scholarly journals Cloud droplet activation through oxidation of organic aerosol influenced by temperature and particle phase state

2017 ◽  
Vol 44 (3) ◽  
pp. 1583-1591 ◽  
Author(s):  
Jonathan H. Slade ◽  
Manabu Shiraiwa ◽  
Andrea Arangio ◽  
Hang Su ◽  
Ulrich Pöschl ◽  
...  
Keyword(s):  
Phase State ◽  
Cloud Droplet ◽  
Organic Aerosol ◽  
Particle Phase ◽  
Droplet Activation

scholarly journals Impact of gas-to-particle partitioning approaches on the simulated radiative effects of biogenic secondary organic aerosol

2015 ◽  
Vol 15 (4) ◽  
pp. 4145-4172 ◽  
Author(s):  
C. E. Scott ◽  
D. V. Spracklen ◽  
J. R. Pierce ◽  
I. Riipinen ◽  
S. D. D'Andrea ◽  
...  
Keyword(s):  
Secondary Organic Aerosol ◽  
Cloud Droplet ◽  
Organic Aerosol ◽  
Oxidation Products ◽  
Kinetic Approach ◽  
Particle Phase ◽  
Climatic Effects ◽  
Cloud Droplets ◽  
Volatile Oxidation Products ◽  
Model Treatment

Abstract. The oxidation of biogenic volatile organic compounds (BVOCs) gives a range of products, from semi-volatile to extremely low-volatility compounds. To treat the interaction of these secondary organic vapours with the particle phase, global aerosol microphysics models generally use either a thermodynamic partitioning approach (assuming instant equilibrium between semi-volatile oxidation products and the particle phase) or a kinetic approach (accounting for the size-dependence of condensation). We show that model treatment of the partitioning of biogenic organic vapours into the particle phase, and consequent distribution of material across the size distribution, controls the magnitude of the first aerosol indirect effect (AIE) due to biogenic secondary organic aerosol (SOA). With a kinetic partitioning approach, SOA is distributed according to the existing condensation sink, enhancing the growth of the smallest particles, i.e., those in the nucleation mode. This process tends to increase cloud droplet number concentrations in the presence of biogenic SOA. By contrast, a thermodynamic approach distributes SOA according to pre-existing organic mass, restricting the growth of the smallest particles, limiting the number that are able to form cloud droplets. With an organically medicated new particle formation mechanism, applying a thermodynamic rather than a kinetic approach reduces our calculated global mean AIE due to biogenic SOA by 24%. Our results suggest that the mechanisms driving organic partitioning need to be fully understood in order to accurately describe the climatic effects of SOA.

Cloud droplet activation of polymerized organic aerosol

Tellus B ◽  
2006 ◽  
Vol 58 (3) ◽  
Author(s):  
Markus D. Petters ◽  
Sonia M. Kreidenweis ◽  
Jefferson R. Snider ◽  
Kirsten A. Koehler ◽  
Qiang Wang ◽  
...  
Keyword(s):  
Cloud Droplet ◽  
Organic Aerosol ◽  
Droplet Activation

scholarly journals Cloud droplet activation and surface tension of mixtures of slightly soluble organics and inorganic salt

2005 ◽  
Vol 5 (2) ◽  
pp. 575-582 ◽  
Author(s):  
S. Henning ◽  
T. Rosenørn ◽  
B. D'Anna ◽  
A. A. Gola ◽  
B. Svenningsson ◽  
...  
Keyword(s):  
Surface Tension ◽  
Sodium Chloride ◽  
Inorganic Salt ◽  
Cloud Droplet ◽  
Dicarboxylic Acids ◽  
Solid Particles ◽  
Particle Phase ◽  
Critical Supersaturation ◽  
Kohler Theory ◽  
Droplet Activation

Abstract. Critical supersaturations for internally mixed particles of adipic acid, succinic acid and sodium chloride were determined experimentally for dry particles sizes in the range 40-130nm. Surface tensions of aqueous solutions of the dicarboxylic acids and sodium chloride corresponding to concentrations at activation were measured and parameterized as a function of carbon content. The activation of solid particles as well as solution droplets were studied and particle phase was found to be important for the critical supersaturation. Experimental data were modelled using Köhler theory modified to account for limited solubility and surface tension lowering.

scholarly journals Cloud droplet activation of polymerized organic aerosol

Tellus B ◽  
2006 ◽  
Vol 58 (3) ◽  
pp. 196-205 ◽  
Author(s):  
Markus D. Petters ◽  
Sonia M. Kreidenweis ◽  
Jefferson R. Snider ◽  
Kirsten A. Koehler ◽  
Qiang Wang ◽  
...  
Keyword(s):  
Cloud Droplet ◽  
Organic Aerosol ◽  
Droplet Activation

scholarly journals Cloud droplet activation and surface tension of mixtures of slightly soluble organics and inorganic salt

2004 ◽  
Vol 4 (6) ◽  
pp. 7463-7485 ◽  
Author(s):  
S. Henning ◽  
T. Rosenørn ◽  
B. D’Anna ◽  
A. A. Gola ◽  
B. Svenningsson ◽  
...  
Keyword(s):  
Surface Tension ◽  
Sodium Chloride ◽  
Inorganic Salt ◽  
Cloud Droplet ◽  
Dicarboxylic Acids ◽  
Solid Particles ◽  
Particle Phase ◽  
Critical Supersaturation ◽  
Kohler Theory ◽  
Droplet Activation

Abstract. Critical supersaturations for internally mixed particles of adipic acid, succinic acid and sodium chloride were determined experimentally for dry particles sizes in the range 40–130 nm. Surface tensions of aqueous solutions of the dicarboxylic acids and sodium chloride corresponding to concentrations at activation were measured and parameterized as a function of carbon content. The activation of solid particles as well as solution droplets were studied and particle phase was found to be important for the critical supersaturation. Experimental data were modelled using Köhler theory modified to account for limited solubility and surface tension lowering.

scholarly journals Impact of gas-to-particle partitioning approaches on the simulated radiative effects of biogenic secondary organic aerosol

2015 ◽  
Vol 15 (22) ◽  
pp. 12989-13001 ◽  
Author(s):  
C. E. Scott ◽  
D. V. Spracklen ◽  
J. R. Pierce ◽  
I. Riipinen ◽  
S. D. D'Andrea ◽  
...  
Keyword(s):  
Secondary Organic Aerosol ◽  
Cloud Droplet ◽  
Organic Aerosol ◽  
Oxidation Products ◽  
Kinetic Approach ◽  
Particle Phase ◽  
Climatic Effects ◽  
Cloud Droplets ◽  
Volatile Oxidation Products ◽  
Model Treatment

Abstract. The oxidation of biogenic volatile organic compounds (BVOCs) gives a range of products, from semi-volatile to extremely low-volatility compounds. To treat the interaction of these secondary organic vapours with the particle phase, global aerosol microphysics models generally use either a thermodynamic partitioning approach (assuming instant equilibrium between semi-volatile oxidation products and the particle phase) or a kinetic approach (accounting for the size dependence of condensation). We show that model treatment of the partitioning of biogenic organic vapours into the particle phase, and consequent distribution of material across the size distribution, controls the magnitude of the first aerosol indirect effect (AIE) due to biogenic secondary organic aerosol (SOA). With a kinetic partitioning approach, SOA is distributed according to the existing condensation sink, enhancing the growth of the smallest particles, i.e. those in the nucleation mode. This process tends to increase cloud droplet number concentrations in the presence of biogenic SOA. By contrast, an approach that distributes SOA according to pre-existing organic mass restricts the growth of the smallest particles, limiting the number that are able to form cloud droplets. With an organically mediated new particle formation mechanism, applying a mass-based rather than a kinetic approach to partitioning reduces our calculated global mean AIE due to biogenic SOA by 24 %. Our results suggest that the mechanisms driving organic partitioning need to be fully understood in order to accurately describe the climatic effects of SOA.

Modelling hygroscopicity-induced gas–aerosol partitioning, organic surface enrichment and cloud droplet formation

2020 ◽  
Author(s):  
Andreas Zuend ◽  
Kyle Gorkowski
Keyword(s):  
Surface Tension ◽  
Phase Separation ◽  
Cloud Droplet ◽  
Organic Aerosol ◽  
Chem Phys ◽  
Computationally Efficient ◽  
Volatile Organic ◽  
Reduced Complexity ◽  
Droplet Activation

<p>The interactions among low and semi-volatile organic compounds, water and other inorganic components within fine-mode aerosols are complex. We show that understanding several features of this complexity can be important in the context of phase separation, a particle surface composition enriched by organics and for related cloud droplet activation modeling.  <br>Context: oxidized organic compounds contribute to the particle hygroscopicity, yet typically to a lesser extent than dissolved inorganic ions. The overall hygroscopicity of aerosols in turn greatly affects their water uptake in an air parcel experiencing increasing relative humidity. The mechanism acts directly in terms of adding water mass, as well as indirectly via a hygroscopicity-induced feedback leading to enhanced gas–to–particle partitioning of semi-volatile organic components alongside a re-equilibration of the aerosol with inorganic acids, ammonia and further water uptake. Furthermore, non-ideal mixing may induce liquid–liquid phase separation, often leading to an organic-rich phase of relatively low surface tension surrounding an inorganic-rich particle core. This phase separation effect and related surface enhancements of organic component concentrations affect not only the morphology but also the potential for near-surface chemical reactions, as well as the thermodynamics controlling an aerosol particle’s activation into a cloud droplet at realistic water vapour supersaturations.  New experimental techniques and field observations over the past few years have encouraged model development for an improved representation of these processes on a detailed level (see, e.g., discussion in Davies et al., 2019). This has led to a better understanding of the potential role of organic aerosol compounds spanning a range of polarities and an associated evolution of surface tension prior to the cloud condensation nucleus (CCN) activation point. While detailed process models still lack finer details to fully capture these composition and phase effects reliably and predictively, important challenges exist in translating these mechanisms into computationally efficient and feasible reduced-complexity models of use for air quality and chemistry-climate modelling.<br>In this presentation, we will outline the current state of a relatively complete process-level aerosol thermodynamics model based on AIOMFAC and introduce key features of a recently developed reduced-complexity organic aerosol model that accounts for water content and hygroscopicity-induced feedbacks on composition (Gorkowski et al., 2019). A key advantage of the reduced-complexity model is its ability to use only input typically known from field measurements or data available in large-scale air quality models. Our approach is compatible with a volatility basis set approach and allows for extending it by adding a realistic humidity dependence. In addition, we account for phase separation and related effects on surface tension in a simplified, computationally efficient manner. This approach and its results for aerosol hygroscopicity and cloud droplet activation will be discussed.</p><p>References:</p><p>Davies, J. F., Zuend, A., and Wilson, K. R.: Technical note: The role of evolving surface tension in the formation of cloud droplets, Atmos. Chem. Phys., 19, 2933–2946, doi:10.5194/acp-19-2933-2019, 2019.</p><p>Gorkowski, K., Preston, T. C., and Zuend, A.: Relative-humidity-dependent organic aerosol thermodynamics via an efficient reduced-complexity model, Atmos. Chem. Phys., 19, 13383–13407, 10.5194/acp-19-13383-2019, 2019.</p>

scholarly journals Cloud droplet activation of secondary organic aerosol

2007 ◽  
Vol 112 (D10) ◽  
Author(s):  
Anthony J. Prenni ◽  
Markus D. Petters ◽  
Sonia M. Kreidenweis ◽  
Paul J. DeMott ◽  
Paul J. Ziemann
Keyword(s):  
Secondary Organic Aerosol ◽  
Cloud Droplet ◽  
Organic Aerosol ◽  
Droplet Activation
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