Phase partitioning of aerosol particles in clouds at Kleiner Feldberg

1994 ◽  
Vol 19 (1-2) ◽  
pp. 107-127 ◽  
Author(s):  
A. Hallberg ◽  
K. J. Noone ◽  
J. A. Ogren ◽  
I. B. Svenningsson ◽  
A. Flossmann ◽  
...  
Keyword(s):  
Aerosol Particles ◽  
Phase Partitioning ◽  
Kleiner Feldberg

Phase Partitioning of Aerosol Particles in Clouds at Kleiner Feldberg

1994 ◽  
pp. 107-127 ◽  
Author(s):  
A. Hallberg ◽  
K. J. Noone ◽  
J. A. Ogren ◽  
I. B. Svenningsson ◽  
A. Flossmann ◽  
...  
Keyword(s):  
Aerosol Particles ◽  
Phase Partitioning ◽  
Kleiner Feldberg

scholarly journals The acidity of atmospheric particles and clouds

2020 ◽  
Vol 20 (8) ◽  
pp. 4809-4888 ◽  
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.

Hygroscopic growth of aerosol particles and its influence on nucleation scavenging in cloud: Experimental results from Kleiner Feldberg

1994 ◽  
Vol 19 (1-2) ◽  
pp. 129-152 ◽  
Author(s):  
Birgitta Svenningsson ◽  
Hans-Christen Hansson ◽  
Alfred Wiedensohler ◽  
Kevin Noone ◽  
John Ogren ◽  
...  
Keyword(s):  
Aerosol Particles ◽  
Experimental Results ◽  
Hygroscopic Growth ◽  
Nucleation Scavenging ◽  
Kleiner Feldberg

scholarly journals The Acidity of Atmospheric Particles and Clouds

2019 ◽  
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 ◽  
Trend Data

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 semi-volatile gases such as HNO3, NH3, and HCl, 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 indicates acidity may be relatively constant due to the semi-volatile 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.

scholarly journals The effect of phase partitioning of semivolatile compounds on the measured CCN activity of aerosol particles

2013 ◽  
Vol 6 (5) ◽  
pp. 8413-8433 ◽  
Author(s):  
S. Romakkaniemi ◽  
A. Jaatinen ◽  
A. Laaksonen ◽  
A. Nenes ◽  
T. Raatikainen
Keyword(s):  
Ammonium Nitrate ◽  
Gas Phase ◽  
Aerosol Particles ◽  
Test Compound ◽  
Ambient Conditions ◽  
Compound A ◽  
Phase Partitioning ◽  
Maximum Water ◽  
Kinetics Of ◽  
Ccn Activity

Abstract. The effect of inorganic semivolatile aerosol compounds on the CCN activity of aerosol particles was studied by using a computational model for a DMT-CCN counter, a cloud parcel model for condensation kinetics and experiments to quantify the modelled results. Concentrations of water vapour and semivolatiles as well as aerosol trajectories in the CCN column were calculated by a computational fluid dynamics model. These trajectories and vapour concentrations were then used as an input for the cloud parcel model to simulate mass transfer kinetics of water and semivolatiles between aerosol particles and the gas phase. Two different questions were studied: (1) how big fraction of semivolatiles is evaporated from particles before activation in the CCN counter? (2) How much the CCN activity can be increased due to condensation of semivolatiles prior to the maximum water supersaturation in the case of high semivolatile concentration in the gas phase? The results show that, to increase the CCN activity of aerosol particles, a very high gas phase concentration (as compared to typical ambient conditions) is needed. We used nitric acid as a test compound. A concentration of several ppb or higher is needed for measurable effect. In the case of particle evaporation, we used ammonium nitrate as a test compound and found that it partially evaporates before maximum supersaturation is reached in the CCN counter, thus causing an underestimation of CCN activity. The effect of evaporation is clearly visible in all supersaturations, leading to an underestimation of the critical dry diameter by 10 to 15 nanometres in the case of ammonium nitrate particles in different supersaturations. This result was also confirmed by measurements in supersaturations between 0.1 and 0.7%.

New MESSy scavenging subroutine to treat aerosol particles gas-phase partitioning in convective clouds

2021 ◽  
Author(s):  
Giorgio Taverna ◽  
Marc Barra ◽  
Holger Tost
Keyword(s):  
Liquid Phase ◽  
Gas Phase ◽  
Aerosol Particles ◽  
Phase Partitioning ◽  
Convective Clouds ◽  
Terrestrial Atmosphere ◽  
Deep Convective Clouds ◽  
High Level

<p>The Modular Earth Submodel System (MESSy) has been proven to be successful in the understanding of several processes which characterize the terrestrial atmosphere and climate.</p><p>However, the complexity of aerosol particles/gas phase partitioning of species in deep convective clouds together with the inherent problems of modelling sub-grid scale processes, make MESSy results significant underestimated, especially in case of SO<sub>2</sub>, when compared with available flight observations. For this reason, the subroutine which reproduce the scavenging of these species has been updated to include a more realistic treatment of liquid/phase partitioning of aerosol induced species in high level clouds.</p><p>Results obtained are shown in this poster.</p>

scholarly journals An analytical solution to calculate bulk mole fractions for any number of components in aerosol droplets after considering partitioning to a surface layer

2010 ◽  
Vol 3 (2) ◽  
pp. 635-642 ◽  
Author(s):  
D. Topping
Keyword(s):  
Surface Tension ◽  
Surface Layer ◽  
Analytical Solution ◽  
Large Scale ◽  
Aerosol Particles ◽  
Ternary Systems ◽  
Equilibrium Composition ◽  
Phase Partitioning ◽  
Number Of Components ◽  
Surface Partitioning

Abstract. Calculating the equilibrium composition of atmospheric aerosol particles, using all variations of Köhler theory, has largely assumed that the total solute concentrations define both the water activity and surface tension. Recently however, bulk to surface phase partitioning has been postulated as a process which significantly alters the predicted point of activation. In this paper, an analytical solution to calculate the removal of material from a bulk to a surface layer in aerosol particles has been derived using a well established and validated surface tension framework. The applicability to an unlimited number of components is possible via reliance on data from each binary system. Whilst assumptions regarding behaviour at the surface layer have been made to facilitate derivation, it is proposed that the framework presented can capture the overall impact of bulk-surface partitioning. Demonstrations of the equations for two and five component mixtures are given while comparisons are made with more detailed frameworks capable at modelling ternary systems at higher levels of complexity. Predictions made by the model across a range of surface active properties should be tested against measurements. Indeed, reccomendations are given for experimental validation and to assess sensitivities to accuracy and required level of complexity within large scale frameworks. Importantly, the computational efficiency of using the solution presented in this paper is roughly a factor of 20 less than a similar iterative approach, a comparison with highly coupled approaches not available beyond a 3 component system.

scholarly journals An analytical solution to calculate bulk mole fractions for any number of components in aerosol droplets after considering partitioning to a surface layer

2010 ◽  
Vol 3 (3) ◽  
pp. 1089-1104 ◽  
Author(s):  
D. Topping
Keyword(s):  
Surface Tension ◽  
Surface Layer ◽  
Analytical Solution ◽  
Aerosol Particles ◽  
Equilibrium Composition ◽  
Phase Partitioning ◽  
Number Of Components ◽  
Surface Partitioning ◽  
Surface Active Properties ◽  
Kohler Theory

Abstract. Calculating the equilibrium composition of atmospheric aerosol particles, using all variations of Köhler theory, has largely assumed that the total solute concentrations define both the water activity and surface tension. Recently however, bulk to surface phase partitioning has been postulated as a process which significantly alters the predicted point of activation. In this paper, an analytical solution to calculate the removal of material from a bulk to a surface layer in aerosol particles has been derived using a well established and validated surface tension framework. The applicability to an unlimited number of components is possible via reliance on data from each binary system. Whilst assumptions regarding behaviour at the surface layer have been made to facilitate derivation, it is proposed that the framework presented can capture the overall impact of bulk-surface partitioning. Predictions made by the model across a range of surface active properties should be tested against measurements. The computational efficiency of using the solution presented in this paper is roughly a factor of 20 less than a similar iterative approach, a comparison with highly coupled approaches not available beyond a 3 component system.

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