Fine Dust Particles Research Articles

Spatial and temporal properties of a winter dust event in North China

The optical properties, time-height distribution and particular matter from a heavy Asian dust transport episode are investigated with a synergistic ground-based, satellite sensors and transport model during 17 to 18 Nov. in 2016 in North China. There are few studies on winter dust storm, especially near the source of Asia dust storm along the transmission path. Use of the observation data from the ground-based instruments and satellite, this paper reports the evolution process of the severe dust event in winter in North China. In winter, the Taklimakan desert is the most important source of Asia dust storm. The floating height of most of dust aerosol is less than 2.5 km above ground level, and it is transported along relatively fixed ‘dust corridor’. After passing through the Loess Plateau, dust particles deposition accelerates since lack of transmission power caused by the decrease of west wind speed and the blockade from the reverse wind. As an example, the air quality has dropped to the level of haze pollution. With maximum PM10 mass concentrations above 4400 μg·m−3 in Wuwei city (a typical observation City). In addition, we also analyze the transport characteristics of dust as well as the change features of weather and meteorological elements. The possible transformation of the dust particles into cloud condensation nodules may appear due to the increase of air temperature and humidity in East China. The wet deposition probably is another reason to prevent the spread of fine dust particles with higher floating height. Above conclusions may reveal why East China is rarely subject to dust storms in winter.

Comparison of support vector regression- and neural network-based soft sensors for cement plant exhaust gas composition

Application of accurate gas sampler and analyzers is the most reliable method for measuring cement kiln stack gas composition; however, both are very prone to frequent maintenance due to the presence of very fine dust particles in kiln stack gas. Reliable soft sensors are necessary for online concentration estimation of required components during down time of sampler or analyzer. Since accurate first principal models for cement kiln are very complex and time consuming to solve, artificial neural networks and support vector regression are applied as modeling tools. These tools are used to develop four soft sensors for prediction of O2, CO, NO and CH4 in kiln stack gas. A data set consisting of 29,600 data points on 25 process variables collected during a period of 7 month is used for soft sensor development. To have a meaningful comparison on performance, the same methods for plant data processing, feature variable selection and model optimization are applied for both artificial neural networks- and support vector regression-based soft sensors. Refined data set after data processing is divided into training, test and validation groups that contain 70%, 10% and 20% of data set, respectively. Both average absolute error and average absolute relative error calculated for soft sensor predictions revealed that support vector regression-based soft sensors are more accurate compared to corresponding artificial neural networks-based soft sensors.

Emulsions stabilized by fine dust particles

We investigated the capability of fine dust particles (FDPs) to be used as stabilizers for preparing emulsions. With the aid of cationic surfactants, it was found that the FDPs formed oil in water emulsions that were extremely stable for a long time period. The stabilization mechanism was quantitatively analyzed via ζ-potential measurements of surface modified FDPs and interface adsorption experiments of FDP-coated microbeads by using optical laser tweezers.

Sr-Nd isotopic characteristics of the Northeast Sandy Land, China and their implications for tracing sources of regional dust

The Sr-Nd isotopic study of the Northeast Sandy Land (NESL), China is of great significance for a thorough understanding of the dust system in this area. The 162 bulk (<63 μm) and 86 size-fractioned samples of surface eolian sands and river sands in the NESL are very suitable to be added to the elaborate Sr-Nd isotopic composition dataset. The results are as follows. The Nenjiang River drainage system (NR) in the Songnen Sandy Land (SNSL) and the Hulun Buir Sandy Land (HLSL) are characterized by more radiogenic Nd values relative to the other areas within the NESL whereas the Onqin Daga Sandy Land (ODSL), the Horqin Sandy Land (HQSL) and the Songhua River drainage system (SR) exhibit a clear overlap of Sr-Nd isotopic composition. Nd isotopic composition (especially in the ODSL) exhibits significant dependency on time effect, indicating instability of geochemical composition in the dust source areas. Sr isotopic composition is slightly affected by grain size with very small variations of size-separated 87Sr/86Sr values, yet Nd isotopic composition exhibits clear grain size-dependent variability. The substantial proportion of Sr-Nd isotopic values show enrichment in the coarse-grained fraction, which is accounted for by source-rock control. Both the HLSL and the NR to the northwest of Harbin play very little role in contribution to eolian dust deposits in the Northeast Plain, either in the geological past or now, whereas Sr-Nd geochemical composition alone is insufficient to unequivocally distinguish exact provenance of the eolian dust deposits in this region. The integrated consideration, as expected, revealed the derivation of the eolian dust deposits. The eolian loess and the modern dust-storm deposits in Harbin share significantly different source areas: Harbin loess is the product of spring dust-storm weather and has a mixed source with the SR being the main dust contributor, whereas 2011 Harbin dust-storm deposits were derived from the ODSL and beyond which also provided minor amounts of fine dust particles to Harbin loess.

FOG Droplet과 석탄분진 입자의 충돌 부착에 의한 비산 저감에 관한 연구

A coal dust scattered from storage and transfer facilities of coal power plant is led to a air pollution. It is difficult to reduce some scattered coal dust by used filter system such as bag filter and electric precipitator because of being scattered in the large area. The need to cut down coal dust generation has been increased as being reinforced regulation to reduce dust from coal power plant. So this is a experimental basic study which reduces coal dust generation. This study is to reduce scattering rate of the coal dust by collision and interception between fine fog droplet and coal dust particles. The reducing rate of coal dust is evaluated by droplet size of 10㎛ sprayed. It is evaluated that capture efficiency is lower as a coal dust concentration become higher. And also it is increase as droplet size is decrase and droplet density is increase. It is resulted that coal dust coefficient to optimize the fog system design is 25μg/m3/l/hr and capture efficiency of coal dust is about 80%.

Airborne transmission may have played a role in the spread of 2015 highly pathogenic avian influenza outbreaks in the United States

The unprecedented 2015 outbreaks of highly pathogenic avian influenza (HPAI) H5N2 in the U.S. devastated its poultry industry and resulted in over $3 billion economic impacts. Today HPAI continues eroding poultry operations and disrupting animal protein supply chains around the world. Anecdotal evidence in 2015 suggested that in some cases the AI virus was aerially introduced into poultry houses, as abnormal bird mortality started near air inlets of the infected houses. This study modeled air movement trajectories and virus concentrations that were used to assess the probability or risk of airborne transmission for the 77 HPAI cases in Iowa. The results show that majority of the positive cases in Iowa might have received airborne virus, carried by fine particulate matter, from infected farms within the state (i.e., intrastate) and infected farms from the neighboring states (i.e., interstate). The modeled airborne virus concentrations at the Iowa recipient sites never exceeded the minimal infective doses for poultry; however, the continuous exposure might have increased airborne infection risks. In the worst-case scenario (i.e., maximum virus shedding rate, highest emission rate, and longest half-life), 33 Iowa cases had > 10% (three cases > 50%) infection probability, indicating a medium to high risk of airborne transmission for these cases. Probability of airborne HPAI infection could be affected by farm type, flock size, and distance to previously infected farms; and more importantly, it can be markedly reduced by swift depopulation and inlet air filtration. The research results provide insights into the risk of airborne transmission of HPAI virus via fine dust particles and the importance of preventative and containment strategies such as air filtration and quick depopulation of infected flocks.

Characteristics and health effects of PM2.5 emissions from various sources in Gwangju, South Korea

Increasing evidence suggests that the toxicity of fine dust particles (PM2.5) is linked to specific components rather than their mass. However, research on the chemical composition and health risk of PM2.5 is insufficient. This study analyzed the metals, polycyclic aromatic hydrocarbon (PAHs), organochlorine pesticides (OCPs), and polychlorinated biphenyls (PCBs) present in PM2.5 and evaluated their risk to health during outdoor activities. The concentration of metals was one order of magnitude higher than that of PAHs and the concentration and detection frequency of OCPs and PCBs were considerably lower than those of metals and PAHs. The lifetime excess cancer risk (LECR) for carcinogens in PM2.5 exceeded de minimis risk (1 × 10−6) as 1.33–3.44 × 10−6 (at 5th–95th percentile) as Cr(VI), As, and Cd showed high contributions. Children in the 2 < years <18 age group had a high risk of cancer due to early-life susceptibility. The proportion of ∑Metals to LECR was approximately 95%, while ∑PAHs attributed to 5% of total LECR. The effects of ∑OCPs and 2,3′,4,4′,5′-Pentachlorobiphenyl (PCB-123) on LECR were negligible. The hazard quotient (HQ) for non-carcinogens was <1, and non-carcinogenic effects were not expected. Mn, BaP, Pb, As, and Cd were the key determinants of the HQ values and among the identified PM2.5 sources they are closely related to industrial activities, oil combustion, and gasoline exhaust. Therefore, control strategies for these sources can effectively reduce PM2.5 risk. This study measured the concentrations of toxic compounds in ambient PM2.5 and considered only PM2.5 exposure during outdoor activities. PM2.5 health risk during the entire day would be higher than the PM2.5 risk determined in this study, and further research is required for this evaluating this risk.

건축물 미세먼지 저감을 위한 실외유입과 실내발생의 경로 및 대응제품의 성능기준 조사연구

건축물 미세먼지 저감을 위한 실외유입과 실내발생의 경로 및 대응제품의 성능기준 조사연구

The influence of the thermal modification of pine (Pinus sylvestris L.) wood on the creation of fine dust particles in plane milling: Fine dust creation in the plane milling of thermally modified pine wood.

ObjectivesThe aim of the study was to determine the effect of parameters of the thermal modification process and machining on the size distribution of dust particles of Scots pine (Pinus sylvestris L.) generated during lengthwise milling.MethodUnmodified wood and thermally modified wood at temperatures of 130, 160, 190, and 220°C were milled lengthwise at cutting depths of 0.5 and 2 mm. Particle size analysis was done using the sieving method. The content of the finest particles was measured using the laser diffraction method.ResultsThe results indicate that at smaller cutting depths, more smaller particles were formed regardless of the wood modification temperature. Thermal treatment of wood does not cause significant differences in the general particle size distribution of dust. However, the content of the finest dust particles depends on the temperature of wood modification. When machined, wood thermally modified at higher temperatures results in the formation of more dust particles that may pose health risks to employees. This is particularly noticeable at a smaller cutting depth.ConclusionWith the increase of the temperature of the modification, the share of the finest dust particles, which are a potential threat to the health of employees, increases. To reduce dust emissions during milling of thermally modified wood, the highest possible cutting depth should be used.

Numerical simulation of electrostatic precipitator considering the dust particle space charge

The coupled electric field, gas-particle flow and particle charging processes are simulated using Eulerian-Lagrangian method in Computational Fluid Dynamics (CFD), for a wire-plate electrostatic precipitator with four-wire electrodes configuration. The effects of particle charging on the electric field distribution, VI characteristics and particle collection efficiency are investigated, as the entry particle loading/concentration varies from 0 up to 50 g/Nm3 for a particle size of 0.25–5.0 μm under fixed gas velocity of 1.0 m/s.The results show that the electric field can be distorted significantly by the secondary electric field generated by the space charges on the floating particles, which mostly reduces particle collection efficiency, except at a very low loading. A maximum collection efficiency exists at a particle loading that depends on particle size. Under fixed voltage applied, the corona current decreases as particle loading/concentration increases. As particle loading increases to some point, the corona current from the downstream wires can be extinguished completely (corona quenching). At high particle loadings, corona ion charges may fail to reach the plate due to the absorption of passing particles. The electric streamlines in a small zone around the last wire reverse direction locally. A charged particle, once falls accidently within the zone, could be trapped and be attracted to the same wire. Thus this wire is subject to heavier dust deposition. The significance of ion transfer and space charge of fine dust particles is clarified systematically.

Protective effect of green tea catechin against urban fine dust particle-induced skin aging by regulation of NF-κB, AP-1, and MAPKs signaling pathways

The increase in ambient fine dust particles (FDP) due to urbanization and industrialization has been identified as a major contributor to air pollution. It has become a serious issue that threatens human health because it causes respiratory diseases and skin aging. In the present study, the protective effect of the green tea catechin, (−)-epigallocatechin gallate (EGCG), against FDP (ERM-CZ100)-stimulated skin aging in human dermal fibroblasts (HDFs) was investigated. The results demonstrate that EGCG significantly and dose-dependently scavenged intracellular reactive oxygen species (ROS) in and increased the viability of FDP-stimulated HDFs. In addition, EGCG dose-dependently recovered collagen synthesis and inhibited intracellular elastase and collagenase activities. Moreover, EGCG decreased the expression of human matrix metalloproteinases (MMPs) via regulation of nuclear factor kappa B (NF-κB), activator protein 1 (AP-1), and mitogen-activated protein kinases (MAPKs) signaling pathways in FDP-stimulated HDFs. This study suggests that EGCG is a potential anti-aging candidate that can be used for FDP-induced skin aging as a therapeutic agent itself or as an ingredient in pharmaceutical and cosmeceutical products.

Hall current effect on unsteady rotational flow of carbon nanotubes with dust particles and nonlinear thermal radiation in Darcy–Forchheimer porous media

The present discussion is about the unsteady two-dimensional flow of mixed convection and nonlinear thermal radiation in the presence of water-based carbon nanotubes over the vertically convected stretched sheet embedded in a Darcy’ Forchheimer porous media. Saffman’s proposed model is used for the suspension of fine dust particles in the nanofluid. A strong magnetic field (MHD) is applied normal to the flow which governs the Hall current effects. Khanafer Vafai Lightstone model estimated the effect of thermal conductivity and viscosity of the carbon nanotubes. Boundary layer approximation is utilized to built the nonlinear partial differential equations (PDEs). Similarity transformation is applied to convert these PDEs into the system of ordinary differential equations. Problem is solved numerically by bvp4c, using MATLAB software. It is observed through the analysis that the thermal field of nanofluid and the temperature boundary layer are much more higher than that of the dust phase, and these are further enhanced for the higher radiation parameter.

Accumulation of polycyclic aromatic hydrocarbons in snow cover near fuel and energy enterprises of the Vorkuta city

The paper deals with the composition of polycyclic aromatic hydrocarbons (PAHs) in snow cover near the city of Vorkuta (Komi Republic, Russia) in the impact zone of the fuel and energy complex. It includes the results on background aero technogenic pollution levels of Vorkuta and its suburbs for subsequent ecological monitoring and on precipitation areas of different PAH fractions within the impact zones of combined heat-and-power plants, the central water boiler plant, and the territory of Vorkuta. “Light” (easily mobile) PAHs are present at almost any test site and attain extreme values in the impact zones of heat-and-power plant 1, heat-and-power plant 2, the central water boiler plant, and the territory of Vorkuta. They are transported at large distances because of high volatility. In addition, light PAHs are transported with air aerosols as they get adsorbed on fine dust particles. “Heavy” PAHs are present on the territory of the city and in the impact zones of the both energy-and-power plants with local pollution extremes from heat-and-power plant 2 at distances of 0.5, 3.0, 11.2 km but are not transported outside 11.2 km. There are interlinks between accumulation of PAHs and other organic and inorganic pollutants. Concerning analyses of PAHs from snow cover, there exist certain territorial groups which allow for understanding pollution sources (fuel and energy complex, auto transport, coal mining). Indicating ratios of PAHs in snow cover of Vorkuta evidence their pyrogenic genesis.

Development of Dust Storm Modeling for Use in Freeway Safety and Operations Management: An Arizona Case Study

Extreme weather conditions such as strong winds, hail, heavy rainfall, heavy snowfall, and high air temperature impact roads, traffic, and operational decisions. Strong winds in arid regions may pick up fine dust particles and create massive blowing plumes dramatically reducing the visibility. This reduced visibility severely impairs driving ability causing catastrophic crashes. The purpose of this research was to investigate the impacts of dust storms on freeway safety and operations. Interstates 8, 10, 15, 17, 19, and 40 running through Arizona were studied in relation to dust loading and crash risks. To achieve this, nine severe Arizona dust storms (2009–2016) were modeled using Weather Research and Forecasting (WRF) model coupled with a chemistry module (WRF-Chem). WRF is a mesoscale numerical weather prediction system with a software architecture allowing for parallel computation. When coupled with a chemistry module (WRF-Chem), it could be used to model the fate and transport of the particulate matter. Dust hot spots were calculated based on Getis-Ord Gi* statistical method and were correlated to dust storm caused crashes. It was shown that a positive Gi* accompanied by dust loading of at least 50 kgm–2 will result in a crash with a 90% confidence level. The outcome of this research could be used by local and federal transportation agencies to communicate warnings to drivers for improved safety.

Carbonate drifts as marine archives of aeolian dust (Santaren Channel, Bahamas)

AbstractSediment data from the Bahamian Santaren carbonate drift reveal the variability of trans‐Atlantic Saharan dust transport back to about 100 ka bp (Marine Isotope Stage 5·3) and demonstrate that carbonate drifts are a valuable pelagic archive of aeolian dust flux. Carbonate drift bodies are common around tropical carbonate platforms; they represent large‐scale accumulations of ocean‐current transported material, which originates from the adjacent shallow‐water carbonate factory as well as from pelagic production, i.e. periplatform ooze. Subordinately, there is a clay‐size to silt‐size non‐carbonate fraction, which typically amounts to less than 10% of the sediment volume and originates from aeolian and fluvial input. Sedimentation rates in the 5·42 m long core GeoHH‐M95‐524 recovered 25 km west of Great Bahama Bank in the Santaren Channel ranges from 1·5 to 24·5 cm ka−1 with lowest values during the last glacial lowstand and highest values following platform re‐flooding around 8 ka bp. These sedimentation rates imply that carbonate drifts have not only the potential to resolve long‐term environmental changes on orbital timescales, but also millennial to centennial fluctuations during interglacials. The sediment core has been investigated with the aim of characterizing the lithogenic dust fraction. Laboratory analyses included X‐ray fluorescence core scanning, determination of carbonate content and grain‐size analyses (of bulk and terrigenous fraction), as well as visual inspections of the lithogenic residue; the age model is based on oxygen isotopes and radiocarbon ages. Data show that the input of aeolian dust in the periplatform ooze as indicated by Ti/Al and Fe/Al element ratios abruptly increases at 57 ka bp, stays elevated during glacial times, and reaches a Holocene minimum around 6·5 ka bp, contemporary to the African Humid Period. Subsequently, there is a gradual increase in dust flux which almost reaches glacial levels during the last centuries. Grain‐size data show that the majority of dust particles fall into the fine silt range (below 10 μm); however, there is a pronounced coarse dust fraction in the size range up to 63 μm and individual ‘giant’ dust particles are up to 515 μm in size. Total dust flux and the relative amounts of fine and coarse dust are decoupled. The time‐variable composition of the grain‐size spectrum is interpreted to reflect different dust transport mechanisms: fine dust particles are delivered by the trade winds and the geostrophic winds of the Saharan Air Layer, whereas coarse dust particles travel with convective storm systems. This mode of transport ensures continuous re‐suspension of large particles and results in a prolonged transport. In this context, grain‐size data from the terrigenous fraction of carbonate drifts provide a measure for past coarse dust transport, and consequently for the frequency of convective storm systems over the dust source areas and the tropical Atlantic.

Spatial distribution and temporal trend of airborne trace metal deposition in Albania studied by moss biomonitoring

This study describes the assessment of air quality in Albania using moss biomonitoring. The moss species, Hypnum cupressiforme (Hedw) sps., was used in this study. Mosses were collected during August and September 2015 at 55 sampling sites more or less homogeneously distributed over the entire territory of the country. The spatial distribution and temporal trends of trace metal atmospheric deposition were studied through the determination of twenty inorganic elements, Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Li, Mg, Mn, Na, Ni, Pb, Sr, V, and Zn. ICP-AES, AAS (As and Cd) and CV AAS (Hg) analysis were used to determine the concentration of the elements. The obtained data show significant differences in the spatial distribution of the elements derived from different emission sources. High emission loads of anthropogenic elements (Cr, Ni, Cu, As and Zn) were detected in the East, and of sea salt elements, particularly Na and K, in the Western coastal line. The distribution trend of the trace metals was studied by comparing the current data with the data of a similar study performed in 2010. Due to the differences in airborne metal concentrations, their scavenging ratios from the atmosphere to the terrestrial ecosystems, and their different uptake-leaching rates during wet and dry deposition respectively of 2015 and 2010 moss grown period, different concentration levels were found in 2010 and 2015 moss metal concentrations. The 2015 moss concentration levels of anthropogenic elements Cr, Ni, Cu, As, Zn and Na had increased, while K, Mg and Hg moss concentration data had declined. Other elements show non significant differences in mosses of both monitoring periods.The contamination levels that were evaluated by calculating the contamination factor (CF) for each element provided similar results for the 2015 and 2010 moss survey. Factor analysis (FA) was applied to identify the possible sources of elements in the 2015 moss samples. Five dominant factors were identified representing long-range and local atmospheric transport of wind-blown soil dust particles (F1); local emission from chromium industry and wind-blown mineral dust particles (F2); anthropogenic sources of traffic emission and wind-blown fine mineral dust particles derived from geogenic origin natural transport from the marine environment (F4); and long-range atmospheric deposition (F5). This study emphasis that moss biomonitoring combined with data analysis and inventory of emission sources are important tools to assess air quality in Albania.

FeinPhone: Low-cost Smartphone Camera-based 2D Particulate Matter Sensor.

Precise, location-specific fine dust measurement is central for the assessment of urban air quality. Classic measurement approaches require dedicated hardware, of which professional equipment is still prohibitively expensive (>10k$) for dense measurements, and inexpensive sensors do not meet accuracy demands. As a step towards filling this gap, we propose FeinPhone, a phone-based fine dust measurement system that uses camera and flashlight functions that are readily available on today’s off-the-shelf smart phones. We introduce a cost-effective passive hardware add-on together with a novel counting approach based on light-scattering particle sensors. Since our approach features a 2D sensor (the camera) instead of a single photodiode, we can employ it to capture the scatter traces from individual particles rather than just retaining a light intensity sum signal as in simple photometers. This is a more direct way of assessing the particle count, it is robust against side effects, e.g., from camera image compression, and enables gaining information on the size spectrum of the particles. Our proof-of-concept evaluation comparing several FeinPhone sensors with data from a high-quality APS/SMPS (Aerodynamic Particle Sizer/Scanning Mobility Particle Sizer) reference device at the World Calibration Center for Aerosol Physics shows that the collected data shows excellent correlation with the inhalable coarse fraction of fine dust particles (r > 0.9) and can successfully capture its levels under realistic conditions.

Air Quality and Chronic Stress: A Representative Study of Air Pollution (PM2.5, PM10) in Germany.

With rising attention on climate change and the aftermath of burning fossil fuels, there is much concern regarding the effects of air pollution on physical and psychological health. However, the relationship between chronic stress and air pollution is relatively unexplored in humans. By combining German representative data with national pollution data and using step-wise regression analyses, this study investigates how air pollution (particulate matter 2.5 and 10 [PM2.5 and PM10]) impacts ones' chronic stress levels (TICS). Results show PM2.5 fine-dust particles significantly affect chronic stress, while PM10 has no such effect. Air pollution (PM2.5), age, and income together explain 3% of variation in chronic stress in a nationally representative sample. Further studies must test pollutants such as NO2 and O3 as well as investigate the potential accumulated effect of pollution and stress combined on human health.

A comparison of the abrasive sanding dust emission characteristics of oil palm wood and rubberwood

With the increasing interest in using oil palm wood (OPW) in the manufacture of value-added wood products in the South East Asian region, the subject of dust emission in relation to the variable density of OPW is a matter of concern. Therefore, this study evaluated the dust emission characteristics of untreated and phenol-formaldehyde-treated OPW during the abrasive sanding process. Rubberwood was the solid wood material used in this study for comparison purposes. The abrasive sanding process was carried out using an orbital sander with aluminium oxide abrasive paper with a grit size of 150. The sample boards were weighed before and after sanding to determine the amount of stock removed. The dust concentration and dust particles diameter was influenced by the material type, material density variation, and material hardness. The study revealed that both untreated and treated OPW produced higher dust concentration and higher proportions of fine respirable dust particles compared with rubberwood during the abrasive sanding processes, and therefore, it is important for a more stringent permissible exposure level (PEL) standard for dust emission to be established for OPW processing. In this context, the existing PEL of 5 mg/m3 of dust is inappropriate and needs a revision if OPW is to be successfully used in the value-added wood products industry.

The AFWA dust emission scheme for the GOCART aerosol model in WRF-Chem v3.8.1

Abstract. Airborne particles of mineral dust play a key role in Earth's climate system and affect human activities around the globe. The numerical weather modeling community has undertaken considerable efforts to accurately forecast these dust emissions. Here, for the first time in the literature, we thoroughly describe and document the Air Force Weather Agency (AFWA) dust emission scheme for the Georgia Institute of Technology–Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) aerosol model within the Weather Research and Forecasting model with chemistry (WRF-Chem) and compare it to the other dust emission schemes available in WRF-Chem. The AFWA dust emission scheme addresses some shortcomings experienced by the earlier GOCART-WRF scheme. Improved model physics are designed to better handle emission of fine dust particles by representing saltation bombardment. WRF-Chem model performance with the AFWA scheme is evaluated against observations of dust emission in southwest Asia and compared to emissions predicted by the other schemes built into the WRF-Chem GOCART model. Results highlight the relative strengths of the available schemes, indicate the reasons for disagreement, and demonstrate the need for improved soil source data.