Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder

Eleanor C. Browne

Research Interests

My group develops instrumentation for measuring gases and aerosols in the atmosphere and uses this instrumentation to investigate how atmospheric processing affects the chemical composition of gases and aerosols. The group is specifically interested in organonitrogen and organosilicon compounds and investigates the fate of these compounds using laboratory and field measurements. Current work focuses on understanding the role of organonitrogen in new particle formation and growth, and in nitrogen deposition. The organosilicon work focuses on constraining the fate of organosilicon compounds that are found in personal care products and preferentially partition to the atmosphere. Our current instrument development work focuses on novel techniques for the fragment-free characterization of aerosol.

Current Research

Ambient Ion Chemistry

Atmospheric ions control the electrical properties of the atmosphere, influence chemical composition via ion-molecule and/or ion-catalyzed reactions, and affect new particle formation. Understanding the role of ions in these processes requires knowledge of ionic chemical composition.  Due to the low concentration of ions, chemical composition measurements have historically been challenging. Recent advances in mass spectrometry, such as the atmospheric pressure interface time-of-flight mass spectrometer (APi-TOF), are now making these measurements more feasible. We study the chemistry of ambient ions through field measurements to understand present day ambient atmosphere and laboratory experiments that simulate other planetary atmospheres such as early Earth and Titan.

Organosilicon Chemistry

Several million tons of organosilicon compounds, most notably volatile methyl siloxanes (VMS), are manufactured annually for use in a variety of applications including personal care products and adhesives. Despite estimates that over 90 percent of VMS environmental loading is present in the atmosphere, the multigenerational chemistry of VMS remains poorly constrained. We use an environmental simulation chamber to simulate atmospheric oxidation of siloxanes so we can detect the products of atmospheric reactions with these compounds as well as gather information about rate constants and reaction pathways of these reactions. 

Nitrogen Chemistry

Reduced nitrogen compounds negatively affect air quality, climate, and human health. These compounds have been shown to enhance new particle formation, promote brown carbon formation, and increase the toxicity of aerosol. Little is known about the impact reduced nitrogen has on either the gas phase or aerosol because measurements detailing their speciation and interactions with aerosol is lacking. Due to increases in food production, the concentrations of reduced nitrogen compounds are expected to increase in the future, and thus it is important to understand their speciation and transformations in the atmosphere. We conduct ambient and lab measurements to understand the sources and transformation of reduced nitrogen compounds in the atmosphere.

Instrument Development

Aerosols (fine particulate matter suspended in air) affect human health and the Earth’s radiative balance. Improving our knowledge of how aerosols affect climate and health requires measurements of aerosol chemical composition in order to improve our understanding of aerosol sources and sinks. These measurements, however, are analytically challenging as the aerosols with the greatest impacts on health and climate are submicron in diameter, present at concentrations of μg or less per cubic meter of air, and are composed of both inorganic and organic compounds. Furthermore, the composition of the organic fraction is complex, consisting of thousands of compounds, including those that are chemically and thermally labile. The group is currently working on developing a novel measurement technique that combines laser desorption with chemical ionization mass spectrometry.

Simplified schematic showing some possible NHx-organic compound reactions that we study. Note acid catalysis is not explicitly shown. Path A represents ammonium carboxylate salt formation, path B is ON oligomer growth, and path C is N catalyzed oligomer growth.

Simplified schematic of chemistry occuring in our Titan-like simulations.

Honors and Awards

  • American Society for Mass Spectrometry Research Award (2019)
  • NOAA Climate and Global Change Postdoctoral Fellowship (2012-2014)
  • NASA Earth Systems Science Fellowship (2010-2012)

View Publications

  • Reed NW; Jansen KT; Schiffman ZR; Tolbert MA; Browne EC. (Sep 2023). The Influence of Hydrogen Sulfide on the Optical Properties of Planetary Organic Hazes: Implications for Exoplanet Climate Modeling. Letters of the Astrophysical Journal , 954(2), L44-L44. 10.3847/2041-8213/acf1a2
  • Alton MW; Stark HJ; Canagaratna MR; Browne EC. (Jun 2023). Generalized Kendrick analysis for improved visualization of atmospheric mass spectral data. Atmospheric Measurement Techniques , 16(12), 3273-3282. 10.5194/amt-16-3273-2023
  • Matthews E; Bannan TJ; Khan MAH; Shallcross DE; Stark H; Browne EC; Archibald AT; Mehra A; Bauguitte SJ-B; Reed C. (Jun 2023). Airborne observations over the North Atlantic Ocean reveal the importance of gas-phase urea in the atmosphere. Proceedings of the National Academy of Sciences of USA , 120(25). 10.1073/pnas.2218127120
  • Katz DJ; Abdelhamid A; Stark H; Canagaratna MR; Worsnop DR; Browne EC. (May 2023). Chemical identification of new particle formation and growth precursors through positive matrix factorization of ambient ion measurements. Atmospheric Chemistry and Physics , 23(9), 5567-5585. 10.5194/acp-23-5567-2023
  • Reed NW; Wing BA; Tolbert MA; Browne EC. (Apr 2022). Trace H; 2; S Promotes Organic Aerosol Production and Organosulfur Compound Formation in Archean Analog Haze Photochemistry Experiments. Geophysical Research Letters. 10.1029/2021gl097032
  • Alton MW; Browne EC. (Feb 2022). Atmospheric Degradation of Cyclic Volatile Methyl Siloxanes: Radical Chemistry and Oxidation Products. 10.1021/acsenvironau.1c00043
  • Reed NW; Browne EC; Tolbert MA. (Jun 2020). Impact of Hydrogen Sulfide on Photochemical Haze Formation in Methane/Nitrogen Atmospheres. ACS Earth and Space Chemistry , 4(6), 897-904. 10.1021/acsearthspacechem.0c00086
  • Alton, MW; Browne, EC. (May 2020). Atmospheric Chemistry of Volatile Methyl Siloxanes: Kinetics and Products of Oxidation by OH Radicals and Cl Atoms. ENVIRONMENTAL SCIENCE & TECHNOLOGY , 54(10). 10.1021/acs.est.0c01368
  • Ugelow MS; Berry JL; Browne EC; Tolbert MA. (Mar 2020). The Impact of Molecular Oxygen on Anion Composition in a Hazy Archean Earth Atmosphere. Astrobiology , 20(5), 658-669. 10.1089/ast.2019.2145
  • Berry, JL; Ugelow, MS; Tolbert, MA; Browne, EC. (Nov 2019). The Influence of Gas-phase Chemistry on Organic Haze Formation. ASTROPHYSICAL JOURNAL LETTERS , 885(1). 10.3847/2041-8213/ab4b5b
  • Browne, E; Stark, H; Abdelhamid, A; Nowak, J; Smith, J; Jayne, J; Worsnop, D. (Aug 2019). Chemistry of organic reduced nitrogen in a rural environment. ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY , 258.
  • Browne, EC; Zhang, XL; Franklin, JP; Ridley, KJ; Kirchstetter, TW; Wilson, KR; Cappa, CD; Kroll, JH. (Jun 2019). Effect of heterogeneous oxidative aging on light absorption by biomass burning organic aerosol. AEROSOL SCIENCE AND TECHNOLOGY , 53(6). 10.1080/02786826.2019.1599321
  • Berry, JL; Ugelow, MS; Tolbert, MA; Browne, EC. (Feb 2019). Chemical Composition of Gas-Phase Positive Ions during Laboratory Simulations of Titans Haze Formation. ACS EARTH AND SPACE CHEMISTRY , 3(2). 10.1021/acsearthspacechem.8b00139
  • Berry, JL, DA Day, T Elseberg, BB Palm, WW Hu, A Abdelhamid, JC Schroder, U Karst, JL Jimenez and EC Browne. (Mar 2018). Laser Ablation-Aerosol Mass Spectrometry-Chemical Ionization Mass Spectrometry for Ambient Surface Imaging. ANALYTICAL CHEMISTRY , 90(6). 10.1021/acs.analchem.7b05255
  • Lim, CY, EC Browne, RA Sugrue and JH Kroll. (Mar 2017). Rapid heterogeneous oxidation of organic coatings on submicron aerosols. GEOPHYSICAL RESEARCH LETTERS , 44(6). 10.1002/2017GL072585
  • Brune, WH, BC Baier, J Thomas, X Ren, RC Cohen, SE Pusede, EC Browne, AH Goldstein, DR Gentner, FN Keutsch, JA Thornton, S Harrold, FD Lopez-Hilfiker and PO Wennberg. (Jan 2016). Ozone production chemistry in the presence of urban plumes. FARADAY DISCUSSIONS , 189. 10.1039/c5fd00204d
  • Pusede, SE, TC VandenBoer, JG Murphy, MZ Markovic, CJ Young, PR Veres, JM Roberts, RA Washenfelder, SS Brown, XR Ren, C Tsai, J Stutz, WH Brune, EC Browne, PJ Wooldridge, AR Graham, R Weber, AH Goldstein, S Dusanter, SM Griffith, PS Stevens, BL Lefer and RC Cohen. (Nov 2015). An Atmospheric Constraint on the NO2 Dependence of Daytime Near-Surface Nitrous Acid (HONO). ENVIRONMENTAL SCIENCE & TECHNOLOGY , 49(21). 10.1021/acs.est.5b02511
  • Canagaratna, MR, P Massoli, EC Browne, JP Franklin, KR Wilson, TB Onasch, TW Kirchstetter, EC Fortner, CE Kolb, JT Jayne, JH Kroll and DR Worsnop. (May 2015). Chemical Compositions of Black Carbon Particle Cores and Coatings via Soot Particle Aerosol Mass Spectrometry with Photoionization and Electron Ionization. JOURNAL OF PHYSICAL CHEMISTRY A , 119(19). 10.1021/jp510711u
  • Browne, EC, JP Franklin, MR Canagaratna, P Massoli, TW Kirchstetter, DR Worsnop, KR Wilson and JH Kroll. (Feb 2015). Changes to the Chemical Composition of Soot from Heterogeneous Oxidation Reactions. JOURNAL OF PHYSICAL CHEMISTRY A , 119(7). 10.1021/jp511507d
  • VandenBoer, TC, MZ Markovic, JE Sanders, X Ren, SE Pusede, EC Browne, RC Cohen, L Zhang, J Thomas, WH Brune and JG Murphy. (Jul 2014). Evidence for a nitrous acid (HONO) reservoir at the ground surface in Bakersfield, CA, during CalNex 2010. JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES , 119(14). 10.1002/2013JD020971
  • Min, KE, SE Pusede, EC Browne, BW LaFranchi, PJ Wooldridge and RC Cohen. (Jan 2014). Eddy covariance fluxes and vertical concentration gradient measurements of NO and NO2 over a ponderosa pine ecosystem: observational evidence for within-canopy chemical removal of NOx. ATMOSPHERIC CHEMISTRY AND PHYSICS , 14(11). 10.5194/acp-14-5495-2014
  • Pusede, SE, DR Gentner, PJ Wooldridge, EC Browne, AW Rollins, KE Min, AR Russell, J Thomas, L Zhang, WH Brune, SB Henry, JP DiGangi, FN Keutsch, SA Harrold, JA Thornton, MR Beaver, JM St Clair, PO Wennberg, J Sanders, X Ren, TC VandenBoer, MZ Markovic, A Guha, R Weber, AH Goldstein and RC Cohen. (Jan 2014). On the temperature dependence of organic reactivity, nitrogen oxides, ozone production, and the impact of emission controls in San Joaquin Valley, California. ATMOSPHERIC CHEMISTRY AND PHYSICS , 14(7). 10.5194/acp-14-3373-2014
  • Browne, EC, PJ Wooldridge, KE Min and RC Cohen. (Jan 2014). On the role of monoterpene chemistry in the remote continental boundary layer. ATMOSPHERIC CHEMISTRY AND PHYSICS , 14(3). 10.5194/acp-14-1225-2014
  • Worton, DR, JD Surratt, BW LaFranchi, AWH Chan, YL Zhao, RJ Weber, JH Park, JB Gilman, J de Gouw, C Park, G Schade, M Beaver, JM St Clair, J Crounse, P Wennberg, GM Wolfe, S Harrold, JA Thornton, DK Farmer, KS Docherty, MJ Cubison, JL Jimenez, AA Frossard, LM Russell, K Kristensen, M Glasius, JQ Mao, XR Ren, W Brune, EC Browne, SE Pusede, RC Cohen, JH Seinfeld and AH Goldsteint. (Oct 2013). Observational Insights into Aerosol Formation from Isoprene. ENVIRONMENTAL SCIENCE & TECHNOLOGY , 47(20). 10.1021/es4011064
  • Browne, EC, KE Min, PJ Wooldridge, E Apel, DR Blake, WH Brune, CA Cantrell, MJ Cubison, GS Diskin, JL Jimenez, AJ Weinheimer, PO Wennberg, A Wisthaler and RC Cohen. (Jan 2013). Observations of total RONO2 over the boreal forest: NOx sinks and HNO3 sources. ATMOSPHERIC CHEMISTRY AND PHYSICS , 13(9). 10.5194/acp-13-4543-2013
  • Rollins, AW, EC Browne, KE Min, SE Pusede, PJ Wooldridge, DR Gentner, AH Goldstein, S Liu, DA Day, LM Russell and RC Cohen. (Sep 2012). Evidence for NOx Control over Nighttime SOA Formation. SCIENCE , 337(6099). 10.1126/science.1221520
  • Browne, EC and RC Cohen. (Jan 2012). Effects of biogenic nitrate chemistry on the NOx lifetime in remote continental regions. ATMOSPHERIC CHEMISTRY AND PHYSICS , 12(24). 10.5194/acp-12-11917-2012
  • Min, KE, SE Pusede, EC Browne, BW LaFranchi, PJ Wooldridge, GM Wolfe, SA Harrold, JA Thornton and RC Cohen. (Jan 2012). Observations of atmosphere-biosphere exchange of total and speciated peroxynitrates: nitrogen fluxes and biogenic sources of peroxynitrates. ATMOSPHERIC CHEMISTRY AND PHYSICS , 12(20). 10.5194/acp-12-9763-2012
  • Wolfe, GM, JA Thornton, NC Bouvier-Brown, AH Goldstein, JH Park, M Mckay, DM Matross, J Mao, WH Brune, BW LaFranchi, EC Browne, KE Min, PJ Wooldridge, RC Cohen, JD Crounse, IC Faloona, JB Gilman, WC Kuster, JA de Gouw, A Huisman and FN Keutsch. (Jan 2011). The Chemistry of Atmosphere-Forest Exchange (CAFE) Model - Part 2: Application to BEARPEX-2007 observations. ATMOSPHERIC CHEMISTRY AND PHYSICS , 11(3). 10.5194/acp-11-1269-2011
  • Browne, EC, AE Perring, PJ Wooldridge, E Apel, SR Hall, LG Huey, J Mao, KM Spencer, JM St Clair, AJ Weinheimer, A Wisthaler and RC Cohen. (Jan 2011). Global and regional effects of the photochemistry of CH3O2NO2: evidence from ARCTAS. ATMOSPHERIC CHEMISTRY AND PHYSICS , 11(9). 10.5194/acp-11-4209-2011
  • Russell, AR, AE Perring, LC Valin, EJ Bucsela, EC Browne, KE Min, PJ Wooldridge and RC Cohen. (Jan 2011). A high spatial resolution retrieval of NO2 column densities from OMI: method and evaluation. ATMOSPHERIC CHEMISTRY AND PHYSICS , 11(16). 10.5194/acp-11-8543-2011
  • Ren, X, JE Sanders, A Rajendran, RJ Weber, AH Goldstein, SE Pusede, EC Browne, KE Min and RC Cohen. (Jan 2011). A relaxed eddy accumulation system for measuring vertical fluxes of nitrous acid. ATMOSPHERIC MEASUREMENT TECHNIQUES , 4(10). 10.5194/amt-4-2093-2011
  • Alvarado, MJ, JA Logan, J Mao, E Apel, D Riemer, D Blake, RC Cohen, KE Min, AE Perring, EC Browne, PJ Wooldridge, GS Diskin, GW Sachse, H Fuelberg, WR Sessions, DL Harrigan, G Huey, J Liao, A Case-Hanks, JL Jimenez, MJ Cubison, SA Vay, AJ Weinheimer, DJ Knapp, DD Montzka, FM Flocke, IB Pollack, PO Wennberg, A Kurten, J Crounse, JM St Clair, A Wisthaler, T Mikoviny, RM Yantosca, CC Carouge and P Le Sager. (Jan 2010). Nitrogen oxides and PAN in plumes from boreal fires during ARCTAS-B and their impact on ozone: an integrated analysis of aircraft and satellite observations. ATMOSPHERIC CHEMISTRY AND PHYSICS , 10(20). 10.5194/acp-10-9739-2010
  • Ren, X, H Gao, X Zhou, JD Crounse, PO Wennberg, EC Browne, BW LaFranchi, RC Cohen, M Mckay, AH Goldstein and J Mao. (Jan 2010). Measurement of atmospheric nitrous acid at Blodgett Forest during BEARPEX2007. ATMOSPHERIC CHEMISTRY AND PHYSICS , 10(13). 10.5194/acp-10-6501-2010
  • LaFranchi, BW, GM Wolfe, JA Thornton, SA Harrold, EC Browne, KE Min, PJ Wooldridge, JB Gilman, WC Kuster, PD Goldan, JA de Gouw, M Mckay, AH Goldstein, X Ren, J Mao and RC Cohen. (Jan 2009). Closing the peroxy acetyl nitrate budget: observations of acyl peroxy nitrates (PAN, PPN, and MPAN) during BEARPEX 2007. ATMOSPHERIC CHEMISTRY AND PHYSICS , 9(19). 10.5194/acp-9-7623-2009