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Carbon oxidation state as a metric for describing the chemistry of atmospheric organic aerosol

Nature Chemistry volume 3, pages 133139 (2011) | Download Citation



A detailed understanding of the sources, transformations and fates of organic species in the environment is crucial because of the central roles that they play in human health, biogeochemical cycles and the Earth's climate. However, such an understanding is hindered by the immense chemical complexity of environmental mixtures of organics; for example, atmospheric organic aerosol consists of at least thousands of individual compounds, all of which likely evolve chemically over their atmospheric lifetimes. Here, we demonstrate the utility of describing organic aerosol (and other complex organic mixtures) in terms of average carbon oxidation state, a quantity that always increases with oxidation, and is readily measured using state-of-the-art analytical techniques. Field and laboratory measurements of the average carbon oxidation state, using several such techniques, constrain the chemical properties of the organics and demonstrate that the formation and evolution of organic aerosol involves simultaneous changes to both carbon oxidation state and carbon number.

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This work was supported by the US Environmental Protection Agency (EPA) Science To Achieve Results (STAR) program (grant R833746 to J.H.K., N.M.D., D.R.W.), the US Department of Energy (DOE: grant DE-FG02-05ER63995), the National Science Foundation (NSF: grant ATM-0904292 to C.E.K., D.R.W. and M.R.C.; grants ATM-0449815 and ATM-0919189 to J.L.J.) and the National Oceanic and Atmospheric Administration (NOAA: grant NA08OAR4310565). K.R.W., H.B., E.R.M. and J.D.S are supported by the Director, Office of Energy Research, Office of Basic Energy Sciences, and Chemical Sciences Division of the US DOE (contract no. DE-AC02-05CH11231), with additional support from the Laboratory Directed Research and Development Program at the Lawrence Berkeley National Laboratory (LBNL). J.D.S. was also supported by the Camille and Henry Dreyfus foundation postdoctoral program in environmental chemistry. This paper has not been subject to peer and policy review by the above agencies, and therefore does not necessarily reflect their views; no official endorsement should be inferred.

Author information

Author notes

    • Erin R. Mysak
    •  & Jared D. Smith

    Present address: L.J. Smith and Associates, 9515 Brooks Drive, Rogers, Arkansas 72756, USA (J.D.S.); Straus Center for Conservation and Technical Studies, Harvard Art Museums, Cambridge, Massachusetts 02138, USA (E.R.M.)


  1. Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA

    • Jesse H. Kroll
  2. Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA

    • Jesse H. Kroll
    •  & Sean H. Kessler
  3. Center for Atmospheric Particle Studies, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA

    • Neil M. Donahue
  4. Cooperative Institute for Research in the Environmental Sciences and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA

    • Jose L. Jimenez
  5. Center for Aerosol and Cloud Chemistry, Aerodyne Research, Billerica, Massachusetts 01821, USA

    • Manjula R. Canagaratna
    • , Charles E. Kolb
    •  & Douglas R. Worsnop
  6. Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA

    • Kevin R. Wilson
    • , Hendrik Bluhm
    • , Erin R. Mysak
    •  & Jared D. Smith
  7. Department of Geosciences, Princeton University, Princeton, New Jersey 08544, USA

    • Katye E. Altieri
  8. Department of Chemistry, Michigan Technological University, Houghton 49931, Michigan, USA

    • Lynn R. Mazzoleni
  9. Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, USA

    • Andrew S. Wozniak
  10. Department of Physics, University of Helsinki, Helsinki, Finland

    • Douglas R. Worsnop
  11. Finnish Meteorological Institute, Helsinki, Finland

    • Douglas R. Worsnop
  12. Department of Physics, University of Eastern Finland, Kuopio, Finland

    • Douglas R. Worsnop


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The present work was originally conceived by J.H.K. with C.E.K. and D.R.W., with substantial input by N.M.D., J.L.J., M.R.C., S.H.K. and K.R.W. The ESI data were provided by K.E.A., L.R.M. and A.S.W. (Table 1 and Fig. 2). S.H.K. carried out the combinatorial calculations to produce Fig. 3. Data on the aging of organics (Fig. 4) were collected by J.D.S., S.H.K., J.H.K. and K.R.W. (squalane, triacontane and levoglucosan) and E.R.M., J.D.S., K.R.W. and H.B. (coronene). J.H.K. wrote the paper with input from all co-authors, especially N.M.D., J.L.J., M.R.C. and C.E.K. The Supplementary Information was written by J.H.K., N.M.D., H.B. and E.R.M.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Jesse H. Kroll or Erin R. Mysak or Jared D. Smith.

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