Investigations of the hygroscopic properties of ammonium sulfate and mixed ammonium sulfate and glutaric acid micro droplets by means of optical levitation and Raman spectroscopy

2006 ◽  
Vol 8 (23) ◽  
pp. 2759 ◽  
Author(s):  
N. Jordanov ◽  
R. Zellner
Keyword(s):  
Raman Spectroscopy ◽  
Ammonium Sulfate ◽  
Glutaric Acid ◽  
Hygroscopic Properties ◽  
Optical Levitation

scholarly journals Depositional ice nucleation on solid ammonium sulfate and glutaric acid particles

2009 ◽  
Vol 9 (5) ◽  
pp. 20949-20977 ◽  
Author(s):  
K. J. Baustian ◽  
M. E. Wise ◽  
M. A. Tolbert
Keyword(s):  
Raman Spectroscopy ◽  
Optical Microscopy ◽  
Ammonium Sulfate ◽  
Glutaric Acid ◽  
Ice Nucleation ◽  
Cloud Formation ◽  
Ice Formation ◽  
Ice Nuclei ◽  
Tropopause Region ◽  
Important Pathway

Abstract. Heterogeneous ice nucleation on solid ammonium sulfate and solid amorphous glutaric acid particles was studied using optical microscopy and Raman spectroscopy. Optical microscopy was used to detect selective nucleation events as water vapor was slowly introduced into an environmental sample cell. Particles that nucleated ice were dried via sublimation and examined in detail using Raman spectroscopy. Depositional ice nucleation occurred preferentially on just a few ammonium sulfate and glutaric acid particles in each sample. For freezing temperatures between 214 K and 235 K average ice saturation ratios of S=1.10±0.07 for solid ammonium sulfate and S=1.39±0.16 for solid amorphous glutaric acid particles were determined. Experiments with externally mixed particles further show that ammonium sulfate is a more potent ice nucleus that glutaric acid. Our results suggest that heterogeneous nucleation on ammonium sulfate may be an important pathway for atmospheric ice nucleation and cirrus cloud formation when solid aerosol particles are available for ice formation. This pathway for ice formation may be particularly significant near the tropopause region where sulfates are abundant and other species known to be good ice nuclei are depleted.

scholarly journals Depositional ice nucleation on solid ammonium sulfate and glutaric acid particles

2010 ◽  
Vol 10 (5) ◽  
pp. 2307-2317 ◽  
Author(s):  
K. J. Baustian ◽  
M. E. Wise ◽  
M. A. Tolbert
Keyword(s):  
Raman Spectroscopy ◽  
Optical Microscopy ◽  
Ammonium Sulfate ◽  
Glutaric Acid ◽  
Ice Nucleation ◽  
Cloud Formation ◽  
Ice Formation ◽  
Tropical Tropopause ◽  
Ice Nuclei ◽  
Tropopause Region

Abstract. Heterogeneous ice nucleation on solid ammonium sulfate and glutaric acid particles was studied using optical microscopy and Raman spectroscopy. Optical microscopy was used to detect selective nucleation events as water vapor was slowly introduced into an environmental sample cell. Particles that nucleated ice were dried via sublimation and examined in detail using Raman spectroscopy. Depositional ice nucleation is highly selective and occurred preferentially on just a few ammonium sulfate and glutaric acid particles in each sample. For freezing temperatures between 214 K and 235 K an average ice saturation ratio of S = 1.10±0.07 for solid ammonium sulfate was observed. Over the same temperature range, S values observed for ice nucleation on glutaric acid particles increased from 1.2 at 235 K to 1.6 at 218 K. Experiments with externally mixed particles further show that ammonium sulfate is a more potent ice nucleus than glutaric acid. Our results suggest that heterogeneous nucleation on ammonium sulfate may be an important pathway for atmospheric ice nucleation and cirrus cloud formation when solid ammonium sulfate aerosol particles are available for ice formation. This pathway for ice formation may be particularly significant near the tropical tropopause region where sulfates are abundant and other species known to be good ice nuclei are depleted.

scholarly journals Deliquescence, efflorescence, and phase miscibility of mixed particles of ammonium sulfate and isoprene-derived secondary organic material

2012 ◽  
Vol 12 (4) ◽  
pp. 9903-9943 ◽  
Author(s):  
M. L. Smith ◽  
A. K. Bertram ◽  
S. T. Martin
Keyword(s):  
Liquid Phase ◽  
Relative Humidity ◽  
Ammonium Sulfate ◽  
Organic Material ◽  
Important Variable ◽  
Oxidation Products ◽  
Liquid Separation ◽  
Inorganic Particles ◽  
Photo Oxidation ◽  
Hygroscopic Properties

Abstract. The hygroscopic phase transitions of ammonium sulfate mixed with isoprene-derived secondary organic material were investigated in aerosol experiments. The organic material was produced by isoprene photo-oxidation at 40% relative humidity. The low volatility fraction of the photo-oxidation products condensed onto ammonium sulfate particles. The particle-phase organic material had oxygen-to-carbon ratios of 0.67 to 0.74 for mass concentrations of 20 to 30 μg m−3. The deliquescence, efflorescence, and phase miscibility of the mixed particles were investigated using a dual arm tandem differential mobility analyzer. The isoprene photo-oxidation products induced deviations in behavior relative to pure ammonium sulfate. Compared to an efflorescence relative humidity (ERH) of 30 to 35% for pure ammonium sulfate, efflorescence was eliminated for mixed aqueous particles having organic volume fractions ε of approximately 0.6 and greater. Compared to a deliquescence relative humidity (DRH) of 80% for pure ammonium sulfate, the DRH steadily decreased for increasing ε, approaching a DRH of 40% for ε of 0.9. Parameterizations of the DRH(ε) and ERH(ε) curves were as follows: DRH(ε)= Σ i ci,d xi valid for 0 ≤ ε ≤ 0.86 and ERH(ε)= Σ i ci,e xi valid for 0 ≤ ε ≤ 0.55 for the coefficients c0,d= 80.67, c0,e = 28.35, c1,d= −11.45, c1,e = −13.66, c2,d = 0, c2,e = 0, c3,d = 57.99, c3,e = −83.80, c4,d = −106.80, and c4,d = 0. The molecular description that is thermodynamically implied by these strongly sloped DRH(ε) and ERH(ε) curves is that the organic isoprene photo-oxidation products, the inorganic ammonium sulfate, and water form a miscible liquid phase even at low relative humidity. This phase miscibility is in contrast to the liquid-liquid separation that occurs for some other types of secondary organic material. These differences in liquid-liquid separation are consistent with a prediction recently presented in the literature that the bifurcation between liquid-liquid phase separation versus mixing depends on the oxygen-to-carbon ratio of the organic material. The conclusions are that the influence of secondary organic material on the hygroscopic properties of ammonium sulfate varies with organic composition and that the degree of oxygenation of the organic material, which is a measurable characteristic of complex organic materials, is an important variable influencing the hygroscopic properties of mixed organic-inorganic particles.

Comparative Thermodynamic Studies of Aqueous Glutaric Acid, Ammonium Sulfate and Sodium Chloride Aerosol at High Humidity⊥

2008 ◽  
Vol 112 (39) ◽  
pp. 9413-9422 ◽  
Author(s):  
Kate L. Hanford ◽  
Laura Mitchem ◽  
Jonathan P. Reid ◽  
Simon L. Clegg ◽  
David O. Topping ◽  
...  
Keyword(s):  
Sodium Chloride ◽  
Ammonium Sulfate ◽  
Glutaric Acid ◽  
High Humidity ◽  
Thermodynamic Studies

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

2017 ◽  
Author(s):  
Xiaowei Wang ◽  
Bo Jing ◽  
Fang Tan ◽  
Jiabi Ma ◽  
Yunhong Zhang ◽  
...  
Keyword(s):  
Growth Factors ◽  
Chemical Composition ◽  
Relative Humidity ◽  
Oxalic Acid ◽  
Ammonium Sulfate ◽  
Water Uptake ◽  
Atmospheric Environment ◽  
Dehydration Process ◽  
Hygroscopic Properties ◽  
Ammonium Hydrogen

Abstract. Although water uptake of aerosols plays an important role in the atmospheric environment, the effects of interactions between components on chemical composition and hygroscopicity of aerosols 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 oxalic acid dihydrate at 77 % relative humidity (RH), and further lose crystalline water to convert into anhydrous oxalic acid 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 % RH, 44.3 ± 2.5 % RH 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 partial deliquescence relative humidity (DRH) for mixed OA/AS particles with OIR of 1:3 and 1:1 is observed to occur at 81.1 ± 1.5 % RH and 77 ± 1.0 % RH, respectively. The Raman spectra of mixed OA/AS droplets indicate the formation of ammonium hydrogen oxalate (NH4HC2O4) and ammonium hydrogen sulfate (NH4HSO4) from interactions between OA and AS in aerosols after slow dehydration process in 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 3:1 ratio exhibit no deliquescence transition over the RH range studied due to the considerable transformation of (NH4)2SO4 into nonhygroscopic NH4HC2O4. 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 NH4HC2O4 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.

Hygroscopic properties of the oxidation products of monoterpenes when condensing on ammonium sulfate aerosols

1998 ◽  
Vol 29 ◽  
pp. S5-S6 ◽  
Author(s):  
A. Virkkula ◽  
R. van Dingenen ◽  
F. Raes ◽  
J. Hjorth ◽  
N. Jensen ◽  
...  
Keyword(s):  
Ammonium Sulfate ◽  
Oxidation Products ◽  
Sulfate Aerosols ◽  
Hygroscopic Properties

Hygroscopic Properties of Internally Mixed Particles of Ammonium Sulfate and Succinic Acid Studied by Infrared Spectroscopy

2010 ◽  
Vol 114 (20) ◽  
pp. 6124-6130 ◽  
Author(s):  
Lorena Miñambres ◽  
María N. Sánchez ◽  
Fernando Castaño ◽  
Francisco J. Basterretxea
Keyword(s):  
Infrared Spectroscopy ◽  
Succinic Acid ◽  
Ammonium Sulfate ◽  
Hygroscopic Properties

scholarly journals In situ Quantification of Ammonium Sulfate in Single Aerosol Droplets by Means of Laser Trapping and Raman Spectroscopy

2013 ◽  
Vol 29 (12) ◽  
pp. 1223-1226 ◽  
Author(s):  
Shoji ISHIZAKA ◽  
Kunihiro YAMAUCHI ◽  
Noboru KITAMURA
Keyword(s):  
Raman Spectroscopy ◽  
Ammonium Sulfate ◽  
Laser Trapping
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