scholarly journals Hygroscopic Properties of Saline Mineral Dust From Different Regions in China: Geographical Variations, Compositional Dependence, and Atmospheric Implications

2019 ◽  
Vol 124 (20) ◽  
pp. 10844-10857 ◽  
Author(s):  
Mingjin Tang ◽  
Huanhuan Zhang ◽  
Wenjun Gu ◽  
Jie Gao ◽  
Xing Jian ◽  
...  
Keyword(s):  
Mineral Dust ◽  
Compositional Dependence ◽  
Hygroscopic Properties ◽  
Geographical Variations

Hygroscopic properties of saline mineral dust from different regions in China

2020 ◽  
Author(s):  
Mingjin Tang ◽  
Huanhuan Zhang ◽  
Wenjun Gu
Keyword(s):  
Growth Factors ◽  
Mineral Dust ◽  
Cloud Condensation Nuclei ◽  
Dust Particles ◽  
Cloud Droplets ◽  
Sample Mass ◽  
Mass Growth ◽  
Hygroscopic Properties ◽  
Geographical Variations ◽  
Tropospheric Aerosol

<p>Saline mineral dust particles, emitted from saline topsoil in arid and semi-arid regions, contribute significantly to tropospheric aerosol particles. However, hygroscopic properties of saline mineral dust particles, especially for those found in regions other than North America, are poorly understood. In this work we investigated hygroscopic properties of thirteen saline mineral dust samples collected from different locations via measuring sample mass change as different relative humidity (RH, up to 90%), and measured their chemical and mineralogical compositions using ion chromatography and X-ray diffraction. The mass growth factors at 90% RH, defined as the sample mass at 90% RH relative to that at <1% RH, were found to display large geographical variations, spanning from ~1.02 to 6.7, and the corresponding single hygroscopicity parameters (κ) were derived to be in the range of <0.01 to >1.0. The saline components (mainly Na<sup>+</sup>, Cl<sup>-</sup> and SO<sub>4</sub><sup>2-</sup>) contained by saline mineral dust particles largely determined their hygroscopicity, and the predicted mass growth factors at 90% RH using an aerosol thermodynamic model (ISORROPIA-II), agreed with measured values within 20% for most of samples examined, though larger discrepancies also occurred for three samples. Our results improve our understanding in hygroscopicity of saline mineral dust particles and thus their heterogeneous chemistry and ability to serve as cloud condensation nuclei to form cloud droplets.</p>

Water Interaction with Mineral Dust Aerosol: Particle Size and Hygroscopic Properties of Dust

2018 ◽  
Vol 2 (4) ◽  
pp. 376-386 ◽  
Author(s):  
Sara Ibrahim ◽  
Manolis N. Romanias ◽  
Laurent Y. Alleman ◽  
Mohamad N. Zeineddine ◽  
Giasemi K. Angeli ◽  
...  
Keyword(s):  
Particle Size ◽  
Aerosol Particle ◽  
Mineral Dust ◽  
Dust Aerosol ◽  
Water Interaction ◽  
Hygroscopic Properties ◽  
Aerosol Particle Size

scholarly journals A comprehensive study of hygroscopic properties of calcium- and magnesium-containing salts: implication for hygroscopicity of mineral dust and sea salt aerosols

2019 ◽  
Vol 19 (4) ◽  
pp. 2115-2133 ◽  
Author(s):  
Liya Guo ◽  
Wenjun Gu ◽  
Chao Peng ◽  
Weigang Wang ◽  
Yong Jie Li ◽  
...  
Keyword(s):  
Growth Factors ◽  
Physicochemical Properties ◽  
Mineral Dust ◽  
Aerosol Particles ◽  
Sea Salt ◽  
Hygroscopic Growth ◽  
Continuous Growth ◽  
Sea Salt Aerosols ◽  
Hygroscopic Properties ◽  
Calcium And Magnesium

Abstract. Calcium- and magnesium-containing salts are important components for mineral dust and sea salt aerosols, but their physicochemical properties are not well understood yet. In this study, hygroscopic properties of eight Ca- and Mg-containing salts, including Ca(NO3)2⚫4H2O, Mg(NO3)2⚫6H2O, MgCl2⚫6H2O, CaCl2⚫6H2O, Ca(HCOO)2, Mg(HCOO)2⚫2H2O, Ca(CH3COO)2⚫H2O and Mg(CH3COO)2⚫4H2O, were investigated using two complementary techniques. A vapor sorption analyzer was used to measure the change of sample mass with relative humidity (RH) under isotherm conditions, and the deliquescence relative humidities (DRHs) for temperature in the range of 5–30 ∘C as well as water-to-solute ratios as a function of RH at 5 and 25 ∘C were reported for these eight compounds. DRH values showed large variation for these compounds; for example, at 25 ∘C DRHs were measured to be ∼ 28.5 % for CaCl2⚫6H2O and >95 % for Ca(HCOO)2 and Mg(HCOO)2⚫2H2O. We further found that the dependence of DRH on temperature can be approximated by the Clausius–Clapeyron equation. In addition, a humidity tandem differential mobility analyzer was used to measure the change in mobility diameter with RH (up to 90 %) at room temperature, in order to determine hygroscopic growth factors of aerosol particles generated by atomizing water solutions of these eight compounds. All the aerosol particles studied in this work, very likely to be amorphous under dry conditions, started to grow at very low RH (as low as 10 %) and showed continuous growth with RH. Hygroscopic growth factors at 90 % RH were found to range from 1.26 ± 0.04 for Ca(HCOO)2 to 1.79 ± 0.03 for Ca(NO3)2, and the single hygroscopicity parameter ranged from 0.09–0.13 for Ca(CH3COO)2 to 0.49–0.56 for Ca(NO3)2. Overall, our work provides a comprehensive investigation of hygroscopic properties of these Ca- and Mg-containing salts, largely improving our knowledge of the physicochemical properties of mineral dust and sea salt aerosols.

scholarly journals Observation of nitrate coatings on atmospheric mineral dust particles

2009 ◽  
Vol 9 (6) ◽  
pp. 1863-1871 ◽  
Author(s):  
W. J. Li ◽  
L. Y. Shao
Keyword(s):  
Mineral Dust ◽  
Cloud Condensation Nuclei ◽  
Northern China ◽  
Heterogeneous Reactions ◽  
Dust Particles ◽  
Sample Collection ◽  
Mineral Particles ◽  
Hygroscopic Properties ◽  
Cooling Effects ◽  
Ccn Activity

Abstract. Nitrate compounds have received much attention because of their ability to alter the hygroscopic properties and cloud condensation nuclei (CCN) activity of mineral dust particles in the atmosphere. However, very little is known about specific characteristics of ambient nitrate-coated mineral particles on an individual particle scale. In this study, sample collection was conducted during brown haze and dust episodes between 24 May and 21 June 2007 in Beijing, northern China. Sizes, morphologies, and compositions of 332 mineral dust particles together with their coatings were analyzed using transmission electron microscopy (TEM) coupled with energy-dispersive X-ray (EDX) microanalyses. Structures of some mineral particles were verified using selected-area electron diffraction (SAED). TEM observation indicates that approximately 90% of the collected mineral particles are covered by visible coatings in haze samples whereas only 5% are coated in the dust sample. 92% of the analyzed mineral particles are covered with Ca-, Mg-, and Na-rich coatings, and 8% are associated with K- and S-rich coatings. The majority of coatings contain Ca, Mg, O, and N with minor amounts of S and Cl, suggesting that they are possibly nitrates mixed with small amounts of sulfates and chlorides. These nitrate coatings are strongly correlated with the presence of alkaline mineral components (e.g., calcite and dolomite). CaSO4 particles with diameters from 10 to 500 nm were also detected in the coatings including Ca(NO3)2 and Mg(NO3)2. Our results indicate that mineral particles in brown haze episodes were involved in atmospheric heterogeneous reactions with two or more acidic gases (e.g., SO2, NO2, HCl, and HNO3). Mineral particles that acquire hygroscopic nitrate coatings tend to be more spherical and larger, enhancing their light scattering and CCN activity, both of which have cooling effects on the climate.

scholarly journals A comprehensive study of hygroscopic properties of calcium- and magnesium-containing salts: implication for hygroscopicity of mineral dust and sea salt aerosols

2018 ◽  
Author(s):  
Liya Guo ◽  
Wenjun Gu ◽  
Chao Peng ◽  
Weigang Wang ◽  
Yong Jie Li ◽  
...  
Keyword(s):  
Growth Factors ◽  
Physicochemical Properties ◽  
Mineral Dust ◽  
Aerosol Particles ◽  
Sea Salt ◽  
Hygroscopic Growth ◽  
Continuous Growth ◽  
Sea Salt Aerosols ◽  
Hygroscopic Properties ◽  
Calcium And Magnesium

Abstract. Calcium- and magnesium-containing salts are important components for mineral dust and sea salt aerosols, but their physicochemical properties are not well understood yet. In this study, the hygroscopic properties of eight Ca- and Mg-containing salts, including Ca(NO3)2 · 4H2O, Mg(NO3)2 · 6H2O, MgCl2 · 6H2O, CaCl2 · 6H2O, Ca(HCOO)2, Mg(HCOO)2 · 2H2O, Ca(CH3COO)2 · H2O and Mg(CH3COO)2 · 4H2O, were systematically investigated using two complementary techniques. A vapor sorption analyzer was used to measure the change of sample mass with relative humidity (RH) under isotherm conditions, and the deliquescence relative humidities (DRH) for temperature in the range of 5–30 °C as well as water-to-solute ratios as a function of RH at 5 and 25 °C were reported for these eight compounds. DRH values showed a large variation for these compounds; for example, at 25 °C the DRH values were measured to be ~ 28.5 % for CaCl2 · 6H2O and > 95 % for Ca(HCOO)2 and Mg(HCOO)2 · 2H2O. In addition, a humidity-tandem differential analyzer was used to measure the change in mobility diameter with RH (up to 90 %) at room temperature, in order to determine the hygroscopic growth factors of aerosol particles generated by atomizing water solutions of these eight compounds. All the aerosol particles studied in this work, very likely to be amorphous, started to grow at very low RH (as low as 10 %) and showed continuous growth with RH. The hygroscopic growth factors at 90 % RH were found to range from 1.26 ± 0.04 for Ca(HCOO2)2 and 1.79 ± 0.03 for Ca(NO3)2, varying significantly for the eight types of aerosols considered herein. Overall, our work provides a systematical and comprehensive investigation of the hygroscopic properties of these Ca- and Mg-containing salts, largely improving our knowledge in the physicochemical properties of mineral dust and sea salt aerosols.

scholarly journals Observation of nitrate coatings on atmospheric mineral dust particles

2008 ◽  
Vol 8 (6) ◽  
pp. 19249-19272 ◽  
Author(s):  
W. J. Li ◽  
L. Y. Shao
Keyword(s):  
Mineral Dust ◽  
Cloud Condensation Nuclei ◽  
Northern China ◽  
Heterogeneous Reactions ◽  
Dust Particles ◽  
Sample Collection ◽  
Mineral Particles ◽  
Hygroscopic Properties ◽  
Cooling Effects ◽  
Ccn Activity

Abstract. Nitrate compounds have recently received much attention because of their ability to alter the hygroscopic properties and cloud condensation nuclei (CCN) activity of mineral dust particles in the atmosphere. However, very little is known about specific characteristics of nitrate-coated mineral particles in an individual particle scale in field study. The sample collection was conducted during brown haze and dust episodes occurred between 24 May and 21 June 2007 in Beijing, northern China. The sizes, morphologies, and compositions of mineral dust particles together with their coatings were analyzed using transmission electron microscopy (TEM). 92% of the internally mixed mineral particles analyzed are covered with Ca-, Mg-, and Na-rich coatings, and 8% are associated with K- and S-rich coatings. The major coatings contain Ca, Mg, O, and N with minor amounts of S and Cl, suggesting that they are possibly nitrates mixed with less sulfates and chlorides. These nitrate coatings strongly relate with the presence of alkaline mineral components (e.g., calcite and dolomite) within individual mineral particles. Calcium sulfate particles with the diameter from 10 to 500 nm were also detected within Ca(NO3)2 and Mg(NO3)2 coatings. Our results indicate that mineral particles in brown haze episodes were involved in atmospheric heterogeneous reactions with two or more acidic gases (e.g., SO2, NO2, HCl, and HNO3). Mineral particles that acquire hygroscopic coatings tend to be more spherical and larger. Such changes enhance their light scattering and CCN activity, both of which have cooling effects on the climate.

Large Variations in Hygroscopic Properties of Unconventional Mineral Dust

2020 ◽  
Vol 4 (10) ◽  
pp. 1823-1830
Author(s):  
Chao Peng ◽  
Wenjun Gu ◽  
Rui Li ◽  
Qinhao Lin ◽  
Qingxin Ma ◽  
...  
Keyword(s):  
Mineral Dust ◽  
Hygroscopic Properties

Geographical features of forest vegetation reflected at the level of the lower-rank syntaxa (evidence from the Russian part of the Upper Dnieper basin)

2017 ◽  
pp. 94-108 ◽  
Author(s):  
Yu. A. Semenishchenkov
Keyword(s):  
Forest Vegetation ◽  
East European Plain ◽  
Early 20Th Century ◽  
Suggested Approach ◽  
Central European ◽  
Classification Schemes ◽  
East European ◽  
Lower Rank ◽  
Geographical Variations ◽  
European Part Of Russia

Phytogeographical features of forest vegetation at the level of lower-rank syntaxa were being discussed in literature since the early 20th century (Cajander, 1903; Sukachev, 1926; Braun-Blanquet, 1964; Kral et al., 1975; Kleopov, 1990; Bulokhov, 2003; Ellenberg, 2009), however, phytocoenologists still have no uniform interpretation and geographical maintenance of lower classification units. Forest vegetation of the European part of Russia is well studied according to Braun-Blanquet approach with association as a system of geographical subassociations. The paper offers the approaches to the reflection of geographical variations of the natural forest vegetation in the basin of the Upper Dnieper (central part of the East European Plain) at the level of lower-rank syntaxa The xeromesophytic oak woods in the basin of the Upper Dnieper belong to the East European ass. Lathyro nigri–Quercetum roboris Bulokhov et Solomeshch 2003. Floristic differentiation of this association from the similar Central European ass. Potentillo-Quercetum is given. These two associations have large blocks of geographically significant differential species that does not allow to consider them as a part of one association. The suggested approach allows to define the chorological content of units of lower syntaxonomical ranks and make regional classification schemes comparable to each other.

Distribution, systematics and nomenclature of the three taxa of Common Stonechats (Aves, Passeriformes, Muscicapidae, Saxicola) that breed in the Caucasian region

2020 ◽  
Vol 29 (1) ◽  
pp. 33-57
Author(s):  
V.M. Loskot ◽  
G.B. Bakhtadze
Keyword(s):  
Geographic Distribution ◽  
Habitat Preferences ◽  
Junior Synonym ◽  
Type Locality ◽  
Diagnostic Features ◽  
Western Turkey ◽  
Geographical Variations ◽  
History Of ◽  
The Individual ◽  
North Western

Geographic distribution and habitat preferences of Saxicola rubicola rubicola (Linnaeus, 1766), S. maurus variegatus (S.G. Gmelin, 1774), and S. m. armenicus (Stegman, 1935) inhabiting the Caucasian Isthmus and adjacent areas are described in detail. We examined the individual, sexual, age, seasonal and geographical variations of seven main diagnostic features of both plumage and morphometrics (exactly, the length of wing and tail) using 381 skin specimens. Substantially improved diagnoses of S. m. variegatus and S. m. armenicus are provided. After a thorough examination of the materials and history of the expedition of Samuel Gmelin in 1768–1774, and his description of Parus variegatus, it was concluded that the type locality of this taxon was the vicinity of Shamakhi in Azerbaijan not Enzeli in North-Western Turkey. It is also shown the fallacy of the recently proposed attribution of the holotype of the northern subspecies S. m. variegatus to the southern taxon S. m. armenicus and synonymisation of these names, as well as the replacement of the name S. m. variegatus by its junior synonym S. m. hemrichii Ehrenberg, 1833 for the northern subspecies.

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