Biomass burning dominates brown carbon absorption in the rural southeastern United States

Journal Article · Thu Jan 29 00:00:00 EST 2015 · Geophysical Research Letters

DOI:https://doi.org/10.1002/2014GL062444· OSTI ID:1402182

Washenfelder, R. A. ^[1]; Attwood, A. R. ^[2]; Brock, C. A. ^[3]; Guo, H. ^[4]; Xu, L. ^[5]; Weber, R. J. ^[4]; Ng, N. L. ^[6]; Allen, H. M. ^[7]; Ayres, B. R. ^[8]; Baumann, K. ^[9]; Cohen, R. C. ^[10]; Draper, D. C. ^[11]; Duffey, K. C. ^[12]; Edgerton, E. ^[9]; Fry, J. L. ^[8]; Hu, W. W. ^[13]; Jimenez, J. L. ^[13]; Palm, B. B. ^[13]; Romer, P. ^[12]; Stone, E. A. ^[14] ; Wooldridge, P. J. ^[12]; Brown, S. S. ^[1]

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1. Cooperative Institute for Research in Environmental Sciences University of Colorado Boulder Boulder Colorado USA, Chemical Sciences Division, Earth System Research Laboratory National Oceanic and Atmospheric Administration Boulder Colorado USA
2. Cooperative Institute for Research in Environmental Sciences University of Colorado Boulder Boulder Colorado USA, Chemical Sciences Division, Earth System Research Laboratory National Oceanic and Atmospheric Administration Boulder Colorado USA, Now at Horiba Scientific Edison New Jersey USA
3. Chemical Sciences Division, Earth System Research Laboratory National Oceanic and Atmospheric Administration Boulder Colorado USA
4. School of Earth and Atmospheric Sciences Georgia Institute of Technology Atlanta Georgia USA
5. School of Chemical and Biomolecular Engineering Georgia Institute of Technology Atlanta Georgia USA
6. School of Earth and Atmospheric Sciences Georgia Institute of Technology Atlanta Georgia USA, School of Chemical and Biomolecular Engineering Georgia Institute of Technology Atlanta Georgia USA
7. Department of Chemistry Reed College Portland Oregon USA, Now at Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena California USA
8. Department of Chemistry Reed College Portland Oregon USA
9. Atmospheric Research &, Analysis, Inc. Cary North Carolina USA
10. Department of Earth and Planetary Science University of California Berkeley California USA, Department of Chemistry University of California Berkeley California USA
11. Department of Chemistry Reed College Portland Oregon USA, Now at Department of Chemistry University of California Irvine California USA
12. Department of Chemistry University of California Berkeley California USA
13. Cooperative Institute for Research in Environmental Sciences University of Colorado Boulder Boulder Colorado USA, Department of Chemistry and Biochemistry University of Colorado Boulder Boulder Colorado USA
14. Department of Chemistry University of Iowa Iowa City Iowa USA

Abstract Brown carbon aerosol consists of light‐absorbing organic particulate matter with wavelength‐dependent absorption. Aerosol optical extinction, absorption, size distributions, and chemical composition were measured in rural Alabama during summer 2013. The field site was well located to examine sources of brown carbon aerosol, with influence by high biogenic organic aerosol concentrations, pollution from two nearby cities, and biomass burning aerosol. We report the optical closure between measured dry aerosol extinction at 365 nm and calculated extinction from composition and size distribution, showing agreement within experiment uncertainties. We find that aerosol optical extinction is dominated by scattering, with single‐scattering albedo values of 0.94 ± 0.02. Black carbon aerosol accounts for 91 ± 9% of the total carbonaceous aerosol absorption at 365 nm, while organic aerosol accounts for 9 ± 9%. The majority of brown carbon aerosol mass is associated with biomass burning, with smaller contributions from biogenically derived secondary organic aerosol.

• Sponsoring Organization: USDOE
• OSTI ID: 1402182
• Journal Information: Geophysical Research Letters, Journal Name: Geophysical Research Letters Vol. 42 Journal Issue: 2; ISSN 0094-8276
• Publisher: American Geophysical Union (AGU)
• Country of Publication: United States
• Language: English