Dust Storm Particles Research Articles

Heterogeneous photochemical reaction of ozone with anthracene adsorbed on mineral dust

The heterogeneous reactions of O3 with anthracene adsorbed on TiO2 and on Asian dust storm particles were investigated in the dark and in the presence of light. The reaction rate constants of the heterogeneous reaction between O3 and anthracene adsorbed on TiO2 were increased by a factor of 1.5 in the presence of light compared to the dark conditions. Anthraquinone, which was identified as the main surface product of anthracene reacted with O3 in the dark, can react with O3 quickly in the presence of light. The reactions on Asian dust storm particles exhibited pseudo-first-order kinetics for anthracene loss, and the reactions between O3 and anthracene adsorbed on Asian dust storm particles proceed by the Langmuir–Hinshelwood mechanism in the dark and in the presence of light. At extremely high ozone concentrations, the degradation of anthracene is enhanced by a factor of 3 in the presence of light compared to the dark conditions.

A case study of Asian dust storm particles: Chemical composition, reactivity to SO 2 and hygroscopic properties

Abstract Mineral dust comprises a great fraction of the global aerosol loading, but remains the largest uncertainty in predictions of the future climate due to its complexity in composition and physico-chemical properties. In this work, a case study characterizing Asian dust storm particles was conducted by multiple analysis methods, including SEM-EDS, XPS, FT-IR, BET, TPD/mass and Knudsen cell/mass. The morphology, elemental fraction, source distribution, true uptake coefficient for SO 2, and hygroscopic behavior were studied. The major components of Asian dust storm particles are aluminosilicate, SiO 2 and CaCO 3, with organic compounds and inorganic nitrate coated on the surface. It has a low reactivity towards SO 2 with a true uptake coefficient, 5.767×10 −6, which limits the conversion of SO 2 to sulfate during dust storm periods. The low reactivity also means that the heterogeneous reactions of SO 2 in both dry and humid air conditions have little effect on the hygroscopic behavior of the dust particles.

Magnetic properties of sediments from major rivers, aeolian dust, loess soil and desert in China

The continent of China delivers huge terrigenous sediments to the East Asian marginal seas and northwest Pacific Ocean by riverine and aeolian inputs, which exerts a great impact on marine sedimentation, primary productivity and biogeochemical cycle. In this study, magnetic properties of the sediments from the Changjiang and Huanghe river systems were investigated, in order to provide potential provenance tracers. Besides, the top soil from the Loess Plateau, Taklimakan desert sand and dust storm particles were comparatively studied to reveal the controls of magnetic properties in various depositional environments. The Changjiang sediment is characterized by the highest concentration of magnetic minerals and the largest variations for most magnetic parameters, while the Huanghe sediment has much lower content of magnetic minerals. The loess soil sediment yields the highest frequency-dependent susceptibility χ fd%, while the aeolian dust has similar magnetic susceptibility but higher saturation isothermal remnant magnetization and lower anhysteretic remnant magnetization χ ARM. The desert sand has the lowest values of all magnetic parameters, indicating the lowest ferrimagnetic mineral concentration with coarser grain size. The magnetic properties of the Changjiang sediments are primarily determined by the diversity of lithology in its large drainage basin, while the sediment grain size basically accounts for the variation of magnetic parameters in the Huanghe sediment. The gradual increase of χ fd% towards the lower reaches suggests it may potentially indicate grain size fractionation in the catchments. Although some magnetic parameters can apparently discriminate the origins of fluvial and aeolian sediments, reliable magnetic proxy for distinguishing sediment origins in marine environment can only be established if hydrodynamic differentiation and post-depositional diagenetic alteration of magnetic minerals are fully understood.

Electrification of particles in dust storms: Field measurements during the monsoon period in Niger

On the first fortnight of June 2010, experiments were carried out at a millet field in Niger to address the electrification of soil particles under natural conditions. The experiments were conducted during a period of high wind erosion, resulting from the passage of mesoscale convective systems (MCSs) which generate “walls” of dust passing through the Sahel. Soil particles are lifted from the ground by the stress exerted by the wind, with a threshold for emission that is particle size dependent. These particles then collide with other particles, leading to electrostatic charging of the particles. Soil samples of either positive or negative polarity were collected from the soil surface in 3 situations: 1) during “quiet” periods (far removed from a dust storm), 2) immediately after a dust storm, and 3) 12h after a dust storm. Our results show that immediately after a dust storm, smaller particles are predominantly charged positive and larger particles are predominantly charged negative; this effect is still evident but smaller in magnitude 12h after a dust storm. This size dependence for the charge polarity is in apparent contradiction with previous investigations; we believe this contradiction is only apparent, because the very fine particles, which we cannot measure with our technique, are expected to be negatively charged. Our results are rationalized by combining a population balance model for charged species trapped in high energy states with the wind threshold for soil particle motion.

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 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.

The mineralogy and possible sources of spring dust particles over Beijing

A severe Asian Dust Storm (ADS) event occurred on 16–17 April 2006 in northern China. The mineral compositions of dust samples were analyzed using X-ray diffraction (XRD). The results indicated that dust particles of the “17 April 2006” dust storm were dominated by quartz (37.4%) and clay (32.9%), followed by plagioclase (13.7%), with small amounts of calcite, K-feldspar, dolomite, hornblende and gypsum (all less than 10%). The clay fractions with diameter less than 2 µm were separated from the dust storm particles by centrifuging and were further analyzed by XRD. The results revealed that the clay species were mainly illite/smectite mixed layers (I/S) (49%) and illite (34%), with small amount of kaolinite (8%) and chlorite (9%).

Damage effects of dust storm PM 2.5 on DNA in alveolar macrophages and lung cells of rats

The aim of the present study was to investigate in vitro toxicological effects of PM 2.5 suspensions, their water-soluble fraction and solvent-extractable organics from dust storm on the viability and DNA of rat alveolar macrophages and in vivo toxicological effects of PM 2.5 suspensions on DNA of lung cells of rats. PM 2.5 samples from dust storm and normal weather were collected in Baotou city, Inner Mongolia Autonomous Region, and Wuwei city, Gansu Province, China, in March, 2004. DNA damage was detected with single cell gel electrophoresis technique and cytotoxicity was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay. The results showed that: (1) In vitro, PM 2.5 suspensions, their water-soluble fraction and solvent-extractable organics from both dust storm and normal weather caused a decrease of the cell viability and an increase of DNA damage of rat alveolar macrophages in a dose–response manner; for both Baotou city and Wuwei city, the samples of normal weather showed higher DNA damage than those of dust storm at the highest treated dosage; for both normal weather PM 2.5 and dust storm PM 2.5, their solvent-extractable organics showed higher DNA damage than the water-soluble fraction. (2) In vivo, PM 2.5 from both dust storm and normal weather caused an increase of DNA damage of rat lung cells in a dose–response manner. (3) Baotou city is one of the heavy industrial cities, while Wuwei is one of agricultural cities in Northwest region of China. The effects induced by normal weather samples in Baotou city slightly higher than those in Wuwei city on DNA damage, though there was no significant difference was found between two cities. These results lead to conclusions that dust storm PM 2.5 as well as normal weather PM 2.5 could lead to DNA damage and the organic compounds and the insoluble particle-core might be the main contributors to DNA damage. Our results suggest that the risk of health effects may be greater during dust storms because dust storm PM 2.5 whose airborne mass were much higher. Further studies are needed to determine the components of dust storm particles that may contribute to the particle toxicity.

Effects of Concentrated Ambient Particles on Heart Rate, Blood Pressure, and Cardiac Contractility in Spontaneously Hypertensive Rats During a Dust Storm Event

Epidemiological studies have suggested that cardiovascular mortality and morbidity increased during Asian dust events. The findings were still inconclusive though. We have shown an increased pulmonary toxicity in diseased animals during a dust storm event. However, the toxicity nature of dust storm particles remains unclear. It is our objective in this study to further investigate the cardiovascular effects of concentrated PM2.5 on spontaneously hypertensive rats during the same dust storm event. Four spontaneously hypertensive rats were implanted with radiotelemetry transmitters at the age of 10 wk. Baseline heart rate, mean blood pressure, and cardiac contractility (measured as QA interval, QAI) data were collected 4 wk before. Exposure group received concentrated ambient particles inhalation for 6 h during a dust storm event, while the control group received room air inhalation at the same time. Self-control data were collected 4 wk after the event during the same clock hours while there was no dust storm. Gravimetric analysis showed a particle mass concentration of 315.55 μg/m3 during the 6 h of exposure. A linear mixed-effects model revealed sigmoid increases in heart rate (to a maximum of 93.8 ± 18.8 bpm) and mean blood pressure (to a maximum of 14.8 ± 5.4 mm Hg), and a sigmoid decrease of QAI (to a maximum of − 3.5 ± 1.5 ms) during the exposure after an initial incubation period. We conclude that concentrated dust storm particles, which are different from products of automobile combustion process, may cause adverse cardiovascular effects on diseased animals.

Individual particle analysis of Asian dust-storm particles over Higashiosaka in 2005 and 2006

Individual particle analysis of Asian dust-storm particles over Higashiosaka in 2005 and 2006

Anthropogenic Calcium Particles Observed in Beijing and Qingdao, China

Analysis of individual particles collected at Beijing in northern China revealed that particles abundant in calcium (Ca) always constituted a large fraction of mineral particles in the urban atmosphere. The particles were characterized by cubic morphologies. The major mineral element in the particles was Ca and few or no other mineral elements were detected. A large number of the particles were in the range of diameter <1 μm, where common natural mineral particles were rarely detected. The contribution of the Ca particles to the volume of total mineral particles greatly exceeded that of other mineral particles during non-dust-storm periods and was comparable to that during dust-storm periods. Reagent film tests showed that particulate sulfate and nitrate formation on the Ca particles was similar to that on common mineral particles. These results indicate that a large portion of Ca in the atmospheric particulate matter in Beijing was from anthropogenic sources rather than from natural sources, and the anthropogenic Ca particles acted as a significant medium for the formation of sulfate and nitrate. Similar particles were also detected at Qingdao, a coastal city in northern China. Data of a dust storm event showed that Ca-abundant particles from East China arrived there and moved out of the continent, similarly to Asian dust storm particles, suggesting possible contributions of anthropogenic Ca even in Asian dust storm samples in the downstream areas. Therefore, Ca may not be a good indicator of Asian dust from natural sources. However, the Ca particles, due to their unique shapes and elemental compositions, may provide an indicator for the atmospheric dispersion of anthropogenic particulate matters in East Asia.

Speciation of the elements and compositions on the surfaces of dust storm particles: The evidence for the coupling of iron with sulfur in aerosol during the long-range transport

The speciation of the elements on the surface of the particles collected during dust storm and non-dust storm in Beijing and Inner Mongolia was studied by XPS. The major species of iron on the surface were oxides, sulfate, silicate, FeOOH and minor part sorbed on SiO2/Al2O3. Sulfate is the dominant species of sulfur on the surface. SiO2 and Al2O3 are the main components of Si and Al on the surface respectively. One of the most important findings was that the Fe(II) (FeS and FeSO4) produced could account for up to 44.3% and 45.6% of the total Fe on the surface in the aerosol sample collected at that night and next day of the “peak” time of the dust storm occurring on March 20, 2002, while Fe2(SO4)3, one of the Fe(III) species on the surface decreased from 67.1% to 49.5% and 48.0% respectively. Both S and Fe enriched on the surface of aerosol particles. Fe(II) accounted for 1.3%–5.3% of total Fe in bulk aerosol samples during dust storm. These results provided strong evidence to support the hypothesis of the coupling between iron and sulfur in aerosols during the long-range transport, which would have important impact on the global biogeochemical cycle.

Speciation of the elements and compositions on the surfaces of dust storm particles: The evidence for the coupling of iron with sulfur in aerosol during the long-range trans-port

Speciation of the elements and compositions on the surfaces of dust storm particles: The evidence for the coupling of iron with sulfur in aerosol during the long-range trans-port

A case study of the size-resolved individual particles collected at a ground-based site on the west coast of Japan during an Asian dust storm event

Abstract To investigate the nature of individual Asian dust storm particles, an intensive field measurement was carried out on the west coast of Japan during a dense Asian dust storm event in March 2002. The giant particles (>5 μm) marked 124 times higher number concentration in the Asian dust storm event than in a non-Asian dust storm period. For the quantification analysis of the ultratrace elements in the size-resolved individual particles, an X-ray microprobe system equipped with super photon ring-8 GeV (SPring-8) BL-39XU was employed. By using this SPring-8 system we could successfully carry out the reconstruction of elemental maps and the quantification analysis of multiple elements in individual particles. The mass of Si showing the maximum value in individual particles was varied in the range from 1.2×10−2 pg to 1.1×100 pg with median 1.4×10−1 pg. In the case of S, mass ranged from 1.6×10−2 pg to 6.7×10−2 pg with median 3.9×10−2 pg, while several minor trace elements like V, Cr, Cu, and Zn show relatively low masses. A strong particle-size dependency of elemental masses was found for all elements, in particular the elemental masses of soil-derived components showed the monomodal maximum values around 2.05–5.07 μm particle size. From the X-ray, fluorescence images replayed corresponding to individual particles, we could simply categorize the visualized particles into two groups, namely internally mixed particles and externally mixed particles. From the factor analysis with variables of each elemental mass in individual particles, 79% of total particle population was found to be modified by sea-salt and sulfur.

The composition of aerosol particles in the middle troposphere over the western Pacific Ocean: aircraft observations from Australia to Japan, January 1994

Abstract Individual aerosol particles were collected in the middle troposphere, at 5–6 km altitude, over the western Pacific Ocean in the Pacific Atmospheric Chemistry Experiment campaign, between 38°S and 38°N, in January 1994. Particles were collected on electron microscope grids, over approximately 1.5° latitude bands using a 1-mm diameter jet impactor and were examined with an energy-dispersive X-ray (EDX) analyzer and transmission electron microscope. Based on the EDX analysis and morphological identification, particles were classified into various types, including sea salt, mineral, sulfate, and sulfuric acid. For the radius range of 0.1–1 μm, sulfuric acid and ammonium sulfate were found across most of the observed regions and are considered important background aerosols. As well, sea salt particles were abundant over the tropical regions (present at up to 67%), in association with vertical transport by convective clouds. North of 20°N, mineral particles were dominant, suggesting transport of Asian dust–storm particles from China in the westerly air stream. Evidence for the modification of mineral particles, prior to their collection in the free troposphere, is also presented and discussed.

Physicochemical characteristics and radiative properties of Asian dust particles observed at Kwangju, Korea, during the 2001 ACE‐Asia intensive observation period

Optical properties of atmospheric extinction, scattering, and absorption coefficients were measured continuously with a transmissometer, an integrating nephelometer, and an aethalometer, respectively. Three Asian dust storm events had been observed at Kwangju on 22 March, 11–13 April, and 25–26 April 2001. The physicochemical and optical properties of Asian dust aerosols were analyzed for those three cases and compared with those observed under clean, marine, and hazy urban atmospheric conditions. Their chemical composition varied depending on the source region and the transport path of the air mass. The first Asian dust storm particles, which originated from the northwestern Chinese desert regions, showed typical dust aerosol characteristics of high loading of mineral dust. The second one, which originated initially from the northwestern Chinese desert regions, had been impacted by long‐range‐transported air pollutants, resulting in increased concentrations of sulfate and organic carbon particles. The third one, which originated from the northeastern Chinese sandy areas, had traveled south to Kwangju, resulting in increased elemental carbon and organic carbon concentrations. Aerosol chemical and optical properties under clean continental, southeastern marine, and stagnant local pollution conditions were also analyzed. The mass scattering coefficient and single‐scattering albedo in the fine and coarse modes were determined for three Asian dust event days. The concentration of black carbon (BC) aerosol in the fine and coarse modes was measured with an aethalometer by alternately switching between a particulate‐matter‐smaller‐than‐2.5‐μm (PM2.5) and a PM10 inlet to it. It was found that BC mass concentration in the coarse mode measured by an aethalometer (BCac) increased because of agglomerated black carbon particles and high loading of dust particles. Single‐scattering albedo ω increased to 0.93, 0.90, and 0.84 for the three Asian dust events, respectively, while it was 0.85 for mean ω during other times.

Properties of the size-resolved and individual cloud droplets collected in western Japan during the Asian dust storm event

Abstract With the point of view of the removal mechanism of Asian dust storm particles, in order to study the physiochemical properties of clouds a field campaign was conducted in western Japan during the Asian dust storm event. The polymeric water absorbent film and collodion film replication techniques were employed in the measurements of size-fractionated precipitation cloud and individual cloud droplets, respectively. In addition, to investigate the source profiles of the elements retained in cloud samples, the original desert sand was collected. Particle-induced X-ray emission was applied for the elemental analysis of size-resolved cloud droplets and desert sand. Also for the quantification analysis of the ultra trace elements in residual particles in individual cloud droplets, the X-ray microprobe system equipped at Super Photon ring-8 GeV (SPring-8) BL-37XU was newly applied. Soil derived components like Si, Ca, and Fe show higher mass concentrations in small droplets ( 6.4 μm), while S and Cl dominate at droplet size larger than 20 μm. Three cloud samples have liquid water content ranging from 0.04 to 0.11 g m −3 . The number size distribution of droplets collected at cloud base is monomodal with the maximum level around 15 μm. The size distribution of cloud droplets is widespread (up to 60 μm). The droplet residues mainly consisting of crustal components were successively reconstructed as elemental maps by the X-ray fluorescence (XRF) microprobe analytical technique. From these XRF elemental maps, it can be understood that crustal components are significantly distributed on and/or in the residual particles in individual cloud droplets. The plotting of enrichment factors calculated from the elemental composition of original desert sand in China not only indicates the good correlationship between elemental masses in residual particles of cloud base droplets and those of precipitation cloud, but also classify elements into soil origin and non-soil origin. Mineral components were identified as the main components of dry residual particles in cloud droplets. These soil-origin elements account for up to 68% of the total elemental mass.

Oxidative stress on plasmid DNA induced by inhalable particles in the urban atmosphere

Plasmid DNA assay is a newly-developedin vitro method to investigate bioreactivity of particles. In this paper, this method was used to study the bioreactivity of PM10 (particulate matter with aerodynamic diameter of less than 10 μm) and PM2.5 (particulate matter with aerodynamic diameter of less than 2.5 μm). Samples and dust storm particles were collected in 2001 in an urban area, a satellite city and a clean air area in Beijing. A big difference was found for oxidative DNA stress induced by different particulate matter (PM) samples, with the TM50 (particle mass causing 50% damage to DNA) values varying by a factor over 10. This was closely dependent on the sizes of particles as well as the variation in relative proportion of mineral matter. PM2.5 samples generally impose larger oxidative stress on plasmid DNA than PM10 samples. Airborne particles collected during dust storm episodes, usually with a higher proportion of mineral matter, have a much lower oxidative capacity than those collected during non-dust storm episodes. PM samples and their water-soluble fractions usually have similar bioreactivities, demonstrating that oxidative capacity of Beijing airborne particles is mainly sourced from their water-soluble fractions.

Properties of individual Asian dust storm particles collected at Kosan, Korea during ACE-Asia

Abstract For the purpose of studying the properties of individual Asian dust storm particles, an intensive field measurement took place at the Kosan ground-based station located on the west coast of Cheju Island, Korea during ACE-Asia campaign. A 2-stage filter pack sampler was employed in the size-resolved (coarse and fine fractions) particle sampling. The trace elements of individual coarse particles (>1.2 μm) were analyzed by the X-ray microprobe analysis system equipped at SPring-8. The result of statistical analysis suggested that individual particles collected in Asian dust storm event could be classified into four groups: sea-salt-rich particles, crustal-rich particles, crustal/sea-salt/sulfur-rich particles, and crustal/sea-salt-rich particles. Moreover, according to the XRF elemental maps and elemental masks replayed corresponding to individual particles, particles could be categorized into two groups, namely internally mixed particles and externally mixed particles. A small part of the CaCO 3 in Asian dust storm particles would be converted to CaSO 4 through the chemical reaction between CaCO 3 and H 2 SO 4 during long-range transport. By means of XANES method, the major chemical state of Fe in Fe-rich particles was found to be Fe 3+ . Several minor trace heavy metals were probably affected by the air masses passed directly over the industrial areas of China.

Effects of Asian dust event particles on inflammation markers in peripheral blood and bronchoalveolar lavage in pulmonary hypertensive rats

The health impact of dust events from China has become a concern within China and in its neighboring countries. Previous epidemiological studies have demonstrated an association between particulate matter exposure and cardiopulmonary mortality. Here, we use pulmonary hypertensive rat models to examine inflammation markers in the lung and in peripheral blood after exposure to Asian dust storm particles. Using a nose-only inhalation system, eight pulmonary hypertensive rats were exposed to concentrated ambient particles (CAPs) from an actual Asian dust storm that took place between March 18 and 19, 2002; four control rats were also exposed to room air. Four rats exposed to CAPs of 315.6μg/m3 for 6h were classified as the low-exposure group, and another four rats exposed to CAPs of 684.5μg/m3 for 4.5h were classified as the high-exposure group. The animals were sacrificed 36h after exposure. Inflammation markers in the peripheral blood and in the bronchoalveolar lavage (BAL) were analyzed, and IL-6 in BAL was also determined using ELISA. White blood cell counts in peripheral blood increased with increased CAP exposure levels (P<0.001, test for trend). In BAL analysis, total cell numbers and the proportion of neutrophil also increased with increased CAP levels (P<0.001, test for trend for both markers). Positive dose–response relationships between CAP exposure and total protein (P<0.05) and between CAPs and LDH activity (P<0.05) were also observed. Moreover, IL-6 protein in BAL increasing with CAP levels (P<0.05, test for trend) was demonstrated. Our results revealed that exposure to particulate matters during an Asian dust storm could increase lung inflammation and injury in pulmonary hypertensive rats. Further studies are needed to determine the components of dust storm particles that may contribute to the particle toxicity.