University of California, Riverside

Environmental Sciences

Roya Bahreini

Roya Bahreini

Roya Bahreini Photo

Assistant Professor of Atmospheric Science

Academic Degrees:

  • Ph.D., California Institute of Technology, 2005
  • M.S., California Institute of Technology, 2003
  • B.S., University of Maryland, College Park, 1999

Selected Awards:

  • CO-LABS Governor’s Award for High-Impact Research, 2012
  • University of Colorado- CIRES Outstanding Performance Award in Science and Engineering, 2011
  • University of Colorado- CIRES Visiting Scholar Fellowship, June 2005-2007
  • NASA Group Achievement Award for CRYSTAL-FACE Field Project, 2003


  • Airborne, ground-based, and laboratory measurements of aerosol composition and microphysical properties
  • Air quality
  • Aerosol direct- and indirect-effects on climate

Research Group:

  • Current Graduate Students
    • Justin Dingle - Ph.D. Student, Environmental Toxicology Program
    • Kennedy Vu - Ph.D. Student, Environmental Toxicology Program
  • Future Group Members
    • Positions (M.S. or Ph.D.) may be open for highly motivated individuals, interested in field and/or laboratory observations of aerosol chemical and optical properties; please email ( if interested

Current Research:

  • Online aerosol composition and optical extinction measurements in Mira Loma, CA, using a compact aerosol mass spectrometer (mAMS) and a cavity phase-shift spectrometer (CAPS-PMex).
  • Offline composition analysis of aerosol samples collected in Mira Loma and Riverside by gas chromatography/mass spectrometry (GC-MS).
  • Click here for pictures from the sampling site in Mira Loma, CA

Selected Publications:

  • Brown, S.S., J.A. Thornton, W.C. Keene, A.A.P. Pszenny, B.C. Sive, W.P. Dube, N.L. Wagner, C.J. Young, T.P. Riedel, J.M. Roberts, T.C. Vanden Boer, R. Bahreini, F. Ozturk, A.M. Middlebrook, S. Kim, G. Hubler, D. Wolfe, Nitrogen, Aerosol Composition and Halogens on a Tall Tower (NACHTT): Overview of a wintertime air chemistry field study in the Front Range urban corridor of Colorado, J. Geophys. Res., DOI: 10.1002/jgrd.50537
  • Ensberg, J.J., J.S. Craven, A.R. Metcalf, J.D. Allan, W.M. Angevine, R. Bahreini, J. Brioude, C. Cai, H. Coe, J.A. de Gouw, R.A. Ellis, J.H. Flynn, C.L. Haman, P.L. Hayes, J.L. Jimenez, B.L. Lefer, A.M. Middlebrook, J.G. Murphy, J.A. Neuman, J.B. Nowak, J.M. Roberts, J. Stutz, J.W. Taylor, P.R. Veres, J.M. Walker, J.H. Seinfeld , Inorganic and black carbon aerosols in the Los Angeles Basin during CalNex, J. Geophys. Res., 118, 10.1029/2012JD018136, 2013
  • Lack, D.A., R. Bahreini, J.M. Langridge, J.B. Gilman, A.M. Middlebrook, Brown carbon absorption linked to organic mass tracers in biomass burning particles, Atmos. Chem. Phys.,13, 10.5194/acp-13-2415-2013, 2013
  • Lack, D.A., J.M. Langridge, R. Bahreini, C.D. Cappa, A.M. Middlebrook, J.P. Schwarz, Brown carbon and internal mixing in biomass burning particles, Proc. Natl. Acad. Sci. USA, 109 (37), 10.1073/pnas.1206575109, 2012.
  • Bahreini, R., A.M. Middlebrook, C.A. Brock, J.A. de Gouw, S.A. McKeen, L.R. Williams, K.E. Daumit, A.T. Lambe, P. Massoli, M.R. Canagaratna, R. Ahmadov, A.J. Carrasquillo, E.S. Cross, B. Ervens, J.S. Holloway, J.F. Hunter, T.B. Onasch, I.B. Pollack, J.M. Roberts, T.B. Ryerson, C. Warneke, P. Davidovitz, D.R. Worsnop, J.H. Kroll, Mass spectral analysis of organic aerosols formed downwind of the Deepwater Horizon oil spill, Environ. Sci. Technol., 46 (15), 10.1021/es301691k, 2012.
  • Nowak, J.B., J. A. Neuman, R. Bahreini, A. M. Middlebrook, J. S. Holloway, S. A. McKeen, D. D. Parrish, T. B. Ryerson, M. Trainer, Ammonia sources in the California South Coast Air Basin and their impact on ammonium nitrate formation, Geophys. Res. Lett., doi:10.1029/2012GL051197, 2012. (Selected as “EOS Research Highlight”)
  • Bahreini, R., A.M. Middlebrook, J.A. de Gouw, C. Warneke, M. Trainer, C.A. Brock, H. Stark, S.S. Brown, W.P. Dube, J.B. Gilman, K. Hall, J.S. Holloway, W.C. Kuster, A.E. Perring, A.S.H. Prevot, J.P. Schwarz, J.R. Spackman, S. Szidat, N.L. Wagner, R.J. Weber, P. Zotter, D.D. Parrish, Gasoline emissions dominate over diesel in formation of secondary organic aerosol mass, Geophys. Res. Lett., doi:10.1029/2011GL050718, 2012. (Selected as “GRL Editor’s Highlight” and “EOS Research Highlight”)
  • Langridge, J. M., D. A. Lack, C. A. Brock, R. Bahreini, A. M. Middlebrook, J. A. Neuman, J. B. Nowak, A. E. Perring, J. P. Schwarz, J. R. Spackman, J. S. S. Holloway, I. B. B. Pollack, T. B. B. Ryerson, J. M. M. Roberts, C. Warneke, J. A. de Gouw, M. K. Trainer, and D. M. Murphy, Evolution of aerosol properties impacting visibility and direct climate forcing in an ammonia-rich urban environment, J. Geophys. Res.- Atmosphere, doi:10.1029/2011JD017116, 2012.
  • de Gouw, J.A., A.M. Middlebrook, C. Warneke, R. Ahmadov, E.L. Atlas, R. Bahreini, D.R. Blake, C.A. Brock, J. Brioude, D.W. Fahey, F.C. Fehsenfeld, J.S. Holloway, M. Le Henaff, R.A. Lueb., S.A. McKeen, J.F. Meagher, D.M. Murphy, C. Paris, D.D. Parrish, A.E. Perring, I.B. Pollack, A.R. Ravishankara, A.L. Robinson, T.B. Ryerson, J.P. Schwarz. J.R. Spackman, A. Srinivasan, L.A. Watts, Organic Aerosol Formation Downwind from the Deepwater Horizon Oil Spill, Science, 331, 1295-1299, 2011.
  • Bahreini, R., B. Ervens, A.M. Middlebrook, C. Warneke, J.A. de. Gouw, P.F. DeCarlo, J.L. Jimenez, C.A. Brock, J.A. Neuman, T.B. Ryerson, H. Stark , E. Atlas, J. Brioude, A. Fried, J.S. Holloway, J. Peischl, D. Richter, J. Walega, P. Weibring, A.G. Wollny, F.C. Fehsenfeld , Organic Aerosol Formation in Urban and Industrial Plumes near Houston and Dallas, TX. J. Geophys. Res.- Atmospheres, doi:101.1029/2008011493, 2009.
  • Bahreini, R., E.J. Dunlea, B.M. Matthew, C. Simons, K.S. Docherty, P.F. DeCarlo, J.L. Jimenez, C.A. Brock, A.M. Middlebrook, Design and Operation of a Pressure-controlled inlet for airborne sampling with an aerodynamic aerosol lens. Aerosol Sci. Technol., 42 (6), doi: 10.1080/02786820802178514, 2008.
  • Bahreini, R., M.D. Keywood, N.L. Ng, V. Varutbangkul, S. Gao, R.C. Flagan, J.H. Seinfeld, D.R. Worsnop, Measurements of Secondary Organic Aerosol (SOA) from oxidation of cycloalkenes, terpenes, and m-xylene using the Aerodyne Aerosol Mass Spectrometer, Environ. Sci. Technol., 39 (15), 10.1021/es048061a, 2005.
  • Bahreini, R., J.L. Jimenez, J. Wang, J.T. Jayne, D.R. Worsnop, R.C. Flagan, J.H. Seinfeld, Aircraft-based aerosol size and composition measurements during ACE-Asia using an Aerodyne Aerosol Mass Spectrometer, J. Geophys. Res.- Atmospheres, 108, D23, 8645, doi:10.1029/2002JD003226, 2003.
  • O'Dowd, C., J.L. Jimenez, R. Bahreini, R.C. Flagan, J.H. Seinfeld, K. Hameri, L. Pirjola, M. Kulmala, S.G. Jennings, T. Hoffmann, Marine aerosol formation from biogenic iodine emissions. Nature, 417: 632-636, 2002.

Courses Taught:

  • ENSC 102- Introductory Atmospheric Science
  • ENSC 265- Special Topics in Earth and Environmental Sciences: Aerosol Physics and Dynamics

Graduate Program Affiliations and Research Focus Areas:


Outreach #1
Outreach #2
Outreach #3

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University of California, Riverside
900 University Ave.
Riverside, CA 92521
Tel: (951) 827-1012

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Environmental Sciences
Geology 2258

Tel: (951) 827-5116
Fax: (951) 827-3993