Deliquescence Relative Humidities of Organic and Inorganic Salts Important in the Atmosphere

Schroeder, J.; Beyer, Keith D.

doi:10.1021/acs.jpca.6b08725

Cited by 17 publications

(18 citation statements)

References 41 publications

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“…However, the Raman growth factors of mixed particles upon hydration show a considerable decrease in comparison to that upon dehydration. The discrepancies for Raman growth factor at high RH between the two processes can be attributed to the formation of NH 4 HC 2 O 4 and residual solid OA, both of which have a high deliquescence point larger than 95 % RH (Schroeder and Beyer, 2016). During the hydration process, NH 4 HC 2 O 4 and OA in the mixed aerosols remains solid even at high RH (also seen in Fig.…”

Section: Hygroscopic Growth Of Pure and Mixed Componentsmentioning

confidence: 89%

Hygroscopic behavior and chemical composition evolution of internally mixed aerosols composed of oxalic acid and ammonium sulfate

et al. 2017

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Abstract. Although water uptake of aerosol particles plays an important role in the atmospheric environment, the effects of interactions between components on chemical composition and hygroscopicity of particles are still not well constrained. The hygroscopic properties and phase transformation of oxalic acid (OA) and mixed particles composed of ammonium sulfate (AS) and OA with different organic to inorganic molar ratios (OIRs) have been investigated by using confocal Raman spectroscopy. It is found that OA droplets first crystallize to form OA dihydrate at 71 % relative humidity (RH), and further lose crystalline water to convert into anhydrous OA around 5 % RH during the dehydration process. The deliquescence and efflorescence point for AS is determined to be 80.1 ± 1.5 % RH and 44.3 ± 2.5 % RH, respectively. The observed efflorescence relative humidity (ERH) for mixed OA / AS droplets with OIRs of 1 : 3, 1 : 1 and 3 : 1 is 34.4 ± 2.0, 44.3 ± 2.5 and 64.4 ± 3.0 % RH, respectively, indicating the elevated OA content appears to favor the crystallization of mixed systems at higher RH. However, the deliquescence relative humidity (DRH) of AS in mixed OA / AS particles with OIRs of 1 : 3 and 1 : 1 is observed to occur at 81.1 ± 1.5 and 77 ± 1.0 % RH, respectively. The Raman spectra of mixed OA / AS droplets indicate the formation of ammonium hydrogen oxalate (NH 4 HC 2 O 4 ) and ammonium hydrogen sulfate (NH 4 HSO 4 ) from interactions between OA and AS in aerosols during the dehydration process on the time scale of hours, which considerably influence the subsequent deliquescence behavior of internally mixed particles with different OIRs. The mixed OA / AS particles with an OIR of 3 : 1 exhibit no deliquescence transition over the RH range studied due to the considerable transformation of (NH 4 ) 2 SO 4 into NH 4 HC 2 O 4 with a high DRH. Although the hygroscopic growth of mixed OA / AS droplets is comparable to that of AS or OA at high RH during the dehydration process, Raman growth factors of mixed particles after deliquescence are substantially lower than those of mixed OA / AS droplets during the efflorescence process and further decrease with elevated OA content. The discrepancies for Raman growth factors of mixed OA / AS particles between the dehydration and hydration process at high RH can be attributed to the significant formation of NH 4 HC 2 O 4 and residual OA, which remain solid at high RH and thus result in less water uptake of mixed particles. These findings improve the understanding of the role of reactions between dicarboxylic acid and inorganic salt in the chemical and physical properties of aerosol particles, and might have important implications for atmospheric chemistry.

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Section: Hygroscopic Growth Of Pure and Mixed Componentsmentioning

confidence: 89%

Hygroscopic behavior and chemical composition evolution of internally mixed aerosols composed of oxalic acid and ammonium sulfate

et al. 2017

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“…In addition, the effect of buoyancy, which varies with RH (Beyer et al, 2014;Schroeder and Beyer, 2016), is also automatically taken into account by using an empty pan as the reference. Semispherical quartz crucibles with a volume of 180 µL, provided by the manufacturer, are used in this work as sample pans.…”

Section: Humidity Chambermentioning

confidence: 99%

“…We note that two groups have used similar techniques to measure water adsorption by CaCO 3 and Arizona test dust (Gustafsson et al, 2005) and DRH of malonic acid, sodium oxalate, and sodium malonate (Beyer et al, 2014;Schroeder and Beyer, 2016). Nevertheless, the performance of this technique has never been systematically evaluated.…”

mentioning

confidence: 99%

Investigation of water adsorption and hygroscopicity of atmospherically relevant particles using a commercial vapor sorption analyzer

Zhu

et al. 2017

Atmos. Meas. Tech.

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Abstract. Water adsorption and hygroscopicity are among the most important physicochemical properties of aerosol particles, largely determining their impacts on atmospheric chemistry, radiative forcing, and climate. Measurements of water adsorption and hygroscopicity of nonspherical particles under subsaturated conditions are nontrivial because many widely used techniques require the assumption of particle sphericity. In this work we describe a method to directly quantify water adsorption and mass hygroscopic growth of atmospheric particles for temperature in the range of 5-30 • C, using a commercial vapor sorption analyzer. A detailed description of instrumental configuration and experimental procedures, including relative humidity (RH) calibration, is provided first. It is then demonstrated that for (NH 4 ) 2 SO 4 and NaCl, deliquescence relative humidities and mass hygroscopic growth factors measured using this method show good agreements with experimental and/or theoretical data from literature. To illustrate its ability to measure water uptake by particles with low hygroscopicity, we used this instrument to investigate water adsorption by CaSO 4 · 2H 2 O as a function of RH at 25 • C. The mass hygroscopic growth factor of CaSO 4 · 2H 2 O at 95 % RH, relative to that under dry conditions (RH < 1 %), was determined to be (0.450 ± 0.004) % (1σ ). In addition, it is shown that this instrument can reliably measure a relative mass change of 0.025 %. Overall, we have demonstrated that this commercial instrument provides a simple, sensitive, and robust method to investigate water adsorption and hygroscopicity of atmospheric particles.

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“…The main advantage of using a reference chamber and a sample chamber is that the amount of water adsorbed by the empty pan and the attached wire can be simultaneously determined (and automatically subtracted using the provided software) under the same condition when water uptake by particles under investigation is being measured. In addition, the effect of buoyancy, which varies with RH (Beyer et al, 2014;Schroeder and Beyer, 2016), is also automatically taken into account by using an empty pan as the reference. Semispherical quartz crucibles with a volume of 180 µL, provided by the manufacturer, are used in this work as sample pans.…”

Section: Humidity Chambermentioning

confidence: 99%

“…In this work we have developed an experimental method to investigate water adsorption and hygroscopicity of atmospheric particles, using a vapor sorption analyzer which is commercially available. We note that two groups have used similar techniques to measure water adsorption by CaCO 3 and Arizona test dust (Gustafsson et al, 2005) and DRH of malonic acid, sodium oxalate, and sodium malonate (Beyer et al, 2014;Schroeder and Beyer, 2016). Nevertheless, the performance of this technique has never been systematically evaluated.…”

Section: Introductionmentioning

confidence: 99%

Investigation of water adsorption and hygroscopicity of atmospheric particles using a commercial vapor sorption analyzer

Gu¹,

Li²,

Zhu³

et al. 2017

Preprint

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Abstract. Water adsorption and hygroscopicity are among the most important physicochemical properties of aerosol particles, largely determining their impacts on atmospheric chemistry, radiative forcing, and climate. Measurements of water adsorption and hygroscopicity of nonspherical particles under subsaturation conditions are non-trivial because many widely used techniques require the assumption of particle sphericity. In this work we describe a method to directly quantify water adsorption and mass hygroscopic growth of atmospheric particles for temperature in the range of 5–30 °C, using a commercial vapor sorption analyzer. A detailed description of instrumental configuration and experimental procedures, including relative humidity (RH) calibration, are provided first. It is then demonstrated that for (NH4)2SO4 and NaCl, deliquescence relative humidities (DRHs) and mass hygroscopic growth factors measured using this method show good agreements with experimental and/or theoretical data from literature. To illustrate its ability to measure water uptake by particles with low hygroscopicity, we used this instrument to investigate water adsorption by CaSO4 ∙ 2H2O as a function of RH at 25 °C. The mass hygroscopic growth factor of CaSO4 ∙ 2H2O at 95 % RH, relative to that under dry conditions (RH

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Deliquescence Relative Humidities of Organic and Inorganic Salts Important in the Atmosphere

Cited by 17 publications

References 41 publications

Hygroscopic behavior and chemical composition evolution of internally mixed aerosols composed of oxalic acid and ammonium sulfate

Hygroscopic behavior and chemical composition evolution of internally mixed aerosols composed of oxalic acid and ammonium sulfate

Investigation of water adsorption and hygroscopicity of atmospherically relevant particles using a commercial vapor sorption analyzer

Investigation of water adsorption and hygroscopicity of atmospheric particles using a commercial vapor sorption analyzer

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