12 results on '"Lauren A. Garofalo"'
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2. Direct Constraints on Secondary HONO Production in Aged Wildfire Smoke From Airborne Measurements Over the Western US
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Qiaoyun Peng, Brett B. Palm, Carley D. Fredrickson, Ben H. Lee, Samuel R. Hall, Kirk Ullmann, Andrew J. Weinheimer, Ezra Levin, Paul DeMott, Lauren A. Garofalo, Matson A. Pothier, Delphine K. Farmer, Emily V. Fischer, and Joel A. Thornton more...
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Geophysics ,General Earth and Planetary Sciences - Published
- 2022
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Catalog
3. Quantification of organic aerosol and brown carbon evolution in fresh wildfire plumes
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Lu Hu, Yingjie Shen, Qiaoyun Peng, Frank Flocke, Matson A. Pothier, Emily V. Fischer, Samuel R. Hall, Sonia M. Kreidenweis, R. P. Pokhrel, Joel A. Thornton, Ben H. Lee, Teresa Campos, Wade Permar, Xuan Zhang, Delphine K. Farmer, Shane M. Murphy, Carley D. Fredrickson, Lauren A. Garofalo, Kirk Ullmann, and Brett B. Palm more...
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Aerosols ,Smoke ,Air Pollutants ,Daytime ,Multidisciplinary ,Particle composition ,010504 meteorology & atmospheric sciences ,010501 environmental sciences ,Particulates ,01 natural sciences ,Carbon ,United States ,Wildfires ,Plume ,Trace gas ,Aerosol ,13. Climate action ,Environmental chemistry ,Physical Sciences ,Environmental science ,Particulate Matter ,Brown carbon ,Environmental Monitoring ,0105 earth and related environmental sciences - Abstract
The evolution of organic aerosol (OA) and brown carbon (BrC) in wildfire plumes, including the relative contributions of primary versus secondary sources, has been uncertain in part because of limited knowledge of the precursor emissions and the chemical environment of smoke plumes. We made airborne measurements of a suite of reactive trace gases, particle composition, and optical properties in fresh western US wildfire smoke in July through August 2018. We use these observations to quantify primary versus secondary sources of biomass-burning OA (BBPOA versus BBSOA) and BrC in wildfire plumes. When a daytime wildfire plume dilutes by a factor of 5 to 10, we estimate that up to one-third of the primary OA has evaporated and subsequently reacted to form BBSOA with near unit yield. The reactions of measured BBSOA precursors contribute only 13 ± 3% of the total BBSOA source, with evaporated BBPOA comprising the rest. We find that oxidation of phenolic compounds contributes the majority of BBSOA from emitted vapors. The corresponding particulate nitrophenolic compounds are estimated to explain 29 ± 15% of average BrC light absorption at 405 nm (BrC Abs(405)) measured in the first few hours of plume evolution, despite accounting for just 4 ± 2% of average OA mass. These measurements provide quantitative constraints on the role of dilution-driven evaporation of OA and subsequent radical-driven oxidation on the fate of biomass-burning OA and BrC in daytime wildfire plumes and point to the need to understand how processing of nighttime emissions differs. more...
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- 2020
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4. Biomass Burning Smoke and Its Influence on Clouds Over the Western U. S
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Ezra J. T. Levin, Lauren A. Garofalo, Delphine K. Farmer, Emily V. Fischer, Bryan Rainwater, Cynthia H. Twohy, Sonia M. Kreidenweis, Paul J. DeMott, Kathryn A. Moore, Matson A. Pothier, R. P. Pokhrel, J. Michael Reeves, Shane M. Murphy, and Darin W. Toohey more...
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Smoke ,Geophysics ,Smoke aerosol ,General Earth and Planetary Sciences ,Environmental science ,Biomass burning ,Atmospheric sciences - Published
- 2021
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5. Investigating Carbonaceous Aerosol and Its Absorption Properties From Fires in the Western United States (WE‐CAN) and Southern Africa (ORACLES and CLARIFY)
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Ezra J. T. Levin, Lu Hu, Kate Szpek, Cathyrn Fox, Jonathan Taylor, Delphine K. Farmer, Huihui Wu, Michael I. Cotterell, Colette L. Heald, Lauren A. Garofalo, Teresa Campos, Justin M. Langridge, Hugh Coe, Jesse H. Kroll, Therese S. Carter, Yingjie Shen, R. P. Pokhrel, Shane M. Murphy, Christopher D. Cappa, and Nicholas W. Davies more...
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Atmospheric Science ,Geophysics ,Materials science ,Space and Planetary Science ,Environmental chemistry ,Earth and Planetary Sciences (miscellaneous) ,Carbonaceous aerosol ,Absorption (electromagnetic radiation) - Published
- 2021
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6. Emission and Evolution of Submicron Organic Aerosol in Smoke from Wildfires in the Western United States
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Ezra J. T. Levin, Delphine K. Farmer, Matson A. Pothier, Sonia M. Kreidenweis, Teresa Campos, and Lauren A. Garofalo
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Smoke ,Atmospheric Science ,Particle composition ,010504 meteorology & atmospheric sciences ,010501 environmental sciences ,01 natural sciences ,Aerosol ,Space and Planetary Science ,Geochemistry and Petrology ,Atmospheric chemistry ,Environmental chemistry ,Aerosol mass spectrometry ,Environmental science ,Biomass burning ,0105 earth and related environmental sciences - Abstract
Despite increasing incidence of wildfires in the United States, wildfire smoke is poorly characterized, with little known about particle composition and emission rates. Chemistry in transported plu... more...
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- 2019
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7. Emissions of Reactive Nitrogen From Western U.S. Wildfires During Summer 2018
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Jeffrey L. Collett, Andrew T. Hudak, Lauren A. Garofalo, Qiaoyun Peng, Lu Hu, Denise D. Montzka, Barkley C. Sive, Emily V. Fischer, Catherine Wielgasz, Andrew J. Weinheimer, Wade Permar, Sonia M. Kreidenweis, Delphine K. Farmer, Brett B. Palm, Jakob Lindaas, Joel A. Thornton, Frank Flocke, I-Ting Ku, Geoffrey S. Tyndall, Ilana B. Pollack, Yong Zhou, Matson A. Pothier, Teresa Campos, Amy P. Sullivan, Roger D. Ottmar, and Joseph C. Restaino more...
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Smoke ,Atmospheric Science ,Ozone ,Volatilisation ,010504 meteorology & atmospheric sciences ,Reactive nitrogen ,chemistry.chemical_element ,Combustion ,Atmospheric sciences ,01 natural sciences ,Nitrogen ,chemistry.chemical_compound ,Geophysics ,Deposition (aerosol physics) ,chemistry ,Space and Planetary Science ,Earth and Planetary Sciences (miscellaneous) ,Environmental science ,NOx ,0105 earth and related environmental sciences - Abstract
Reactive nitrogen (Nr) within smoke plumes plays important roles in the production of ozone, the formation of secondary aerosols, and deposition of fixed N to ecosystems. The Western Wildfire Experiment for Cloud Chemistry, Aerosol Absorption, and Nitrogen (WE-CAN) field campaign sampled smoke from 23 wildfires throughout the western U.S. during summer 2018 using the NSF/NCAR C-130 research aircraft. We empirically estimate Nr normalized excess mixing ratios and emission factors from fires sampled within 80 min of estimated emission and explore variability in the dominant forms of Nr between these fires. We find that reduced N compounds comprise a majority (39%-80%; median = 66%) of total measured reactive nitrogen (ΣNr) emissions. The smoke plumes sampled during WE-CAN feature rapid chemical transformations after emission. As a result, within minutes after emission total measured oxidized nitrogen (ΣNOy) and measured total ΣNHx (NH3 + pNH4) are more robustly correlated with modified combustion efficiency (MCE) than NOx and NH3 by themselves. The ratio of ΣNHx/ΣNOy displays a negative relationship with MCE, consistent with previous studies. A positive relationship with total measured ΣNr suggests that both burn conditions and fuel N content/volatilization differences contribute to the observed variability in the distribution of reduced and oxidized Nr. Additionally, we compare our in situ field estimates of Nr EFs to previous lab and field studies. For similar fuel types, we find ΣNHx EFs are of the same magnitude or larger than lab-based NH3 EF estimates, and ΣNOy EFs are smaller than lab NOx EFs. more...
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- 2021
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8. Particle Size Distribution Dynamics Can Help Constrain the Phase State of Secondary Organic Aerosol
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Christopher D. Cappa, Manabu Shiraiwa, Jeffrey R. Pierce, Ali Akherati, Yicong He, Theodora Nah, Nga L. Ng, Delphine K. Farmer, Shantanu H. Jathar, Rahul A. Zaveri, and Lauren A. Garofalo
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Aerosols ,Work (thermodynamics) ,Air Pollutants ,Microphysics ,Computer Science::Software Engineering ,General Chemistry ,010501 environmental sciences ,01 natural sciences ,Aerosol ,Computational physics ,Moment (mathematics) ,Particle-size distribution ,Monoterpenes ,Environmental Chemistry ,Particle ,Particle size ,Diffusion (business) ,Particle Size ,Oxidation-Reduction ,0105 earth and related environmental sciences - Abstract
Particle phase state is a property of atmospheric aerosols that has important implications for the formation, evolution, and gas/particle partitioning of secondary organic aerosol (SOA). In this work, we use a size-resolved chemistry and microphysics model (Statistical Oxidation Model coupled to the TwO Moment Aerosol Sectional (SOM-TOMAS)), updated to include an explicit treatment of particle phase state, to constrain the bulk diffusion coefficient (Db) of SOA produced from α-pinene ozonolysis. By leveraging data from laboratory experiments performed in the absence of a seed and under dry conditions, we find that the Db for SOA can be constrained ((1-7) × 10-15 cm2 s-1 in these experiments) by simultaneously reproducing the time-varying SOA mass concentrations and the evolution of the particle size distribution. Another version of our model that used the predicted SOA composition to calculate the glass-transition temperature, viscosity, and, ultimately, Db (∼10-15 cm2 s-1) of the SOA was able to reproduce the mass and size distribution measurements when we included oligomer formation (oligomers accounted for about a fifth of the SOA mass). Our work highlights the potential of a size-resolved SOA model to constrain the particle phase state of SOA using historical measurements of the evolution of the particle size distribution. more...
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- 2021
9. Acidity across the interface from the ocean surface to sea spray aerosol
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Vicki H. Grassian, Jon S. Sauer, Lauren A. Garofalo, Christopher T. Lee, Christopher D. Cappa, Victor W. Or, Todd R. Martz, Matson A. Pothier, Daniel R. Crocker, Kyle J. Angle, Mahum Farhan, Kathryn J. Mayer, Timothy H. Bertram, Sudarshan Srinivasan, Rebecca M. C. Simpson, Stephanie L. Mora Garcia, Delphine K. Farmer, Alexia N. Moore, and Kimberly A. Prather more...
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Oceans and Seas ,Environment ,complex mixtures ,Atmosphere ,Human health ,chemistry.chemical_compound ,Earth, Atmospheric, and Planetary Sciences ,Humans ,Seawater ,sea spray ,acidity ,Aerosols ,Marine biology ,Multidisciplinary ,Air ,Hydrogen-Ion Concentration ,respiratory system ,Sea spray ,Aerosol ,chemistry ,Environmental chemistry ,Atmospheric chemistry ,Phytoplankton ,Physical Sciences ,Carbon dioxide ,Environmental science ,aerosols - Abstract
Significance Sea spray aerosol, produced through breaking waves, is one of the largest sources of environmental particles. Once in the atmosphere, sea spray aerosol influences cloud formation, serves as microenvironments for multiphase atmospheric chemical reactions, and impacts human health. All of these impacts are affected by aerosol acidity. Here we show that freshly emitted sea spray aerosol particles become highly acidic within minutes as they are transferred across the ocean−air interface. These results have important implications for atmospheric chemistry and climate, including aerosol/gas partitioning, heterogeneous reactions, and chemical speciation at the surface and within sea spray aerosol., Aerosols impact climate, human health, and the chemistry of the atmosphere, and aerosol pH plays a major role in the physicochemical properties of the aerosol. However, there remains uncertainty as to whether aerosols are acidic, neutral, or basic. In this research, we show that the pH of freshly emitted (nascent) sea spray aerosols is significantly lower than that of sea water (approximately four pH units, with pH being a log scale value) and that smaller aerosol particles below 1 μm in diameter have pH values that are even lower. These measurements of nascent sea spray aerosol pH, performed in a unique ocean−atmosphere facility, provide convincing data to show that acidification occurs “across the interface” within minutes, when aerosols formed from ocean surface waters become airborne. We also show there is a correlation between aerosol acidity and dissolved carbon dioxide but no correlation with marine biology within the seawater. We discuss the mechanisms and contributing factors to this acidity and its implications on atmospheric chemistry. more...
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- 2020
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10. Correction to Hazardous Air Pollutants in Fresh and Aged Western US Wildfire Smoke and Implications for Long-Term Exposure
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Katelyn O’Dell, Rebecca S. Hornbrook, Wade Permar, Ezra J. T. Levin, Lauren A. Garofalo, Eric C. Apel, Nicola J. Blake, Alex Jarnot, Matson A. Pothier, Delphine K. Farmer, Lu Hu, Teresa Campos, Bonne Ford, Jeffrey R. Pierce, and Emily V. Fischer more...
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Environmental Chemistry ,General Chemistry - Published
- 2022
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11. Vibrational overtone spectroscopy, energy levels, and intensities of (CH3)3C-C≡C-H
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Carlos E. Manzanares, Yasnahir Perez-Delgado, Jenny Z. Barroso, and Lauren A. Garofalo
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chemistry.chemical_compound ,Acetylene ,Chemistry ,Overtone ,Analytical chemistry ,Physical and Theoretical Chemistry ,Spectroscopy ,Ring (chemistry) ,Spectral line - Abstract
The vibrational overtone spectra of the acetylenic (Δυ = 4, 5) and methyl (Δυ = 5, 6) C-H stretch transitions of tert-butyl acetylene [(CH(3))(3)C-C≡C-H] were obtained using the phase shift cavity ring down (PS-CRD) technique at 295 K. The C-H stretch fundamental and overtone absorptions of the acetylenic (Δυ = 2 and 3) and methyl (Δυ = 2-4) C-H bonds have been obtained using a Fourier transform infrared and near-infrared spectrophotometer. Harmonic frequency ω(ν(1)) and anharmonicities x(ν(1)) and x(ν(1), ν(24)) are reported for the acetylenic C-H bond. Molecular orbital calculations of geometry and vibrational frequencies were performed. A harmonically coupled anharmonic oscillator (HCAO) model was used to determine the overtone energy levels and assign the absorption bands to vibrational transitions of methyl C-H bonds. Band strength values were obtained experimentally and compared with intensities calculated in terms of the HCAO model where only the C-H modes are considered. No adjustable parameters were used to get order of magnitude agreement with experimental intensities for all pure local mode C-H transitions. more...
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- 2012
12. Electronic quenching of O(1D) by Xe: Oscillations in the product angular distribution and their dependence on collision energy
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Paul J. Dagdigian, Millard H. Alexander, Kristie A. Boering, Jacek Kłos, Jim J. Lin, Mica C. Smith, and Lauren A. Garofalo
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Quenching ,Xenon ,Chemistry ,Scattering ,General Physics and Astronomy ,chemistry.chemical_element ,Quantum phases ,Physical and Theoretical Chemistry ,Inelastic scattering ,Atomic physics ,Collision ,Interference (wave propagation) ,Beam (structure) - Abstract
The dynamics of the O((1)D) + Xe electronic quenching reaction was investigated in a crossed beam experiment at four collision energies. Marked large-scale oscillations in the differential cross sections were observed for the inelastic scattering products, O((3)P) and Xe. The shape and relative phases of the oscillatory structure depend strongly on collision energy. Comparison of the experimental results with time-independent scattering calculations shows qualitatively that this behavior is caused by Stueckelberg interferences, for which the quantum phases of the multiple reaction pathways accessible during electronic quenching constructively and destructively interfere. more...
- Published
- 2015
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