Document Detail


Acid-base chemical reaction model for nucleation rates in the polluted atmospheric boundary layer.
MedLine Citation:
PMID:  23091030     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Climate models show that particles formed by nucleation can affect cloud cover and, therefore, the earth's radiation budget. Measurements worldwide show that nucleation rates in the atmospheric boundary layer are positively correlated with concentrations of sulfuric acid vapor. However, current nucleation theories do not correctly predict either the observed nucleation rates or their functional dependence on sulfuric acid concentrations. This paper develops an alternative approach for modeling nucleation rates, based on a sequence of acid-base reactions. The model uses empirical estimates of sulfuric acid evaporation rates obtained from new measurements of neutral molecular clusters. The model predicts that nucleation rates equal the sulfuric acid vapor collision rate times a prefactor that is less than unity and that depends on the concentrations of basic gaseous compounds and preexisting particles. Predicted nucleation rates and their dependence on sulfuric acid vapor concentrations are in reasonable agreement with measurements from Mexico City and Atlanta.
Authors:
Modi Chen; Mari Titcombe; Jingkun Jiang; Coty Jen; Chongai Kuang; Marc L Fischer; Fred L Eisele; J Ilja Siepmann; David R Hanson; Jun Zhao; Peter H McMurry
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2012-10-22
Journal Detail:
Title:  Proceedings of the National Academy of Sciences of the United States of America     Volume:  109     ISSN:  1091-6490     ISO Abbreviation:  Proc. Natl. Acad. Sci. U.S.A.     Publication Date:  2012 Nov 
Date Detail:
Created Date:  2012-11-15     Completed Date:  2013-02-01     Revised Date:  2013-07-11    
Medline Journal Info:
Nlm Unique ID:  7505876     Medline TA:  Proc Natl Acad Sci U S A     Country:  United States    
Other Details:
Languages:  eng     Pagination:  18713-8     Citation Subset:  IM    
Affiliation:
Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455, USA.
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MeSH Terms
Descriptor/Qualifier:
Acid-Base Equilibrium*
Air*
Air Pollution*
Georgia
Mexico
Models, Chemical*
Comments/Corrections

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