scholarly journals Diffusivity measurements of volatile organics in levitated viscous aerosol particles

2017 ◽  
Vol 17 (13) ◽  
pp. 8453-8471 ◽  
Author(s):  
Sandra Bastelberger ◽  
Ulrich K. Krieger ◽  
Beiping Luo ◽  
Thomas Peter
Keyword(s):  
Atmospheric Chemistry ◽  
Aerosol Particles ◽  
Glassy State ◽  
Organic Aerosol ◽  
Diffusion Activation Energy ◽  
Tetraethylene Glycol ◽  
Resonance Spectroscopy ◽  
Hygroscopic Growth ◽  
Diffusion Limitations ◽  
Volatile Organic

Abstract. Field measurements indicating that atmospheric secondary organic aerosol (SOA) particles can be present in a highly viscous, glassy state have spurred numerous studies addressing low diffusivities of water in glassy aerosols. The focus of these studies is on kinetic limitations of hygroscopic growth and the plasticizing effect of water. In contrast, much less is known about diffusion limitations of organic molecules and oxidants in viscous matrices. These may affect atmospheric chemistry and gas–particle partitioning of complex mixtures with constituents of different volatility. In this study, we quantify the diffusivity of a volatile organic in a viscous matrix. Evaporation of single particles generated from an aqueous solution of sucrose and small amounts of volatile tetraethylene glycol (PEG-4) is investigated in an electrodynamic balance at controlled relative humidity (RH) and temperature. The evaporative loss of PEG-4 as determined by Mie resonance spectroscopy is used in conjunction with a radially resolved diffusion model to retrieve translational diffusion coefficients of PEG-4. Comparison of the experimentally derived diffusivities with viscosity estimates for the ternary system reveals a breakdown of the Stokes–Einstein relationship, which has often been invoked to infer diffusivity from viscosity. The evaporation of PEG-4 shows pronounced RH and temperature dependencies and is severely depressed for RH ≲ 30 %, corresponding to diffusivities < 10−14 cm2 s−1 at temperatures < 15 °C. The temperature dependence is strong, suggesting a diffusion activation energy of about 300 kJ mol−1. We conclude that atmospheric volatile organic compounds can be subject to severe diffusion limitations in viscous organic aerosol particles. This may enable an important long-range transport mechanism for organic material, including pollutant molecules such as polycyclic aromatic hydrocarbons (PAHs).

scholarly journals Diffusivity measurements of volatile organics in levitated viscous aerosol particles

2017 ◽  
Author(s):  
Sandra Bastelberger ◽  
Ulrich K. Krieger ◽  
Beiping Luo ◽  
Thomas Peter
Keyword(s):  
Atmospheric Chemistry ◽  
Glassy State ◽  
Field Measurements ◽  
Tetraethylene Glycol ◽  
Resonance Spectroscopy ◽  
Hygroscopic Growth ◽  
Single Particles ◽  
Diffusion Limitations ◽  
Electrodynamic Balance ◽  
Evaporative Loss

Abstract. Field measurements indicating that atmospheric secondary aerosol (SOA) particles can be present in a highly viscous, glassy state have spurred numerous studies addressing low diffusivities of water in glassy aerosols. The focus of these studies is on kinetic limitations of hygroscopic growth and the plasticizing effect of water. In contrast, much less is known about diffusion limitations of organic molecules and oxidants in viscous matrices. These may affect atmospheric chemistry and gas-particle partitioning of complex mixtures with constituents of different volatility. In this study, we quantify the diffusivity of a volatile organic in a viscous matrix. Evaporation of single particles generated from an aqueous solution of sucrose and small amounts of volatile tetraethylene glycol (PEG-4) is investigated in an electrodynamic balance at controlled humidity (RH) and temperature. The evaporative loss of PEG-4 as determined by Mie resonance spectroscopy is used in conjunction with a radially resolved diffusion model to retrieve translational diffusion coefficients of PEG-4. Comparison of the experimentally derived diffusivities with viscosity estimates for the ternary system reveals a breakdown of the Stokes-Einstein relationship, which has often been invoked to infer diffusivity from viscosity. The evaporation of PEG-4 shows pronounced RH and temperature dependencies and is severely depressed for RH &amp;lesssim; 30 %, corresponding to diffusivities

scholarly journals Nitrate radicals and biogenic volatile organic compounds: oxidation, mechanisms and organic aerosol

2016 ◽  
Author(s):  
N. L. Ng ◽  
S. S. Brown ◽  
A. T. Archibald ◽  
E. Atlas ◽  
R. C. Cohen ◽  
...  
Keyword(s):  
Air Quality ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Atmospheric Chemistry ◽  
Climate Models ◽  
Large Body ◽  
Organic Aerosol ◽  
Organic Nitrate ◽  
Biogenic Volatile Organic Compounds ◽  
Volatile Organic

Abstract. Oxidation of biogenic volatile organic compounds (BVOC) by the nitrate radical (NO3) represents one of the important interactions between anthropogenic emissions related to combustion and natural emissions from the biosphere. This interaction has been recognized for more than three decades, during which time a large body of research has emerged from laboratory, field and modeling studies. NO3-BVOC reactions influence air quality, climate and visibility through regional and global budgets for reactive nitrogen (particularly organic nitrates), ozone and organic aerosol. Despite its long history of research and the significance of this topic in atmospheric chemistry, a number of important uncertainties remain. These include an incomplete understanding of the rates, mechanisms and organic aerosol yields for NO3-BVOC reactions, lack of constraints on the role of heterogeneous oxidative processes associated with the NO3 radical, the difficulty of characterizing the spatial distributions of BVOC and NO3 within the poorly mixed nocturnal atmosphere and the challenge of constructing appropriate boundary layer schemes and non-photochemical mechanisms for use in state-of-the-art chemical transport and chemistry-climate models. This review is the result of a workshop of the same title held at the Georgia Institute of Technology in June 2015. The first section summarizes the current literature on NO3-BVOC chemistry, with a particular focus on recent advances in instrumentation and models, and in organic nitrate and secondary organic aerosol (SOA) formation chemistry. Building on this current understanding, the second half of the review outlines impacts of NO3-BVOC chemistry on air quality and climate, and suggests critical research needs to better constrain this interaction to improve the predictive capabilities of atmospheric models.

scholarly journals Simulation of organics in the atmosphere: evaluation of EMACv2.54 with the Mainz Organic Mechanism (MOM) coupled to the ORACLE (v1.0) submodel

2021 ◽  
Author(s):  
Andrea Pozzer ◽  
Simon Reifenberg ◽  
Vinod Kumar ◽  
Bruno Franco ◽  
Domenico Taraborrelli ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
General Circulation ◽  
Circulation Model ◽  
Organic Aerosol ◽  
Efficient Estimation ◽  
Chemical Degradation ◽  
Aerosol Formation ◽  
Organic Species ◽  
Volatile Organic ◽  
Good Agreement

Abstract. An updated and expanded representation of organics in the chemistry general circulation model EMAC (ECHAM5/MESSy for Atmospheric Chemistry) has been evaluated. First, the comprehensive Mainz Organic Mechanism (MOM) in the submodel MECCA (Module Efficiently Calculating the Chemistry of the Atmosphere) was activated with explicit degradation of organic species up to five carbon atoms and a simplified mechanism for larger molecules. Second, the ORACLE submodel (version 1.0) considers now condensation on aerosols for all organics in the mechanism. Parameterizations for aerosol yields are used only for the lumped species that are not included in the explicit mechanism. The simultaneous usage of MOM and ORACLE allows an efficient estimation, not only of the chemical degradation of the simulated volatile organic compounds, but also of the contribution of organics to the growth and fate of (organic) aerosol, with a complexity of the mechanism largely increased compared to EMAC simulations with more simplified chemistry. The model evaluation presented here reveals that the OH concentration is well reproduced globally, while significant biases for observed oxygenated organics are present. We also investigate the general properties of the aerosols and their composition, showing that the more sophisticated and process-oriented secondary aerosol formation does not degrade the good agreement of previous model configurations with observations at the surface, allowing further research in the field of gas-aerosol interactions.

Influence of humidity and iron(iii) on photodegradation of atmospheric secondary organic aerosol particles

2018 ◽  
Vol 20 (47) ◽  
pp. 30021-30031 ◽  
Author(s):  
Pablo Corral Arroyo ◽  
Kurtis T. Malecha ◽  
Markus Ammann ◽  
Sergey A. Nizkorodov
Keyword(s):  
Volatile Organic Compounds ◽  
Mass Loss ◽  
Organic Compounds ◽  
Condensed Phase ◽  
Secondary Organic Aerosol ◽  
Aerosol Particles ◽  
Organic Aerosol ◽  
Oxygenated Volatile Organic Compounds ◽  
Volatile Organic ◽  
Actinic Radiation

The absorption of solar actinic radiation by atmospheric secondary organic aerosol (SOA) particles drives condensed-phase photochemical processes, which lead to particle mass loss by the production of CO, CO2, hydrocarbons, and various oxygenated volatile organic compounds (OVOCs).

scholarly journals Characterising the evaporation kinetics of water and semi-volatile organic compounds from viscous multicomponent organic aerosol particles

2017 ◽  
Vol 19 (47) ◽  
pp. 31634-31646 ◽  
Author(s):  
Stephen Ingram ◽  
Chen Cai ◽  
Young-Chul Song ◽  
David R. Glowacki ◽  
David O. Topping ◽  
...  
Keyword(s):  
Particle Size ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Aerosol Particle ◽  
Aerosol Particles ◽  
Organic Aerosol ◽  
Volatile Organic ◽  
Aerosol Particle Size ◽  
Kinetics Of ◽  
Evaporation Kinetics

Here we present methods to simultaneously investigate diffusivities and volatilities in studies of evolving single aerosol particle size and composition.

scholarly journals <i>α</i>-Pinene Nitrates: synthesis, yields and atmospheric chemistry

2011 ◽  
Vol 11 (2) ◽  
pp. 6845-6874
Author(s):  
S. X. Ma ◽  
J. D. Rindelaub ◽  
K. M. McAvey ◽  
P. D. Gagare ◽  
B. A. Nault ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Organic Aerosol ◽  
Reaction Chamber ◽  
Oxidation Products ◽  
Ozone Production ◽  
Organic Nitrate ◽  
Peroxy Radicals ◽  
Nitrate Precursor ◽  
Volatile Organic ◽  
Major Oxidation

Abstract. The biogenic volatile organic compound α-pinene is one of the dominant monoterpenes emitted to the Earth's atmosphere at an estimated rate of ~50 Tg yr−1. Its atmospheric oxidation products in the presence of NO can lead to ozone production, as well as production of secondary organic aerosol (SOA). The major oxidation pathway of α-pinene is reaction with OH, which in the presence of NO can form either α-pinene nitrates or convert NO to NO2, which can photolyze to form ozone. In this work, we successfully synthesized four α-pinene hydroxy nitrates through three different routes, and have identified the 4 individual isomers in α-pinene/OH/NO reaction chamber experiments. From the experiments, we determined their individual production yields, estimated the total RONO2 yield, and calculated the relative branching ratios of the nitrate precursor peroxy radicals (RO2). The combined yield of the four α-pinene nitrates was found to be 13.0 (±0.7) % at atmospheric pressure and 296 K, and the total organic nitrate yield was estimated to be 0.19 (+0.10/−0.06). We also determined the OH rate constants for two of the isomers, and have calculated their overall atmospheric lifetimes, which range between 22 and 38 h.

scholarly journals <i>α</i>-Pinene nitrates: synthesis, yields and atmospheric chemistry

2011 ◽  
Vol 11 (13) ◽  
pp. 6337-6347 ◽  
Author(s):  
S. X. Ma ◽  
J. D. Rindelaub ◽  
K. M. McAvey ◽  
P. D. Gagare ◽  
B. A. Nault ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Organic Aerosol ◽  
Reaction Chamber ◽  
Oxidation Products ◽  
Ozone Production ◽  
Organic Nitrate ◽  
Peroxy Radicals ◽  
Nitrate Precursor ◽  
Volatile Organic ◽  
Major Oxidation

Abstract. The biogenic volatile organic compound α-pinene is one of the dominant monoterpenes emitted to the Earth's atmosphere at an estimated rate of ~50 Tg C yr−1. Its atmospheric oxidation products in the presence of NO can lead to ozone production, as well as production of secondary organic aerosol (SOA). The major oxidation pathway of α-pinene is reaction with OH, which in the presence of NO can form either α-pinene nitrates or convert NO to NO2, which can photolyze to form ozone. In this work, we successfully synthesized four α-pinene hydroxy nitrates through three different routes, and have identified these 4 individual isomers in α-pinene/OH/NO reaction chamber experiments. From the experiments, we determined their individual production yields, estimated the total RONO2 yield, and calculated the relative branching ratios of the nitrate precursor peroxy radicals (RO2). The combined yield of the four α-pinene nitrates was found to be 0.130 (±0.035) at atmospheric pressure and 296 K, and the total organic nitrate yield was estimated to be 0.19 (+0.10/−0.06). We also determined the OH rate constants for two of the isomers, and have calculated their overall atmospheric lifetimes, which range between 22 and 38 h.

scholarly journals Hygroscopicity of Internally Mixed Ammonium Sulfate and Secondary Organic Aerosol Particles Formed at Low and High Relative Humidity

2022 ◽  
Author(s):  
Patricia N Razafindrambinina ◽  
Kotiba A Malek ◽  
Joseph Nelson Dawson ◽  
Kristin DiMonte ◽  
Timothy M Raymond ◽  
...  
Keyword(s):  
Organic Matter ◽  
Relative Humidity ◽  
Ammonium Sulfate ◽  
Secondary Organic Aerosol ◽  
Aerosol Particles ◽  
Organic Aerosol ◽  
High Relative Humidity ◽  
Volatile Organic

Volatile organic matter that is suspended in the atmosphere such as α-Pinene and β-caryophyllene undergoes aging processes, as well as chemical and photooxidation reactions to create secondary organic aerosol (SOA),...

scholarly journals Nitrate radicals and biogenic volatile organic compounds: oxidation, mechanisms, and organic aerosol

2017 ◽  
Vol 17 (3) ◽  
pp. 2103-2162 ◽  
Author(s):  
Nga Lee Ng ◽  
Steven S. Brown ◽  
Alexander T. Archibald ◽  
Elliot Atlas ◽  
Ronald C. Cohen ◽  
...  
Keyword(s):  
Air Quality ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Atmospheric Chemistry ◽  
Climate Models ◽  
Large Body ◽  
Organic Aerosol ◽  
Organic Nitrate ◽  
Biogenic Volatile Organic Compounds ◽  
Volatile Organic

Abstract. Oxidation of biogenic volatile organic compounds (BVOC) by the nitrate radical (NO3) represents one of the important interactions between anthropogenic emissions related to combustion and natural emissions from the biosphere. This interaction has been recognized for more than 3 decades, during which time a large body of research has emerged from laboratory, field, and modeling studies. NO3-BVOC reactions influence air quality, climate and visibility through regional and global budgets for reactive nitrogen (particularly organic nitrates), ozone, and organic aerosol. Despite its long history of research and the significance of this topic in atmospheric chemistry, a number of important uncertainties remain. These include an incomplete understanding of the rates, mechanisms, and organic aerosol yields for NO3-BVOC reactions, lack of constraints on the role of heterogeneous oxidative processes associated with the NO3 radical, the difficulty of characterizing the spatial distributions of BVOC and NO3 within the poorly mixed nocturnal atmosphere, and the challenge of constructing appropriate boundary layer schemes and non-photochemical mechanisms for use in state-of-the-art chemical transport and chemistry–climate models. This review is the result of a workshop of the same title held at the Georgia Institute of Technology in June 2015. The first half of the review summarizes the current literature on NO3-BVOC chemistry, with a particular focus on recent advances in instrumentation and models, and in organic nitrate and secondary organic aerosol (SOA) formation chemistry. Building on this current understanding, the second half of the review outlines impacts of NO3-BVOC chemistry on air quality and climate, and suggests critical research needs to better constrain this interaction to improve the predictive capabilities of atmospheric models.

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