and desert dust to aerosol absorption in the atmosphere of the Eastern Arabian Peninsula

Discriminating the absorption coefficients of aerosol mineral dust and black carbon (BC) in different aerosol size fractions is a challenge because of BC's large mass absorption cross-section compared to dust. Ambient aerosol wavelength dependent absorption coefficients (babs) in supermicron and submicron size fractions were determined with a high time resolution. The measurements were performed simultaneously using identical systems at an urban and a regional background site in Qatar. At each site, measurements were taken by co-located Aethalometers, one with a virtual impactor (VI) and the other with a PM1 cyclone to respectively collect super-micron-enhanced and submicron fractions. The combined measurement of aerosol absorption and scattering coefficients enabled the particles to be classified based on their optical properties' wavelength dependence. The classification reveals the presence of BC internally/externally mixed with different aerosols. Helium ion microscopy images provided information concerning the extent of mineral dust in the submicron fraction. The determination of absorption coefficients during dust storms and non-dust periods was used to establish the absorption Ångström exponent for dust and BC. Non-parametric wind regression, potential source contribution function and back-trajectory analysis reveal major regional sources of desert dust associated with north-westerly winds and a minor local dust contribution. In contrast, major BC sources found locally were associated with south-westerly winds with a smaller contribution made by offshore emissions transported by north-easterly and easterly winds. The use of a pair of Aethalometers with VI and PM1 inlets separates contributions of BC and dust to the aerosol absorption coefficient.

Long-Term Spatiotemporal Characteristics and Influencing Factors of Dust Aerosols in East Asia (2000–2022)

The Taklamakan Desert Region (TDR) and the Gobi Desert Region (GDR) in East Asia significantly impact air quality, human health, and climate through dust aerosols. Utilizing the MERRA-2 dataset’s long-term dust aerosol optical depth (DAOD) at 550 nm from 2000 to 2022, we systematically monitored the spatiotemporal dynamics of DAOD. Our analysis covered annual, seasonal, and monthly scales, employing geographical detector analyses to investigate the impact of eight factors on DAOD distribution. Over the 23-year period, the interannual variability in DAOD across East Asia was not pronounced, but a discernible decreasing trend was observed, averaging an annual decrease of −0.0002. The TDR had higher DAOD values (0.337) than the GDR (0.103). The TDR showed an average annual increase of 0.004, while the GDR exhibited an average annual decrease of −0.0003. The spatial distribution displayed significant seasonal variations, with peak values in spring, although the peak months varied between the TDR and GDR. The driving factor analysis revealed that relative humidity and soil moisture significantly impacted the DAOD spatial distribution in East Asia, which were identified as common driving factors for both the region and the major dust sources. Complex mechanisms influenced the variation in DAOD, with interactions between variables having a greater impact than individual effects. The geodetector-derived interaction q-value identified the collective impact of soil temperature and relative humidity (0.896) as having the highest impact on the spatial and temporal DAOD distribution. The overall spatial pattern exhibited a nonlinear enhancement trend, with the TDR and GDR showing bilinear enhancement patterns. These findings contribute to a better understanding of the factors influencing DAOD, offering a theoretical basis for atmospheric pollution control in East Asia.

Aerosol classification by application of machine learning spectral clustering algorithm

Precise understanding of aerosol classification is crucial for accurately quantifying the effects of aerosols on the Earth’s energy budget, improving remote sensing retrieval algorithms, formulating climate change-related policies, and more. In this study, we used aerosol measurements from the quality assured AERosol Robotic NETwork (AERONET) and utilized a multivariate spectral clustering algorithm, a machine learning tool, to classify global aerosols. The spectral clustering algorithm is a variant of the clustering algorithm that employs eigenvalues and eigenvectors of the data matrix to project the data into a lower-dimensional space of a similar cluster. To accomplish this, we considered five aerosol optical parameters: fine-mode Aerosol Optical Depth, Extinction Angstrom Exponent, Absorption Angstrom Exponent, Single Scattering Albedo, and Refractive Index from 150 AERONET sites distributed in six continents (Africa, Asia, Australia, Europe, North and South America) during 1993 to 2022. Using the clustering analysis, we identified four primary aerosol types: dust, urban, biomass burning, and mixed aerosols. Among the continents, the African and Asian sites exhibited the highest contribution of dust aerosols, as the region has significant global dust sources. Conversely, Australia, Europe, North, and South America are predominantly influenced by fine-mode aerosols, given their considerable distance from major dust source regions.

Long-term variations of global dust emissions and climate control

Dust discharged from the surface into the air has an important impact on global climate change, the ecological environment, and human health. However, the spatiotemporal variations of global dust emissions and the climate control of dust emissions from different dust sources in recent decades are still unclear. This study explores the spatiotemporal variations of global dust emissions from 1980 to 2020 based on the MERRA-2 dust emissions dataset and provides a detailed investigation of the interannual variations of dust emissions from major dust sources in the world and their contribution to the global dust cycle. On this basis, the association between global dust emissions and average wind speed (AWS), surface air temperature (SAT), precipitation (Ppt), relative humidity (RH), soil evaporation (SE), soil moisture (SM), and solar radiation (SR) were explored. In particular, the comparative importance of these climatic factors and their combined structures on dust emissions from different dust sources. The results show that North Africa contributed the most to global dust emissions, contributing 58% of the total global emissions, while South Africa and North America contributed the least to global dust emissions, at less than 1%, respectively. Classification and Regression Tree (CART) analysis shows that SR was the major factor affecting the dust emissions of Australia, East Asia, South America, and Central Asia. AWS was the major factor influencing dust emissions in North Africa and South Asia. SAT, RH, and SM were the major factors affecting dust emissions in West Asia, North America, and South Africa, respectively. There were great differences in the climatic factors combinations on dust emissions intensity in different dust sources. These findings assist us in better understanding the control of climatic factors on dust emissions from global dust sources and have important scientific significance for accurately predicting dust events and reducing disaster risks.

Significance of site-specific factors to peat accumulation indicated by differences in Holocene histories of dust delivery and peat deposition at two neighboring locations in the Altai Mountains, northwestern China

Peatlands can archive exceptional paleoenvironmental histories of dust delivery because of their uninterrupted and elevated accumulation rates, yet long-term records of dust deposition and its effect on peat accumulation are rare in the arid and semiarid Asian regions that can be major dust sources. We present here high-resolution Holocene peat accumulation and paleodust records from the Tielishahan (TLSH) and Halashazi (HLSZ) peatlands in the Altai Mountains of northwestern China. We find that although the two peatlands share common histories of external climate forcing and dust delivery, they have significantly different long-term rates of peat accumulations. Peat deposition initiated ~2 kyr earlier in the HLSZ peatland than in the TLSH peatland, exhibiting higher peat accumulation rates and greater mineral dust fluxes during the early Holocene, but it has constantly smaller values from the mid-Holocene to the present. The TLSH peatland has a higher peat accumulation rate and mineral dust flux during the early Holocene, lower values during the mid-Holocene, and increasing values during the latest Holocene. The elemental proxies in the two peat cores indicate that atmospheric deposition is the major factor in controlling delivery of mineral elements in HLSZ peatland, whereas elemental delivery in the TLSH peat record is affected by both the regional atmospheric dust flux and the water table under this sequence.We also find that peat accumulation is closely related to mineral dust deposition, as most Asian locations generally share similar patterns in long-term peat accumulation and dust deposition. We postulate that increased aridity in the dust sources of arid central Asia and stronger westerly winds induced by negative NAO variations are key drivers on greater dust deliveries. We further postulate that local factors, such as site-specific differences in permafrost thawing, the areas of the peatlands, and their hydrology are the main reasons for the asynchronous Holocene histories of these two neighboring peatlands. These local factors should be considered when interpreting long-term paleoclimate records from rates of peat accumulation and paleodust delivery.

Unraveling source-to-sink dust transport in Central and East Asia by identifying provenances of aeolian sediments

Loess deposits as a unique terrestrial archive of paleo-dust contribute to understanding the wide-scale and long-term dust transport from source to sink. This study provided diagnostic constraints on the sources of clay-sized particles in the Chinese Loess Plateau (CLP) loess by expanding the potential dust source areas with the Kyzylkum Desert and the Central Asian loess. Based on the grain sizes and the particle-size-specific trace elements, we characterized the major provenance and the sedimentary process of the Kyzylkum Desert sands. The results indicate the main derivation of Kyzylkum Desert sands from the Tian Shan-derived sediments, with limited large-scale mixing. The desert was thought to be a sink region, instead of an important dust source, which was supported by its weak genetic links to the Central Asian loess. With integration of the published data set about trace element and SrNd isotopic composition and our results, combined with the simulation results, we revealed that the Badain Jaran and Tengger deserts in northwestern CLP, rather than the Taklimakan and Kyzylkum deserts further west, played an important role in supply of the clay-sized particles for the CLP loess. The findings implied that the fine particles were primarily related to the East Asian winter monsoon, instead of the high-level westerly airstreams. In this context, we attributed the asynchronous timing of enhanced dust accumulation during the last glacial maximum (LGM) over Greenland and North Pacific (early LGM) and on the CLP (late LGM) to the differences in the major dust sources and in the atmospheric circulation systems.

Adaptation of a Neuro-Variational Algorithm from SeaWiFS to MODIS-Aqua Sensor for the Determination of Atmospheric and Oceanic Variables

The Sahara desert is a major global source of dust that is mostly transported southwest over the ocean off West Africa. The presence of this dust impacts the remote sensing of ocean surface properties. These aerosols have absorbing properties that are poorly accounted for in the standard ocean color data processing algorithm. This can result in an overestimation of the atmospheric contribution to the ocean color signal and consequently an underestimation of the oceanic contribution. A two-step algorithm initially applied to the Sea-viewing Wide field-of-view Sensor (SeaWiFS) data was adapted to the Moderate Resolution Imaging Spectroradiometer (MODIS-Aqua) sensor in the Northwest African region. The Northwest African region is a very productive region, where pelagic resources are an important socio-economic sector. Improving atmospheric correction of ocean color products is, thus, of particular interest for this oceanic region. The two-step approach of classifying the top-of-atmosphere radiance spectra for a better estimate of aerosol type on the one hand, and using an optimization method to fit the parameters of these aerosols and chlorophyll-a concentration (Chla) on the other hand, allows for a better representation of the optical thickness, a correction of the marine reflectance spectrum, and an increase in the spatio-temporal coverage of the area. To the extent that the properties of the water color signal are improved by this data processing, the Chla estimates should also be improved by this approach. However, it is difficult to conclude on this point from the available in situ observations.

Investigation of Severe Dust Storms Over Baghdad City by Using Remote Sensing Measurements and Ground Data

Dust aerosols have serious influences on different sectors such as the economy, climate change, pollution, transportation and public health. Dust storms have increased over the Middle East especially impacting central Iraq lately. The goal of the work is to identify possible dust sources and pathways influencing the study area. Using remote sensing data by employing the monthly average of Aerosol Index (AI-OMI), HYSPLIT model and MODIS satellite to examine potential dust storms sources and their transport pathways through spring season in 2012. The results of aerosol index (AI) values by OMI satellite were high during spring and summer but were low during autumn and winter. AI values are increased in the likely major dust sources including eastern parts of Syria, Kuwait, north Saudi Arabia, southwestern parts of Iran, as well as south and central parts of Iraq. Also, analyses of the HYSPLIT model show possible dust storms sources and predominate directions of dust which can reach Baghdad city including transported dust aerosols from the eastern region of Syria, north-western, western Iraq. The findings of pathways by the HYSPLIT model for possible dust sources are agreement with satellite images from MODIS – OMI satellites (dust storms are revealed by the MODIS – OMI satellites). The information of CALIPSO satellite revealed that the dust activity had reached 18 kilometres to the stratosphere layer. The HYSPLIT trajectories findings for dust storms travel are like to the image of the MODIS satellite.

Comparison of dust optical depth from multi-sensor products and MONARCH (Multiscale Online Non-hydrostatic AtmospheRe CHemistry) dust reanalysis over North Africa, the Middle East, and Europe

Abstract. Aerosol reanalysis datasets are model-based, observationally constrained, continuous 3D aerosol fields with a relatively high temporal frequency that can be used to assess aerosol variations and trends, climate effects, and impacts on socioeconomic sectors, such as health. Here we compare and assess the recently published MONARCH (Multiscale Online Non-hydrostatic AtmospheRe CHemistry) high-resolution regional desert dust reanalysis over northern Africa, the Middle East, and Europe (NAMEE) with a combination of ground-based observations and space-based dust retrievals and products. In particular, we compare the total and coarse dust optical depth (DOD) from the new reanalysis with DOD products derived from MODIS (MODerate resolution Imaging Spectroradiometer), MISR (Multi-angle Imaging SpectroRadiometer), and IASI (Infrared Atmospheric Sounding Interferometer) spaceborne instruments. Despite the larger uncertainties, satellite-based datasets provide a better geographical coverage than ground-based observations, and the use of different retrievals and products allows at least partially overcoming some single-product weaknesses in the comparison. Nevertheless, limitations and uncertainties due to the type of sensor, its operating principle, its sensitivity, its temporal and spatial resolution, and the methodology for retrieving or further deriving dust products are factors that bias the reanalysis assessment. We, therefore, also use ground-based DOD observations provided by 238 stations of the AERONET (AErosol RObotic NETwork) located within the NAMEE region as a reference evaluation dataset. In particular, prior to the reanalysis assessment, the satellite datasets were evaluated against AERONET, showing moderate underestimations in the vicinities of dust sources and downwind regions, whereas small or significant overestimations, depending on the dataset, can be found in the remote regions. Taking these results into consideration, the MONARCH reanalysis assessment shows that total and coarse-DOD simulations are consistent with satellite- and ground-based data, qualitatively capturing the major dust sources in the area in addition to the dust transport patterns. Moreover, the MONARCH reanalysis reproduces the seasonal dust cycle, identifying the increased dust activity that occurred in the NAMEE region during spring and summer. The quantitative comparison between the MONARCH reanalysis DOD and satellite multi-sensor products shows that the reanalysis tends to slightly overestimate the desert dust that is emitted from the source regions and underestimate the transported dust over the outflow regions, implying that the model's removal of dust particles from the atmosphere, through deposition processes, is too effective. More specifically, small positive biases are found over the Sahara desert (0.04) and negative biases over the Atlantic Ocean and the Arabian Sea (−0.04), which constitute the main pathways of the long-range dust transport. Considering the DOD values recorded on average there, such discrepancies can be considered low, as the low relative bias in the Sahara desert (< 50 %) and over the adjacent maritime regions (< 100 %) certifies. Similarly, over areas with intense dust activity, the linear correlation coefficient between the MONARCH reanalysis simulations and the ensemble of the satellite products is significantly high for both total and coarse DOD, reaching 0.8 over the Middle East, the Atlantic Ocean, and the Arabian Sea and exceeding it over the African continent. Moreover, the low relative biases and high correlations are associated with regions for which large numbers of observations are available, thus allowing for robust reanalysis assessment.

Bark, soil and lichens are effective indicators of dust from limestone industries in Thailand.

Cement production, quarrying and stone crushing are major emission sources of alkaline dust that can affect human health and vegetation. The main objectives of this study were to evaluate the potential of using bark pH, soil pH and lichen community for indicating alkaline dust pollution. Twelve polluted sites were in a limestone industrial area. Bark pH and the lichen community were observed on Alstonia scholaris trees, and soil pH was obtained from topsoil samples. The bark pH at all polluted sites was significantly higher (5.5 to 7.3) than that at the unpolluted site (4.3). Among the polluted sites, the highest bark pH value was observed at the nearest site to the center of the industrial area, while the lowest value was discovered at the farthest site. Bark pH showed a strongly negative correlation with the distance from the center. Soil pH at the unpolluted site (6.3) was also significantly lower than that at the polluted sites (7.6 to 8.1), except at the farthest site (6.5). The soil pH also tended to increase closer to the center. Seven lichen species were observed on the trunks of investigated trees in all polluted sites and were observed only at sites more than 4.7km away from the center, where bark pH ranged from 5.5 to 6.3. The extent of dust impact on vegetation seemed to be within 6-7km from the center. The results of this study confirm the potential of the bark pH of A. scholaris, soil pH and lichen community as long-term indicators of alkaline dust pollution.

Interannual Variability of Dust Deposition in Japan during Spring Season and Related Atmospheric Circulation Fields

Mineral dust affects health, climate, and ecosystems in various ways. East Asia is one of the major sources of mineral dust in the world. This study examines the year-to-year variability of dust deposition over Japan in April from the perspective of large-scale atmospheric circulations using atmospheric and aerosol reanalysis datasets for the period from 2011 to 2017. The increased dust deposition in Japan is explained by the intensified dust transport from the Mongolian Plateau by the anomalous westerly winds associated with a deepened trough over the East Asian continent toward the northwest of the Japanese islands in the middle to lower troposphere. The enhanced dust emission over Gobi Desert and the intensified extratropical cyclone activity are consistent with the larger-than-normal amount of dust in East Asia. Comparing the dust depositions over western and northern Japan, it is suggested that the slightly different anomalous trough positions may determine whether or not a large amount of dust is carried. A further analysis using the long-term (1967-2022) observation data of dust in Japan supports the importance of the intensified trough over the East Asian continent. Dust flux decomposed into cyclonic and anticyclonic components showed that both vortices contribute to the eastward dust transport in East Asia. These results suggest that Japanese dust events and their variability are affected by the stationary circulation anomaly as well as the baroclinic instability waves including transient cyclones and anticyclones.