Chemistry Commons^™

Spatial Fingerprinting Of Biogenic And Anthropogenic Volatile Organic Compounds In An Arid Unsaturated Zone, Christopher T. Green, Wentai Luo, Christopher H. Conaway, Karl B. Haase, Ronald J. Baker

Chemistry Faculty Publications and Presentations

Subsurface volatile organic compounds (VOCs) can pose risks to human and environmental health and mediate biological processes. Volatile organic compounds have both anthropogenic and biogenic origins, but the relative importance of these sources has not been explored in subsurface environments. This study synthesized 17 yr of VOC data from the Amargosa Desert Research Site in Nevada with the goal of improving understanding of spatial and temporal variations that distinguish sources of VOCs from a landfill and from ambient sources including biogenic VOCs (bVOCs). Gas samples were collected from 1999 to 2016 from an array of shallow sample points (0.5- and …

Flavour Chemicals In A Sample Of Non-Cigarette Tobacco Products Without Explicit Flavour Names Sold In New York City In 2015, Shannon M. Farley, Kevin R.J. Schroth, Victoria Grimshaw, Wentai Luo, Julia Lynn Degagne, Peyton A. Tierney, Kilsun Kim, James F. Pankow

Chemistry Faculty Publications and Presentations

Background Youth who experiment with tobacco often start with flavoured products. In New York City (NYC), local law restricts sales of all tobacco products with ‘characterising flavours’ except for ‘tobacco, menthol, mint and wintergreen’. Enforcement is based on packaging: explicit use of a flavour name (eg, ‘strawberry’) or image depicting a flavour (eg, a fruit) is presumptive evidence that a product is flavoured and therefore prohibited. However, a tobacco product may contain significant levels of added flavour chemicals even when the label does not explicitly use a flavour name.

Methods Sixteen tobacco products were purchased within NYC in 2015 that …

Benzene Formation In Electronic Cigarettes, James F. Pankow, Kilsun Kim, Kevin J. Mcwhirter, Wentai Luo, Jorge O. Escobedo, Robert M. Strongin, Anna K. Duell, David H. Peyton

Chemistry Faculty Publications and Presentations

The heating of the fluids used in electronic cigarettes (“e-cigarettes”) used to create “vaping” aerosols is capable of causing a wide range of degradation reaction products. We investigated formation of benzene (an important human carcinogen) from e-cigarette fluids containing propylene glycol (PG), glycerol (GL), benzoic acid, the flavor chemical benzaldehyde, and nicotine.

Molecular View Modeling Of Atmospheric Organic Particulate Matter: Incorporating Molecular Structure And Co-Condensation Of Water, James F. Pankow, Marguerite Colasurdo Marks, Kelley C. Barsanti, Abdullah Mahmud, William E. Asher, Jingyi Li, Qi Ying, Shantanu H. Jathar, Michael J. Kleeman

Chemistry Faculty Publications and Presentations

Most urban and regional models used to predict levels of organic particulate matter (OPM) are based on fundamental equations for gas/particle partitioning, but make the highly simplifying, anonymized-view (AV) assumptions that OPM levels are not affected by either: a) the molecular. characteristics of the condensing organic compounds (other than simple volatility); or b) co-condensation of water as driven by non-zero relative humidity (RH) values. The simplifying assumptions have allowed parameterized chamber results for formation of secondary organic aerosol (SOA) (e.g., “two-product” (2p) coefficients) to be incorporated in chemical transport models. However, a return towards a less simplistic (and more computationally …

Flavour Chemicals In Electronic Cigarette Fluids, Peyton A. Tierney, Clarissa D. Karpinski, Jessica E. Brown, Wentai Luo, James F. Pankow

Chemistry Faculty Publications and Presentations

Background: Most e-cigarette liquids contain flavour chemicals. Flavour chemicals certified as safe for ingestion by the Flavor Extracts Manufacturers Association may not be safe for use in e-cigarettes. This study identified and measured flavour chemicals in 30 e-cigarette fluids.

Methods: Two brands of single-use e-cigarettes were selected and their fluids in multiple flavour types analysed by gas chromatography/mass spectrometry. For the same flavour types, and for selected confectionary flavours (eg, bubble gum and cotton candy), also analysed were convenience samples of e-cigarette fluids in refill bottles from local ‘vape’ shops and online retailers.

Results: In many liquids, total flavour chemicals …

Aerosol Optical Hygroscopicity Measurements During The 2010 Cares Campaign, Dean B. Atkinson, James Gregory Radney, Janel Lum, Katheryn R. Kolesar, Daniel J. Cziczo, Mikhail Pekour, Qi Zhang, Ari Setyan, Alla Zelenyuk, Christopher D. Cappa

Chemistry Faculty Publications and Presentations

Measurements of the effect of water uptake on particulate light extinction or scattering made at two locations during the 2010 CARES study around Sacramento, CA are reported. The observed influence of water uptake, characterized through the dimensionless optical hygroscopicity parameter γ, is compared with calculations constrained by observed particle size distributions and size-dependent particle composition. A closure assessment has been carried out that allowed for determination of the average hygroscopic growth factors (GF) at 85% relative humidity and the dimensionless hygroscopicity parameter κ for oxygenated organic aerosol (OA) and for supermicron particles, yielding κ = 0.1–0.15 and 0.9–1.0, respectively. The …

Picture Of A Chelate In Exchange: The Crystal Structure Of Nahodotma, A 'Semi'-Hydrated Chelate, Katherine M. Payne, Edward J. Valente, Silvio Aime, Mauro Botta, Mark Woods

Chemistry Faculty Publications and Presentations

Crystallography generally only provides static structural information. This can render it an ineffective technique for probing dynamic solution state processes. A crystal of HoDOTMA affords unique structures that effectively represent that of a lanthanide tetra-acetate chelate mid-way through the water exchange process.

Evolution Of Multispectral Aerosol Optical Properties In A Biogenically-Influenced Urban Environment During The Cares Campaign, Madhu Gyawali, W. Patrick Arnott, Rahul A. Zaveri, C. Song, Mikhail Pekour, B. Flowers, Manvendra K. Dubey, Ari Setyan, Qi Zhang, Joseph Harworth, James Gregory Radney, Dean B. Atkinson, S. China, Claudio Mazzoleni, Kyle Gorkowski, R. Subramanian, B. Tom Jobson, Hans Moosmüller

Chemistry Faculty Publications and Presentations

Ground-based aerosol measurements made in June 2010 within Sacramento urban area (site T0) and at a 40-km downwind location (site T1) in the forested Sierra Nevada foothills area are used to investigate the evolution of multispectral optical properties as the urban aerosols aged and interacted with biogenic emissions. Along with black carbon and non-refractory aerosol mass and composition observations, spectral absorption (ᵝabs), scattering (ᵝsca), and extinction (ᵝext) coefficients for wavelengths ranging from 355 to 1064nm were measured at both sites using photoacoustic (PA) instruments with integrating nephelometers and using cavity ring-down (CRD) instruments. The …

Overview Of The 2010 Carbonaceous Aerosols And Radiative Effects Study (Cares), Rahul A. Zaveri, William J. Shaw, Daniel J. Cziczo, Beat Schmid, Richard Ferrare, M. Lizabeth Alexander, Raul Alvarez, W. Patrick Arnott, Dean B. Atkinson, Sunil Baidar, Robert M. Banta, James Barnard, Josef Beranek, Larry K. Berg, Fred Brechtel, W. Alan Brewer, John F. Cahill, Brian Cairns, Christopher D. Cappa, D. Chand, S. China, Jennifer M. Comstock, Manvendra K. Dubey, Robert C. Easter, M. H. Erickson, Jerome Fast, Cody Floerchinger, B. Flowers, Edward C. Fortner, Jeffrey S. Gaffney, Mary K. Gilles, Kyle Gorkowski, William Gustafson, Madhu Gyawali, J. Hair, R. M. Hardesty, Joseph Harworth, Scott C. Herndon, Naruki Hiranuma, Chris Hostetler, John M. Hubbe, John T. Jayne, H. Jeong, B. Tom Jobson, Evgueni Kassianov, Lawrence I. Kleinman, C. Kluzek, W. Berk Knighton, Katheryn R. Kolesar, Chongai Kuang, Alena Kubátová, Andrew O. Langford, Alexander Laskin, N. Laulainen, Richard D. Marchbanks, Claudio Mazzoleni, Fan Mei, Ryan C. Moffet, Dan Nelson, Michael Obland, Hilke Oetjen, Timothy B. Onasch, I. Ortega, Matteo Ottaviani, Mikhail Pekour, Kimberly A. Prather, James Gregory Radney, Raymond R. Rogers, Scott P. Sandberg, Arthur J. Sedlacek, Christoph J. Senff, Gunnar I. Senum, Ari Setyan, John E. Shilling, Manishkumar Shrivastava, C. Song, Stephen R. Springston, R. Subramanian, Kaitlyn Suski, Jason Tomlinson, Rainer M. Volkamer, H. W. Wallace, Jian Wang, A. M. Weickmann, Douglas R. Worsnop, Xiao-Ying Yu, Alla Zelenyuk, Qi Zhang

Chemistry Faculty Publications and Presentations

Substantial uncertainties still exist in the scientific understanding of the possible interactions between urban and natural (biogenic) emissions in the production and transformation of atmospheric aerosol and the resulting impact on climate change. The US Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program’s Carbonaceous Aerosol and Radiative Effects Study (CARES) carried out in June 2010 in Central Valley, California, was a comprehensive effort designed to improve this understanding. The primary objective of the field study was to investigate the evolution of secondary organic and black carbon aerosols and their climate-related properties in the Sacramento urban plume as it was …

Neutron-Scattering Study Of Librations And Intramolecular Phonons In Rb_{2.6}K_{0.4}C_{60}, D. Reznik, W. A. Kamitakahara, D. A. Neumann, J. R. D. Copley, J. E. Fischer, Robert M. Strongin, M. A. Cichy, Amos B. Smith Iii

Chemistry Faculty Publications and Presentations

We report the results of inelastic neutron-scattering measurements on Rb_2.6K_0.4C₆₀. Librational modes were observed as broad peaks with maxima between 4.1 and 4.7 meV, as the temperature is lowered from 300 to 12 K. As in K₃C₆₀, no change in the width or position of the librational peak was observed when the sample was cooled through the superconducting transition. Thus any coupling of the librations to electronic states is small. The magnitude of the orientational potential barrier was estimated from the librational peak frequency. A flat background observed in the …