Hygroscopicity of Fresh and Aged Salt Mixtures from Saline Lakes

The high hygroscopicity of salt aerosol particles makes the particles active in aerosol and cloud formations. Inland saline lakes are an important and dynamic source of salt aerosol. The salt particles can be mixed with mineral dust and transported over long distances. During transportation, these particles participate in atmospheric heterogeneous chemistry and further impact the climate and air quality on a global scale. Despite their importance and potential, relatively little research has been done on saline lake salt mixtures from atmospheric perspectives. In this study, we use experimental and model methods to evaluate the hygroscopic properties of saline lake brines, fresh salt aerosol particles, and aged salt aerosol particles. Both original samples and literature data are investigated. The original brine samples are collected from six salt lakes in Shanxi and Qinghai provinces in China. The ionic compositions of the brines are determined and the hygroscopicity measurements are performed on crystallized brines. The experimental results agree well with theoretical deliquescence relative humidity (DRH) values estimated by a thermodynamic model. The correlations between DRHs of different salt components and the correlations between DRHs and ionic concentrations are presented and discussed. Positive matrix factorization (PMF) analysis is performed on the ionic concentrations data and the hygroscopicity results, and the solutions are interpreted and discussed. The fresh and aged salt aerosol particles are analyzed in the same way as the brines, and the comparison shows that the aged salt aerosol particles completely alter their hygroscopic property, i.e., transferring from MgCl2− governed to NH4NO3− governed.

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Chemical Characterization of Saline Lake and Playa Salts in Qaidam Basin: Implications for Climates of Planet Earth and Mars

10.5194/egusphere-egu21-1233 ◽

2021 ◽

Author(s):

Wanyu Liu ◽

Jun Li ◽

Luis Santos ◽

Johan Boman ◽

Xiying Zhang ◽

...

Keyword(s):

Chemical Composition ◽

Saline Lakes ◽

Saline Lake ◽

Qaidam Basin ◽

Chemical Characterization ◽

Physicochemical Characteristics ◽

Global Scale ◽

Factors Affecting ◽

Complex Chemical Composition ◽

The Common

Salt aerosol from saline lakes and playas has been recognized to affect climate in the global scale, but the understandings of the chemical and physical natures of these salts are still limited due to their complex chemical composition. The Qaidam Basin, one of the largest and driest deserts on Earth, is composed of many saline lakes and is regarded as a good terrestrial&#160;analogue for Mars due to similar environment conditions&#160;and elementary composition(Xiao et al., 2017). The study on the chemical characteristics of salts from Qaidam Basin is helpful to explore their influences&#160;on climate and reveal the physical and chemical factors affecting the paleoclimate of both Planet Earth and Mars.&#160;In this study, four types of salt samples (brines, crystalized brines, lakebed salts and crust salts) collected at and near four saline lakes&#160;(Chaka, Keke, Qarhan and Mang&#8217;ai)&#160;in the Qaidam Basin are studied for their physicochemical characteristics. The common cations (Na+, K+, Mg2+&#160;and Ca2+) and anions (Cl&#8722;, SO42&#8722;, and NO3&#8722;) are determined by&#160;ion chromatography (IC), and the elemental compositions are measured&#160;by energy dispersive X-ray fluorescence (EDXRF) spectrometry. The chemical composition results are analyzed by positive matrix factorization (PMF)(Paatero and Tapper, 1994). The pH of sample brines and solutions are measured, and the governing factors are discussed.&#160;The common elements detected by XRF and IC have excellent consistency. Notably, the crystalized brines exhibit similar ionic compositions with brines, suggesting&#160;that the crystalized brines well reflect the complex mineral composition of brines and evaporative crystallization can be used for brine preservation. However, the natural solid salts (lakebed salts and crust salts) present obvious composition differences. Mg2+&#160;and SO42-&#160;are primarily found in brines, while the natural solid salts are dominated by NaCl and KCl.&#160;The pH of the brines and salt solutions are found to correlate to Mg2+&#160;concentrations and potentially affected by ambient CO2&#160;uptake. The electrical conductivities of sample solutions are not&#160;linearly scaled by the dilution factors, indicating that balanced reactions and buffer systems exist in the salt textures. Three interpretable factors are identified by the PMF analysis, and the differences of sample types and sampling sites are clearly reflected by the three factors. The lakebed salts (except for the QH lakebed salt) presented excellently correlation with the crust salts, and the crystalized salts are greatly correlated with the brines. This study improves the understandings of the physiochemical features of saline lake and playa salts in Qaidam Basin, and the roles that surface salts potentially play in the climate systems of both Planet Earth and Mars are discussed.&#160;ReferencePaatero, P., and Tapper, U., Environmetrics, 5, 111-126, 1994.Xiao, L., Wang, J., Dang, Y., et al., Earth-Sci Rev, 164, 84-101, 2017.

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Influence of Collecting Substrates on the Characterization of Hygroscopic Properties of Inorganic Aerosol Particles

Analytical Chemistry ◽

10.1021/ac4042075 ◽

2014 ◽

Vol 86 (5) ◽

pp. 2648-2656 ◽

Cited By ~ 28

Author(s):

Hyo-Jin Eom ◽

Dhrubajyoti Gupta ◽

Xue Li ◽

Hae-Jin Jung ◽

HyeKyeong Kim ◽

...

Keyword(s):

Aerosol Particles ◽

Hygroscopic Properties ◽

Inorganic Aerosol

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Hygroscopic properties of ultrafine aerosol particles in the boreal forest: diurnal variation, solubility and the influence of sulfuric acid

Atmospheric Chemistry and Physics ◽

10.5194/acp-7-211-2007 ◽

2007 ◽

Vol 7 (1) ◽

pp. 211-222 ◽

Cited By ~ 82

Author(s):

M. Ehn ◽

T. Petäjä ◽

H. Aufmhoff ◽

P. Aalto ◽

K. Hämeri ◽

...

Keyword(s):

Sulfuric Acid ◽

Boreal Forest ◽

Diurnal Variation ◽

Gas Phase ◽

Aerosol Particles ◽

Particle Formation ◽

Time Of Day ◽

New Particle Formation ◽

Hygroscopic Growth ◽

Hygroscopic Properties

Abstract. The hygroscopic growth of aerosol particles present in a boreal forest was measured at a relative humidity of 88%. Simultaneously the gas phase concentration of sulfuric acid, a very hygroscopic compound, was monitored. The focus was mainly on days with new particle formation by nucleation. The measured hygroscopic growth factors (GF) correlated positively with the gaseous phase sulfuric acid concentrations. The smaller the particles, the stronger the correlation, with r=0.20 for 50 nm and r=0.50 for 10 nm particles. The increase in GF due to condensing sulfuric acid is expected to be larger for particles with initially smaller masses. During new particle formation, the changes in solubility of the new particles were calculated during their growth to Aitken mode sizes. As the modal diameter increased, the solubility of the particles decreased. This indicated that the initial particle growth was due to more hygroscopic compounds, whereas the later growth during the evening and night was mainly caused by less hygroscopic or even hydrophobic compounds. For all the measured sizes, a diurnal variation in GF was observed both during days with and without particle formation. The GF was lowest at around midnight, with a mean value of 1.12–1.24 depending on particle size and if new particle formation occurred during the day, and increased to 1.25–1.34 around noon. This can be tentatively explained by day- and nighttime gas-phase chemistry; different vapors will be present depending on the time of day, and through condensation these compounds will alter the hygroscopic properties of the particles in different ways.

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Performance Evaluation of the Brechtel Mfg. Humidified Tandem Differential Mobility Analyzer (BMI HTDMA) for Studying Hygroscopic Properties of Aerosol Particles

Aerosol Science and Technology ◽

10.1080/02786826.2014.952366 ◽

2014 ◽

Vol 48 (9) ◽

pp. 969-980 ◽

Cited By ~ 19

Author(s):

Xerxes F. Lopez-Yglesias ◽

Ming Chee Yeung ◽

Stephen E. Dey ◽

Fred J. Brechtel ◽

Chak K. Chan

Keyword(s):

Performance Evaluation ◽

Aerosol Particles ◽

Differential Mobility Analyzer ◽

Differential Mobility ◽

Hygroscopic Properties

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The acidity of atmospheric particles and clouds

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-4809-2020 ◽

2020 ◽

Vol 20 (8) ◽

pp. 4809-4888 ◽

Cited By ~ 38

Author(s):

Havala O. T. Pye ◽

Athanasios Nenes ◽

Becky Alexander ◽

Andrew P. Ault ◽

Mary C. Barth ◽

...

Keyword(s):

Fine Particles ◽

Aerosol Particles ◽

Reaction Rates ◽

Global Scale ◽

Anthropogenic Emissions ◽

Central Component ◽

Condensed Phases ◽

Model Calculations ◽

Phase Partitioning ◽

Acids And Bases

Abstract. Acidity, defined as pH, is a central component of aqueous chemistry. In the atmosphere, the acidity of condensed phases (aerosol particles, cloud water, and fog droplets) governs the phase partitioning of semivolatile gases such as HNO3, NH3, HCl, and organic acids and bases as well as chemical reaction rates. It has implications for the atmospheric lifetime of pollutants, deposition, and human health. Despite its fundamental role in atmospheric processes, only recently has this field seen a growth in the number of studies on particle acidity. Even with this growth, many fine-particle pH estimates must be based on thermodynamic model calculations since no operational techniques exist for direct measurements. Current information indicates acidic fine particles are ubiquitous, but observationally constrained pH estimates are limited in spatial and temporal coverage. Clouds and fogs are also generally acidic, but to a lesser degree than particles, and have a range of pH that is quite sensitive to anthropogenic emissions of sulfur and nitrogen oxides, as well as ambient ammonia. Historical measurements indicate that cloud and fog droplet pH has changed in recent decades in response to controls on anthropogenic emissions, while the limited trend data for aerosol particles indicate acidity may be relatively constant due to the semivolatile nature of the key acids and bases and buffering in particles. This paper reviews and synthesizes the current state of knowledge on the acidity of atmospheric condensed phases, specifically particles and cloud droplets. It includes recommendations for estimating acidity and pH, standard nomenclature, a synthesis of current pH estimates based on observations, and new model calculations on the local and global scale.

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Tandem configuration of differential mobility and centrifugal particle mass analysers for investigating aerosol hygroscopic properties

Atmospheric Measurement Techniques ◽

10.5194/amt-10-1269-2017 ◽

2017 ◽

Vol 10 (3) ◽

pp. 1269-1280 ◽

Cited By ~ 6

Author(s):

Sergey S. Vlasenko ◽

Hang Su ◽

Ulrich Pöschl ◽

Meinrat O. Andreae ◽

Eugene F. Mikhailov

Keyword(s):

Water Uptake ◽

Aerosol Particles ◽

Interaction Model ◽

Growth Curves ◽

Particle Mass ◽

Submicron Particles ◽

Hygroscopic Growth ◽

Differential Mobility ◽

Hygroscopic Properties ◽

Modal Mass

Abstract. A tandem arrangement of Differential Mobility Analyser and Humidified Centrifugal Particle Mass Analyser (DMA-HCPMA) was developed to measure the deliquescence and efflorescence thresholds and the water uptake of submicron particles over the relative humidity (RH) range from 10 to 95 %. The hygroscopic growth curves obtained for ammonium sulfate and sodium chloride test aerosols are consistent with thermodynamic model predictions and literature data. The DMA-HCPMA system was applied to measure the hygroscopic properties of urban aerosol particles, and the kappa mass interaction model (KIM) was used to characterize and parameterize the concentration-dependent water uptake observed in the 50–95 % RH range. For DMA-selected 160 nm dry particles (modal mass of 3.5 fg), we obtained a volume-based hygroscopicity parameter, κv ≈  0.2, which is consistent with literature data for freshly emitted urban aerosols.Overall, our results show that the DMA-HCPMA system can be used to measure size-resolved mass growth factors of atmospheric aerosol particles upon hydration and dehydration up to 95 % RH. Direct measurements of particle mass avoid the typical complications associated with the commonly used mobility-diameter-based HTDMA technique (mainly due to poorly defined or unknown morphology and density).

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Chemical composition, microstructure, and hygroscopic properties of aerosol particles at the Zotino Tall Tower Observatory (ZOTTO), Siberia, during a summer campaign

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-8847-2015 ◽

2015 ◽

Vol 15 (15) ◽

pp. 8847-8869 ◽

Cited By ~ 24

Author(s):

E. F. Mikhailov ◽

G. N. Mironov ◽

C. Pöhlker ◽

X. Chi ◽

M. L. Krüger ◽

...

Keyword(s):

Organic Carbon ◽

Water Uptake ◽

Aerosol Particles ◽

Organic Coating ◽

Water Soluble ◽

Submicron Particles ◽

Hygroscopic Growth ◽

Accumulation Mode ◽

Hygroscopic Properties ◽

Coarse Mode

Abstract. In this study we describe the hygroscopic properties of accumulation- and coarse-mode aerosol particles sampled at the Zotino Tall Tower Observatory (ZOTTO) in central Siberia (61° N, 89° E) from 16 to 21 June 2013. The hygroscopic growth measurements were supplemented with chemical analyses of the samples, including inorganic ions and organic/elemental carbon. In addition, the microstructure and chemical compositions of aerosol particles were analyzed by x-ray micro-spectroscopy (STXM-NEXAFS) and transmission electron microscopy (TEM). A mass closure analysis indicates that organic carbon accounted for 61 and 38 % of particulate matter (PM) in the accumulation mode and coarse mode, respectively. The water-soluble fraction of organic matter was estimated to be 52 and 8 % of PM in these modes. Sulfate, predominantly in the form of ammoniated sulfate, was the dominant inorganic component in both size modes: ~ 34 % in the accumulation mode vs. ~ 47 % in the coarse mode. The hygroscopic growth measurements were conducted with a filter-based differential hygroscopicity analyzer (FDHA) over the range of 5–99.4 % RH in the hydration and dehydration operation modes. The FDHA study indicates that both accumulation and coarse modes exhibit pronounced water uptake approximately at the same relative humidity (RH), starting at ~ 70 %, while efflorescence occurred at different humidities, i.e., at ~ 35 % RH for submicron particles vs. ~ 50 % RH for supermicron particles. This ~ 15 % RH difference was attributed to higher content of organic material in the submicron particles, which suppresses water release in the dehydration experiments. The kappa mass interaction model (KIM) was applied to characterize and parameterize non-ideal solution behavior and concentration-dependent water uptake by atmospheric aerosol samples in the 5–99.4 % RH range. Based on KIM, the volume-based hygroscopicity parameter, κv, was calculated. The κv,ws value related to the water-soluble (ws) fraction was estimated to be ~ 0.15 for the accumulation mode and ~ 0.36 for the coarse mode, respectively. The obtained κv,ws for the accumulation mode is in good agreement with earlier data reported for remote sites in the Amazon rain forest (κv &approx; 0.15) and a Colorado mountain forest (κv &approx; 0.16 ). We used the Zdanovskii–Stokes–Robinson (ZSR) mixing rule to predict the chemical composition dependent hygroscopicity, κv,p. The obtained κv,p values overestimate the experimental FDHA-KIM-derived κv,ws by factors of 1.8 and 1.5 for the accumulation and coarse modes, respectively. This divergence can be explained by incomplete dissolution of the hygroscopic inorganic compounds resulting from kinetic limitations due to a sparingly soluble organic coating. The TEM and STXM-NEXAFS results indicate that aged submicron (> 300 nm) and supermicron aerosol particles possess core–shell structures with an inorganic core, and are enriched in organic carbon at the mixed particle surface. The direct FDHA kinetic studies provide a bulk diffusion coefficient of water of ~ 10−12 cm2 s−1 indicating a semi-solid state of the organic-rich phase leading to kinetic limitations of water uptake and release during hydration and dehydration cycles. Overall, the present ZOTTO data set, obtained in the growing season, has revealed a strong influence of organic carbon on the hygroscopic properties of the ambient aerosols. The sparingly soluble organic coating controls hygroscopic growth, phase transitions, and microstructural rearrangement processes. The observed kinetic limitations can strongly influence the outcome of experiments performed on multi-second timescales, such as the commonly applied HTDMA (Hygroscopicity Tandem Differential Mobility Analyzer) and CCNC (Cloud Condensation Nuclei Counter) measurements.

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MADE-IN: a new aerosol microphysics submodel for global simulation of potential atmospheric ice nuclei

Geoscientific Model Development Discussions ◽

10.5194/gmdd-3-2221-2010 ◽

2010 ◽

Vol 3 (4) ◽

pp. 2221-2290 ◽

Cited By ~ 1

Author(s):

V. Aquila ◽

J. Hendricks ◽

A. Lauer ◽

N. Riemer ◽

H. Vogel ◽

...

Keyword(s):

Atmospheric Chemistry ◽

Aerosol Particles ◽

Ice Crystals ◽

Dust Particles ◽

Airborne Measurements ◽

Cloud Processing ◽

Ice Nuclei ◽

Hygroscopic Properties ◽

Mixing States ◽

Made In

Abstract. Black carbon (BC) and mineral dust are among the dominant atmospheric ice nuclei, i.e. aerosol particles that can initiate heterogeneous nucleation of ice crystals. When released, most BC and dust particles are externally mixed with other aerosol compounds. Through coagulation with particles containing soluble material and condensation of gases, externally mixed particles may obtain a coating and be transferred into an internal mixture. The mixing state of BC and dust aerosol particles influences their radiative and hygroscopic properties, as well as their ability of building ice crystals. We introduce the new aerosol microphysics submodel MADE-IN, implemented within the ECHAM/MESSy Atmospheric Chemistry global model (EMAC). MADE-IN is able to track separately mass and number concentrations of BC and dust particles in their different mixing states, as well as particles free of BC and dust. MADE-IN describes these three classes of particles through a superposition of seven log-normally distributed modes, and predicts the evolution of their size distribution and chemical composition. Six out of the seven modes are mutually interacting, allowing for the transfer of mass and number among them. Separate modes for the different mixing states of BC and dust particles in EMAC/MADE-IN allow for explicit simulations of the relevant aging processes, i.e. condensation, coagulation and cloud processing. EMAC/MADE-IN has been evaluated with surface and airborne measurements and performs well both in the planetary boundary layer and in the upper troposphere and lowermost stratosphere. Such a model represents a highly appropriate tool for the study of the concentration and composition of potential atmospheric ice nuclei.

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