Renyi Zhang et al., PNAS, Variability in morphology, hygroscopicity, and optical properties of soot aerosols during atmospheric processing

Proceedings of the National Academy of Sciences, Vol. 105, No. 30 (2008) 10291-10296; doi: 10.1073/pnas.0804860105

Variability in morphology, hygroscopicity, and optical properties of soot aerosols during atmospheric processing

Renyi Zhang* and Alexei F. Khalizov (Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843), Joakim Pagels (Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455; and Division of Aerosol Technology, Ergonomics and Aerosol Technology, SE-211 00 Lund, Sweden), Dan Zhang (Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843), Huaxin Xue (Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843), and Peter H. McMurry (Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455)

Communicated by Mario J. Molina, University of California at San Diego, La Jolla, CA, May 19, 2008 (received for review February 20, 2008)

Abstract

The atmospheric effects of soot aerosols include interference with radiative transfer, visibility impairment, and alteration of cloud formation and are highly sensitive to the manner by which soot is internally mixed with other aerosol constituents. We present experimental studies to show that soot particles acquire a large mass fraction of sulfuric acid during atmospheric aging, considerably altering their properties. Soot particles exposed to subsaturated sulfuric acid vapor exhibit a marked change in morphology, characterized by a decreased mobility-based diameter but an increased fractal dimension and effective density. These particles experience large hygroscopic size and mass growth at subsaturated conditions (<90%>

• *To whom correspondence should be addressed. e-mail: zhang@ariel.met.tamu.edu

• Author contributions: R.Z., A.F.K., and P.H.M. designed research; R.Z., A.F.K., J.P., D.Z., H.X., and P.H.M. performed research; R.Z., A.F.K., J.P., D.Z., H.X., and P.H.M. contributed new reagents/analytic tools; R.Z., A.F.K., J.P., D.Z., H.X., and P.H.M. analyzed data; and R.Z. and A.F.K. wrote the paper.

• The authors declare no conflict of interest.

• Freely available online through the PNAS open-access option.

Link to full, open-access article: http://www.pnas.org/content/105/30/10291.full

• © 2008 by The National Academy of Sciences of the U.S.A.

Link to abstract: http://www.pnas.org/content/105/30/10291