Physical Sciences and Mathematics Commons^™

Peroxide Content Of Secondary Organic Aerosol, Ryan Caylor, Matthew Wise, John Shilling

Matthew E. Wise

Secondary organic aerosol (SOA) formed from the oxidation of monoterpenes can impact the Earth’s radiation balance, act as cloud condensation nuclei and negatively affect human health. In the summer of 2015, the Secondary Organic Aerosol From Forest Emission Experiment (SOAFFEE) laboratory campaign was launched in order to study the physical properties of SOA generated from the oxidation of α−pinene and Δ-carene. Both compounds are gas-phase monoterpenes emitted into the atmosphere via biogenic sources. In this study, the peroxide content of SOA was determined using an iodometricspectrophotometric (IS) technique. It was found that the peroxide content of SOA generated during the …

Optical Properties Of Secondary Organic Aerosols, Felisha Imholt, Ryan Caylor, Matthew Wise, John Shilling

Matthew E. Wise

It is well known that the increased warming effect due to greenhouse gases is a major environmental concern. While the amount of solar radiation absorbed by greenhouse gases is known to a high certainty, the amount absorbed by secondary organic aerosols (SOA) is not. The experimental procedure used to measure the amount of radiation absorbed by SOA was optimized using fulvic acid. The optimized method was then used to measure how much radiation SOA absorb between ~200 and 800 nm. Using this data, mass absorption coefficient (MAC) values at 405 nm and imaginary refractive indexes (k) were calculated. These values …

Composition And Optical Properties Of Secondary Organic Aerosol Particles, Felisha Imholt, Ryan Caylor, Matthew Wise, John Shilling

Matthew E. Wise

Research Questions: What is the chemical composition of SOA? Does SOA absorb UV/Vis radiation? If SOA does absorb UV/Vis radiation, how strong of an absorber is it?

Composition Of Secondary Organic Aerosols, Ryan Caylor, Felisha Imholt, Matthew Wise, John Shilling

Matthew E. Wise

The enhanced greenhouse effect is considered one our greatest global environmental problems. The amount of radiation absorbed by greenhouse gases is known to high certainty. However, absorbance from atmospheric aerosols particles is not. This study was conducted to determine the chemical composition of secondary organic aerosol particles (SOA) and to determine the compositional effect on their optical properties. The SOA were created in a temperature controlled chamber at Pacific Northwest National Laboratory (PNNL) in Richland, WA and collected on filters. The SOA were then analyzed for chemical composition using Fourier Transform Spectroscopy (FTIR). Analysis of the IR spectra revealed specific …

Laboratory Studies Of Ice Formation Pathways From Ammonium Sulfate Particles, M. E. Wise, K. J. Baustian, M. A. Tolbert

Matthew E. Wise

Cirrus clouds are composed of ice particles and their formation pathways have been studied extensively in the laboratory. The ability of ammonium sulfate particles to act as nuclei for cirrus clouds has been of particular importance because of their ubiquitous presence in the upper troposphere. The results of past laboratory experiments of homogeneous ice nucleation from ammonium sulfate particles show a wide range of freezing conditions. In the present study, a flow tube apparatus equipped with Fourier transform infrared spectroscopy was used to resolve these discrepancies. It was found that when ammonium sulfate particles were preconditioned at 100% relative humidity …

Laboratory Studies Of Ice Formation Pathways From Ammonium Sulfate Particles, M. E. Wise, K. J. Baustian, M. A. Tolbert

Matthew E. Wise

Cirrus clouds are composed of ice particles and their formation pathways have been studied extensively in the laboratory. The ability of ammonium sulfate particles to act as nuclei for cirrus clouds has been of particular importance because of their ubiquitous presence in the upper troposphere. The results of past laboratory experiments of homogeneous ice nucleation from ammonium sulfate particles show a wide range of freezing conditions. In the present study, a flow tube apparatus equipped with Fourier transform infrared spectroscopy was used to reexamine these discrepancies. It was found that when ammonium sulfate particles were preconditioned at 100% relative humidity …

Importance Of Aerosol Composition, Mixing State And Morphology For Heterogeneous Ice Nucleation: A Combined Field And Laboratory Approach, Kelly J. Baustian, Daniel J. Cziczo, Matthew E. Wise, Kerri A. Pratt, Gourihar Kulkarni, A. Gannet Hallar, Margaret A. Tolbert

Matthew E. Wise

In this study chemical compositions of background aerosol and ice nuclei were examined through laboratory investigations using Raman spectroscopy and field measurements by single-particle mass spectrometry. Aerosol sampling took place at Storm Peak Laboratory in Steamboat Springs, Colorado (elevation of 3210 m). A cascade impactor was used to collect coarse-mode aerosol particles for laboratory analysis by Raman spectroscopy; the composition, mixing state, and heterogeneous ice nucleation activity of individual particles were examined. For in situ analysis of fine-mode aerosol, ice nucleation on ambient particles was observed using a compact ice nucleation chamber. Ice crystals were separated from unactivated aerosol using …

Ice Nucleation In Internally Mixed Ammonium Sulfate/Dicarboxylic Acid Particles, Matthew E. Wise, Rebecca M. Garland, Margaret A. Tolbert

Matthew E. Wise

Recent studies have shown that tropospheric sulfate aerosols commonly contain 50% or more by mass organic species. The influence of these organics on the chemical and physical properties of sulfate aerosols is not fully established. Using an aerosol flow tube technique, we have determined ice nucleation temperatures for particles composed of ammonium sulfate and mixtures of ammonium sulfate with a series of dicarboxylic acids. A calibration curve was developed to allow us to convert the freezing temperatures to a saturation ratio required for ice nucleation. At levels detectable by our experimental technique we find that the freezing temperatures and critical …

Impact Of Palmitic Acid Coating On The Water Uptake And Loss Of Ammonium Sulfate Particles, R. M. Garland, M. E. Wise, M. R. Beaver, H. L. Dewitt, A. C. Aiken, J. L. Jimenez, M. A. Tolbert

Matthew E. Wise

While water insoluble organics are prevalent in the atmosphere, it is not clear how the presence of such species alters the chemical and physical properties of atmospheric aerosols. Here we use a combination of FTIR spectroscopy, Transmission Electron Microscopy (TEM) and Aerosol Mass Spectrometry (AMS) to characterize ammonium sulfate particles coated with palmitic acid. Coated aerosols were generated by atomizing pure ammonium sulfate, mixing the particles with a heated flow of nitrogen with palmitic acid vapor, and then flowing the mixture through an in-line oven to create internally mixed particles. The mixing state of the particles was probed using the …

Solubility And Freezing Effects Of Fe2+ And Mg2+ In H2so4 Solutions Representative Of Upper Tropospheric And Lower Stratospheric Sulfate Particles, Matthew E. Wise, Sarah D. Brooks, Rebecca M. Garland, Daniel J. Cziczo, Scot T. Martin, Margaret A. Tolbert

Matthew E. Wise

Chemical elements characteristic of earth minerals and meteorites are present within background tropospheric and stratospheric sulfate aerosol particles. However, it is unknown if these elements are present predominantly as solids, including possible sulfates, carbonates, and oxides, or rather as soluble aqueous metal ions or complexes. Further, it is unclear how these impurities could affect particle freezing. To address these questions, we have determined the total equilibrium metal solubility ([Fe²⁺]_T and [Mg²⁺]_T) in 20–90 wt % sulfuric acid solutions over the temperature range 200–300 K. We have measured solubilities using samples of MgSO_{4 …}

Phase Changes In Internally Mixed Maleic Acid/Ammonium Sulfate Aerosols, Sarah D. Brooks, Rebecca M. Garland, Matthew E. Wise, Anthony J. Prenni, Melinda Cushing, Erika Hewitt, Margaret A. Tolbert

Matthew E. Wise

A temperature controlled flow tube system equipped with Fourier transform infrared (FTIR) detection of particle phase and relative humidity was used to measure the deliquescence and efflorescence of ammonium sulfate, maleic acid, and internally mixed maleic acid/ammonium sulfate particles. Our results indicate that maleic acid aerosols begin to take up water starting at a low relative humidity, ∼20%, and continue the constant uptake of water until the final deliquescence relative humidity (DRH), 89%, is reached. Internally mixed particles containing maleic acid and ammonium sulfate were found to deliquesce at a lower relative humidity (RH) than either of the pure species. …

Hygroscopic Growth Of Ammonium Sulfate/Dicarboxylic Acids, Matthew E. Wise, Jason D. Surratt, Daniel B. Curtis, John E. Shilling, Margaret A. Tolbert

Matthew E. Wise

Recent studies have shown that tropospheric sulfate aerosols commonly contain 50% by mass organic species. The influence of these organics on the chemical and physical properties of sulfate aerosols is not fully established. We have measured the water activity of pure dicarboxylic acids and eutonic mixtures of ammonium sulfate/dicarboxylic acids at 25°C and have calculated van't Hoff factors for each individual system. We have also used the vapor pressure data to determine the hygroscopic growth curves for pure dicarboxylic acids and eutonic mixtures and provide power law fits to the data. For the systems studied we find that the presence …

Hygroscopic Behavior Of Nacl-Bearing Natural Aerosol Particles Using Environmental Transmission Electron Microscopy, Matthew E. Wise, Trudi A. Semeniuk, Roelof Bruintjes, Scot T. Martin, Lynn M. Russell, Peter R. Buseck

Matthew E. Wise

We used conventional and environmental transmission electron microscopes to determine morphology, composition, and water uptake of individual natural inorganic aerosol particles collected from industrial pollution plumes and from clean and polluted marine environments. Five particle types are described in detail. They range from relatively insoluble mineral grains to internally mixed particles containing NaCl with other soluble or relatively insoluble material. We studied the hygroscopic behavior of these particles from 0 to 100% relative humidity (RH). Relatively insoluble materials do not take up water over the experimental RH range. Single crystals of NaCl from both natural and laboratory sources have a …

Ice Nucleation In Sulfuric Acid And Ammonium Sulfate Particles, Anthony J. Prenni, Matthew E. Wise, Sarah D. Brooks, Margaret A. Tolbert

Matthew E. Wise

Cirrus clouds are composed of ice particles and are expected to form in the upper troposphere when highly dilute sulfate aerosols cool and become supersaturated with respect to ice. In the laboratory we have used Fourier transform infrared spectroscopy to monitor ice nucleation from sulfate particles for relevant compositions of sulfuric acid/water and ammonium sulfate/water aerosols. Measured freezing temperatures are presented as a function of aerosol composition, and results are compared to existing aerosol data. We find that sulfuric acid solution aerosol exhibits greater supercooling than ammonium sulfate solution aerosol of similar weight percent. Ice saturation ratios based on these …

State Transformations And Ice Nucleation In Amorphous (Semi-) Solid Organic Aerosol, K. J. Baustian, M. E. Wise, E. J. Jensen, G. P. Schill, M. A. Freedman, M. A. Tolbert

Matthew E. Wise

Amorphous (semi-)solid organic aerosol particles have the potential to serve as surfaces for heterogeneous ice nucleation in cirrus clouds. Raman spectroscopy and optical microscopy have been used in conjunction with a cold stage to examine water uptake and ice nucleation on individual amorphous (semi-)solid particles at atmospherically relevant temperatures (200–273 K). Three organic compounds considered proxies for atmospheric secondary organic aerosol (SOA) were used in this investigation: sucrose, citric acid and glucose. Internally mixed particles consisting of each organic and ammonium sulfate were also investigated. Results from water uptake experiments followed the shape of a humidity-induced glass transition (Tg(RH)) curve …

State Transformations And Ice Nucleation In Glassy Or (Semi-) Solid Amorphous Organic Aerosol, K. J. Baustian, M. E. Wise, E. J. Jensen, G. P. Schill, M. A. Freedman, M. A. Tolbert

Matthew E. Wise

Glassy or amorphous (semi-)solid organic aerosol particles have the potential to serve as surfaces for heterogeneous ice nucleation in cirrus clouds. Raman spectroscopy and optical microscopy have been used in conjunction with a cold stage to examine water uptake and ice nucleation on individual aqueous organic glass particles at atmospherically relevant temperatures (200–273 K). Three organic compounds considered proxies for atmospheric secondary organic aerosol (SOA) were used in this investigation: sucrose, citric acid and glucose. Internally mixed particles consisting of each organic species and ammonium sulfate were also investigated. Results from water uptake experiments were used to construct glass transition …

Determination Of The Optical Properties Of Secondary Organic Aerosol Particles, Matthew E. Wise, John Shilling, Felisha Imholt, Ryan Caylor

Matthew E. Wise

The enhanced greenhouse effect is currently considered to be our most important global environmental problem. While the magnitude of radiation absorbed by greenhouse gases is known to a high certainty, the absorption of radiation by atmospheric aerosol particles is not. In the initial Visiting Faculty Program application, we proposed the use of an ultraviolet-visible (UV/Vis) spectrometer equipped with a liquid waveguide capillary flow cell to determine the extent to which secondary organic aerosol particles (SOA) absorb visible light. Early in the research period, the UV/Vis technique was optimized for three solvent systems (methanol, water and 0.1 M hydrochloric acid). Using …

Depositional Ice Nucleation Onto Hydrated Nacl Particles: A New Mechanism For Ice Formation In The Troposphere, M. E. Wise, K. J. Baustian, T. Koop, M. A. Freedman, E. J. Jensen, M. A. Tolbert

Matthew E. Wise

Sea-salt aerosol (SSA) particles are ubiquitous in the marine boundary layer and over coastal areas. Therefore SSA have ability to directly and indirectly affect the Earth's radiation balance. The influence SSA have on climate is related to their water uptake and ice nucleation characteristics. In this study, optical microscopy coupled with Raman spectroscopy was used to detect the formation of a crystalline NaCl hydrate that could form under atmospheric conditions. NaCl(s) particles (~1 to 10 μm in diameter) deliquesced at 75.7 ± 2.5% RH which agrees well with values previously established in the literature. NaCl(aq) particles effloresced to a mixture …

Determination Of Total Peroxide Content In Secondary Organic Aerosol Particles, Matthew E. Wise, John Shilling, Ryan Caylor

Matthew E. Wise

Secondary organic aerosol particles (SOA) formed from the oxidation of monoterpenes can impact the Earth’s radiation balance, act as cloud condensation nuclei and negatively affect human health. In the initial Visiting Faculty Program application, we proposed the use of an ultraviolet-visible spectrometer equipped with a liquid waveguide capillary flow cell to determine the extent to which SOA absorb visible light. The inclusion of Concordia University in the Secondary Organic Aerosol From Forest Emissions Experiment (SOAFFEE) laboratory campaign at PNNL necessitated a change in the proposed experiments. An iodometric-spectrophotometric (IS) technique was developed to quantify the total peroxide content in SOA. …

Deliquescence Behavior Of Organic/Ammonium Sulfate Aerosol, Sarah D. Brooks, Matthew E. Wise, Melinda Cushing, Margaret A. Tolbert

Matthew E. Wise

Recent studies have shown that tropospheric aerosols composed of internal mixtures of organics with sulfates are quite common with the organic composing up to 50% of the particle mass. The influences of the organics on the chemical and physical properties of the aerosol are not known. In this paper, we report the solubility of a series of dicarboxylic acids in saturated ammonium sulfate solution as a function of temperature. We also report the deliquescence relative humidity (DRH) of the pure dicarboxylic acids and of mixtures of dicarboxylic acids with ammonium sulfate. For the systems studied, we find that the presence …

Hygroscopic Behavior And Liquid-Layer Composition Of Aerosol Particles Generated From Natural And Artificial Seawater, Matthew E. Wise, Evelyn J. Freney, Corey A. Tyree, Jonathan O. Allen, Scot T. Martin, Lynn M. Russell, Peter R. Buseck

Matthew E. Wise

Sea-salt aerosol (SSA) particles affect the Earth's radiative balance and moderate heterogeneous chemistry in the marine boundary layer. Using conventional and environmental transmission electron microscopes (ETEM), we investigated the hygroscopic growth and liquid-layer compositions of particles generated from three types of aqueous salt solutions: sodium chloride, laboratory-synthesized seawater (S-SSA particles), and natural seawater (N-SSA particles). Three levels of morphological change were observed with the ETEM as the laboratory-generated particles were exposed to increasing relative humidity (RH). The first level, onset of observable morphological changes, occurred on average at 70, 48, and 35% RH for the NaCl, S-SSA, and N-SSA particles, …

Depositional Ice Nucleation Onto Hydrated Nacl Particles: A New Mechanism For Ice Formation In The Troposphere, M. E. Wise, K. J. Baustian, T. Koop, M. A. Freedman, E. J. Jensen, M. A. Tolbert

Matthew E. Wise

Sea-salt aerosol particles (SSA) are ubiquitous in the marine boundary layer and over coastal areas. Therefore SSA have ability to directly and indirectly affect the Earth’s radiation balance. The influence SSA have on climate is related to their water uptake and ice nucleation characteristics. In this study, optical microscopy coupled with Raman spectroscopy was used to detect the formation of an NaCl hydrate that could form under atmospheric conditions. NaCl(s) particles deliquesced at the well established value of 75.7±2.5% RH. NaCl(aq) particles effloresced to a mixture of hydrated and non-hydrated particles at temperatures between 236 and 252 K. The aqueous …

Depositional Ice Nucleation On Solid Ammonium Sulfate And Glutaric Acid Particles, K. J. Baustian, M. E. Wise, M. A. Tolbert

Matthew E. Wise

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. …

Depositional Ice Nucleation On Solid Ammonium Sulfate And Glutaric Acid Particles, K. J. Baustian, M. E. Wise, M. A. Tolbert

Matthew E. Wise

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 235K 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 …

Vanessa Selimovic, Vanessa Selimovic

Matthew E. Wise

Felisha Imholt, Felisha Imholt

Matthew E. Wise