Document Detail


Effects of coating of dicarboxylic acids on the mass-mobility relationship of soot particles.
MedLine Citation:
PMID:  19475951     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Atandem differential mobility analyzer (TDMA) and a differential mobility analyzer-aerosol particle mass analyzer (DMA-APM) have been employed to study morphology and hygroscopicity of soot aerosol internally mixed with dicarboxylic acids. The effective densities, fractal dimensions, and dynamic shape factors of soot particles before and after coating with succinic and glutaric acids are determined. Coating of soot with succinic acid results in a significant increase in the particle mobility diameter, mass, and effective density, but these properties recover to their initial values once succinic acid is removed by heating, suggesting that no restructuring of the soot core occurs. This conclusion is also supported from the observation of similar fractal dimensions and dynamic shape factors for fresh and coated/heated soot aggregates. Also, no change is observed when succinic acid-coated aggregates are cycled through elevated relative humidity (5% to 90% to 5% RH) below the succinic acid deliquescence point. When soot is coated with glutaric acid, the particle mass increases, but the mobility diameter shrinks by 10-40%. Cycling the soot aerosol coated with glutaric acid through elevated relative humidity leads to an additional mass increase, indicating that condensed water remains within the coating even at low RH. The fractal dimension of soot particles increases after coating and remains high when glutaric acid is removed by heating. The dynamic shape factor of glutaric acid-coated and heated soot is significantly lower than that of fresh soot, suggesting a significant restructuring of the soot agglomerates by glutaric acid. The results imply that internal mixing of soot aerosol during atmospheric aging leads to changes in hygroscopicity, morphology, and effective density, which likely modify their effects on direct and indirect climate forcing and deposition in the human respiratory system.
Authors:
Huaxin Xue; Alexei F Khalizov; Lin Wang; Jun Zheng; Renyi Zhang
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Environmental science & technology     Volume:  43     ISSN:  0013-936X     ISO Abbreviation:  Environ. Sci. Technol.     Publication Date:  2009 Apr 
Date Detail:
Created Date:  2009-05-29     Completed Date:  2009-06-22     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0213155     Medline TA:  Environ Sci Technol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2787-92     Citation Subset:  IM    
Affiliation:
Department of Atmospheric Sciences, Texas A&M University, College Station, Texas 77843, USA.
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MeSH Terms
Descriptor/Qualifier:
Atmosphere
Dicarboxylic Acids / chemistry*
Soot*
Chemical
Reg. No./Substance:
0/Dicarboxylic Acids; 0/Soot

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


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