%0 Conference Paper
%A Modi Chen
%A Mari Titcombe
%A Jingkun Jiang
%A Coty Jen
%A Chongai Kuang
%A Marc L Fischer
%A Fred L Eisele
%A J. J Ilja Siepmann
%A David R Hanson
%A Jun Zhao
%A Peter H McMurry
%B Nucleation and Atmospheric Aerosols: 19th International Conference
%C Fort Collins, CO
%D 2013
%I AIP Publishing LLC
%R 10.1063/1.4803354
%T Acid–base chemical reaction model for nucleation rates in the polluted atmospheric boundary layer
%8 04/2013
%X <p>Measurements of aerosol number distributions down to one molecule have provided information that we’ve used to develop a new approach for modeling atmospheric nucleation rates. Measurements were carried out with the Cluster Chemical Ionization Mass Spectrometer (Cluster CIMS), the scanning mobility spectrometer using a diethylene glycol condensation particle counter as detector (DEG SMPS), and an ambient pressure proton transfer mass spectrometer for ammonia and amines (AmPMS). The model explains nucleation as a result of cluster evolution due to a sequence of acid-base reactions. We conclude that the smallest stable cluster contains four sulfuric acid molecules. The model leads to a simple analytic expression for nucleation rates that is reasonably consistent (i.e., ± 10x) with atmospheric observations. The model predicts that nucleation rates are equal to a prefactor, P&lt;1, times the sulfuric acid vapor collision rate, (i.e., J=P⋅0.5⋅k<sub>11</sub> ∗[H<sub>2</sub>SO<sub>4</sub>]<sup>2</sup>).</p>