Document Detail

Variability in morphology, hygroscopicity, and optical properties of soot aerosols during atmospheric processing.
MedLine Citation:
PMID:  18645179     Owner:  NLM     Status:  MEDLINE    
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% relative humidity) and act efficiently as cloud-condensation nuclei. Coating with sulfuric acid and subsequent hygroscopic growth enhance the optical properties of soot aerosols, increasing scattering by approximately 10-fold and absorption by nearly 2-fold at 80% relative humidity relative to fresh particles. In addition, condensation of sulfuric acid is shown to occur at a similar rate on ambient aerosols of various types of a given mobility size, regardless of their chemical compositions and microphysical structures. Representing an important mechanism of atmospheric aging, internal mixing of soot with sulfuric acid has profound implications on visibility, human health, and direct and indirect climate forcing.
Renyi Zhang; Alexei F Khalizov; Joakim Pagels; Dan Zhang; Huaxin Xue; Peter H McMurry
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2008-07-21
Journal Detail:
Title:  Proceedings of the National Academy of Sciences of the United States of America     Volume:  105     ISSN:  1091-6490     ISO Abbreviation:  Proc. Natl. Acad. Sci. U.S.A.     Publication Date:  2008 Jul 
Date Detail:
Created Date:  2008-07-30     Completed Date:  2008-08-28     Revised Date:  2010-09-22    
Medline Journal Info:
Nlm Unique ID:  7505876     Medline TA:  Proc Natl Acad Sci U S A     Country:  United States    
Other Details:
Languages:  eng     Pagination:  10291-6     Citation Subset:  IM    
Department of Atmospheric Sciences, Texas A&M University, College Station, TX 77843, USA.
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MeSH Terms
Air Pollutants / analysis*,  chemistry
Air Pollution
Carbon / analysis*
Chemistry / methods
Microscopy, Electron, Transmission
Models, Chemical*
Optics and Photonics
Particle Size
Research Design
Sulfuric Acids / analysis*
Time Factors
Reg. No./Substance:
0/Aerosols; 0/Air Pollutants; 0/Soot; 0/Sulfuric Acids; 7440-44-0/Carbon

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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