Asian Dust Particles Research Articles

An Orchestrated Attempt to Determine the Chemical Properties of Asian Dust Particles by PIXE and XRF Techniques

An Orchestrated Attempt to Determine the Chemical Properties of Asian Dust Particles by PIXE and XRF Techniques

Asian dust storm particles induce a broad toxicological transcriptional program in human epidermal keratinocytes

Exposure to airborne dust particles originated from seasonal Asian dust storms in Chinese and Mongolian deserts results in increased incidence of a range of diseases including asthma, contact dermatitis and conjunctivitis. The areas affected by Asian dust particles extend from East China to the west coast of North America. In order to study toxicological mechanisms in human skin, we evaluated the effects of dust particles collected during Asian dust storms (Asian dust particles) on gene expression in human epidermal keratinocytes (HEK). In HEK, exposure to Asian dust particles significantly increased gene expressions of cytochrome P450 1A1 (CYP1A1), CYP1A2, and CYP1B1, which is an indication of aryl hydrocarbon receptor (AHR) activation. In addition, Asian dust particles increased gene transcription of the cytokines IL-6, IL-8, and GM-CSF, which have broad pro-inflammatory and immunomodulatory properties. Asian dust particles significantly up-regulated expression of caspase 14 in HEK, suggesting that Asian dust particles directly affect keratinocyte differentiation. We also demonstrated that protein extract of pollen, a material frequently adsorbed onto Asian dust particles, potentially contributes to the increased transcription of IL-6, CYP1A1, CYP1A2, and CYP1B1. Taken together, these studies suggest that Asian dust particles can exert toxicological effects on human skin through the activation of the cellular detoxification system, the production of pro-inflammatory and immunomodulatory cytokines, and changes in the expression of proteins essential in normal epidermal differentiation.

Asian dust and titanium dioxide particles–induced inflammation and oxidative DNA damage in C57BL/6 mice

Inhaled particulate matter (PM) might influence many adverse health effects in human body, including increased exacerbations of pulmonary and cardiovascular diseases. In this study, we examined the associations between PM and pulmonary adverse effects. Two types of particles, Asian dust (AD) and titanium dioxide (TiO2), were administered intratracheally to C57BL/6 mice. The mice were exposed to saline and saline suspensions of 20 mg/ kg of AD, TiO2 particles twice a week for 12 weeks. Following exposure with these particles, the lungs were analyzed histopathologically by hematoxylin and eosin (H&E) and Masson’s trichrome (MT) staining. Oxidative injuries were determined by immunohistochemistry (IHC) for 8-oxoguanine in the lungs and Comet assays in peripheral blood mononuclear cells (PBMCs) of C57BL/6 mice. Mice exposed to AD and TiO2 showed significant inflammatory changes and oxidative damages in the lungs as compared with the control group. DNA damage in PBMCs was also increased significantly in AD and TiO2-exposed mice. However, lung fibrosis was minimal and there was no significant difference between PM exposed and control mice. Exposure to AD and TiO2 particles–induced similar inflammatory damages in the lungs and elicited oxidative DNA damage in the PBMCs.

Asian dust particles converted into aqueous droplets under remote marine atmospheric conditions

The chemical history of dust particles in the atmosphere is crucial for assessing their impact on both the Earth's climate and ecosystem. So far, a number of studies have shown that, in the vicinity of strong anthropogenic emission sources, Ca-rich dust particles can be converted into aqueous droplets mainly by the reaction with gaseous HNO(3) to form Ca(NO(3))(2). Here we show that other similar processes have the potential to be activated under typical remote marine atmospheric conditions. Based on field measurements at several sites in East Asia and thermodynamic predictions, we examined the possibility for the formation of two highly soluble calcium salts, Ca(NO(3))(2) and CaCl(2), which can deliquesce at low relative humidity. According to the results, the conversion of insoluble CaCO(3) to Ca(NO(3))(2) tends to be dominated over urban and industrialized areas of the Asian continent, where the concentrations of HNO(3) exceed those of HCl ([HNO(3)/HCl]>∼1). In this regime, CaCl(2) is hardly detected from dust particles. However, the generation of CaCl(2) becomes detectable around the Japan Islands, where the concentrations of HCl are much higher than those of HNO(3) ([HNO(3)/HCl]<∼0.3). We suggest that elevated concentrations of HCl in the remote marine boundary layer are sufficient to modify Ca-rich particles in dust storms and can play a more important role in forming a deliquescent layer on the particle surfaces as they are transported toward remote ocean regions.

Pathological Study of Acute Pulmonary Toxicity Induced by Intratracheally Instilled Asian Sand Dust (Kosa)

The objective of this study was to investigate acute lung toxicity caused by Asian sand dust. Simulated Asian sand dust collected from the Tennger desert in China (CJ-2 particles) and Asian sand dust collected from the atmosphere in Japan (Tottori particles) were used. Saline suspensions of 50, 200, 800, and 3,000 µg Asian sand dust were intratracheally instilled to ICR mice. Localized accumulation of the dust particles was observed in the bronchioles and the alveoli of the lung tissues; acute inflammatory changes characterized by infiltration of macrophages and neutrophils were observed around the particles. Degenerated alveolar walls and bronchial epithelial cells, as well as a weakened positive immunolabeling for laminin, were observed to be associated with particle attachment. Positive immunolabelings for interleukin-6, tumor necrosis factor-α inducible nitric oxide synthase, and dimeric copper- and zinc-containing superoxide dismutase were observed mainly in the inflammatory cells in the lesions; these findings were not observed in the controls or in areas lacking lesions. These results suggest that Asian sand dust particles caused damage to the lung tissue through a direct physical effect. In addition, secondary released cytokines and oxidative stress generated in the lesion may be involved in the development of the acute lung toxicity.

Chemical Transformation of Individual Asian Dust Particles Estimated by the Novel Double Detector System of Micro-PIXE

By the application of novel double detector system of micro-PIXE that can detect light elements (Z<14), we made an attempt to provide a thorough discussion on the aging processes of Asian dust (hereafter called "AD") particle by reaction with sea-slat. The elemental spectra and maps obtained from the microbeam radiation of micro-PIXE to individual AD particles were useful for fractionating AD particles into both internally and externally mixed particles. A spatial distribution of elements in a minute domain of single particle obtained by scanning the microbeam irradiation enabled us not only to estimate the chemical mixing state of individual AD particles but also to presume their aging processes in both ambient air and cloud. By calculating the normalized micro-PIXE net count of elements, it was possible to classify individual AD particles into three distinct groups (i.e., (1) Aging type 1: AD particle coated by the gaseous Cl evaporated by the reaction between artificial acids and sea salt; (2) Aging type 2: AD particle mixed with sea salt but no additional reaction with artificial acids; and (3) Non-aged type) A relatively high transformation rate (63.3-75.9%) was shown in large particles (greater than <TEX>$5.1\;{\mu}m$</TEX> in diameter).

Chemical Transformation of Individual Asian Dust Particles Estimated by the Novel Double Detector System of Micro-PIXE

Chemical Transformation of Individual Asian Dust Particles Estimated by the Novel Double Detector System of Micro-PIXE

Effect of chemical mixing state on the hygroscopicity and cloud nucleation properties of calcium mineral dust particles

Abstract. Atmospheric mineral dust particles can alter cloud properties and thus climate by acting as cloud condensation nuclei (CCN) that form cloud droplets. The CCN activation properties of various calcium mineral dust particles were studied experimentally to investigate the consequences of field observations showing the segregation of sulphate from nitrate and chloride between individual aged Asian dust particles, and the enrichment of oxalic acid in Asian dust. Each mineral's observed apparent hygroscopicity was primarily controlled by its solubility, which determines the degree to which the mineral's intrinsic hygroscopicity can be expressed. The significant increase in hygroscopicity caused by mixing soluble hygroscopic material with insoluble mineral particles is also presented. Insoluble minerals including calcium carbonate, representing fresh unprocessed dust, and calcium sulphate, representing atmospherically processed dust, had similarly small apparent hygroscopicities. Their activation is accurately described by a deliquescence limit following the Kelvin effect and corresponded to an apparent single-hygroscopicity parameter, κ, of ~0.001. Soluble calcium chloride and calcium nitrate, representing atmospherically processed mineral dust particles, were much more hygroscopic, activating similar to ammonium sulphate with κ~0.5. Calcium oxalate monohydrate (κ=0.05) was significantly less CCN-active than oxalic acid (κ=0.3), but not as inactive as its low solubility would predict. These results indicate that the common assumption that all mineral dust particles become more hygroscopic and CCN-active after atmospheric processing should be revisited. Calcium sulphate and calcium oxalate are two realistic proxies for aged mineral dust that remain non-hygroscopic. The dust's apparent hygroscopicity will be controlled by its chemical mixing state, which is determined by its mineralogy and the chemical reaction pathways it experiences during transport.

Influence of Surface-Based Stable Layer Development on Asian Dust Behaviour Over Tokyo

The relationship between local meteorological fields and the behaviour of airborne Asian dust that arrived in the Tokyo metropolitan area on 1 April 2007 with the passage of a synoptic-scale cold front has been investigated through Doppler lidar observations, experiments using a regional atmospheric numerical model, and analyses of surface and upper-air meteorological observations. Results of the Doppler lidar observations showed that the Asian dust passed above the metropolitan area with strong south-westerly winds with speeds of 15–26 m s−1. Meteorological fields reproduced by the numerical experiments showed the development of a surface-based stable layer in the metropolitan area caused by nocturnal radiational cooling near the ground surface and south-westerly warm air advection at upper levels. The blocking effect of the mountainous region located to the west of the metropolitan area induced an area of stagnant air inside the metropolitan area and promoted the stable layer development. Although strong downdrafts prevailed in the upper air, the airborne Asian dust did not spread to the ground when the stable layer was formed. These results strongly indicate that the developed stable layer prevented strong downdrafts from spreading to the ground, acting as an obstacle to the transport of the Asian dust particles from the upper air towards the ground. This is considered to be one of the main causes of the low appearance frequency of Asian dust phenomena near the ground in the Tokyo metropolitan area and eastern Japan.

Asian Dust particles impacts on air quality and radiative forcing over Korea

Asian Dust particles originated from the deserts and loess areas of the Asian continent are often transported over Korea, Japan, and the North Pacific Ocean during spring season. Major air mass pathway of Asian dust storm to Korea is from either north-western Chinese desert regions or north-eastern Chinese sandy areas. The local atmospheric environment condition in Korea is greatly impacted by Asian dust particles transported by prevailing westerly wind. Since these Asian dust particles pass through heavily populated urban and industrial areas in China before it reach Korean peninsular, their physical, chemical and optical properties vary depending on the atmospheric conditions and air mass pathway characteristics. An integrated system approach has been adopted at the Advanced Environment Monitoring Research Center (ADEMRC), Gwangju Institute Science and Technology (GIST), Korea for effective monitoring of atmospheric aerosols utilizing various in-situ and optical remote sensing methods, which include a multi-channel Raman LIDAR system, sunphotometer, satellite, and in-situ instruments. Results from recent studies on impacts of Asian dust particles on local air quality and radiative forcing over Korea are summarized here.

Mixture of Kosa (Asian dust) and bioaerosols detected in the atmosphere over the Kosa particles source regions with balloon-borne measurements: possibility of long-range transport

Long-range transport of atmospheric microbiota with Asian dust (Kosa) particles is of great concern in Northeast Asia in view of the health effect of Kosa particles on human being, disturbance of ecosystems caused through invasion of new microbe, contribution of microorganisms to biogeochemical cycle on global/regional scales, and others. Information on atmospheric microbes over the desert areas has been desired for a long time. Detection of atmospheric microbiota on the desert regions, on the base of balloon-borne measurements, has been made at Dunhuang, China (40°00′ N, 94°30′ E; east end of Taklamakan desert) in the summer of 2007. The measurements showed that microbiota mixed internally with Kosa particles were frequently floating from the ground to about 2-km heights (above sea level), and possible long-range transport of atmospheric microbiota with dust particles taking local circulations is strongly suggested, causing active mixing of atmospheric dust over the Taklamakan desert from the ground to the free troposphere where westerly jet dominates (Iwasaka et al. in J Geophys Res 108:8652, 2003a, J Geophys Res 108:8644, b). The concentration of the mixed particles of Kosa and microbiota having a size larger than about 1 μm in diameter is estimated to be about 1 particle/cm3 at those heights on the basis of measurements of particle concentration with an optical particle counter and analysis of particles having fluorescence light due to dye of DAPI (4′6-diamidino-2 phenylindole) with an epifluorescence microscope. The mixing situation of microbiota and Kosa particles is the important factor controlling atmospheric lifetime of floating microbiota, since the mixing state certainly can protect microbiota from stressful environments [dryness, solar ultraviolet (UV) radiation, low temperature] in the atmosphere, and therefore, it is useful to discuss the data of the first description of microbiota in the atmosphere on the Taklamakan desert.

The Case Study on Elemental Analyses of Asian Dust Particles by Using an Analytical Scanning Electron Microscope

The individual particle analyses of suspended particulate matter (SPM:particles less than 10μm in size) collected on tape filters during April 17-18, 2006, in Kawasaki, Japan, were carried out. The chemical elements present in aerosol particles were investigated by using a scanning electron microscope with an energy-dispersive X-ray spectrometer. The fraction of chemical elements detected in the particles collected on April 18, 2006, except for S, was in good agreement with that in Asian dust particles from the Loess Plateau, China. S was not detected in Asian dust particles but was detected in the particles collected on April 18, 2006. Therefore, it was concluded that the particles collected on April 18, 2006, in Kawasaki were Asian dust particles transported from the Asian continent, and the absorption of SO2 or the coagulation of sulfate occurred during the transportation of Asian dust particles.

The Effect of Particulate Matter 10 from Asian Dust on the Production of Reactive Oxygen Species, TGF-β, NF-κB, PDGF-α and Fibronectin in MRC-5 Fibroblast Cells

Background: Dust clouds blown by the wind from the arid deserts of Mongolia and Northeast China are known as Asian dust storms. Ambient particulate matter with a diameter <10 μm (PM10) is associated with the exacerbation of respiratory diseases and increased mortality of heart and lung disease patients. The fibrotic effects of PM10 of Asian dust to pulmonary fibroblast cells are unknown. This study examined the production of reactive oxygen species (ROS), TGF-β, NF-κB, PDGF-α and Fibronectin in fibroblasts exposed to Asian dust particles. Methods: Air samples were collected using a high volume air sampler (Sibata model HV500F) with an air flow of 500 L/min for at least 6 hours. The MRC-5 cells were exposed to 0, 50 and 100 μg/mL of PM10 for 24 hours. ROS was detected by measuring the level of oxidized DCF using FACS. TGF-β, NF-κB, PDGF-α and fibronectin were detected by western blotting. Results: There was no increase in the ROS, TGF-s and PDGF-α levels in the MRC-5 cells exposed to PM10. The NF-κ B level was higher in the MRC-5 cells exposed to 50 and 100 μg/mL of PM10 for 24 hours. The fibronectin level in the MRC-5 cells after 24 hours incubation with 50 μg/mL PM10 was significantly higher than the control group (PM10 50 μg/mL 113.27±8.65 of control, p=0.005). Conclusion: PM10 from Asian dust increases the activation of NF-κB and fibronectin expression in MRC-5 fibroblast cells.

Characteristics of atmospheric dust deposition in snow on the glaciers of the eastern Tien Shan, China

AbstractWind-blown mineral aerosol dust derived from the crustal surface is an important atmospheric component affecting the Earth’s radiation budget. Deposition of water-insoluble dust was determined in snow deposited on Ürümqi glacier No. 1, Haxilegen glacier No. 51 and Miaoergou glacier, eastern Tien Shan, China. Analysis of the horizontal distribution of snow depth and concentration, and flux of dust particles in the snow cover suggests that dust deposition differs on each of these glaciers as the atmospheric environment changes from west to east. Mean mass concentrations of micro-particles in the size range 0.57–26 μm diameter at the three locations are respectively 969, 1442 and 3690 μg kg−1, with an increasing trend from west to east. Dust layers in the snow cover contain Na- and Ca-rich materials typically found in central Asian dust particles. Volume size distributions of dust particles in the snow showed single-modal structures having volume median diameters of 3–22 μm. Dust profiles in the snow cover over the past 4 years reveal frequent, sporadic high dust concentrations with a large year-to-year variability, implying that dust deposition in the eastern Tien Shan is very sensitive to atmospheric environment change.

An analysis of individual Asian-dust particles collected at Higashiosaka, Japan in 2007 and 2008

An analysis of individual Asian-dust particles collected at Higashiosaka, Japan in 2007 and 2008

Single-particle characterization of aerosol samples collected before and during an Asian dust storm in Chuncheon, Korea

Low- Z particle electron probe X-ray microanalysis, a single-particle analysis method, was used to characterize aerosol samples collected in Chuncheon, Korea, before and during a dust storm that occurred between 10 and 12 March, 2004. Four different samples were analyzed: just before the storm, peak time of the storm, late stage of the storm, and end of the storm. All four of the samples were found to have experienced chemical modifications during long-range transport due to elevated levels of nitrate and sulfate that resulted from atmospheric reactions with CaCO 3 and sea-salt particles. The sample collected just before the storm underwent the most extensive chemical modification during transport. For this particular sample, the overall relative abundances of reacted CaCO 3 and sea-salt particles were 9.8% and 44.2%, respectively. The sample collected at the peak time of the storm also experienced extensive chemical modification with overall relative abundances of reacted CaCO 3 and sea-salt particles at 4.3% and 23.3%, respectively. The backward trajectory analysis for this particular sample revealed two different types of air-masses arriving at the sampling site in Korea; one is high-altitude air-masses moving rapidly and carrying Asian dust particles and the other a slow-moving low-altitude air-mass from eastern China coastal areas. The single-particle characterization of this same sample showed that the Asian dust particles were mixed with sea-salts entrained over the Yellow Sea, as well as air pollutants from the eastern China coastal areas. However, as the Asian dust storm continued, soil-derived mineral particles became dominant in the samples that were collected at the late stage of the storm and at the end. For this specific Asian dust storm, the mixing of sea-salts and pollution with Asian dust particles was observed to occur just at the early stage of the storm.

Dynamics of southwest Asian dust particle size characteristics with implications for global dust research

As part of the United Arab Emirates Unified Aerosol Experiment (UAE2), the size distribution and chemistry of dust particles were measured for the months of August and September 2004 at an Arabian Gulf coastal site impacted by dust from several sources within southwest Asia. The characteristics of common mode dust (0.8 &lt; dp &lt; 10 μm) were examined using an aerodynamic particle sizer (APS), a DRUM cascade impactor, and AERONET Sun/sky retrievals. While size properties from these distinct methods do correlate, accurate dust measurement is still an outstanding challenge. But when instruments are applied consistently in the correct context, the dynamics of dust particle size can be accurately studied. Here, observations are used to study the stability of dust size and chemistry characteristics. We found that dust particle size, chemistry, and morphology appear to be fairly static from individual sources, confirming preliminary hypotheses based on large‐scale observations of Saharan dust. Thus, our data provide experimental evidence that on regional scales, common mode dust is not functionally impacted by production wind speed, but rather influenced by soil properties such as geomorphology or roughness length. Similarly, we found transport processes from the mesoscale to near synoptic scale do not significantly impact common mode dust size either. When combined with other APS observations around the world, the dust coarse mode is found to be fairly robust with a volume median diameter on the order of ∼3.5 μm ± 30%. Finally, evidence for a strong submicron dust mode, suggested in previous studies, was inconclusive.

Physicochemical Properties of Asian Dust Sources

In order to fully understand the chemical properties of Asian dust particles, especially their transformation and aging processes, it is desirable to investigate the nature of original sands collected at local source areas in China. This study presents the de-tailed properties of sands collected at four different desert regions (Yinchuan, Wuwei, Dulan, and Yanchi) in China. Most of sands have irregular shape with yellowish coloration, whereas some of them show peculiar colors. The relative size distribution of sands collected at Yinchuan, Wuwei, and Dulan deserts exhibits monomodal with the maximum level between 200 and 300 μm, whereas that of Yanchi desert is formed between 100 and 200 μm. The mass concentration ratio of each element to that of Si (Z/Si) determined by PIXE analysis has a tendency towards higher Z/Si ratios for soil derived elements. It was possible to visually reconstruct the elemental maps on the surface of individual sands by XRF microprobe technique. In addition, the multielemental mass concentration could be quantitatively calculated for numerous spots of desert sands.

Asian dust storm influence on North American ambient PM levels: observational evidence and controlling factors

Abstract. New observational evidence of the trans-Pacific transport of Asian dust and its contribution to the ambient particulate matter (PM) levels in North America was revealed, based on the interannual variations between Asian dust storms and the ambient PM levels in western North America from year 2000 to 2006. A high correlation was found between them with an R2 value of 0.83. From analysis of the differences in the correlation between 2005 and 2006, three factors explain the variation of trans-Pacific transport and influences of Asian dust storms on PM levels in western North America. These were identified by modeling results and the re-analysis data. They were 1) Strength of frontal cyclones from Mongolia to north eastern China: The frontal cyclones in East Asia not only bring strong cold air outbreaks, generating dust storms in East Asia, but also lift Asian dust into westerly winds of the free troposphere for trans-Pacific transport; 2) Pattern of transport pathway over the North Pacific: The circulation patterns of westerlies over the North Pacific govern the trans-Pacific transport pattern. Strong zonal airflow of the westerly jet in the free troposphere over the North Pacific favor significant trans-Pacific transport of Asian dust; 3) Variation of precipitation in the North Pacific: The scavenging of Asian dust particles by precipitation is a major process of dust removal on the trans-Pacific transport pathway. Therefore, variation of precipitation in the North Pacific could affect trans-Pacific transport of Asian dust.

Observation of Asian Dust Aerosols with Depolarization Lidar Using a Coherent White Light Continuum

We performed a lidar observation of Asian dust aerosols for the first time using a white light lidar system. The lidar used in the observation utilized a coherent white light continuum generated in Kr gas as a light source and was used as a three-wavelength Mie-scattering lidar having a depolarization measurement capability at 450, 550, and 800 nm. Lidar depolarization ratios of 0.30–0.70 at 800 nm were measured. These data reveal a higher depolarization ratio than usual (normally almost zero) in the lower troposphere. Thus, the white light lidar can identify Asian dust particles that pose a threat to cross-border pollution in Japan.