scholarly journals Water uptake of subpollen aerosol particles: hygroscopic growth, cloud condensation nuclei activation, and liquid–liquid phase separation

2021 ◽  
Vol 21 (9) ◽  
pp. 6999-7022
Author(s):  
Eugene F. Mikhailov ◽  
Mira L. Pöhlker ◽  
Kathrin Reinmuth-Selzle ◽  
Sergey S. Vlasenko ◽  
Ovid O. Krüger ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Water Uptake ◽  
Cloud Condensation Nuclei ◽  
Liquid Phase Separation ◽  
Hygroscopic Growth ◽  
Differential Mobility Analyzer ◽  
Condensation Nuclei ◽  
Differential Mobility ◽  
Liquid Liquid Phase Separation

Abstract. Pollen grains emitted from vegetation can release subpollen particles (SPPs) that contribute to the fine fraction of atmospheric aerosols and may act as cloud condensation nuclei (CCN), ice nuclei (IN), or aeroallergens. Here, we investigate and characterize the hygroscopic growth and CCN activation of birch, pine, and rapeseed SPPs. A high-humidity tandem differential mobility analyzer (HHTDMA) was used to measure particle restructuring and water uptake over a wide range of relative humidity (RH) from 2 % to 99.5 %, and a continuous flow CCN counter was used for size-resolved measurements of CCN activation at supersaturations (S) in the range of 0.2 % to 1.2 %. For both subsaturated and supersaturated conditions, effective hygroscopicity parameters, κ, were obtained by Köhler model calculations. Gravimetric and chemical analyses, electron microscopy, and dynamic light scattering measurements were performed to characterize further properties of SPPs from aqueous pollen extracts such as chemical composition (starch, proteins, DNA, and inorganic ions) and the hydrodynamic size distribution of water-insoluble material. All investigated SPP samples exhibited a sharp increase of water uptake and κ above ∼95 % RH, suggesting a liquid–liquid phase separation (LLPS). The HHTDMA measurements at RH >95 % enable closure between the CCN activation at water vapor supersaturation and hygroscopic growth at subsaturated conditions, which is often not achieved when hygroscopicity tandem differential mobility analyzer (HTDMA) measurements are performed at lower RH where the water uptake and effective hygroscopicity may be limited by the effects of LLPS. Such effects may be important not only for closure between hygroscopic growth and CCN activation but also for the chemical reactivity, allergenic potential, and related health effects of SPPs.

scholarly journals Water uptake of subpollen aerosol particles: hygroscopic growth, CCN activation, and liquid-liquid phase separation

2020 ◽  
Author(s):  
Eugene F. Mikhailov ◽  
Mira L. Pöhlker ◽  
Kathrin Reinmuth-Selzle ◽  
Sergey S. Vlasenko ◽  
Ovid O. Krüger ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Water Uptake ◽  
Chemical Reactivity ◽  
Fine Fraction ◽  
Liquid Phase Separation ◽  
Hygroscopic Growth ◽  
Model Calculations ◽  
Wide Range ◽  
Liquid Liquid Phase Separation

Abstract. Pollen grains emitted from vegetation can release subpollen particles (SPP) that contribute to the fine fraction of atmospheric aerosols and may act as cloud condensation nuclei (CCN), ice nuclei (IN), or aeroallergens. Here, we investigate and characterize the hygroscopic growth and CCN activation of birch, pine, and rapeseed SPP. A high humidity tandem differential mobility analyzer (HHTDMA) was used to measure particle restructuring and water uptake over a wide range of relative humidity (RH) from 2 % to 99.5 %, and a continuous flow CCN counter was used for size-resolved measurements of CCN activation at supersaturations (S) in the range of 0.2 % to 1.2 %. For both, subsaturated and supersaturated conditions, effective hygroscopicity parameters κ, were obtained by Köhler model calculations. Gravimetric and chemical analyses, electron microscopy, and dynamic light scattering measurements were performed to characterize further properties of SPP from aqueous pollen extracts such as chemical composition (starch, proteins, DNA, and inorganic ions) and the hydrodynamic size distribution of water-insoluble material. All investigated SPP samples exhibited sharp increases of water uptake and κ above ~95 % RH, suggesting a liquid-liquid phase separation (LLPS). The HHTDMA measurements at RH > 95 % enable closure between the CCN activation at water vapor supersaturation and hygroscopic growth at subsaturated conditions, which is often not achieved when HTDMA measurements are performed at lower RH where the water uptake and effective hygroscopicity may be limited by the effects of LLPS. Such effects may be important not only for closure between hygroscopic growth and CCN activation but also for the chemical reactivity, allergenic potential, and related health effects of SPP.

Water uptake of subpollen aerosol particles: hygroscopic growth, CCN activation, and liquid-liquid phase separation

2021 ◽  
Author(s):  
Eugene Mikhailov ◽  
Mira Pöhlker ◽  
Kathrin Reinmuth-Selzle ◽  
Sergey Vlasenko ◽  
Christopher Pöhlker ◽  
...  
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Water Uptake ◽  
Chemical Reactivity ◽  
Fine Fraction ◽  
Liquid Phase Separation ◽  
Hygroscopic Growth ◽  
Model Calculations ◽  
Wide Range ◽  
Liquid Liquid Phase Separation

<p>Pollen grains emitted from vegetation can release subpollen particles (SPP) that contribute to the fine fraction of atmospheric aerosols and may act as cloud condensation nuclei (CCN), ice nuclei (IN), or aeroallergens. Here, we investigate and characterize the hygroscopic growth and CCN activation of birch, pine, and rapeseed SPP. A high humidity tandem differential mobility analyzer (HHTDMA) was used to measure particle restructuring and water uptake over a wide range of relative humidity (RH) from 2 % to 99.5 %, and a continuous flow CCN counter was used for size-resolved measurements of CCN activation at supersaturations (S) in the range of 0.2 % to 1.2 %. For both subsaturated and supersaturated conditions, effective hygroscopicity parameters к , were obtained by Köhler model calculations. Gravimetric and chemical analyses, electron microscopy, and dynamic light scattering measurements were performed to characterize further properties of SPP from aqueous pollen extracts such as chemical composition (starch, proteins, DNA, and inorganic ions) and the hydrodynamic size distribution of water-insoluble material. All investigated SPP samples exhibited a sharp increase of water uptake and k above ~95 % RH, suggesting a liquid-liquid phase separation (LLPS). The HHTDMA measurements at RH> 95% enable closure between the CCN activation at water vapor supersaturation and hygroscopic growth at subsaturated conditions, which is often not achieved when HTDMA measurements are performed at lower RH where the water uptake and effective hygroscopicity may be limited by the effects of LLPS. Such effects may be important not only for closure between hygroscopic growth and CCN activation but also for the chemical reactivity, allergenic potential, and related health effects of SPP.</p><p>This research has been supported by the Russian Science Foundation (grant no. 18-10 17-00076) and Max Planck Society.</p>

scholarly journals Observations on hygroscopic growth and phase transitions of mixed 1, 2, 6-hexanetriol/(NH4</sub>)<sub>2</sub>SO<sub>4</sub> particles: Investigation of liquid-liquid phase separation (LLPS) dynamic process and mechanism and secondary LLPS

2021 ◽  
Author(s):  
Shuai-Shuai Ma ◽  
Zhe Chen ◽  
Shu-Feng Pang ◽  
Yun-Hong Zhang
Keyword(s):  
Phase Transitions ◽  
Phase Separation ◽  
Liquid Phase ◽  
Liquid Phase Separation ◽  
Solution Phase ◽  
High Time Resolution ◽  
Hygroscopic Growth ◽  
Inorganic Particles ◽  
Inorganic Components ◽  
Liquid Liquid Phase Separation

Abstract. Atmospheric aerosols consisting of organic and inorganic components may undergo liquid-liquid phase separation (LLPS) and liquid-solid phase transitions during ambient relative humidity (RH) fluctuation. However, the knowledge of dynamic phase evolution processes for mixed organic-inorganic particles is scarce. Here we present a universal and visualized observation on LLPS, efflorescence and deliquescence transitions as well as hygroscopic growth of mixed 1, 2, 6-hexanetriol/ammonium sulfate (AS) particles with different organic-inorganic mole ratios (OIR = 1:4, 1:2, 1:1, 2:1 and 4:1) with the high time resolution (0.5 s), using an optical microscope with a video camera. The optical images suggest that an inner AS solution phase is surrounded by an outer organic-rich phase after LLPS for all mixed particles. The LLPS mechanism for particles with different OIRs differs, meanwhile, multiple mechanisms may dominate successively in individual particles with a certain OIR, somewhat inconsistent with earlier observations by literature. More importantly, another phase separation in inner AS solution phase, defined as secondary LLPS here, is observed for OIR = 1:1, 1:2 and 1:4 particles. The secondary LLPS may be attributed to the formation of more concentrated AS inclusions in the inner phase, and becomes more obvious with decreasing RH and increasing AS mole fraction. Furthermore, the changes in size and amount of AS inclusions during LLPS are quantitatively characterized, which further illustrate the equilibrium partitioning process of organic and inorganic components. The experimental results have significant implications for revelation of complex phase transitions of internally mixed atmospheric particles and evaluation of liquid-liquid and liquid-solid equilibria in thermodynamic models.

scholarly journals Observations on hygroscopic growth and phase transitions of mixed 1, 2, 6-hexanetriol ∕ (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> particles: investigation of the liquid–liquid phase separation (LLPS) dynamic process and mechanism and secondary LLPS during the dehumidification

2021 ◽  
Vol 21 (12) ◽  
pp. 9705-9717
Author(s):  
Shuaishuai Ma ◽  
Zhe Chen ◽  
Shufeng Pang ◽  
Yunhong Zhang
Keyword(s):  
Phase Transitions ◽  
Phase Separation ◽  
Liquid Phase ◽  
Liquid Phase Separation ◽  
Solution Phase ◽  
High Time Resolution ◽  
Hygroscopic Growth ◽  
Inorganic Particles ◽  
Inorganic Components ◽  
Liquid Liquid Phase Separation

Abstract. Atmospheric aerosols consisting of organic and inorganic components may undergo liquid–liquid phase separation (LLPS) and liquid–solid phase transitions during ambient relative humidity (RH) fluctuation. However, the knowledge of dynamic phase evolution processes for mixed organic–inorganic particles is scarce. Here we present a universal and visualized observation of LLPS, efflorescence and deliquescence transitions as well as hygroscopic growth of laboratory-generated mixed 1, 2, 6-hexanetriol / ammonium sulfate (AS) particles with different organic–inorganic mole ratios (OIR = 1:4, 1:2, 1:1, 2:1 and 4:1) with high time resolution (0.5 s) using an optical microscope operated with a video camera. The optical images suggest that an inner AS solution phase is surrounded by an outer organic-rich phase after LLPS for all mixed particles. The LLPS mechanism for particles with different OIRs is found to be distinct; meanwhile, multiple mechanisms may dominate successively in individual particles with a certain OIR, somewhat inconsistently with previously reported observations. More importantly, another phase separation in the inner AS solution phase, defined as secondary LLPS here, is observed for OIR = 1:1, 1:2 and 1:4 particles. The secondary LLPS may be attributed to the formation of more concentrated AS inclusions in the inner phase and becomes more obvious with decreasing RH and increasing AS mole fraction. Furthermore, the changes in size and number of AS inclusions during LLPS are quantitatively characterized, which further illustrate the equilibrium partitioning process of organic and inorganic components. These experimental results have significant implications for the revelation of complex phase transitions of internally mixed atmospheric particles and evaluation of liquid–liquid and liquid–solid equilibria in thermodynamic models.

scholarly journals Liquid-liquid phase separation in secondary organic aerosol particles produced from α-pinene ozonolysis and α-pinene photo-oxidation with/without ammonia

2019 ◽  
Author(s):  
Suhan Ham ◽  
Zaeem Bin Babar ◽  
Jaebong Lee ◽  
Hojin Lim ◽  
Mijung Song
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Secondary Organic Aerosol ◽  
Cloud Condensation Nuclei ◽  
Aerosol Particles ◽  
Organic Aerosol ◽  
Liquid Phase Separation ◽  
Photo Oxidation ◽  
Different Types ◽  
Liquid Liquid Phase Separation

Abstract. Recently, liquid–liquid phase separation (LLPS) of secondary organic aerosol (SOA) particles free of inorganic salts has been intensively studied because of their importance on cloud condensation nuclei (CCN) properties. Herein, we investigated LLPS in four different types of SOA particles generated from α-pinene ozonolysis and α-pinene photo-oxidation in the absence and presence of NH3. LLPS was observed in SOA particles produced from α-pinene ozonolysis at ~ 95.8 % relative humidity (RH) and α-pinene ozonolysis with NH3 at ~ 95.4 % RH. However, LLPS was not observed in SOA particles produced from α-pinene photo-oxidation and α-pinene photo-oxidation with NH3. With datasets of average oxygen to carbon elemental ratio (O : C) for different types of SOA particles of this study and previous studies, LLPS occurred when the O : C ratio was less than ~ 0.44 and LLPS did not occur when the O : C ratio was greater than ~ 0.40. When LLPS was observed, the two liquid phases were present up to ~ 100 % RH. This result can help to predict more accurate results of CCN properties of organic aerosol particles.

scholarly journals Liquid-liquid phase separation in organic particles containing one and two organic species: importance of the average O:C

2018 ◽  
Author(s):  
Mijung Song ◽  
Suhan Ham ◽  
Ryan J. Andrews ◽  
Yuan You ◽  
Allan K. Bertram
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Cloud Condensation Nuclei ◽  
Experimental Studies ◽  
Liquid Phase Separation ◽  
Inorganic Salts ◽  
Organic Species ◽  
Organic Particles ◽  
Almost All ◽  
Liquid Liquid Phase Separation

Abstract. Recently, experimental studies have shown that liquid-liquid phase separation (LLPS) can occur in organic particles free of inorganic salts. Most of these studies used organic particles consisting of secondary organic materials generated in environmental chambers. To gain additional insight into LLPS in organic particles free of inorganic salts, we studied LLPS in organic particles consisting of one and two commercially available organic species. For particles containing one organic species, three out of the six particle types investigated underwent LLPS. In these cases, LLPS was observed when the O:C was ≤ 0.44 and the RH was between ~ 97 and ~ 100 %. The mechanism of phase separation was likely nucleation and growth. For particles containing two organic species, thirteen out of the fifteen particle types investigated underwent LLPS. In these cases, LLPS was observed when the O:C was ≤ 0.58 and mostly when the RH was between ~ 90 and ~ 100 % RH. The mechanism of phase separation was likely spinodal decomposition. In almost all cases when LLPS was observed (for both one-component and two-component particles), the highest RH at which two liquids was observed was 100 ± 2.0 %, which has important implications for the cloud condensation nuclei (CCN) properties of these particles. These combined results provide additional evidence that LLPS needs to be considered when predicting the CCN properties of organic particles in the atmosphere.

scholarly journals Liquid–liquid phase separation in organic particles containing one and two organic species: importance of the average O : C

2018 ◽  
Vol 18 (16) ◽  
pp. 12075-12084 ◽  
Author(s):  
Mijung Song ◽  
Suhan Ham ◽  
Ryan J. Andrews ◽  
Yuan You ◽  
Allan K. Bertram
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Cloud Condensation Nuclei ◽  
Experimental Studies ◽  
Liquid Phase Separation ◽  
Inorganic Salts ◽  
Organic Species ◽  
Organic Particles ◽  
Almost All ◽  
Liquid Liquid Phase Separation

Abstract. Recently, experimental studies have shown that liquid–liquid phase separation (LLPS) can occur in organic particles free of inorganic salts. Most of these studies used organic particles consisting of secondary organic materials generated in environmental chambers. To gain additional insight into LLPS in organic particles free of inorganic salts, we studied LLPS in organic particles consisting of one and two commercially available organic species. For particles containing one organic species, three out of the six particle types investigated underwent LLPS. In these cases, LLPS was observed when the O : C was  ≤ 0.44 (but not always) and the relative humidity (RH) was between  ∼ 97 % and  ∼ 100 %. The mechanism of phase separation was likely nucleation and growth. For particles containing two organic species, 13 out of the 15 particle types investigated underwent LLPS. In these cases, LLPS was observed when the O : C was  ≤ 0.58 (but not always) and mostly when the RH was between  ∼ 90 % RH and  ∼ 100 % RH. The mechanism of phase separation was likely spinodal decomposition. In almost all cases when LLPS was observed (for both one-component and two-component particles), the highest RH at which two liquids was observed was 100±2.0 %, which has important implications for the cloud condensation nuclei (CCN) properties of these particles. These combined results provide additional evidence that LLPS needs to be considered when predicting the CCN properties of organic particles in the atmosphere.

scholarly journals Liquid–liquid phase separation in secondary organic aerosol particles produced from <i>α</i>-pinene ozonolysis and <i>α</i>-pinene photooxidation with/without ammonia

2019 ◽  
Vol 19 (14) ◽  
pp. 9321-9331 ◽  
Author(s):  
Suhan Ham ◽  
Zaeem Bin Babar ◽  
Jae Bong Lee ◽  
Ho-Jin Lim ◽  
Mijung Song
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Secondary Organic Aerosol ◽  
Cloud Condensation Nuclei ◽  
Aerosol Particles ◽  
Organic Aerosol ◽  
Liquid Phase Separation ◽  
Liquid Phases ◽  
Different Types ◽  
Liquid Liquid Phase Separation

Abstract. Recently, liquid–liquid phase separation (LLPS) of secondary organic aerosol (SOA) particles free of inorganic salts has been intensively studied due to the importance of cloud condensation nuclei (CCN) properties. In this study, we investigated LLPS in four different types of SOA particles generated from α-pinene ozonolysis and α-pinene photooxidation in the absence and presence of ammonia (NH3). LLPS was observed in SOA particles produced from α-pinene ozonolysis at ∼95.8 % relative humidity (RH) and α-pinene ozonolysis with NH3 at ∼95.4 % RH. However, LLPS was not observed in SOA particles produced from α-pinene photooxidation and α-pinene photooxidation with NH3. Based on datasets of the average oxygen to carbon elemental ratio (O:C) for different types of SOA particles from this study and from previous studies, there appears to be a relationship between the occurrence of LLPS and the O:C of the SOA particles. When LLPS was observed, the two liquid phases were present up to ∼100 % RH. This result can help more accurately predict the CCN properties of organic aerosol particles.

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