Abstract View
Modeling Sulfuric Acid Nucleation of Complex Mixtures
JACK JOHNSON, Sandra Fomete, Coty Jen, Carnegie Mellon University
Abstract Number: 86
Working Group: Aerosol Chemistry
Abstract
Aerosol particles form in the atmosphere when gas phase compounds react to form stable clusters in a process known as nucleation. In recent decades, sulfuric acid has been shown to drive nucleation in the lower troposphere by reacting with various stabilizing compounds, such as ammonia or dimethyl amine. However, there are potentially hundreds of atmospherically relevant compounds that assist in sulfuric acid nucleation. These compounds could range in concentration from pptv to ppbv and vary in space and time. Consequently, modeling all the potential nucleation reactions in the atmosphere is challenging and requires a model that can broadly capture sulfuric acid nucleation.
For this study, we propose the use of a semi-empirical acid-base reaction scheme to determine an effective concentration of stabilizing compounds and mixtures of compounds for sulfuric acid nucleation. Using a parameterization technique, we can determine the effective concentration of stabilizing compounds by reacting a known amount of sulfuric acid to form measurable particles. Our results show that the parameterized concentration is correlated with the measured concentration of stabilizing compounds and reflects the effectiveness of each compound in stabilizing sulfuric acid particles. In addition, sulfuric acid reacted with mixtures of stabilizing compounds to demonstrate how synergistic nucleation mechanisms are captured by our model. The simplicity and accuracy of the model to estimate stabilizing compounds will help improve nucleation rate predictions in diverse regions around the world.