Abstract:
: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.
journal_name
Proc Natl Acad Sci U S Aauthors
Chen M,Titcombe M,Jiang J,Jen C,Kuang C,Fischer ML,Eisele FL,Siepmann JI,Hanson DR,Zhao J,McMurry PHdoi
10.1073/pnas.1210285109subject
Has Abstractpub_date
2012-11-13 00:00:00pages
18713-8issue
46eissn
0027-8424issn
1091-6490pii
1210285109journal_volume
109pub_type
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